another source for agm batteries

pianotuna wrote:
Any truth to AGM's REQUIRING high charge rates to survive?

pianotuna;

I totally screwed up my previous reply because I missed that you were asking about Amps and not Volts. I revise my reply:

Lifeline 5.4, wrote:
For repetitive deep cycling, chargers should have an output current of at least 0.2C (20 Amps for a 100 Ah battery). If the output current is less than this value, the cycle life of the battery may be negatively affected.

I believe what they are saying here is that in a cyclic use as opposed to a standby use that there may not be enough Amp replacement between cycles. A cycle is use then charge activity. That is exactly the case when we are RVing.

just previous to the above quote

Lifeline 5.4 wrote:
The charging current during the Bulk stage should be set as high as practical; higher current levels mean faster recharge time.

Note that there is no encouragement to change from their regular 14.3V temp-comp. If you are not getting to full charge then increase Amps.

Further down:

Lifeline 5.4 wrote:
full charge state should be verified using the
criteria(I quote: time to full charge formula) given above (current drops below 0.5% of rated capacity).

There seems to be a belief that AGMs must be fully charge with each cycle. I don't see that in the Lifeline manual. I do believe in sulphation. I believe I monitor sulphation progress by observing morning Volts with my Turnigy. I observe two Voltages, morning and overnight low. If they are trending down, I am sulphating. When they hit my low threshold, out comes the genny and I run it until the solar takes over. I look for the solar controller to show float sometime that day. The longest consecutive days doing this is 31 when I retreated to shore power.

Now there is Lifeline's paragraph 5.5 Conditioning which describes a use of high volts to recover a battery that is exhibiting a loss of capacity AFTER a regular charge cycle. There is nothing routine or scheduled here. (Contrast to that to the regular process of bubbling wets.) In fact, Lifeline goes on to explain that this is not to be confused with wet-equalization.

I have not felt the need to recover my AGMs as described by Lifeline. There is nothing wrong with the procedure.

I do feel the Deka is below its 79AH spec because it drops to 13.8V after resting over 24hrs. One Optima drops to 13.84 and the other drops to 13.02.

I can assure you I have used these batteries as lab rats in my driveway. I am very comfortable with their performance.

YMMV and IMHO. :)

HTH;
John

BFL13 wrote:
"AGM's are a siren song"

Especially Odyssey. ( Engineers, that's a joke BTW ) :)

Mena, don't worry. Forum members are totally unbiased on all topics. Especially MPPT guys, AGM guys, Ford guys, Dodge guys, (Chev guys are biased--you can tell by their big smiles), Iota guys, PD guys, 12v battery guys, MH guys, TT guys, TC guys, and all gals brave enough to post here.

Big smiles! LOL! Oh it's not the bias that bugs me B.

"AGM's are a siren song"

Especially Odyssey. ( Engineers, that's a joke BTW ) :)

Mena, don't worry. Forum members are totally unbiased on all topics. Especially MPPT guys, AGM guys, Ford guys, Dodge guys, (Chev guys are biased--you can tell by their big smiles), Iota guys, PD guys, 12v battery guys, MH guys, TT guys, TC guys, and all gals brave enough to post here.

pianotuna wrote:
Hi mena,

AGM's are a siren song. LI even more so but oh the cost....

It's hateful to have champagne battery tastes and a beer budget. (gazing fondly at Surrette two volts @ 800 amp-hours)

Hey PT, an avenue you might investigate (I know you get around a bit) is a Hospital or Telecom vault, someone who services them. They usually take AGM's out of service on a schedule, much shorter than the battery's life, usually annual or every two years. You may be able to ask one of these battery Mfg.'s who does their service or distribution in your area.
That may get you the bubbly on a Labatts budget.

Indeed PT! I'd have LI batts today and would be like that forum member with LI batts that rarely says anything and when he does it's never about batteries (yes there is a forum member with LI batts...big bank too).

Hi mena,

AGM's are a siren song. LI even more so but oh the cost....

It's hateful to have champagne battery tastes and a beer budget. (gazing fondly at Surrette two volts @ 800 amp-hours)

BFL13, I know you're just trying to learn but you are wasting your time trying to convince or even inform a RV.net AGM owner (there are exceptions...thanks to you guys) of anything other than their experiences with their batteries. They even ignore MEX, who knows more about batteries (the man did this for a LIVING for God's sake) than most of us will ever know. I would ask questions to those few directly and save the rest for other forums like the sailing forums. IMO, it sucks to have to do that (because people like myself lose out on that info) but it just seems all the AGM threads (except for Hitech's oddly) just devolve into a playground full of of bully's beating their chests on how dumb or cheap every non-AGM owner is.

pianotuna wrote:
Any truth to AGM's REQUIRING high charge rates to survive?

No, except for famous Lifeline ;) - they recommend 0.2C minimum and 5C maximum. Most others don't mention any minimum current, and recommended maximum is typically 0.3C.

pianotuna wrote:
Any truth to AGM's REQUIRING high charge rates to survive?

No, except for famous Lifeline ;) - they recommend 0.2C minimum and 5C maximum. Most others don't mention any minimum current, and recommended maximum is 0.3C.

Full M, do you in fact camp like in that first case, where you spend many days in a row below full charge and then get back to full somehow, with no "recovery" procedure required, then start over?

If so and you have no problems, then I would need a re-think for sure.