Greetings all
Just landed on my feet!! Tonight I get to unload 21 12v 100amp-hr UPS batteries from my trailer having picked them up yesterday. They aren't very old (couple of years I think) so should have plenty of their 10 year life left. Perfect timing as the 8 golf cart style batteries I bought new 4 years ago have just about died
These AGM batteries came out of an 80KVA UPS that was operational until last week so they all have a reasonable state of charge (all 13.2<>13.3 volts) apart from one which is sitting at 12.95V.
I don't have a great deal of experience with AGMs so the question is, when I'm doing a *Bulk Charge*, what should I limit the charge voltage to or should I allow them to sit at whatever voltage they like provided the charge current is within spec. I realise that once I get to *Absorption Charge* I should limit the voltage and just keep an eye on current, similarly *Float Charge* should be constant current with an eye that the voltage doesn't get too high.
I want to make sure I characterise these batteries before I wreck them!! I'll be using a charge counter to track where in the charge cycle they are, the problem being they are AGM so I can't check the SG to see what the starting point is. What I *don't* want to do is just go out and buy a controller where I have no knowledge of the algorithms being used - I trust my own software development skills better than that!!
This is my starting point for moving from wind to solar power so I'd like to get it right - there is another few KW of Oztules panels about to take shape