Here is a general chart of the battery charge:
http://rvroadtrip.us/library/12v_system.php
State of Charge | 12v Battery | Volts Per Cell |
100%
| 12.6+
| 2.12
|
90%
| 12.5
| 2.08
|
80%
| 12.42
| 2.07
|
70%
| 12.32
| 2.05
|
60%
| 12.20
| 2.03
|
50%
| 12.06
| 2.01
|
40%
| 11.9
| 1.98
|
30%
| 11.75
| 1.96
|
20%
| 11.58
| 1.93
|
10%
| 11.31
| 1.89
|
0
| 10.5
| 1.75
|