Duracell GC2 charging specs

[Antilag]

I'm trying to figure out the charging specs since I'm replacing my AGM batteries with these and of course Duracell and Deka's website does'nt give this precious information.

I'm sure I saw a post here giving this information but I cannot find it. There is a post on Duracell branded 6v info - northernarizona-windandsun but someone said the float values seemed high.

Also, is the charging rate really limited to 10% of the bank's capacity?

Thank you.

[darylat8750]

I sent them an email and was given:
Bulk/absorb 14.7
Float 13.5???? Aww. It's heck getting old. I can't find the email right now and I'm not on the boat. I put it in my charger some time ago. I'm pretty sure condition was 15.3 but I wouldn't bet that it isn't 15.5. Sorry.
Condition ....

[Antilag]

Originally Posted by darylat8750

I sent them an email and was given:
Bulk/absorb 14.7
Float 13.5???? Aww. It's heck getting old. I can't find the email right now and I'm not on the boat. I put it in my charger some time ago. I'm pretty sure condition was 15.3 but I wouldn't bet that it isn't 15.5. Sorry.
Condition ....

Thank you! 14.7 seems to be the same value the other person I gave the link got. The float value seems better than with the other guy getting 14.04v.

Anyone else can confirm the values? Also for the equalizing?

[Antilag]

Just bringing my post to the top looking for any other input.

Thanks

[sailorboy1]

Originally Posted by Antilag

I'm trying to figure out the charging specs since I'm replacing my AGM batteries with these and of course Duracell and Deka's website does'nt give this precious information.

I'm sure I saw a post here giving this information but I cannot find it. There is a post on Duracell branded 6v info - northernarizona-windandsun but someone said the float values seemed high.

Also, is the charging rate really limited to 10% of the bank's capacity?

Thank you.

I have the same batteries and use 14.6 for absorption and 13.2 for float. There's no current limit, the batteries limit themselves.

[Sternwake]

I view manufacturer voltage recommendations as starting points, but rely on the hydrometer to tell me if my absorption voltage is high enough, and held long enough, in my particular usage/recharge regimen.

I had a petulant group31 USbattery whose sweet spot with a solar only recharge was 14.9v absorption and then 15.3v float/Finish for the rest of the afternoon, when cycling 35 to 60AH nightly.

Even then it needed a 16v EQ for ~50 minutes every 14 to 20 cycles.

If it did not get these rather absurd voltages, but just 3 to 4 hours of 14.7v, its SG would quickly walk down each cycle, and be in the 1.220 range after 14 cycles. If I went longer between 16v EQ's then it took many hours at 16v before SG would rise to 1.275. 15.5v or 15.7v EQs would not raise the SG to the maximum. It needed 16v. I thought this was ridiculous, but witnessed it half a dozen times. 15.7 for 4 hours could not do what 16v could do in 1.

I wound up getting nearly 500 deep cycles from that battery before taking it from service. The cell closest to the (-) post was heating up at the bottom.

This battery is still being lightly cycled, as a 12v source in my workshop. No EQs in a year. Surprised really.

[Antilag]

Thank you sailorboy and Sternwake

[donradcliffe]

In the link, the east penn guy says the duracell is the same as a deka GC15, which is FLA battery. Duracell does market a FLA GC2 battery, but their GC2 AGM is more like the deka intimidator.

There is some info on the intimidator charging which give the bulk rate at 14.4-14.6v, but no float recommendation.

Deka Marine Intimidator Series model GC2

In looking around, I also found this news on the duracell agms, which you probably don't want to hear

6V house batteries are deformed after 6 months use!! - Page 3 - iRV2 Forums

[Antilag]

Thanks Donradcliffe, but the Duracell I'm looking at are the FLA GC2 not the GC2AGM. I guess I will contact the manufacturer to see what numbers I can get from them.

[Maine Sail]

Originally Posted by Antilag

I'm trying to figure out the charging specs since I'm replacing my AGM batteries with these and of course Duracell and Deka's website does'nt give this precious information.

I'm sure I saw a post here giving this information but I cannot find it. There is a post on Duracell branded 6v info - northernarizona-windandsun but someone said the float values seemed high.

Also, is the charging rate really limited to 10% of the bank's capacity?

Thank you.

The Sam's East Penn made Duracell GC2 is a Deka GC-10 with a Duracell Sticker. The Sam's EGC2 is a Deka GC-15 with a Duracell Sticker.

The recommendations from East Penn, for that battery, in a cycling / off-grid application are. (Note: floats are higher in off-grid than typical golf cart use).

At 12V:

Max Charge Current = 30% or less of Ah capacity (20 hour)

Absorption Voltage = 14.4V - 14.7V
Absorption End Point = Current change over 1 hour period of less than 0.1A
Max Absorption Time = 12 Hours

Float Voltage = 13.8V - 14.1V
Float End Time = No Limit

Equalization = 15.0V to 15.3V
Equalization End Point = Current change over 1 hour period of less than 0.1A
Max Equalization Time = 12 Hours

Temp Compensation = -.018V for every degree °C rise above 25C

Note:

For dock charging you may want to compensate float down to 13.4V to 13.6V the guidance above is for off-grid or deep cycling applications where the batteries are cycled daily.

Stick to the 14.7V end of the absorption range and the batteries will do much better if they are cycled while cruising.

[Antilag]

Thank you very much for your input Maine Sail!

[Yeti]

I've had the Sam's club GC2 x 4 on my boat for right at 4 years now plus a group 27 reserve. The boat is on a mooring in SD 24/7/365 and I keep the batteries up with a solar system. The solar system is a 225 watt panel mounted flat over the bimini that is controlled by a Morningstar Sunsaver MPPT with the temperature sensor.

My usual voltages as I see them through a link 1000.
Absorption 14.4
Float 13.8
Equalization 14.65

I often wonder if I should get the programming tool and bump the absorption and EQ points a little higher to like 14.7 and 14.9 as I wonder if they are slowly sulfating but I never have as the batteries seem to be doing quite well still. The batteries do get lightly cycled everyday as I leave the fridge on 24/7 but when I do stay overnight on the boat the usual voltage in the morning before first light is around 12.55 - 12.6 with the reserve sitting at 12.75 - 12.8.


I do check the cells with a hydrometer every few months and all cells seem equal and at the right place. I do also wonder though if I'm getting an accurate reading as my batteries are never really at a "resting state".