Deep discharge

[fabricator]

I have a battery question, I have been flying my 17 on a test tower with four new johnson controls deep cycle batteries, I have a 12 volt headlight across each battery to use as a manual dump load, the other day the batteries were getting to around 56-57 volts so I shut the mill down and turned the lights on, and went about my business, after a long while I remembered the lights were on and went to check on them, they were down to an orange glow and my DMM said they were down to 39 volts, they are back up to 46-47 volts but are taking a long time to get above 48, I've never dealt with this kind of battery bank, is this normal after a deep discharge?

[wpowokal]

simple answer yes it is normal, they are still talking bulk charge, what you don't tell is how much current they are receiving and how long in hours/ days a long time is. If this works there is a graph that illustrates a typical charge curve just multiply the volts by 4 for your bank.

http://www.arttec.net/Solar_Mower/4_Electrical/Battery%20Charging.pdf

allan

[fabricator]

Well that is part of the problem, I don't have an ammeter hooked up yet, we had some good wind today, I think it it would have been around 5-6 amps for most of the day, the bank is back up over 48 volts now.