Gel cell longevity question; What am i doin' wrong?

Having gone through three 7 AH gel cell field batteries in less than three years, i got a 12 AH and a dedicated 13.8V 'float' charger to be 'sure' this one would last a while. Well it went belly up after just a few months just like the others. Drain during use is 1.7A, occasionally as high as 2.5A, never higher. These were different brands. Is there a brand that *might* stand a chance of lasting a while? Any tips or advice appreciated. Many Thanks.

Bill(oc)

On Mon, 26 Sep 2005 07:47:42 -0700, snipped-for-privacy@webtv.net (Bill Sheppard) wrote in :

I don't know.

But that's not gonna stop me from speculatin'. :o)

Maybe you should go to a larger battery--for motorcycles or tractors.

I have heard that gel cells and lead-acid batteries don't like being fully discharged, but it seems that you're already covering that aspect with your float charger.

I use nicads for my starter equipment. I don't do any field charging, unless I borrow someone else's charger (very, very rare).

Marty

I suspect the brand of battery is not the issue. I get multiple seasons from these batteries - the one I am using now is 2 years old and going strong. I don't recall exactly how long the previous one lasted but I suspect about 4 years. I wonder if you could be over charging.

Ed

Bill Sheppard wrote:

Just as a data point, I've been using my current Hobbico "TorqMaster" 12V

7A gel cell (re-branded PowerSonic I think) for two years now and it's still going strong. I normally fly at least twice a week, year round and in temperatures down to about +5 degrees F. During the winter I use the starter pretty regularly and I normally fast charge my radios at least once off the battery while I'm at the field. I do disconnect the battery from my power panel when not at the field. I use a PowerSonic PSC-12800A charger which has a little more intelligence than a regular trickle charger, and I try to remember to put the battery on to charge the night before I fly and I try to make it a point not to leave the battery connected to the charger for more than a day or so after the LED indicates it has reached a full charge - although I'm not 100% on either point by any means.

| Having gone through three 7 AH gel cell field batteries in less than | three years, i got a 12 AH and a dedicated 13.8V 'float' charger to be | 'sure' this one would last a while. Well it went belly up after just a | few months just like the others.

A few things to check ...

1) They don't like being fully discharged, and especially don't like being left discharged for any length of time. Keep them at least half charged at all times.

2) How fast does your charger charge? C/10 is the suggested charge rate, so that would be 700 mA. Going faster than that is not a good idea unless you have a smarter charger than most.

3) I don't know how smart your charger is, but the cheap ones don't know when to quit. If you can hear your battery charging (especially if it sounds sort of like frying eggs) then it's full and you're doing damage already.

(The sound is due to the electrolyte being turned into hydrogen and oxygen, which is vented. Since these batteries don't allow you to put water in them, you can't replace any lost electrolyte.)

My guess is #3 ...

What's the failure mode? Does it lose capacity over time and then have none? Any bulging noticable? Any `gunk' appearing on the outside of the battery?

Do the batteries get warm or hot when charging? A tiny bit warm is to be expected, but hot is not.

Your link to the Video doesn't seem to work. When I try to right click and save target as..... I.E. doesn't find the site.

Bill-

I've had the same 7AH gel cell, a Hobbico Torquemaster for 6 years now and it is doing fine. I charge it with an auto 12 V battery tender. Output is 1

1/2 amps, and it stops charging when the battery is fully charged. I think that maybe the gentle, slow charging has helped keep it healthy.

Swede

My guess is that the battery is being overcharged. I get several years out of mine. I have a simple 15V wall wart with a full wave bridge rectifier. I use the battery until my starter motor has trouble starting my YS .91 then I charge until the voltage gets up to about 14V with the charger attached. I know it isn't scientific but it has worked for better than two decades.

Now that I am tinkering with electric powered models in addition to my traditional gas and glow powered models, I finally have an excuse to buy an RV/Marine deep discharge/cycle battery. I already have the float charger for my motorcycle. Look out Wal-Marts!

Ed Cregger