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Battery Things
Alan Applegate (K0BG)
on
February 14, 2006
View comments about this article!
There is a lot of misunderstanding about the use of batteries in general, and in mobile operation specifically. Hopefully this article will address some of these misunderstandings. So we’re all on the same field, and using the same game rules, there are a few terms which need to be defined.
There are literally dozens of different types of batteries. In this context we’ll be discussing just one, and that will be the ubiquitous lead-acid battery. I recognize that some of the newer types are encroaching on our old standby, including NiCads (nickel cadmium), Li ion (lithium ion), and NiMH (Nickel metal hydride). While some of these types are used in vehicles, they are for very specific applications (hybrid vehicles come to mind), so we won't be discussing them here.
There are two types of lead-acid batteries amateurs typically deal with, as well as a few sub-types. The most popular SLI (starting, lights, ignition) battery is the flooded electrolyte one usually referred to as a plain old car battery. It’s been with us for well over 100 years, and most everyone knows its general make up. A newer entry is the AGM (absorbed glass mat). It’s only about 75 years old. Although there are minor differences between manufacturers, in all cases the electrolyte is a gel which is absorbed into a glass mat. In most designs, this mat and the battery’s plates are spirally wrapped which greatly increases their vibration resistance. The matted design and gelled electrolyte further allows the AGM battery to be used in any position. If properly utilized, AGM batteries do not out gas which allows their use in non-vented areas like the trunk of a vehicle.
Although there are many battery companies making AGM batteries, I’m going to stick with just one; The Optima® series. The three types which will be discussed are the RedTop®, YellowTop®, and BlueTop®.
These product names are registered trademarks of Optima Batteries, as are the charts herein, and they are used with express permission from Stir Marketing, Optima Division's advertising agency.
Each of these flavors (colors) has a specific use, albeit the line between them is both fuzzy and ill-defined. It is the misunderstanding about which type to use, that is one of the themes of this article. The other theme deals with the connections of the battery to the vehicle's electrical system.
 In general terms, the RedTop® is designed for SLI use. Therefore, they deliver higher amperage than the other types, but for a shorter duration, just like we expect them to when starting our engines. This is the battery of choice for all mobile-in-motion applications, irrespective of a second battery and/or amplifier in use. They are considered discharged when their static voltage drops below 11 VDC.
The YellowTop® battery is a special design offering attributes of both a deep cycle, and an SLI. Typical applications include mobile sound systems, hydraulic winches and tailgates (even low rider hardware), and as an SLI if properly sized 20 to 25 percent larger than a RedTop®. They're considered discharged when their static voltage drops to 10.5 VDC.
 The BlueTop® battery is designed primarily for marine applications. Their strong point is their extended long storage capability which is much better than that of a RedTop® if kept below room temperature. They have thicker plates, and an even lower internal resistance. These design features make them more expensive than the other two types. In most amateur mobile applications, this is NOT the battery of choice.
For example, if you're running a field day operation, or extended portable operation, the YellowTop® is a better, less expensive choice. Even for emergency standby where the battery is kept on float, the YellowTop is still the one to use.
Because of its inherently low internal resistance (especially the BlueTop), an AGM battery has at least two advantages over a flooded, plane old car battery; they can be charged and discharged at very high rates. In a mobile scenario this is of minor concern as most vehicle charging systems can't supply much over 100 amps (usually much less) which is well within their maximum charge rating. As for current draw, there is a safety concern that should be noted. On a dead short an AGM of good quality can deliver in excess of 3,000 amps! Enough current in fact, to destroy the most robust of wiring schemes. This includes circuit breakers as their contacts will typically fuse together at this current level. Proper fusing is an absolute must for remote mounted batteries.
Some amateurs believe AGM batteries require special three stage chargers, which is not the case. The most important consideration is the maximum static charge voltage. Note that every manufacturer has different specifications with respect to rates of discharge, charging rates, charge levels, be it recharging or keeping the battery on float (constant low amperage charge). Thus, it behooves the user to research and apply these figures to what ever type of battery you use, lead acid or otherwise, if maximum service life is to be achieved.
All of these batteries have a finite charge/discharge cycle life. While they will usually outlast a flooded car battery in any application, continuing to discharge them past their rated discharge level (give or take 10.5 VDC), will drastically shorten their life. For example, repeatedly discharging one (intentionally or unintentionally) down to 9 VDC, will cause them to fail after a few dozen charge/discharge cycles.
If there is any doubt about what battery type to choose, allow me to reiterate. If you are using one as a primary and/or secondary battery, in a mobile-in-motion application, the RedTop® is the battery of choice.
If this is a fixed station operation (mobile mounted or not), you're better off with a YellowTop® if for no other reason than a cost/performance one. While a BlueTop® will work in this application, the up-front cost is 40 percent more. There is another reason not to use one, and that fact will become evident further on.
Regressing for a moment, we have two applications in the subject matter; mobile-in-motion, and fixed station use (mobile mounted or not). These two applications require different wiring strategies. The former does not, nor should it, include any isolating devices. The latter does require an isolating device, and a very specific one, especially if the battery is a BlueTop®.
Mobile-in-motion is seldom a battery-run application, although I know of a few amateurs who think this is a correct usage. It isn't, if you factor in the aforementioned charge/discharge cycle ratings, and the maximum discharge level ratings. It isn't the correct methodology to reduce RFI and EMI either. In any case, I'm ignoring this sub application.
Intermittent amateur use is exactly what the SLI battery is designed to do. It isn't the battery that is supplying the long term power, it's the alternator. The battery is only acting as a buffer. While most vehicle electrical systems have enough reserve to easily handle a 100 watt output transceiver, it's another story if we're running a power amplifier. Even if the alternator can handle the average load (about 50 amps in an average installation), the peaks will be over 100 amps which the SLI is happy to supply.
If the amplifier is trunk mounted, it is prudent to use a second battery mounted along side to handle these peaks which further allows the interconnecting wire to be smaller in size. When we use a second battery in this manner, it should be hard wired to the existing battery with only fuses in line to protect the wiring against shorts. If you think this is a bad idea, here is some food for thought; Just about every diesel pickup truck on the road that is equipped with a heavy duty electrical system has two batteries wired in parallel. In most cases, there isn't even a fusible link between them. In other words, no relays, and no battery isolators. There are a couple of really good reasons for this if you'll bear with me.
Fixed station operation requires a different strategy. Here if the batteries are hard wired together, they share the load and the level of discharge. Go a little too far, and you don't start your vehicle when the contest is over. In this application, some form of isolation is required. There are two types of isolation amateurs use, and they're both wrought with problems. Let's look at the isolation relay scenario first.
Aside from the complexity is adds, when the vehicle is started, and this relay is closed by what ever method, the alternator sees the load as a discharge below the SLI battery's actually discharge state. In the majority of the cases, the alternator delivers a higher voltage than would otherwise be necessary. If the primary SLI is of flooded design, this higher charge voltage causes it to out gas excessively. This can, and does, shorten its life.
Most amateurs assume they can prevent this occurrence by using a (cheap) battery isolator. These are no more complicated than a couple of diodes. About all they manage to do, is charge the batteries to a lower voltage. Depending on the unit and current draw, the voltage drop across them is between .7 and 1.4 volts. So instead of a nominal 13.8 VDC, the battery is closer to 12.8 volts. It also takes longer to charge both batteries even up to this sub-standard level. One way around this would be to adjust the alternators output voltage to compensate for this diode's drop. Almost without exception, the output voltage is fixed, and non adjustable.
There are special alternators and special isolators designed to work with them. They use remote sensing to measure the voltage (discharge level) of one or more secondary batteries, and supply the correct amount of charge current and voltage to each one. I can almost guarantee the average amateur won't spend the monies these systems cost.
Lets digress back to the alternator for a moment. The vast majority have build in regulators, and their complexity and capabilities are all over the map. They may or may not have maximum output voltage protection, or even current limiting. With one exception I'm aware of, none are designed to be used with an isolator. About the only place you ever see these is in recreational vehicles (where they're rare), and boats.
In all fairness, these systems work well enough so the average joe ham never relates any shortened battery life, or low voltage (or high voltage) problems to the vehicle's electrical system, irrespective of the wiring contained there in. Education can be a powerful thing if you apply it. Knowing that cheaply built, inexpensive isolators, connected to alternators not designed for their inclusion, can and will lead to problems, some of which can be expensive to fix.
Whether you use one battery or two, regardless of the inclusion of an isolating relay or any diode isolator, it is imperative that the wiring be regularly checked for integrity. I'll give you an example of why this is so important. Assuming you have your radio directly connected at the battery where it should be, and the positive battery clamp loosens, the alternator sees this as a battery discharge condition. It compensates by increasing its output (voltage). While the regulator in the alternator may contain some voltage limiting, it is nonetheless possible for the voltage fed to your radio to exceed it's rating with predictable results.
Direct battery connection is my last subject, but certainly not the least important. The debate over how to wire will continue long after I'm dead and gone. Nonetheless, lets take another look at the debate.
The first scenario is to connect the radio directly to the battery's positive and negative leads, with both leads fused. This is the exact methodology recommended by most automobile manufacturers, and most text books covering the subject.
The second scenario is connecting the negative lead to the same chassis point the battery's negative lead is connected, sans any fusing. There is a problem with this in the majority of the cases. To wit, the battery actually has four leads, not just two. Two of these wires are rather large, and run to the engine's block and the starter motor's solenoid relay. The smaller sized wires run to the aforementioned frame connection, and to the vehicle's power distribution system. If either of these smaller wires fail, current can flow through the radio's wiring harness, and/or through what ever commonality there may be through the vehicle's chassis and drive train. If the positive lead to the starting system fails, it may or may not cause a problem other than not being able to start the vehicle. However, the return for the alternator is the heaver negative wire. If it fails it might cause the alternator to act up. Whether it does or not, is moot. Regardless of your outlook on which scenario to use, my caution about keeping the wiring in good condition is paramount in either case.
There is one more item I wish to cover, and I thank Mark Brueggemann, K5LXP for this. Any auxiliary battery should be installed in a battery box and properly restrained. The rule of thumb for battery restraints is 6Gs lateral and 4Gs vertical. The last thing you want is a 60 pound battery flinging acid all over the insides of your vehicle! If you use a plane old car battery, the box must be vented to the outside.
Alan Applegate, K0BG
Roswell, NM
There are a few of finer points I want to cover. First, a second rear mounted battery isn't a necessity even if you run an amplifier. However, without one the wire size has to be somewhat larger to minimize voltage drop. In some cases, it is actually less expensive to purchase a second battery. For example, size 6 awg costs about .35 cents a foot, and size 2 awg is about $3 a foot. The latter is also harder to install.
There are several different styles of marine batteries including the BlueTop® series. Some are meant to be used as an SLI, and others for deep discharge use like that imposed by a trolling motor. Still others are designed for sitting long periods of time without any charge applied. Looking at a battery's shape, size, or color is not an indication of which is which.
A common question might be, can the colors be mixed and matched? Yes they can if proper circuitry is used. However, some types are better suited for a specific application. While using a substitute may indeed work, it may be more costly from a purchase and/or life cycle standpoint. It pays to read the fine print.
During the research for this article I learned something I didn't know, and I want to pass it on. If you own a Honda product (including Acura) there is something very special about their alternator and it's control circuitry. As I stated above, most alternators have built in regulators, and their capabilities are all over the place. In every case except Honda, these regulators are essentially stand alone devices. The only thing the alternator needs is a power source to turn it, a battery connected to its output, and they'll generate power. Some are self exciting and don't even need the battery.
Hondas are different. There is control circuitry between the engine's electronic controls (EEC), and the regulator. This information is used to adjust the injector timing. Thus the EEC knows what kind of electrical (accessory) load is on the engine. For example, as the air conditioning compressor cycles, the injector timing is adjusted accordingly. While this system is designed to increase fuel mileage, it can play havoc with mobile amateur radio.
The interconnection doesn't seems to cause any problems with a nominal 100 watt transceiver. However, when you draw a lot of current (amplifier use, a second battery notwithstanding), this causes the EEC to enrich the fuel mixture. At highway speeds the resulting enrichment doesn't do much except cut the mileage a tad. At slow speeds it causes the engine to hunt (miss and stumble), and can cause the OBD II system to send an error code which turns of the "Check Engine" light. I've done this several times, and I thought it was RFI. Because the dealer charges $49 to reset the system, I purchased an OBD II compliant reader to reset the codes. Luckily it hasn't happened since, but fore warned is fore armed.
 This fact also means that any after-market alternator must meet Honda's specifications. Be advised, none do even though their literature says otherwise. This information came from the chief engineer at Alternator Parts, and was confirmed by my local Honda dealer. By the way, if you're looking for a really BIG alternator, Alternator Parts makes the highest specific output unit available (see photo) in a standard frame size. It's rated at 250 amps continuous duty!
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Battery Things
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by WD0M on February 14, 2006
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There's a Yellow Top Optima in my Corvette because it has so much electronics/computers aboard that it drains a "normal" battery" if it isn't driven regularly. And that's without any ham gear.
73,
Joe
WDØM
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Worth The Extra Price?
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by K3AN on February 14, 2006
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Optima batteries appear to cost considerably more than other brands of starting or deep cycle batteries. What's the compensating benefit- longer life? More Amp-Hours? More deep-discharge cycles before failure? It would help to know.
I get about 7 years out of a plain old size 27 deep cycle battery (whatever brand Wall-Mart happens to be selling). It's used at the home QTH and for Field Day. It still works after that length of time, but the capacity is considerably diminished.
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Battery Things
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by N9XCR on February 14, 2006
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Nice article, Alan! Thank you for passing on the information regarding Hondas. I own a 2000 Honda Civic LX, and would like to install some equipment in it at some point. You provided some very useful information for me to consider while designing my mobile setup.
Chris
N9XCR
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Battery Things
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by AB0RE on February 14, 2006
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Great article, Alan. I always thought the blue-tops were the most desired of the Optima line-up. Thanks for setting the record straight.
As a '02 Honda Accord owner I also appreciate the info on the Honda's unique alternator situation. It appears I can't upgrade to the "monster alternator".... bummer.
73,
Dan / ab0re
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RE: Worth The Extra Price?
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by AG4RQ on February 14, 2006
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Posted by K3AN:
"Optima batteries appear to cost considerably more than other brands of starting or deep cycle batteries. What's the compensating benefit- longer life? More Amp-Hours? More deep-discharge cycles before failure? It would help to know."
I don't know if there's any advantage that Optima has over other brands. Lifeline marine and RV AGM deep cycle batteries cost less and have higher Ah ratings than their Optima counterparts. I guess you could compare Lifeline AGMs to Optima Yellow-Tops. Lifeline batteries are made by Concorde, who also makes aviation batteries. I'm planning on buying some AGM deep cycle batteries for next hurricane season (Thanks, Katrina and Wilma!) and I'm leaning toward the Lifeline batteries. See http://www.lifelinebatteries.com/marinebatteries.php for the specs on the Lifeline batteries. If you do your homework, you will pay less for a 100 Ah Lifeline than you will pay for a 75 Ah Optima Yellow-Top.
73 de Mark
AG4RQ
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Battery Things
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by G0GQK on February 14, 2006
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Last year I looked at a number of batteries which I thought were suitable for portable activity and among those listed were the ones discussed in the article.
They are not generally available in the UK and after having details given to me by the UK representative I am not at all surprised. I can't recall the colour of the cheapest battery, but the retail cost in the UK was £236, no mistake, 236 quid, for a battery !
A battery of a similiar type is manufactured in the UK and is available throughout Europe. The manufacturer is Elecsol and a 70 aH 13.8v battery costs about £85 Details about the Elecsol range can be found on www.elecsol.com and they can be purchased from many of the leading mobile and motor home distributers in the UK.
Mel G0GQK
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RE: Battery Things
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by VE3WPJ on February 14, 2006
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I have a Dodge Dakota 2003 Quad Cab 4x4, was haivng some issues on the OEM battery, so I group 27 i think, but the Optima Commercial Group 31 fits under the hood.
So in went a Optima Commercial Starting Deep Cycle D31A boy does it have the power, radios can stay one (opps) over 2 days in a deep Canadian winter cold and the truck starts like it was the middle of july.
If you can fit the Size go for the comercial D31A in your truck/car.
I just wish I could fit two.
Will
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RE: Battery Things
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by N6AJR on February 14, 2006
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If you do choose to "split" the engine and "rv" batteries, there is a device you should know about. I used to work in Emergency Service on the bridges in northern California and to handle the red lights on the vehicles ( 2 sets of 2 to 4 ten amp draw bulbs) we used a device called a constant duty soloniod.
It is just about the same as a ford starter relay EXCEPT it is rated for constant duty, The ford relays burn out in less than 20 minutes, ( with a large puff of smoke.. don't ask how I know:) )
you hook the battery power across the solinoid on the 2 large lugs, and on of the smaller lugs goes to ground, and the other goes to a switch and to 12 volts. This is the control switch, and when you apply 12 volts to the small terminal, the relay engages and runs the full battery power across the big terminals.
I ran my control switch to a fused 12 volt lead that was on the ignition switch. so I could start the motor and charge the main battery, ( and watch the amp meter go to zero) then flip the switch and watch the amp meter go from charge to 0 again. this let me control when I wanted to charge the back battery.
Being it was on the switch if I forgot to turn off the solonoid, it would drop out any how when I turned off the motor. so I could use the back battery and the starting battery stayed good.
you cna but these at autoparts stores for about $10 to $15 , and they work well, depending on your use.
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Battery Things
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by W7ZZT on February 14, 2006
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I can vouch for the YellowTop Optima. I've been using four of these batteries frequently over the last three years and they all seem as good as new.
I use two wired in parallel on a float in my shack for emergency power. My day-to-day mobile operation uses one, independent of the car battery--lasts about a month between charges with occasional use. When I rove in VHF/UHF contests, I use two sets of two batteries, each set wired parallel--keeps me going for about two days on the road.
Pricey, but I would buy again because of the low maintenance and reliability. Great safety comment about tieing these batteries down when mobile. I use two tie-straps per battery case.
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RE: Worth The Extra Price?
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by KD6NEM on February 14, 2006
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For me AGM batteries are worth the extra price, even though I do not presently operate HF mobile. They are pretty much the only TRUE maintenance free battery aside from gel cells, but are much more rugged. So far I haven't lost an AGM from age, but I do see how a good one will normally outlast an ordinary wet cell easily even if the wet cell is properly cared for; the AGM will last far longer in comparison if the wet cell receives only "average" maintenance.
I'm one who might consider using a "blue top" equivalent in a car anyway if I had room to size it appropriately; true deep cycle AGM's if enough oversized are tough to kill. A lot of the emergency services folks have this setup in their police, fire, & ambulance rigs I hear, because of the great extra reserve which can be called upon. I prefer MK (or sister company Deka batteries) because of equal quality but greater bang for the buck. Lifeline is one of several other excellent options. Most AGM's leave their plates flat instead of spiraled as in the Optima, Orbital, Maxima, etc- not much is really gained by the extra fanciness of the spiral versions.
One thing about adding a second battery in parallel- if you have two identical batteries of the same lot# installed new at the same time you'll probably find a lot less grief in the long run. It is strongly urged to avoid mixing batteries of a different age much less of a different size. A balanced pair performs in unison (unless truly isolated); unbalanced and one becomes lazy and loads down performance while the other struggles. As expensive as they are it is best to look toward protecting your investment and do it right the first time.
True, special chargers are not required, but they can have real advantages. Since good three stage chargers have a lot tighter control they can deliver the bulk charge quickly then finish safely with no worries- and the battery will be fully ready without over or under charging. Some even pulse the charging which breaks up sufiding and promotes longer life. Many of these have a battery mounted thermistor to monitor battery temperature which maximizes the charge rate while providing an even greater level of safety.
http://www.windsun.com/Batteries/Battery_FAQ.htm
Stu KD6NEM
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RE: Worth The Extra Price?
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by AD5TD on February 14, 2006
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Schumacher makes a great "Trickle/Float" charger for AGM batteries. It's called the "BatteryCompanion". It sells for $18.00 at WalMart. It charges at 1.5 amps up to 14.2 volts and then "floats" the charge at 13.2 FOREVER.(has a nice little light that changes from yellow to green to tell you it's charged) It will adjust the charge up to an amp and will allow you to run a radio on receive without going to full charge mode. It comes with clamps and ring terminals that have a polarized plug on them. I use on on my size 8D AGM (255aH, 165lbs!) battery that I use here in the shack. I can go for MONTHS and not have to charge it. However, I leave it on charge all the time.
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RE: Worth The Extra Price?
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by KC8VWM on February 14, 2006
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Just one comment... Good article BTW!
Just to clarify, the Battery "Crank Amp" ratings chart does not always accurately determine how "long" the battery will in fact last in terms of operating your radio equipment over a period of time.
Cold Crank Amp (CCA) ratings are the equivalent confusion in terms of measuring Db ratings many antenna manufacturers claim to "Boast" their ratings and this can sometimes be deceiving.
Cold Cranking Amps (CCA) is supposed to be the number of amps the battery can deliver at 0° Fahrenheit for 30 seconds, while maintaining a voltage of at least 7.2 volts, for a 12 volt battery.
However, many battery manufactures will "Boast" the CCR ratings of a particular battery model based on a different set of measurement criteria. i.e. Delivered amps at a different temperature for a different period of time.
CCR ratings are much different in context than "AH" or "RC" ratings when looking to acquire a battery that will run your radio equipment for an extended period of time.
More information here:
http://electronic-components.globalspec.com/Specifications/Electrical_Electronic_Components/Batteries/Lead_Acid_Batteries
Knowledge is Power. ...Literally!
Thanks for another great article and 73
Charles - KC8VWM
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RE: Worth The Extra Price?
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by N3FQL on February 15, 2006
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K3AN - I'd like to talk to you about your home use if the Wal-Mart battery. Bill, W3LAB
wmenk@mcasd.net
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RE: Worth The Extra Price?
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by N3FQL on February 15, 2006
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K3AN - I'd like to talk to you about your home use if the Wal-Mart battery. Bill, W3LAB
wmenk@mcasd.net
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RE: Worth The Extra Price?
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by K0BG on February 15, 2006
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Charles, you are correct about advertising hype, and it extends to all parts of our society, not just our corner of it. However, the Optima has a unique, patented construction which results in a lower internal resistance than other similar batteries. Lower resistance equates to higher amperage capabilities to a point.
The construction also affords it longer life. Consumer Reports did a comparison a couple of years ago, and the Optima was way ahead of its competition. This is the basic reason I use them myself. I'm also of the opinion, that their cost versus performance is better, but to be honest, I haven't used anyone else's AGM.
When I purchased a new one last year, I priced Interstate's and Excide's versions, and the difference was less than $10.
One of the responders made comments to me about using a triple rate charger to extend the life of an AGM. When I was researching the information for this article, I ask this very question. I was told it wasn't necessary. After the post and e-mail, I called my contact at Optima and ask again if there was a cost benefit to using a triple stage charger. The answer was no, but with a caveat. The triple stage charger could very well extend the life, but not nearly enough to pay for the difference between it and a standard charger. Whether it will charge the battery faster depends on the charger, not the battery.
Alan, KØBG
www.k0bg.com
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Battery Things
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by WA8MEA on February 15, 2006
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Alan:
This is a masterful piece of literary work. I mean it!
Whenever I see a well written, documented and well presented composition such as this, I'm curious as to why it wasn't published in one of "the big three" ham magazines?
*Did you present it to one of "the big three" ham magazines and they never used it or turned it down?
*Do you feel you'll reach a much larger audience through a site like Eham.net?
*Is it just too much of a pain in the butt to go through all of the hoops that "the big three" ham magazines want authors to jump through?
*Are "the big three" ham magazines just too cheap with their articles compensation, so it actually pays more to write it for free on Eham.net??
Again, fine job. This is actually the very first article I've ever printed up and saved in my tech files! GREAT job!
73, Bill - WA8MEA
http://HamRadioFun.com
wa8mea@hotmail.com
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RE: Battery Things
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by W9AC on February 15, 2006
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Great article. I wish I had this information two weeks ago when I purchased an Optima Blue-Top for my shack's back-up DC power system.
I am using the West Mountain Radio Super PWRgate and it works very well, even with the Blue-Top gel cell.
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RE: Battery Things
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by KD6NEM on February 15, 2006
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W9AC- Don't fret!
Your Blue Top was the best choice Optima for your shack. In that setting the yellow would have been a slight compromise & red a larger compromise. Blue is best in the shack. But remember, it is NOT a gel battery- it is an AGM. They have similarities, but the differences are very significant. Premium gel cells can have a longevity advantage in solar systems, but for most the AGM is the preferred solution.
I forgot to say it before but it reallly was a good article.
Stu KD6NEM
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RE: Battery Things
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by KD6NEM on February 15, 2006
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W9AC- Don't fret!
Your Blue Top was the best choice Optima for your shack. In that setting the yellow would have been a slight compromise & red a larger compromise. Blue is best in the shack. But remember, it is NOT a gel battery- it is an AGM. They have similarities, but the differences are very significant. Premium gel cells can have a longevity advantage in solar systems, but for most the AGM is the preferred solution.
I forgot to say it before but it reallly was a good article.
Stu KD6NEM
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Battery Things
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by NH7L on February 15, 2006
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"Fixed station operation requires a different strategy. Here if the batteries are hard wired together, they share the load and the level of discharge. Go a little too far, and you don't start your vehicle when the contest is over. In this application, some form of isolation is required."
I operate parked mobile, 100 watts out, in a pickup with two 80 amp-hour deep-cycle batteries wired together with fuses but no isolation. These also start the engine. Have been using this setup for two years.
Alan's right about going a little too far, but in practice, it hasn't been a problem for me. Generally I operate for no more than several hours, and much of that time I'm not transmitting and thus not drawing many amps. More extended operation -- say, after a hurricane or while contesting -- would make restarting the engine more of an issue. Even so, you can take precautions ...
Last spring, in a small rental car with only one normal starting battery, I operated at 100 watts parked mobile most of a day for quite a few days. Every hour or so, I'd start the engine and run it at fast idle for five minutes to restore some battery charge. Never found myself unable to restart the engine.
Usually I run a small digital meter, the Medusa Research Power Analyzer II, between battery(ies) and transceiver. Got it from Quicksilver Radio, www.qsradio.com. It's made for radio-control model hobbyists. Can be bought with Anderson PowerPoles on both leads. Tells me volts, amps, watts, amp hours and watt hours. Highly recommended.
Optima batteries are available for less at Costco and probably other big-box discounters as well.
Thanks, Alan, for posting this excellent article. I'm saving a copy too.
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Battery Things
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by N4UE on February 15, 2006
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This is a WONDERFUL post. Alhough I don't have time right now to read the entire article, allow me to add a couple of comments....These may be in the text.....
1. Optima batteries can be mounted in ANY position, even upside down!
I have 2 very fast street rods. I have 'red tops' in both. Because one has a completely polished aluminum trunk (where the battery is), I did not want any problems with acid, etc. The other (a 1965 AC Cobra) is too valuable to risk acid problems, so it got an Optima also.
2. Be aware that any battery, that has both side and top mounting provisions, will provide about 100 amps LESS capacity when using the side terminals. If I had not proven this to myself with 5 different batteries (different mfg) and using a microprocessor battery load tester, I would not have believed it. This was confirmed talking to an Optima rep at the Moltrie, Ga. auto event 2 weeks ago.
All it takes is .25 ohms resistance in the internal straps, to account for the voltage drop.
I have been a drag racer for a loooong time, and I would never consider a different battery. I have ZERO affiliation with Optima, just a VERY satisfied user.
ron
N4UE
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RE: Battery Things
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by KC8VWM on February 15, 2006
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I admit I was a little "optimistic" about the "Optima" battery at first, but it does seem there are many good points to list.
For example, besides Alan' explanation about it's patent and improved performance over conventional battery technologies, someone mentioned they are used in solar applications in which I am heavily involved.
Someone else mentioned you can even tip them upside down without risk of leakage. It sounds to me like this is similar to a GEL battery design without the added cost.
Also, my past experience tells me that Gel batteries tend to be very "fussy" in terms of charging and one must never let one go completely dead or else they reach the point of no return.
The Optima battery on the other hand seems to provide all of these added benefits we are seeking without the added costs.
I admit I am from the old school of battery technology, but it really sounds like I really need to try one of these Optima batteries.
It sure is nice to have informed individuals like Alan researching and writing these articles for the rest of us. He is a valuable asset to the amateur radio community.
73 Charles - KC8VWM
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Battery Things
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by KC2MMI on February 15, 2006
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Alan, I usually agree with what you say but have to vehemently disagree this time around. I did a lot of lead battery research a year or two ago, more than I ever wanted to. Both for my car, and for a total repowering on a boat system.
First off, the Optima batteries should be qualified as what they are: A unique spiral-wound design instead of a stack of plates. Optima makes various claims for this, the only one I can confirm is that it is cheaper to manufacture than a stacked-plate design, and easier to build reliably because of the simple construction.
But flat-plate AGM batteries usually are available at 2/3 of the cost of Optima, with equal or better warranties. When you're talking about $90 versus $150, that's a huge difference.
I spoke to the Optima folks (and others) directly because in my application, the car may sit for one or two weeks between starts and there are more than the usual loads on it. They said specifically DO NOT use the Red Top in that application, anything that routinely took the battery down even 10% between uses was too much for the Red Top and might ruin it before two yeas were up, and a Yellow Top would outlast it--even though the Yellow Top was then warranteed for a year less time. From the horses mouth: If you are cycling that battery on any regular basis, even down by only 10-15% of the rating, DO NOT use the Red Top. Or, use it and take advantage of the frequent replacement under warranty. (Go figure, they admitted that would be one option.) I'd expect that if you are using a radio when the car is not running, the situation could be the same. The red tops are really meant for starting use only. The yellow tops are sold for "dual" use, and while the blue tops supposedly are true deep cycle...their warranty is the shortest of all. None compare to flat plate AGMs.
Then there's the matter of "gelled" electrolyte. Everyone in the battery business made it clear ot me the electrolyte in AGMs is not "gel" of any kind, that would be a "gel cell" which is entirely different and inferior to AGMs. They say one of the big advantages of AGM is that the electrolyte is NOT gelled, it is "absorbed" in the glass and the lack of gelling ingredients allows it to be a stronger electrolyte--more concentrated, as such. If Optima is now saying they use "gel"....well, that wouldn't surprise me. Delco has gone from calling their integral alternators "Delcotrons" to "alternators" and now back to "generators"!
Personally I use a West Marine "Battery Combiner" to run dual batteries. This is a marine grade continuous duty relay that combines both batteries when there is full (13.8) voltage, and splits them when the alternator is off. That's not ideal by any means but for me, it works out well enough. And the second battery? A flat-plate AGM. The extra cost and short warranty on the Optima just don't impress me. My plain storage type AGM has plenty of reserve power to start the car (looks a bit odd to see jumper cables from the trunk to the hood<G>) simply be choosing one rated to provide the power I needed.
On fuses and breakers...you're right to say fuses. Once you move into the realm of 80Ah batteries, they can provide some 3600A instantaneous power surge into the cables, and that's over the normal rating (3300 or 3500?) where conventional marine and household breakers will weld their points. There ARE special duty breakers rated around 5000A duty which can be used for this service--but the price is something like $75 each, against $10 for a high amperage "car stereo" type fuse with holder. I protect the rear battery twice, once at the battery, and again where the cables join up to the starting battery, since the loads come "out the middle" and I want those cables protected from both ends, both sources.
But Optima? Too much "magic smoke" in their sales pitches. Yes, they have a great idea but they're charging an arm and a leg--a 40-50% premium--for the colorful tops. And, the spiral construction means less area (less amperage) per effective cubic foot of battery. Not for hams--unless you need a pretty battery rack.
I know they extended their warranties about two years ago, when they had some major sales to clear out old inventory (in some cases batteries that had been "in the channel" for 18 months!) but they're still simply not competitive when you know there are alternatives.
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Battery Things
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by KC2ORG on February 16, 2006
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So whats the best way to go then. Say i have an 857D, or 706MKIIG or the like... and I want to run portable somewhere or in a car or where have you, or even int he house. Would I be better off going with a power supply for in the house, and batteries for portable and then more batteries for the car? Or can this be simplified into just 2 batteries and one of those battery rechargers? then I can take the rig to the middle of a field under a nice big tree and not drive the car there, I can run it at home without a power supply, I can put it in the car, with the necessary provisions taken of course... to me it seems like some justification of not buying a power supply in my situation as a college student... anyone else have comments?
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RE: Battery Things
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by K0BG on February 16, 2006
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You're pretty much on track Jared. I don't work for Optima as some of my e-mail would suggest. They were (maybe still are) manufactured in Denver, where I used to live. This is the main reason I bought the first one. That and the price was right.
Their main claim to fame it their resistance to vibration damage, and they are on the top of the heap in that regard. Due of course to the spiral design. Whether they are superior to any other brand in length of life, I can't say as I don't have any experience with any other brand. The one RedTop I have that has never been in a vehicle, is 7 years old and it still works well as a buffer for my big bench supply.
I used the term gel (referring to the electrolyte) in my article, and as you pointed out, it isn't a gel even though it pours like it is thickened up with something. My intention wasn't to add to the confusion, but apparently it did based on the other comments posted above.
Additionally, true gelled electrolyte batteries are actually a form of a flooded design, but you can get into a real argument calling them that. Further, gels can be other than lead acid.
As for which color to use in a vehicle depends again on the expected usage. This is why I added the caveat about checking with the manufacturer on a specific usage. If you have a garage kitty like my neighbor's cherry 67 Corvette, then the YellowTop makes better sense; it's long term storage capability is a lot better than the RedTop.
I appreciate the additional information, and trust others will read it. I'll correct that little faux pas (the G word) in my web article too.
One comment on GM. The write up on their web site uses just about all of the terms you mentioned. The one you didn't mention is "GenMotor"; an obvious play on their logo. For shame!
Alan, KØBG
www.k0bg.com
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RE: Battery Things
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by KC2MMI on February 16, 2006
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Alan-
No, I hadn't seen GM's site or the term GenMotor. I'd spoken to the many generous people at what used to be Delco (Delco, ACDelco, Delphi) and some battery makers directly.
AFAIK only Mazda uses an AGM battery standard now, in the Miata to prevent Fiat's mistake of having the trunk-mounted battery eat the trunk. But apparently there is some federal push to stop using wet acid batteries in favor of AGM, because of acid hazards at car and bus accidents. Of course Detroit keeps telling us everything will be 48VDC "soon" with no belts, just motors, and batteries hidden within the frame in all odd sizes and configurations to lower the center of gravity and make them harder to cause burns when they burst. (Not holding my breath.<G>)
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RE: Battery Things
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by KC2MMI on February 16, 2006
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Brad, if you want one "best" solution you need to decide on one 'best' case scenario. In the home, in the car, under a tree, are three conflicting ones.
In the car a nice AGM deep cycle battery is a great way to go. 40-50 POUNDS of power. (What, the FCC exam didn't mention how POUNDS are convertible to volts and amps and watts?<G>)
But you wouldn't want to carry that very far on foot. On foot, you'd want a small "UPS" type battery, which is sometimes gel, sometimes AGM, from the 12V 6AH kind used for exit sign lighting and alarms, probably up to the 12V 17AH kind which is about all you can pick up with one hand unless it has a carrying strap added to it.
And at home, an AC power supply will be the way to go so you're not wasting the finite life of your batteries on routine use. A power supply...plus another AGM deep cycle battery for blackout power, or your smaller "man-portable" one. Plus a good charger for your home batteries, of course.<G>
[George Carlin on "Stuff" comes to mind.<G>]
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RE: Battery Things
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by KI4ENS on February 16, 2006
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Note on circuit breakers.
SquareD QOU circuit breakers are rated for DC too.
Rated at 48VDC and 5000 AIR. I.E. maxium amps they can interrupt is 5000 amps DC. You take a hit going from AC to DC. The AC rating is 10,000 amps.
These are DIN rail and surface mount devices.
Prices are about $20 on single pole units from 10 to 60 amp rating. Grainger sells them.
Standard SquareD QO breakers are also useable on DC. Same ratings. I had a 70 amp circuit with the leads shorted together in the pull box. Another engineer turned the power on. The QO circuit breaker tripped nice. It was connected to a 48VDC battery plant rated at 200 amp/hr. No damage, no exploding breakers etc. I do have a main fuse on it just incase.
Yes I should have locked out/tagged out the system while I was pulling wires.
Have fun
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RE: Battery Things
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by KC2MMI on February 16, 2006
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On the SquareD breakers? Yeah, as I said, expect to pay $100 for something you'd put on a deep cycle battery. From grainer:
5U999, Thermal Magnetic Miniature Circuit Breaker, Current Rating 60 Amps,...$125.75
5B993 Thermal Magnetic Miniature Circuit Breaker, Current Rating 70 Amps,...$83.65
Even the 10-AMp model, useless for a battery primary breaker, is over $42.
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RE: Battery Things
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by KI4ENS on February 17, 2006
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"5U999, Thermal Magnetic Miniature Circuit Breaker, Current Rating 60 Amps,...$125.75"
That's a triple pole circuit breaker.
"http://www.grainger.com/Grainger/wwg/itemDetailsRender.shtml?xi=xi&ItemId=1611720739&ccitem="
5B978 is the single pole version at $19.42.
"5B993 Thermal Magnetic Miniature Circuit Breaker, Current Rating 70 Amps,...$83.65"
That's a double pole model.
5B979 is the single pole at $38.
"Even the 10-AMp model, useless for a battery primary breaker, is over $42. "
That would be 5B982. A double pole circuit breaker.
Again, the single pole version is much cheaper
5B966 at $19.42.
Don't know about you, I usually just use 1 pole on a grounded DC system.
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by K0BG on February 17, 2006
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Max, you want to be very careful about circuit breaker ratings. If you look closely at the ratings (www.squared.com) on the QO breakers, only the low amperage ones have the 5KA rating. Personally, I'm even leery of that (I spent 11+ years of my life with Graybar Electric, Square D's largest distributor).
There are a few of other points too. Wire size on the smaller amp breakers are up to #6, or barely adequate for our needs. Their input side is designed to clip over a buss; something we can't do in a mobile scenario. Their instant trip, if you can call it that, is several seconds on a 200% load. Under the same conditions, a fuse will open in a few milliseconds.
To be sure, there are breakers designed to overcome some of these drawbacks. As pointed out, they are not cheap. While a lot of amateurs use breakers for their switching convenience, the ultimate protection should still be a correctly sized (and typed) fuse.
In a vehicle application, even a 3ag has an adequate arc suppression rating, but for use at line voltages, special fuses are required to prevent arcing. Arc over turns a fuse (or breaker) into a very good conductor!
All of this points out the level of misunderstanding about protection in general, and most importantly when a fuse and/or breaker is adequate to prevent damage to our installations. In other applications (homes, businesses, industry, etc.), there are NEC, UL, IEC, and ASEE bodies to set standards of use. In our case, there isn't, so we have to be well informed, and we need the all important peer review. When we don't, the wives tales and fables all too often become the norm to the detriment of us all.
Alan, KØBG
www.k0bg.com
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RE: Battery Things
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by KI4ENS on February 17, 2006
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From:
http://ecatalog.squared.com/pubs/Circuit%20Protection/Miniature%20Circuit%20Breakers/QOU%20Miniature%20Circuit%20Breakers/0720CT9401R105.pdf
The QOU breakers 15 to 70 amps are rated at 5KA for DC voltages up to 48 VDC.
The QOU breakers 80 to 125 amps are rated at 5KA for DC voltages to 60 VDC.
The QOU breakers take 2 to 14 AWG wire on both their line and load sides.
True fuses are cheaper. I just mentioned these breakers since they exist and are rated for this applicatin via UL 489.
Obviously the QO breakers are not as convenient due to the limited wire size and mounting method.
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RE: Battery Things
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by KI4ENS on February 17, 2006
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Also check your fuse ratings. Don't use a slow blow fuse if you need a fast acting fuse.
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RE: Battery Things
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by K0BG on February 18, 2006
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Max, I would have liked to have taken this off line, but your e-mail address isn't listed.
The document you refer to is the exact document I was referring to. Look further down the page, and read the caveats. They are listed with the NEMA and NEC ratings for the breakers in question.
Also, pay attention to their trip time. Depending on the amperage, a 200% load will not trip the breaker for about 100 seconds (on average). Their rated magnetic trip is even higher. Note there is a temperature rating too. The colder they get, the worse they are in terms of trip times. Temperature effects fuses too, but their low thermal mass makes them superior to breakers in cold weather applications.
You are correct about slow blow fuses. I mention this in my web page Wiring article. They are designed with additional thermal mass to slow their trip times. Even a standard fuse will handle an overload of 125% for at least several seconds, perhaps more in cold weather. These factors must be taken into account in any application.
Automobile manufacturers (with a couple of exceptions) do not use circuit breakers. Aside from the extra weight and bulk, their hysteresis trip curves will not provide the necessary protection. Those applications where they are used, the breakers are of self-reseting, thermal design, and only used in critical circuits like headlights, and even here they are now rare.
Alan, KØBG
www.k0bg.com
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RE: Worth The Extra Price?
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by N0SP on February 18, 2006
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A few people asked if the Optima is "worth the extra cost"... In a nutshell, the Optima Red and Yellow offer two advantages. The first is their high current density. They can reliably deliver lots of starting current. The second advantage is their internal chemistry allows them to last almost twice as long as common flooded lead acid batteries in cars. (this has lots to do with the chemical purity of the plates as well as a few other things) The high starting current is due to the spiral-form plate construction. It allows a lot more surface area to be placed in the small package, but this comes at a price. The plates are thinner, therein lies the disadvantage... a lower amp-hour rating for a given size. Twenty or thirty years ago car battery manufacturers often prominently displayed the amp-hour capacity of batteries. Those days are long gone, it's almost impossible to find the amp-hour rating of consumer grade batteries. (to their credit, Optima tells you!) Instead, specsmanship has taken over and "cranking amps" is king. But it tells us darn little. It's very easy to achieve high cranking amps in a small battery.... simple use of high porosity plates does the trick, but again, at the expense of amp-hours. So while your Exide Maxi-Force 911 might deliver enough cranking amps to start a 6,000 horsepower locomotive, you'll find it dead as a post if you leave your headlights on for two hours. I drive two diesel cars that come factory equipped with 105 amp-hour batteries. I considered the Optimas for their long life and high starting current (important in diesels!)but decided against it because of their substantially reduced capacity. 20 years ago or so I ran a kilowatt in my mobile (tube powered!) and installed a 110 ah battery and 100 amp alternator to run the system. The large battery paid off one day... I went for a 5 hour training session and returned to see my headlights on. The car started just fine. That would never happen with the Optima... or almost any other common battery.
When it comes to backup power systems in the shack there are LOTS of choices. If size/weight are not a consideration the careful selection of AGM or Gel deep-cycle batteries can give you years of service. All AGMs are not alike, the same for the other technologies. Quality of construction and materials is very important. It's expensive to acheive the high chemical purity in the plates for long life. Good vendors, like West Marine, will offer several battries with essentially the same specs, but some will last longer than others, and you'll pay marginally more for the good ones.
Having said all that, IF your goal is for the INFREQUENT need of backup power, and you're not afraid of a good old flooded lead acid battery, you can get very long standby service from a good car battery. The one important caveat is to KEEP IT CHARGED... preferably with a properly calibrated float charger. When even the best lead acid loses it's surface charge it's life-clock speeds up very rapidly. A good one could easily give 7 years or more of service and still have the majority of it's capacity available.
Most of the car batteries in this country are made by one company, Johnson Controls. But that does not mean they're all alike. J.C. makes them to the specification the brand wants. I had a Champion last me almost 10 years, while a Sears Die-hard didn't make half of that.. in the same car and same alternator. Both are Johnson Controls batteries. (at least they were at that time)
This is a GREAT topic since there is a lot to know about batteries and we all use them. Glad to see it discussed here...
One more thing, a great example of the high current characteristics of spiral cells can be found in the those round Sealed Lead Acid cells often used in backup power supplies. Shorting a paper clip across one of those little D-sized, Hawker Cyclon (formally Gates) 2-volt cells will turn a paper clip red hot in an instant. That little thing can deliver hundreds of amps, they have to be handled carefully.
73,
Dennis
N0SP
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RE: Battery Things
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by KC2MMI on February 18, 2006
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Alan, while looking for a new car battery I've found a nice new alternative. From East-Penn, who quietly make a large number of battery brands in the US, the DEKA Intimidator.
I'm not sure how or why a battery should be intimidating <G> but this is also a "yellow top" obviously meant to compete for the Optima market. A dual-purpose AGM with conventional flat panels, priced about 3/4 the Optima street price, with higher power ratings. Not as easy to find so I'm not certain of the price comparison "apples to apples" yet, and I can't find any warranty terms, but an interesting alternative from "the other" major battery maker.
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RE: Battery Things
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by W2BRI on February 19, 2006
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I have two batteries in my Dodge Ram 1500. The front battery supplies the starting energy and the stock accessories for the truck. The back battery is installed in the back pickup toolbox and powers four amateur radios including an HF rig running 100 watts. I think this article is very helpful to the ham community because I too have learned the hard lessons of being cheap and skimping on parts. The first isolator I bought was a 70 dollar 50 amp isolator which burned out after a year or so because of the super high alternator current caused by the cheap left over battery I installed in the back. I used an old 125 amp hour sealed led acid which was on its way to the graveyard. That alternator huffed and puffed its output to make up for the dying battery running my radios.
After the isolators complete failure I replaced the system completely. I bought a yellow top Optima and installed a Hellroaring isolator. The new isolator is rated at 250 amps and compensates for voltage as well. It’s a lot more than a few diodes isolating the battery. It will set you back almost 200 dollars, but you get what you pay for damn it.
My new system is working very well and the trouble I caused myself from running cheap and old parts are long gone. I now cruise the bands with confidence and fearless energy potential. And so should you!
Brian, W2BRI
www.standpipe.com/w2bri
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RE: Worth The Extra Price?
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by KC2MMI on February 19, 2006
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Dennis-
I think you are crediting the Optima with things that have got nothing to do with that brand, or that construction--even though Optima would like people to think that way.
<<the Optima Red and Yellow offer two advantages. The first is their high current density. They can reliably deliver lots of starting current.>> That's got nothing to do with Optima. Check their ratings, then check conventional flat plate batteries in the same size group. The conventional AGM batteries outperform them or equal them.
<<The second advantage is their internal chemistry allows them to last almost twice as long as common flooded lead acid batteries in cars.>>
Ah, but first you are making the mistake of comparing AGM to wet lead. Let's stick to apples versus apples here. In fact, Optima warranties are no longer than anyone else's, wet or AGM. And for a long time, they were substantially shorter. Twice as long? Well, again, let's keep things on a par and compare them to equally "premium" lines which have equal chemical purity. Funny thing--the Optima specs don't outlast or outperform anyone else with a comparable product. Optima has no lock on chemisty, any battery maker can duplicate it. Or choose to differ on it.
<<The high starting current is due to the spiral-form plate construction. It allows a lot more surface area to be placed in the small package>> Not necessarily. Compare the volume of a flat stack of plates in a cube, to the volume LOST by placing that spiral in what is still going to be a cubical array, that is, six cells grouped in a box. The Optima loses more than 10% of the volume that flat cell batteries have, group size being the same.
And the high starting current? Not from the spiral at all. AGM's in general have higher charge acceptance rates, and more powerful discharges, due to the AGM chemistry "binding" the electrolyte and preventing electrolyte exhaustion. You get high current by using thinner plate material, which makes the plates physically less able to take multiple cycling. Which in turn is why any starting battery uses "thin" plates compared to the "thick" plates in a deep cycle.
By comparison, Optima claims the Red Top is capable of some 50 cycles (cycle depth not stated) versus 350 cycles for a Yellow Top. That's a difference of 7x in the battery life due to changing only one thing: Plate thickness. Applies to all technologies, wet or AGM.
<<Twenty or thirty years ago car battery manufacturers often prominently displayed the amp-hour capacity of batteries. Those days are long gone,>> The figures are still available. They are not widely promoted for car batteries, because the total amp/hour capacity of a car battery is simply NOT RELEVANT to "proper" use of the battery. How would you keep the FTC happy if you advertised a 50AH battery...but had to note, that was not at a 20-hour rate, it was at a 40mA discharge rate (typical for parked cars) AND that actually cycling the battery to a 100% discharge would also totally ruin it in less than ten cycles? That's right, Johnson and East-Penn (JCI doesn't have the whole market<G>) both will warn you that even a half dozen total discharges can permanently ruin a car battery. They're just not made for deep cycling, at all.
<<it's almost impossible to find the amp-hour rating of consumer grade batteries. (to their credit, Optima tells you!)>> Again, look at any other AGM battery. AGM technology is what makes dual purposing more feasible. Optima has nothing to do with that. AGM batteries are common in "traction" and "motive" uses, and I've never seen one without the AH listing. AGM starting batteries are somewhat rare (with good reasons) but the dual and deep cycle models? Always have AH ratings.
<<Instead, specsmanship has taken over>>
Welcom to the 21st century and mass marketing. (sigh.)
<<"cranking amps" is king. But it tells us darn little.>> It can tell you a lot. It tells you if that battery has enough power to roll your starter, which is rated in kilowatts.
<<It's very easy to achieve high cranking amps in a small battery.... simple use of high porosity plates does the trick, but again, at the expense of amp-hours. >> Again, like plate thickness, that's got nothing to do with how Optima compares to AGM in general.
<<I drive two diesel cars that>> are a whole different story. The typical gasoline engine has about 1/3 the compression ratio of a diesel engine, so diesel starters need to run 3x harder, and their starting demands are very different.
<<105 amp-hour batteries. I considered the Optimas ...but decided against it because of their substantially reduced capacity.>> Not really. There are flat plate AGM batteries (DEKA) in the "Group31" size which provide 100AH of deep cycle capacity. That's close to 105. Check out the Optima group31, it has less power.
<<All AGMs are not alike, the same for the other technologies. Quality of construction and materials is very important. It's expensive to acheive the high chemical purity in the plates for long life.>>
Fully agreed! But while Optima did increase their laughable warranties (to get rid of an 18-month old unsold inventory on shelves!) they still don't back up their claims with a warranty any better than anyone else. Claims are easy.
<<I had a Champion last me almost 10 years, while a Sears Die-hard didn't make half of that...Both are Johnson Controls batteries.>>
Sears solicits bids for their batteries, there is no telling what you get in a "Sears" product from year to year. Just goes to prove, as you say, that you can't tell what's inside but quality counts. IF you can locate it.
One big advantage to AGM batteries for deep cycle use is that they have a 25% charge acceptance, compared to 20% in wet cells. So they can be totally recharged in 4 hours instead of 5. In a car...that's not relevant since car alternators taper off to a float charge very quickly.
And again, in a car, AGM cells may be problematic. Until recently they had lower voltage chemistry, so a car would overcharge them. And once you overcharge a sealed battery of any type--you cook it dead. For that reason alone a conventional wet cell is still an advantage in a car, since water can be added if the battery has been cooked a bit.
Is the Optima a premium priced battery? Sure. Is it any better than any flat plate premium AGM battery for 75% of the same price with 5% higher capacity? Well...Optima hasn't proven that yet. Not to anyone, anyhow. Since their construction method is SUPPOSED to be cheaper, more precise, and more reliable all at the same time...I can't see any reason to pay a 25% surcharge for them. If they'd back their product with the best warranty on the market, I might reconsider.
But they don't do that.
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RE: Battery Things
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by N2HBZ on February 20, 2006
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Mail this to a friend!
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I have been looking at the Hellroaring unit for a few weeks. Does this unit address Alan's "issues" with cheap isolators? Is this the one that Alan says most hams won't spring for?
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RE: Battery Things
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by N4AOF on March 10, 2006
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Mail this to a friend!
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Re the "constant duty selenoid" solution. This is exactly the approach that the article author was talking about when he wrote: "Aside from the complexity is adds, when the vehicle is started, and this relay is closed by what ever method, the alternator sees the load as a discharge below the SLI battery's actually discharge state. In the majority of the cases, the alternator delivers a higher voltage than would otherwise be necessary. If the primary SLI is of flooded design, this higher charge voltage causes it to out gas excessively. This can, and does, shorten its life."
Still, given that some form of isolation is generally needed, this approach may be better than the diode-based method.
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