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Author Topic: Cheap Sealed AGM Gel Lead Acid Batteries  (Read 52004 times)
KF7VXA
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« on: August 16, 2013, 08:59:14 PM »

Can be used in any position, they look just like the kind in the emergency lights.
One 12 volt 18 AH battery is $59.00, but if you buy two 6 volt 12 AH batteries at $19.50 each, wire two in series, you get 48 AH at 12 volts for about $20.00 less than the price of a single 12 volt battery along with 4 more AH. Shipping is reasonable also. I plan on buying at least 4 more to make a small power box for others to use. They charge to almost 14 volts.
I have bought 4 of them to go in the bottom of my Go box on wheels and they have held their voltage for 4 months now and I have used them with an inverter and they work perfect. They measure 5.94" X 1.94" X 3.82" each
They would power a 50 watt radio for quite a few hours and if used to power a hand held VHF/UHF radio using a car plug adapter, you should get many, many hours out of them.
It's like getting a 96AH gell battery for under $100.00, great deal and the batteries are fresh and new, not recycled..
Part # GC-610, $19.50 each at All Electronics,  WWW.allelectronics.com
I used to put one full size AGM battery in the bottom of my go box, but 4 of these batteries take up less space and weigh less.
This leaves me ready to get on the air in only minutes and I put my 4 full size batteries in the back of my Blazer along with the solar panels and 1000 generator so I can stay on the air for days if necessary.
All Electronics also has some pretty good prices on many things needed to build a good go box, their catalog is worth getting even if you don't order the batteries. Not everything is a great deal, but most things are, so check prices.
When charging the batteries, wire two with a wire to the positive terminal of one and the negative terminal of the other, then put the positive lead of the charger on one battery positive terminal and the negative clip from the charger to the other negative terminal on the second battery. This way the batteries will be evenly charged and last longer.

73's John KF7VXA
« Last Edit: August 16, 2013, 09:17:51 PM by KF7VXA » Logged
K1CJS
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« Reply #1 on: August 17, 2013, 05:32:34 AM »

First of all for series batteries, voltage will add, but the amp hour rating does not.  Two 6 volt 12 AH batteries in series equals a 12 volt 12 AH battery, not a 12 volt 24 AH battery.  Now, if you're talking about parallel connections, two 6 volt 12 AH batteries equal a six volt 24 AH battery.

If, as you say you did, connect four of those batteries together to get a 12 volt source, the AH rating of that combined battery would then be 24 AH--not 48 AH as you think.

I wrote an article about building a power pack that may interest you, here is the link:  

http://www.eham.net/articles/23730

Remember, batteries in series adds the voltage of the two (or more) but the AH rating would remain the same as a single battery if the same type battery is used.  Paralleling the same type batteries would add the AH rating--but the battery voltage would remain the same as a single battery.
« Last Edit: August 17, 2013, 05:39:45 AM by K1CJS » Logged
KF7VXA
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« Reply #2 on: August 17, 2013, 07:28:29 AM »

Thank You, you are 100% right, I'm just used to thinking about parallel connections.
I guess you would still get twice the operating time or at least close with them in series.
I hope someone can take advantage of the good price, I know that these make a nice compact battery source.
Your set up is really clean, I like it.

73's John KF7VXA
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K1CJS
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« Reply #3 on: August 18, 2013, 05:47:16 AM »

Thanks, I hope you found the article helpful.  One thing I've found is that the prices of batteries that you buy and have shipped to you gets upped by the shipping charges, sometimes past the point that you could buy the same batteries locally.  If you have a friend that has a commercial account, you could get the batteries from a supply house for the same price--or cheaper.

One other source is your local hospital or medical supply store that sells portable powered equipment, especially wheelchairs.  They have to pay to get rid of the older batteries, some of which still have enough capacity in them to run radios since regulations demand replacement of the batteries is some equipment on a yearly basis.  You may be able to get some good batteries for the asking--or for pennies on the dollar.
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KF7VXA
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« Reply #4 on: September 02, 2013, 06:07:30 PM »

The shipping from ALLELECTRONICS is not that expensive.
I usually find more than a few good deals on some little things I need from them and then sometimes add a couple of batteries to the order. Shipping still ends up being less than most places charge just for a few small parts.
I'll just add some batteries as I feel I need them. Besides, where I live, it will cost me more in gas to go get batteries than have them shipped. No one where I live sells the smaller batteries, just car and deep cycle at inflated prices compared to a larger town. I use FED-x and UPS a lot.

73's John KF7VXA
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K1CJS
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« Reply #5 on: September 03, 2013, 04:52:39 AM »

I realize that some companies charge shipping rates that are reasonable.  Some companies, however, do not.  For example, some charge flat rate shipping per pound starting at about ten dollars!  You're right, some companies are very reasonable. 

I should have qualified my answer by saying locally in a large city or municipal area.  The area I live in, however, is almost all municipal, with a person having to go around ten miles to get from one municipal area to another--something that I sometimes forget.  73!
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N9AOP
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« Reply #6 on: September 03, 2013, 09:13:05 AM »

Since you are in a large metro area as am  I, you will find it cheaper to buy what you need from a local battry supplier.  It may be slightly more than mail order but don't forget that lead is very heavy and when the cartage fees are added on, I found it cheaper just to buy locally.  The last 8amp hour ones I bought this summer were $6.95 each from a solar power business.  They even had 7; 12; and 24Ah LiPO batteries that were very light but very pricy.

Pulls can be found almost anywhere but the question is how long they were in service before being pulled and how long they sat around before being offered for sale.  If you can buy a 7AH pull for $1 or $2 it is probably worth it but I have seen those pulls at local hamfests for $10 to $15 and that is outrageous.
Art
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KB4QAA
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« Reply #7 on: September 03, 2013, 11:11:35 AM »

Why pick Gel cells?

Unless you are operating upside down or at high G's like in an aerobatic airplane, there is no advantage to Gel cells, the cost is much higher, and you have the risk of damaging the cell by creating bubbles if charged too rapidly.

Absorbed Glass Mat, AGM, have most of the same features at lower cost.  They can be found in Deep Cycle or Hybrid formats.

Basic Sealed Lead Acid, SLA, are the cheapest of all.
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K1CJS
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« Reply #8 on: September 04, 2013, 06:27:06 AM »

Semantics once again.  I'm not saying you're wrong--you're right, but go to most uninformed salesperson and ask for an AGM battery, and they'll tell you they don't stock them.  Go and ask for a gel cell, however, and the salesperson will ask you which one you want--and they'll include the usual AGM batteries in that selection.

For people who aren't "battery educated," there are two types of batteries.  'Wet' batteries and gel batteries.
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KF7VXA
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« Reply #9 on: September 08, 2013, 07:05:25 PM »

The gel cell batteries I bought are smaller, by quite a bit from a normal deep cycle.
They are great to use with a handheld or a lightweight for a portable 50 watter used at lesser wattage.
I have a power cart that is on two bigger wheels that a regular deep cycle fits in and also have a MFJ voltage booster in it that is removable, it works great with any kind of 12V battery, keeping the voltage at 13.8V output.
I can also put one or two smaller gel cells in a waist pack to power a handheld.
Handhelds not being the best radio for EMCOMM work fine with some repeaters and extended run time with the higher capacity battery(s). Having several ways to power radios and different types of radios to me is key to changing operations.

73's John KF7VXA
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KA4KOE
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« Reply #10 on: September 10, 2013, 05:19:27 AM »

I went ahead and ordered a lithium iron phosphate 10AH, 12V battery from battery space. It's 1/2 the weight of a comparable AGM. Yes, it was more expensive. The thing is, you will kill lead acid batteries if you repeatedly deep discharge them (AGMs). Rule of thumb, no more than 50% of rated capacity, say 5 AH from a 10 AH battery. The big kicker is voltage drop. Some rigs start acting up due to low voltage. Here is what I got coming in the mail:

http://www.batteryspace.com/LiFePO4-Battery-12V-10Ah-120Wh-40A-rate-----Replace-SLA-12V-10Ah.aspx

Good luck.

Philip
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K5LXP
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« Reply #11 on: September 10, 2013, 06:35:36 AM »

you will kill lead acid batteries if you repeatedly deep discharge them (AGMs). Rule of thumb, no more than 50% of rated capacity, say 5 AH from a 10 AH battery.

Consider that rule of thumb from a practical level.

A battery like a gel or AGM is rated for at least 250-300 cycles down to 80% DOD.  That's at least one deep cycle a week for 5 years straight.  I suspect most hams operating portable might do that once a month, or less.  So by that rule of thumb you're buying and carrying around twice as big a battery as you need, only to throw away most of its' cycles in 5-6 years when it goes toes up from age.  I don't see anything wrong at all with running them into the ground and getting every Ah you can, with the idea they'll still die from old age than cycles.  Cheaper and less weight to haul around.


Mark K5LXP
Albuquerque, NM
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KC2MWJ
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« Reply #12 on: September 10, 2013, 08:01:18 PM »

  I recently purchased a 12 Volt-18 AH, sealed AGM battery, on eBay for $37.49, free shipping included. These batteries are made in China, but are distributed through a US seller. I received the battery in 4 days. We'll see how it holds up in a Harley, so far, so good. I just ordered another for the shack. eBay item # 180776964890, Seller is bid4ez.

http://www.ebay.com/itm/180776964890?ssPageName=STRK%3AMEWNX%3AIT&_trksid=p3984.m1497.l2649

Tony
« Last Edit: September 10, 2013, 08:27:21 PM by KC2MWJ » Logged
K5LXP
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« Reply #13 on: September 11, 2013, 03:36:16 AM »

 I recently purchased a 12 Volt-18 AH, sealed AGM battery, on eBay for $37.49, free shipping included.

This is a starting battery so deep cycling may do it in.  Depending on how many cycles you need this may or may not be a problem but it's something to consider.

Mark K5LXP
Albuquerque, NM
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KF7VXA
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Posts: 412




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« Reply #14 on: September 11, 2013, 11:26:29 AM »

you will kill lead acid batteries if you repeatedly deep discharge them (AGMs). Rule of thumb, no more than 50% of rated capacity, say 5 AH from a 10 AH battery.

Consider that rule of thumb from a practical level.

A battery like a gel or AGM is rated for at least 250-300 cycles down to 80% DOD.  That's at least one deep cycle a week for 5 years straight.  I suspect most hams operating portable might do that once a month, or less.  So by that rule of thumb you're buying and carrying around twice as big a battery as you need, only to throw away most of its' cycles in 5-6 years when it goes toes up from age.  I don't see anything wrong at all with running them into the ground and getting every Ah you can, with the idea they'll still die from old age than cycles.  Cheaper and less weight to haul around.


Mark K5LXP
Albuquerque, NM


I agree with the other poster, unless you are going to use the battery all the time, it will go bad before it's been recharged all those extra times and is a lot more expensive than a regular AGM battery of the same specs.

As far as keeping battery voltage up, MFJ makes a voltage  booster that keeps voltage at 13.8 volts when the battery is as low as 9, 10 or 11 volts or anywhere inbetween. It's just over 90% efficient and they do work well. Some say they produce a little noise. You can see it with a good O scope, but don't really hear it in the transceiver. It's good to 30 amps. Another company makes one also to 40 amps, over $200.00 which is also a good unit (it allows you to run it at less than 13.8 volts, a plus). The MFJ unit is $150.00
Another guy has one for $69.95, stay away from it, lots of problems and is very noisy, you get what you pay for.
The MFJ unit works well and gives a lot more use time on a larger battery especially.
A lot of gear won't work at less than 12 volts and you lose quite a few watts in power at lower voltage also. Not cheap, but worth the money for extended power outages. I think I'd have bought the more expensive unit, but money is tight. It has a fan and 40 amp fuse (they also make a 30 amp version, no fan for $190.00, it looks exactly like the 40 amp version. I think the 40 amp just uses a fan to keep things cooler and a 40 amp fuse). I'm thinking a small fan like in the other unit and a 35 amp fuse just might work great in the MFJ unit. Small fans are cheap, I have a bunch of them.
30 amps is really enough for one HF unit and accessories, but having an extra 5 amps available would be good insurance. For VHF/UHF 50 watt radios, it's plenty.

John
« Last Edit: September 11, 2013, 11:29:30 AM by KF7VXA » Logged
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