The below figures are in volts
| State of Charge | Sealed or Flooded Lead Acid | Gel battery | AGM battery |
| 100% | 12.70+ | 12.85+ | 12.80+ |
| 75% | 12.40 | 12.65 | 12.60 |
| 50% | 12.20 | 12.35 | 12.30 |
| 25% | 12.00 | 12.00 | 12.00 |
| 0% | 11.80 | 11.80 | 11.80 |
Ref; http://www.energymatters.com.au/components/battery-voltage-discharge/
Other notes;
11.5v = 50%
12v = 70%
12.8 – 128v = 100%
12.3v / 12.4v – 13v
Solar panel should be +5v on top of the battery voltage