Charging antimony-free VRLA batteries without float

I cannot either. No idea.

But to gauge full charge I am going to hundredths of a volt so a small difference might matter until I really have a good feeling on exact amp hours in/out (or sometimes as a handy short cut). I actually saw different pages on battery university, one said Voc goes up with temp and one said down, and neither how much.

The volts <-> SG thread had a really good link that looks like it goes up with temp (makes more sense to me). If I can quit avoiding chemistry and research how to convert the molar strength of sulphuric acid to specific gravity, that will be a pretty good theoretical formula. But it does not give the temperature function, just a point value at 77 degrees so I'll have to look into that next.

Jim

HiTech wrote:

I actually hit this paper researching to find out the effect of Temperature on a battery's open circuit voltage.

I haven't seen a difference on mine. Or would that difference be pretty small?

Mex what about this paper? They seem to be on the "some voltage below ideal float" band wagon too?

I'm not a fan of the charge and sit cycles since you skip from one size of the positive plate corrosion curve to the other without much time in the sweet spot in the middle. But there does seem to be a set of researchers thinking the reduction in dry out may be worth some balance above Voc but below Videalfloat.

More research into floating below theoretical ideal float voltage for AGMs

I actually hit this paper researching to find out the effect of Temperature on a battery's open circuit voltage. I can find a few references to the idea that it changes, but no pointer to how much it would change by so far.

Jim

Now yer talkin'!

By observing trends & tendencies, you can play a battery bank like a pipe organ with one hand tied behind your back while watching a football playoff game (the other hand clutches a brewskie).

There has got to be a reason I get a dozen years out of a set of T-105's, twenty plus on 2-volt cells and a dozen years out of a car battery. I am less a slave to my battery banks than you can imagine. Glance at a meter and if it seems odd, determine within 30 seconds if there is a problem.

I just had a person I was trying to help blow a grand on some L-16's he did not need. I told him to test first, he did not, and now US Battery has his 11 crisp Franklins, he has batteries that can not be paralleled with his old Rolls batteries and is several days south of the border. Sure his home is 200 miles from here, but my testing would have saved him a chunk of change. Such is life. I'd hate to be the person in US Battery that would have to deal with his whining about the no return policy.

Hi-Tech is learning on a pretty steep ramp. When you stop learning, you start dying.

full_mosey wrote:

HiTech wrote:

Clattertruck wrote:
As a practical matter, my Deka AGM batteries are 5 years old, and they have been on charge 24/7 when we are not on the road. My converter is a Xantrex that puts out a float of 13.6 volts. The batteries seem to be performing fine.

So far so good. 13.6 is barely over the specific float voltage spec I got from Deka, and within the float range they allow, I think.

I need to calibrate my volt meters. They agree with each other to within a few hundredths, but the volt meter in my charger is sometimes many tenths off one way or the other, and not by a constant amount.

Jim

Jim;

There you go Obssessive-Compulsive-Disorder(OCD) on Volts again! :)

Set your chargers for 14.4V temp comp and calibrate your Amp meters!

Take a deep breath, let it out slowly while saying Amps, Amps....

How many AGM owners with 5-10yr old batteries it going to take?

MY solar two stage MS SS-10PWM doesn't even have a float stage! It simply holds 14.4V temp comp and tapers Amps so low that the battery reaches stasis. Rinse and repeat every day. This is the system that runs my 12V fridge and freezer. We're talking about my beer and ice cream, man!

Think Amps! ;)

HTH;
John

You know to be really obsessive, you alphabetize it into CDO...

Lol it is true. Amps and amp hours are very low indeed. I need to look at amp hours from more sources than solar and verify.

For non float you do have some flexibility on voltage. For 24x7 float everything I read says volts matter.

Time to measure some amps and amp hours on the chargers over time.

Jim

full_mosey wrote:

HiTech wrote:
You never want to either. It is an extreme recovery procedure for an otherwise dead battery. Lifeline has one for batteries that have run dead and some other recovery procedure too. I used only as a last resort and it did work, but guaranteed the battery was stressed. It was not valve noise, it was a bubbling/crackling sound inside the battery.

Jim

Ah! That clears things up considerably. Your AGMs were already ruined. I had a grp31 trolling FLA that I ruined and it sizzled and crackled when I tried to recover it with a VEC1093.

It had run dry over Winter because I brought it inside and used it with an APC 1250 UPS without checking or adding water.

HTH;
John

Little 32 amp hour car AGM. But the recovery procedure actually worked and it is back in service. But at the time I ran the procedure, it would not start the car so Ah capacity and CCA were way down.

I have 2 not really in service yet Deka AGMs and 2 older small SLI AGMs.

Jim

HiTech wrote:

Clattertruck wrote:
As a practical matter, my Deka AGM batteries are 5 years old, and they have been on charge 24/7 when we are not on the road. My converter is a Xantrex that puts out a float of 13.6 volts. The batteries seem to be performing fine.

So far so good. 13.6 is barely over the specific float voltage spec I got from Deka, and within the float range they allow, I think.

I need to calibrate my volt meters. They agree with each other to within a few hundredths, but the volt meter in my charger is sometimes many tenths off one way or the other, and not by a constant amount.

Jim

Jim;

There you go Obssessive-Compulsive-Disorder(OCD) on Volts again! :)

Set your chargers for 14.4V temp comp and calibrate your Amp meters!

Take a deep breath, let it out slowly while saying Amps, Amps....

How many AGM owners with 5-10yr old batteries it going to take?

MY solar two stage MS SS-10PWM doesn't even have a float stage! It simply holds 14.4V temp comp and tapers Amps so low that the battery reaches stasis. Rinse and repeat every day. This is the system that runs my 12V fridge and freezer. We're talking about my beer and ice cream, man!

Think Amps! ;)

HTH;
John

At 13.6 what is the current, the amperage aggregate over a day or a month? If you want to fine tune, use an adjustable regulated power supply for constant loads. That and a verified accurate kWh meter is the least expensive way I can think of to establish long term float "precise" reliability.

HiTech wrote:
You never want to either. It is an extreme recovery procedure for an otherwise dead battery. Lifeline has one for batteries that have run dead and some other recovery procedure too. I used only as a last resort and it did work, but guaranteed the battery was stressed. It was not valve noise, it was a bubbling/crackling sound inside the battery.

Jim

Ah! That clears things up considerably. Your AGMs were already ruined. I had a grp31 trolling FLA that I ruined and it sizzled and crackled when I tried to recover it with a VEC1093.

It had run dry over Winter because I brought it inside and used it with an APC 1250 UPS without checking or adding water.

HTH;
John

Clattertruck wrote:
As a practical matter, my Deka AGM batteries are 5 years old, and they have been on charge 24/7 when we are not on the road. My converter is a Xantrex that puts out a float of 13.6 volts. The batteries seem to be performing fine.

So far so good. 13.6 is barely over the specific float voltage spec I got from Deka, and within the float range they allow, I think.

I need to calibrate my volt meters. They agree with each other to within a few hundredths, but the volt meter in my charger is sometimes many tenths off one way or the other, and not by a constant amount.

Jim