Top Charge Question

[joelmyer]

Well it's been 33 days since I've seen hookups. The 245 watts of solar gets the Trimetric into the positive AH from full most days.

Specific gravity has dropped. A couple of cells to 1250, and a couple to 1260.

There are 4 x 6 volt batteries in two banks.

So at sunset tonight I'll switch to bank 2 and hit bank one with an hour of 15.3 volts from the Megawatt.

And then.... Bank 1 will have a higher voltage than bank 2. Is it ok to just switch back to 1+2? The voltages will equalize pretty quickly.

Or should I just stay on bank 2 for a week, switch to bank 2 and zap bank 1 with the megawatt? Then I can check weekly and zap the weaker bank as required.

The batteries are 232 AH so total nameplate rating is 464. Morning AH from full is averaging -30 so the batteries are living in their top 10%.

Joel

[jrnymn7]

I had my bank split into two strings for a few months this past fall. And when I attempted to go back to series/parallel, I found I had to get the two strings to a very similar resting voltage, before they would play well with each other. For example, the two strings would continue to maintain different resting voltages, and the string with the higher voltage tended to hog most of the charge. It was worse, the further apart they were in resting voltage. And I'm talking only about .03v difference. Now they're sitting dead even, throughout.

[wa8yxm]

Short answer: YES, it is ok. Only possible danger is a blown fuse, and that is not likely.

[MEXICOWANDERER]

Unfortunately a formula must be used. 5% of amp hour rating in amperes until voltage rises to 15.0

For 6 of your cells, 11-amps constant current would be appropriate. But top charging is designed to minimize sulfation not undo it. Equalization is needed. So continue on to 16.0 volts if need be. This means 11-amps at 15.8 volts should going that high be necessary. This is where most apparatus falls flat on it's face.

[mena661]

Just run off of one bank until you get the other full then switch to the full bank. Swap back and forth as required. There is another more complicated way too.