Join Date: Jun 2008
Location: Tampa, FL
Thanked 32 Times in 32 Posts
Rep Power: 9
Re: Voltage puzzle
Actually, the "resting" voltage of a lead-acid battery is quite a good indicator of its state of charge. It needs to be completely disconnected from any charging or discharging source for at least 12 hours, though, and 24 hours is better. Most people, however, check the voltage far too soon after charging or discharging to get useful information.
If you are saying, davidpm, that after 24 hours with absolutely no charging or discharging, the battery voltage was 12.9, then it is either very nearly fully charged, or your voltage meter is not reading accurately.
Last edited by denverd0n; 05-31-2012 at 09:06 AM.