Jul 10, 2011 12:26 am
Re: gel batteries at different volts
dear tom,
i beg to differ. i think perhaps an occasional (once a year?) deep discharge may not be terribly bad. but to drain them basically all the way down will do much more harm than good. these are lead acid, not nicad/nimh like the batteries on a cordless phone, or lithium as per a cell phone.
my guess is that they are not getting enough charge. this is why we have an equalizing charge, to bring all cells up to a full (over)charge.
on the plus side, sealed batteries (sla) are maintenance free. the down side they are maintenance free (unmaintainable). they also dont take an equalization charge well (irreversible offgassing, explosions, etc.). without looking, i think james said that he has had these for about 3-4 years. while thats not an exceptionally long life span, i would not expect a whole lot longer for sealed batteries under regular, moderately strenuous charge/discharge cycles (daily use, 30-40% dod, occasional undercharging).
you can apply an equalization charge, but it must be very carefully applied, at the absolute minimum voltage that will create an overcharge condition, and not for very long. i would hope that you do a little more homework to figure out for exactly how long and how much voltage to apply before doing so, if you should choose to take any of my advice (god help you!). -m