# AGM life cycle vs DoD.....



## Jason Lattimer (Dec 27, 2008)

Interesting.....The cycle chart that is in that pdf file is the same one i've seen for other batteries from different manufacturers. It looks like 50% DOD is only going to get you 420 to 500 cycles. 80% would probably fall in the 300-350 range. Doesn't seem like a very long life. I am wondering if there is any way to charge them differently so as to increase their life cycle?


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## rmay635703 (Oct 23, 2008)

Unfortunately AGM batteries and gel batteries really do not respond to the normal tricks to fix aging flooded batteries, pulse charging is out, electrolite changes are out, distilled water trick is out.

AGM from my personal dealings with them are more predictable than flooded but also have a much shorter life normally.

The AGMs from Miles regardless of how they are used rarely make it past 4 years whereas flooded batteries used lightly can easily outlast this.

I am waiting for more reports on greensavers and lithium batteries before I replace my aging and severely abused 6 yr old trojans.

Hmm, that chart looks awfull familiar, see if I can find one almost the same for another brand


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## DIYguy (Sep 18, 2008)

rmay635703 said:


> Unfortunately AGM batteries and gel batteries really do not respond to the normal tricks to fix aging flooded batteries, pulse charging is out, electrolite changes are out, distilled water trick is out.
> 
> AGM from my personal dealings with them are more predictable than flooded but also have a much shorter life normally.
> 
> ...


Is 500 cycles at 50% really shorter? How many cycles do you have at what avg discharge...do u know?

Thanks,


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## DIYguy (Sep 18, 2008)

Jason Lattimer said:


> Interesting.....The cycle chart that is in that pdf file is the same one i've seen for other batteries from different manufacturers. It looks like 50% DOD is only going to get you 420 to 500 cycles. 80% would probably fall in the 300-350 range. Doesn't seem like a very long life. I am wondering if there is any way to charge them differently so as to increase their life cycle?


What would you say is "long life" for floodies? I don't recall longer cycle life than this from what I remember when I was looking some time back....

Thanks


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## Jason Lattimer (Dec 27, 2008)

If I recall correctly I thought Trojan floodies had a 700 cycle life at 80%. I have a hard time finding cycle info on any battery though, they don't seem to want to publish it.


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## DIYguy (Sep 18, 2008)

Jason Lattimer said:


> If I recall correctly I thought Trojan floodies had a 700 cycle life at 80%. I have a hard time finding cycle info on any battery though, they don't seem to want to publish it.


Really? hmmm, that sounds high to me. I thought it was more like 450 from my faded memories......


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## rmay635703 (Oct 23, 2008)

Well since you ask...

I have the benefit of knowing who 1st owner of my car was.

My batteries by 2006 had 8000 miles on them from a kewett.

The 2nd/3rd owners transpired in under a year but when I got the car with these T-875's the batteries were dried out.

We did a cycling and edta regiment and my batteries were back to a 50mile range at 100%dod in about a month. (and yes we did add a little acid, blasphemy!)

I have driven the car 5100 miles 2007-2008, I typically drive ONLY ELECTRIC 4-5days a week and I probably average 50% dod, that is including the rather frequent 100% dod when I would go out too far with no opportunity charge and the many 10-20% DODs when I have access to power somewhere.

If I do a 100% DOD I do a dump charge, just long enough to get into the 11-12v area on the low/reversed batteries with jumper cables right after I crawl home and leave the pulser on those batts.

I probably have well over 400 deep discharges myself (not including when I repeatedly charge and go on many smaller trips during the day) despite the fact my car has been out of commission a couple months to repair wiring & the reverse. (its taking longer because its bloody cold)
Now since I know I have at least 400 "deep" discharges and the batteries are from 2004 this means that there must be a few more cycles than that on the raster not counting the small discharges that I try to do whenever possible. I would think between 2004 & 2007 there would have to be more than 100 deep discharges but maybe not, there were enough miles recorded by the first owner on the pack to mean a lot of potenial discharges.

As you probably guessed my batteries are NOT in very good condition maybe 50% of what I started with but I have done many unorthodox things to save my batteries after destroying them so you might consider me atypical. How many here have dumped the acid into containers, rinsed with water and put in distilled water with a trickle charger to clean?

Still from what I have read of others I am NOT doing too bad considering how much abuse I have given, I know better but until I buy a new pack I don't care too much, heck my terminals and casings are all deformed and all the lifting straps are broken off. Also I have had OK luck with chemicals and pulsing, I probably waste a lot more time than others though maintaining and checking batteries. I also must be a little lucky since I haven't had any short circuits in my set... yet. Though I have taken measures to avoid that after bad experiences with 12v batteries.

My acid at the moment is very weak but little sulphate which means I probably will have to break down and buy acid  That is the main trouble with adding chemicals to cure abuse, weak electrolite!

My father unfortunately has followed my example (even when I said it was a bad idea) with his electric car and batteries and thus has short circuits in his less durable 12v batteries. 

He also managed to freeze one, I will definately love the day I can get off lead and have a better range without the theatrics.

Yes you can abuse flooded batteries if they have nice thick plates but you pay in the form of either money or work.

If you don't believe floodeds can last a long time with meticulous maintenance ask on the C-car yahoo group there are several there with 15yr old flooded batteries that still function in their cars, something I doubt will ever happen to me but they also probably do not overdischarge or add chemicals.

Cheers
Ryan


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## DIYguy (Sep 18, 2008)

Wow, thank you Ryan for taking the time to right such detail. I do appreciate it. Nothing stands up like experience, and you have plenty. I'll take that to the bank.

cheers.
Gary


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