Battery Voltage Chart
Quick reference for Li-ion, LiFePO4, lead-acid, AGM, gel, 12V battery packs and NiMH cells. Use it to estimate state of charge from rested battery voltage.
🔋 Important: Voltage charts are approximate. Measure after the battery has rested, and avoid judging battery percentage while charging or under heavy load. For solar systems, use this with the Battery Life Calculator, Off-Grid Solar Calculator and Inverter Battery Runtime Calculator.
🔋 Common battery voltage reference at a glance
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🔋 Li-ion Cell Voltage Chart1S cell
Typical lithium-ion cell values. For packs, multiply by series count: 3S full ≈ 12.6V, 4S full ≈ 16.8V.
🟢 LiFePO4 Voltage Chart3.2V cell
LiFePO4 has a very flat voltage curve. A 12V pack is usually 4 cells in series; full charge is about 14.6V.
🚗 12V Lead-Acid Battery ChartRested
For flooded/AGM/gel batteries, voltage should be measured after rest. Charging voltage can be 13.6–14.8V depending on stage.
☀️ 12V LiFePO4 Pack Chart4S pack
Useful for solar batteries and inverter systems. Always follow the BMS and battery manufacturer's low-voltage cutoff.
| Battery Type | Approx. 100% | Approx. 50% | Approx. Low | Notes |
|---|---|---|---|---|
| Li-ion / LiPo 1S | 4.20V | 3.70V | 3.0V | High energy Common in 18650, phone, drone and RC packs. |
| Li-ion pack | 4.20V × S | 3.70V × S | 3.0V × S | Multiply cell voltage by series count. |
| LiFePO4 cell | 3.45–3.65V | 3.26V | 2.5–2.8V | Flat curve Voltage alone is less accurate for SOC. |
| 12V LiFePO4 pack | 13.6–14.6V | 13.0–13.1V | 10.0–11.2V | Usually 4 cells in series. |
| 12V lead-acid | 12.7–12.8V | 12.1–12.2V | 11.8V | Rested Used in cars, UPS, solar and backup systems. |
| 6V lead-acid | 6.35–6.4V | 6.05–6.1V | 5.9V | Half of 12V lead-acid values. |
| 24V lead-acid bank | 25.4–25.6V | 24.2–24.4V | 23.6V | Two 12V batteries in series. |
| NiMH cell | 1.40–1.45V | 1.20V | 1.0V | Common AA/AAA rechargeable cells. |
📋 Quick Reference
12V Lead-Acid
Full rested12.7–12.8V
About 50%12.1–12.2V
Low≤11.8V
LiFePO4
Cell full3.65V
12V pack full14.6V
Flat region≈13.0V
Li-ion
Cell full4.20V
Cell nominal3.6–3.7V
3S full12.6V
📚 Battery Voltage Notes
Rested voltage is more useful Check voltage after the battery has rested without charge/load. Under load, voltage sag can make the battery look emptier than it is.
LiFePO4 is very flat A LiFePO4 pack may stay near the same voltage over a large SOC range. A BMS or shunt monitor gives better accuracy.
Temperature changes voltage Cold batteries often show lower available capacity and different voltage behavior. Lead-acid charging voltage is temperature-sensitive.
Do not over-discharge Deep discharge can damage batteries. Follow the battery datasheet, BMS cutoff and inverter low-voltage settings.
Battery Voltage Chart
This battery voltage chart helps estimate state of charge for common battery chemistries, including lithium-ion, LiFePO4, lead-acid, AGM, gel and NiMH batteries. It is useful for solar battery banks, UPS systems, inverter batteries, electric projects and electronics testing.
Why battery voltage is only an estimate
Battery voltage changes with load current, charging state, temperature, battery age and internal resistance. A rested open-circuit voltage reading is better than a reading taken while the battery is charging or powering a heavy load.
❓ Frequently Asked Questions
A rested 12V lead-acid battery is typically around 12.7V to 12.8V when fully charged. While charging, it can be much higher depending on the charger stage.
A 12V LiFePO4 battery is usually a 4S pack. Full charge is commonly around 14.4V to 14.6V, and the middle of the discharge curve often stays near 13.0V to 13.2V.
Yes, but only approximately. It works better after the battery has rested. For accurate percentage, use a BMS, shunt monitor or coulomb counter.
Around 11.8V rested is already deeply discharged for many 12V lead-acid batteries. Regular deep discharge shortens battery life.
Voltage drops because of internal resistance, cable resistance and load current. The higher the current and the weaker the battery, the more voltage sag you will see.
The state-of-charge voltage range is similar, but exact charging and float voltage settings can differ by battery manufacturer and type.