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Author Topic: AGM vs Gel Battery for FT-897D?  (Read 55403 times)
W5WSS
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Posts: 2272




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« Reply #30 on: October 07, 2014, 10:31:03 PM »

My Yellow top is 6 years old. I installed it new as a direct replacement in an old 1990 Ford Taurus wagon. So not only does it supply the automobile but also to power the HF rig and Tokyo Hi Power HL 450b amplifier installed in the car when hill topping.

The stock alternator has been the sole source of charging for this battery.

6 years is a long time for an automotive application and No dead battery issues.

I am going to see how much longer it will provide reliable service.

I am impressed!

73
« Last Edit: October 07, 2014, 10:34:21 PM by W5WSS » Logged
W8JX
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Posts: 12081




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« Reply #31 on: October 08, 2014, 03:49:29 AM »

My Yellow top is 6 years old. I installed it new as a direct replacement in an old 1990 Ford Taurus wagon. So not only does it supply the automobile but also to power the HF rig and Tokyo Hi Power HL 450b amplifier installed in the car when hill topping.

The stock alternator has been the sole source of charging for this battery.

6 years is a long time for an automotive application and No dead battery issues.

I am going to see how much longer it will provide reliable service.

I am impressed!

73

Honestly, 5 or 6 years with a stock battery is not unusual at all and I have seen stock batteries go longer. 6 volt battery in my tractor is 11 years old. Alternators in cars have been 100 amp or better for over 25 years now with birth of electronic fuel injection. 
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Ham since 1969....  Old School 20wpm REAL Extra Class..
K5LXP
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Posts: 5330


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« Reply #32 on: October 08, 2014, 08:23:42 AM »

5 or 6 years with a stock battery is not unusual at all and I have seen stock batteries go longer.

I think it matters where you live.  Since I've lived in ABQ I consistently get 7 years out of SLI batteries but we don't get the heat of Phoenix nor the sub-zero's of the midwest.  Heat accelerates a battery's demise, and cold diminishes its cranking ability.  So a battery that cranks my car over in my 55F garage may not work at all in Minnesota at -15F.  Another plus to living here is cars don't rust.  Smiley

Mark K5LXP
Albuquerque, NM
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W8JX
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Posts: 12081




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« Reply #33 on: October 08, 2014, 09:40:36 AM »

5 or 6 years with a stock battery is not unusual at all and I have seen stock batteries go longer.

I think it matters where you live.  Since I've lived in ABQ I consistently get 7 years out of SLI batteries but we don't get the heat of Phoenix nor the sub-zero's of the midwest.  Heat accelerates a battery's demise, and cold diminishes its cranking ability.  So a battery that cranks my car over in my 55F garage may not work at all in Minnesota at -15F.  Another plus to living here is cars don't rust.  Smiley

Mark K5LXP
Albuquerque, NM

What you say has merit but todays cars generally have 4 or small V6 engines and use a lighter weight oil too vs car of days of old and as such place a lot less demand on battery starting.
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Ham since 1969....  Old School 20wpm REAL Extra Class..
N8YQX
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Posts: 98




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« Reply #34 on: October 08, 2014, 11:58:42 AM »

Today for portable I would not lug heavy gel cell batteries. I would use lithium. It is more expensive for sure but it supports more charge cycles and has about 4x as much stored power per pound vs  lead gel cells. If you are going to lug a 40 lb battery you would do better to lug a 40lb generator. There a several 1000 watt or less generators out there and gas is about 6.3 pounds a gallon.

Can you buy a generic lithium or nimh battery? I would be interested in a solution like that. The closet solution I can think of is R/C battery pack, but they're not in the 13.8V range.

I think most lithium chemistry is around 3.7V, so would you put about 4 in series?
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73,
N8YQX
W8JX
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Posts: 12081




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« Reply #35 on: October 08, 2014, 01:09:07 PM »

I think most lithium chemistry is around 3.7V, so would you put about 4 in series?

Yes, a electric car has a lot of cells in series. Most are in packs or 24 or 48 volts batteries that are also in series.
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Ham since 1969....  Old School 20wpm REAL Extra Class..
N3QE
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Posts: 4921




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« Reply #36 on: October 08, 2014, 07:34:51 PM »

Can you buy a generic lithium or nimh battery? I would be interested in a solution like that. The closet solution I can think of is R/C battery pack, but they're not in the 13.8V range.

Sure thing, for lithium-ion: http://www.lithiumion-batteries.com/products/12v-300ah-lithium-ion-battery/

NIMH batteries are pretty much just like NiCads were in the past, assemble from cells yourself or have the vendor weld the tabs together for you. e.g: http://www.digikey.com/product-detail/en/HR-DUX(10.0AH)F2X5/SY148-F025-ND/1203861
« Last Edit: October 08, 2014, 07:37:07 PM by N3QE » Logged
KC2MMI
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Posts: 812




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« Reply #37 on: November 26, 2014, 05:17:53 PM »

Those companies that make both AGM and Gel batteries all say about the same things about the two. Gel is more sensitive to damage from overcharging, it needs a lower voltage and not all chargers can match that. But when properly charged, gel also will have something like 2x-4x the number of deep discharge cycles that AGM can provide. Gel simply gives you more cycles, with a battery of the same form factor and amperage rating. IF your charger is designed to properly maintain it.

Wet lead is still the most economical way to go, but a sealed battery (AGM or gel) won't eat your clothing and carpet, or emit hydrogen during routine charging, or acid vapors. "Golf cart" batteries tend to be the most economical for deep cycle wet batteries.

Lithium-whatever is a bit more like religion than science. Every maker contradicts the next one, agreeing only that lithium batteries should have 5x-10x the number of deep cycles, and a comparably high price. Most of the folks who actually MAKE lithium cells, insist that unless you use an equally expensive battery management system (BMS) they may die very early, or catch fire and explode. LiFePO4 chemistry is the only one that doesn't use a flammable electrolyte, supposedly it is about 10% less powerful than all the others trading this off for safety.

If you've got lots of money, and are willing to do lots of homework, lithium might be the cheapest in the long term--if it lasts that long. But it will certainly cost way more, which is a waste if you're only using it for occasional backup power.
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W8JX
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Posts: 12081




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« Reply #38 on: November 26, 2014, 05:45:49 PM »


Lithium-whatever is a bit more like religion than science. Every maker contradicts the next one, agreeing only that lithium batteries should have 5x-10x the number of deep cycles, and a comparably high price. Most of the folks who actually MAKE lithium cells, insist that unless you use an equally expensive battery management system (BMS) they may die very early, or catch fire and explode. LiFePO4 chemistry is the only one that doesn't use a flammable electrolyte, supposedly it is about 10% less powerful than all the others trading this off for safety.


Lithium is a lot of science and very proven. There are different types but some like those used in cars are good for thousands of cycles. We have a Chevy Volt which has a 440lb, 370v 17kw Lithium battery pack that is also heated and cooled as needed. It the case of cars they generally only use 70 to 80% of capacity in normal use which is said to extend life a lot as does maintaining optimum operating temperature. (like I said a lot of science) I would think same would apply with portable Lithium batteries.
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Ham since 1969....  Old School 20wpm REAL Extra Class..
KC8VWM
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Posts: 3188




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« Reply #39 on: December 27, 2014, 11:42:58 PM »

Gel cell is the very last battery I would choose.

They make very nice paperweights when you neglect them or charge them incorrectly just one time. All you need to do to "brick" a gel battery forever is simply not charge them exactly right or neglect to keep the voltage from falling below a certain level. Once they do that, forget about trying to "recover" them once they go dead, it's simply not in the cards. It's now a paperweight, and you need to replace the battery.

AGM chemistry is far more forgiving and you don't need to apply just the exact correct amount of current to prevent air bubbles from forming inside the gel, nor do you need to monitor a stopwatch when charging them. They are specifically designed for user abuse and low maintenance in mind.
« Last Edit: December 27, 2014, 11:52:26 PM by KC8VWM » Logged
W8JX
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Posts: 12081




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« Reply #40 on: December 28, 2014, 04:53:00 AM »

AGM chemistry is far more forgiving and you don't need to apply just the exact correct amount of current to prevent air bubbles from forming inside the gel, nor do you need to monitor a stopwatch when charging them. They are specifically designed for user abuse and low maintenance in mind.

While not a big fan of gel cells, if you charge them slowly at .1c  or less they are not prone to easy overcharge and damage. If you fast charge them you do need to be careful and should use a smart charger.
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Ham since 1969....  Old School 20wpm REAL Extra Class..
KB1GMX
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Posts: 1505




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« Reply #41 on: December 29, 2014, 03:17:17 PM »

First I've used a lot of batteries so experience has a place for me.

Gell cells:
I use them where modest peak power needs and low cost are important.  By
low peak power I mean not more than 3C (21A for a 7ah gell).  properly charged
I expect and get years from them.  I use a simple CC/CV charger at .1C.

AGM:
I use that where I need a bit more bulk and power but want it without leakage.
Those that I use are in the 33ah range.  Not meant to be for backpacking but
still transportable without a hand truck.  CV/CC at .1C does the trick and no issues
with batteries in the 3 to 5 years and getting older.

Over all for lead maintaining a charge, and not letting them sit discharged are
the two watch for things.  A discharged battery will sulfate and die fast.

NiCd:
My solar/battery system for running the station is a set of 10 AL150 wet NiCds.
These are 150ah/20hr wet electrolyte unsealed NiCds.  Large and capable of
pushing any peak amperage imaginable.  For those that say its expensive,
these were salvage and free.  They are known for exceptional lifespan.
Charging efficiency for NiCd is not as good as lead or Lion but in the
system works.

Small nicds: AA cells
They have fallen to disfavor and I use them for cheap.  They require much
more care in charging to get good life (lots of cycles)

NiMH small AA:
Common and the current crop is both good and getting better.  Still like
just about every sealed technology battery care in charging is a must for the
best life.   I use a lot of this type as many things I have use that size.
About the easiest to live with rechargeables.

LION/LiPo:
I've been using these for powered computer (not common laptop) and other
applications for about 20 years.  Most of that was commercial packs and
chargers.  The batteries have improved, the chargers have improved more.
The 18650 is the common use cell here and the BMS [battery management
system) or CMS (charge management system) boards are small and cheap.
they charge well with simple CC/CV with attention to the CV (never exceed
recommended cell voltage) and more sophisticated chargers are cheap.
Battery life has exceeded expectations and there have been no blowups.
I'm not running models and the like at 10C or greater with them or fast
charging them.

The other area has been with salvaged Laptop batteries.  The common cell
is 18650 in the ones I've ripped apart. considering the age of some they have
done well.  The most common failure is loss of capacity.  Those remaining are
often at 90% of their rated capacity.  I remove and reuse with new BMS
these and they have done well.

Larger LION/LIPo batteries aimed at the 7-8ah gell cell size are appealing
as they often contain the whole BMS/CMS and can easily supply 5 to 10C
intermittent.  I have one for running radios, lots lighter than lead and performs
about the same in actual use.  This is not one of those "blue shrink wrap"
types of uncertain Ah ratings. 

Lithium tech does well in storage.  Keep them above their BMS fall asleep
but less than 60% and they store very well.  Top them off before use and
they just work.  The other feature i if you can't charge them fully unlike NiCd
partial charge is acceptable and does not hurt life at all as best I can determine.

One last type for Emcom:
AA alkaline non-rechargeable.  Common as house files good life for its weight.
They no special concerns in the field such as transporting them.


The is no one best battery.  If I have to carry it LION, for best life more choices
if weight is less a concern.  It often comes down to availability, ease of use, ability
to maintains, and cost over life.  Most sealed systems if charged correctly will
do well.  Sometimes the common AA alkaline is a winner.


Allison
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