Misread Trojan Battery Manual

NinerBikes wrote:

landyacht318 wrote:
I've not seen this particular Link before.
I like the "tips on how to maximize your battery life" at the bottom:

As a general rule of thumb, the total amps from your PV panels should be sized between 10% and 20% of the total amp-hours (Ah) of the battery pack.

I deliberately lowered my battery capacity so that my solar can just barely reach 10%.
198 watts for a 130 A/h battery

I've taken some minor grief here and there on this forum for employing this strategy.

So a 210 amp 6v pair of GC-2's should get between 21 and 42 amp/hours capacity from the solar panels, for the day, if I am reading that correctly? I get 6.5 to 7 amps/hour at as close to 15.0V as I can for a Trojan T -1275... and 50% of a 150 amp hr battery is 75 amps to be replaced max, per day. No way I am going to get that kind of output come short days of winter and the sun low on the horizon. Summer time, yes.

I think many are misinterpreting this. I am pretty sure what is meant is to charge at the C10 or C20 the AH rate, ie for a 210 AH battery the MAX charging rate should be 21 Amps (C10) or 42 Amps (C20) That is the charging current in AMPS, not total AMP HOURS. When the batteries are low they will accept for example a max of 42 amps which will reduce as the batteries approach full charge.

On a somewhat related note, my BlueSky solar controller will supply a max of 25 Amps. BUT at that current there is a full volt drop between the controller and the battery because of the long #6 leads so although the battery had only reached 13.8 volts the controller thought they had reached 14.8V and began to reduce the charge voltage. To try overcome this I increased the controller output voltage but this of course allowed the battery voltage to go too high when the current (and thus voltage drop loss) decreased.

The point of this last: Ensure that the solar controller is very close to the batteries or at least use a controller with remote battery voltage sense.