Lead Acid Batteries (12v)
The nominal voltage of lead acid is 2 volts per cell, however when measuring the open circuit voltage, the OCV of a charged and rested battery should be 2.1V/cell. Keeping lead acid much below 2.1V/cell will cause the buildup of sulfation.
A lead-acid battery's theoretical voltage is 2 V for each cell. For a single cell, the voltage can range from 1.8 V at full discharge, to 2.10 V in an open circuit at full charge.
Charging
The correct setting of the charge voltage limit is critical and ranges from 2.30V to 2.45V per cell or 13.8V to 14.7V for a 12V battery.
Power Levels
| Percentage | Cell Voltage | Voltage |
|---|---|---|
| 100 | 2.12 | 12.73 |
| 90 | 2.10 | 12.62 |
| 80 | 2.08 | 12.50 |
| 70 | 2.06 | 12.37 |
| 60 | 2.04 | 12.24 |
| 50 | 2.02 | 12.10 |
| 40 | 1.99 | 11.96 |
| 30 | 1.97 | 11.81 |
| 20 | 1.94 | 11.66 |
| 10 | 1.91 | 11.51 |
| 0 | 1.80 | 10.8 |
Batter Capacity Meter Readings
These readings were taken from my batter capacity meter.
| Percentage | Voltage |
|---|---|
| 12.9 | 88 |
| 12.8 | 85 |
| 12.6 | 79 |
| 12.5 | 73 |
| 12.4 | 70 |
Extrapolating from above
| Voltage | Percentage |
|---|---|
| 14.7 | 100 |
| 90 | |
| 80 | |
| 12.4 | 70 |
| 60 | |
| 50 |
References
| Reference | URL |
|---|---|
| Wikipedia | https://en.wikipedia.org/wiki/Lead%E2%80%93acid_battery |
| Charging Lead Acid Batteries | https://batteryuniversity.com/learn/article/charging_the_lead_acid_battery |