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RVing message boards => Tech Talk => Solar => Topic started by: Desert_Rat on January 09, 2017, 12:10:37 PM

Title: Battery Bank charges
Post by: Desert_Rat on January 09, 2017, 12:10:37 PM
So Deca CS tells me that 50% charge on my GC15's http://www.dekabatteries.com/assets/base/0248.pdf (http://www.dekabatteries.com/assets/base/0248.pdf) is reflected with 24.4v charge on bank, and 100% charge is 25.2. That doesn't sound right to me because 24.4 is still over 24v rating. I would think that 50% depletion is less then that? maybe around 22v or something? Should I take her word as word? Without my MPPT which isn't installed yet, is there any other way to properly determine depletion?
Title: Re: Battery Bank charges
Post by: Gary RV_Wizard on January 09, 2017, 06:02:50 PM
Sounds about right. 50% on a typical 12v battery is about 12.06v.

For batteries built of multiple standard cells, 2.01-2.05 volts per cell is widely accepted as the 50% mark, and 2.1 volts/cell is 100%. I'd call it an even 24v for 50% on 12 cells, since it's only a yardstick anyway. No need to be over-precise.
Title: Re: Battery Bank charges
Post by: Desert_Rat on January 09, 2017, 06:29:23 PM
Thanks for input
Title: Re: Battery Bank charges
Post by: AStravelers on January 11, 2017, 07:34:04 AM
So Deca CS tells me that 50% charge on my GC15's http://www.dekabatteries.com/assets/base/0248.pdf (http://www.dekabatteries.com/assets/base/0248.pdf) is reflected with 24.4v charge on bank, and 100% charge is 25.2. That doesn't sound right to me because 24.4 is still over 24v rating. I would think that 50% depletion is less then that? maybe around 22v or something? Should I take her word as word? Without my MPPT which isn't installed yet, is there any other way to properly determine depletion?

Go to this link http://www.marxrv.com/12volt/12volt.htm (http://www.marxrv.com/12volt/12volt.htm) about the 12V side of RV's.  Yes, I know you are 24V, but you are still using lead acid batteries, so just double the voltages.   Scroll down to see the chart about state of charge (SOC) and the corresponding voltages.