Our Rolls 2HHG325 wet cell batteries have given us over 8 years of reliable service
on our live aboard catamaran
. Now, however, they are failing to hold a charge overnight, even after several equalization
These batteries are composed of 6 individual 2.1V cells bolted together in series, with Hydro Caps; we have two for a total of 650 AH.
Prior to equalization
, the SG of several cells appeared low: 1.160, 1.200, and 1.210. After equalization and rest, these cells came up to 1.210, 1.230, and 1.260 respectively. The other cells are all in the 1.250 to 1.280 range after equalization.
Since the batteries are this old, and since we are located in a place where we cannot get new batteries until we return to Cartagena
this spring/summer, I am considering taking all the cells apart from each other, measuring the SG of each along with the open circuit voltage, and then combining the best 6 into just one 325 AH battery
that hopefully will hold a charge better than the original arrangement of two in parallel. My thinking is that perhaps two or more of the cells are so bad as to be dragging down the whole bank. Granted, we will halve our capacity, but we don't have huge DC loads; our charging
system consists of 300W of solar panels
and a KISS wind generator
...plenty of sun and wind
here in the San Blas most of the time.
Does this sound reasonable; is it worth the effort to try it? I know one should not mix "old" with "new", but in theory this would not be doing that since all the cells are the same age and have had the same maintenance
over the years.
Or, should we leave it as is and limp through this season, running the engine
more on those cloudy days? We would keep the worst of the cells not being used, just in case this "new" combination of cells proves to be no better.
BTW, the price
of new Rolls cells (I dont' need the Hydro Caps and Blue Sea boxes again) is $143 USD each, (times 12!) plus shipping
360 lbs at $1.65/lb...do the math; not cheap! Thinking of replacing with new Trojan T-145's when back in Colombia
, but that's not cheap
either at over $300 each!
Thanks for your help with this.