>From the Battery FAQ at www.windsun.com
On the table below, you have to be careful that you are not just measuring
the surface charge. To properly check the voltages, the battery should sit
at rest for a few hours, or you should put a small load on it, such as a
small automotive bulb, for a few minutes. The voltages below apply to ALL
Lead-Acid batteries, except gelled. For gel cells, subtract .2 volts. Note
that the voltages when actually charging will be quite different, so do not
use these numbers for a battery that is under charge.
Voltage at DOD
Here are some no load typical voltages vs depth of discharge.
(figured at 80% max discharge and 77 degrees F)
1% = 12.91 Volts.
10% = 12.8
20% = 12.66
30% = 12.52
40% = 12.38
50% = 12.22
60% = 12.06
70% = 11.90
80% = 11.70
90% = 11.42
100% = 10.50.
Regards
Jobst