Duralast 31DC-DL chargins specs

[drjenk]

Hi,
I've bought a few Duralast 31DC-DL for temporary use in my solar solution for the next few years until I get lithium.

I've got a Victron charge controller hooked up, and am trying to find accurate charging specs (absorption voltage, float voltage, equalization voltage etc), but I can't seem to find it. Apparently Johnson controls makes the battery, I've run into a dead end there too.
Wondering if anyone has a go-to battery spec resource they use, or can point me in the right direction to enter the proper specs for maximum life of these batteries? Thank you so much for any info.
Kind Regards,
David J

 

[sunshine_eggo]

Hi,
I've bought a few Duralast 31DC-DL for temporary use in my solar solution for the next few years until I get lithium.

I've got a Victron charge controller hooked up, and am trying to find accurate charging specs (absorption voltage, float voltage, equalization voltage etc), but I can't seem to find it. Apparently Johnson controls makes the battery, I've run into a dead end there too.
Wondering if anyone has a go-to battery spec resource they use, or can point me in the right direction to enter the proper specs for maximum life of these batteries? Thank you so much for any info.
Kind Regards,
David J

205 RC is approximately 110Ah

I'm a little confused by the 65Ah claim. 205 RC means 205 minutes at 25A... 205/60 * 25 = 85Ah @ 25A where 65Ah is 65/20 = 3.25A

Impossible for a battery to have a higher capacity at 25A than at 3.25A.

The 59.7# of the battery is far more consistent with a 100-110Ah battery.

Typical FLA (mix of similar Trojan and/or Rolls batteries):
14.6V absorption until current drops to 2.2A
13.5V float
16.2V equalization
Fully charged specific gravity >=1.265
Only equalize if you can't achieve 1.265 or cells vary by more than 0.03
Check electrolyte weekly. Top off to max level ONLY when fully charged.
Charge between 6.6 (0.06C) and 14A (0.13C)

None of the above are gospel, but they are generally good numbers for FLA batteries.

 

[drjenk]

Thank you, looks like I wasn't far off in my guess based on other data. I would just love to have the actual factory specs though. I currently have it set to:

14.5v absorption
13.25v float
16.1v equalization

This was based on a 31DC-XD2, not sure of any relation. But it sounds like I am awfully close to the norm.

Is it ok to equalize every so often just to prevent differences? I read somewhere else every 30 days.

BTW what is FLA?

 

[sunshine_eggo]

Is it ok to equalize every so often just to prevent differences? I read somewhere else every 30 days.

Equalizing is stressful to cells. If you can achieve full charge specific gravity, and they are within 0.03 of each other, there's really no reason to equalize. If you want to do it on principle, I'd do it every 90 days.

BTW what is FLA?

Flooded Lead Acid