Here is a table of the rough state of charge of a 12V sealed lead acid / AGM battery at different open circuit / no load voltages.
| State of charge | 12V battery | Volts per cell |
| 100% | 12.7 | 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% | 11.90 | 1.98 |
| 30% | 11.75 | 1.96 |
| 20% | 11.58 | 1.93 |
| 10% | 11.31 | 1.89 |
| 0% | 10.5 | 1.75 |
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