Re: [Amel Yacht Owners] Wet Cell Batteries
Hi Duane, I also have the DEKA group 31 Marine Master batteries (DC31DT) , installed December 2016. I am not an expert, but can only relate my specific experience.toggle quoted messageShow quoted text
After 6 mos on the hard in Trinidad this summer I was down to 1mm of electrolyte over the cells. It took over 3 gallons to get the 12 batteries back to the mark. Initially, 5 of the batteries tested "bad" with very low CCA results and overnight the voltage would drop to 24.6- 24.7 volts with only about 45 amp hrs consumed.
But over time, with "excercise" they have regained some performance. They charge well, and now test over 650CCA per battery, and the fully charged electrolyte SG ranged from 1.240 to 1.260, with most at 1.250. And the drop in the SG in the over night is about 0.010. Last night we used 55 amp/hrs overnight and the voltage was 24.9 at 6:30am. I am trying to see if I can recover a bit more performance.
I have 405 watts of solar. The MPPT is set to 28.2 absorb and 27.2 float. I think 27.6 might be a bit high. When I left to boat on the hard with no load it would still start each day with 28.2 for an hour, that was not good. And by my calculations, even the 27.2v float was to high for the hot on shore temperatures.
DEKA does have a pretty good manual for care for their industrial batteries, and they also answer their technical support phone +1 610 682 4231.
Here are some of the specs that they gave me:
- bulk/absorb - up to 29.2v
- float - 13.5v
- equalization - 31.5v until voltage stabilizes
I also have the Dolphin chargers without equalization capability. For me, it seemed that discharging the bank down to about 80 - 85% of the theoretical capacity and then fully recharging with the 100amp charger gave me noticeable improvement in overnight voltage drop.
Perhaps that helps.
Regards, Dan Carlson on sv BeBe, SM#387