Key takeaways
- DC current ≈ inverter watts ÷ battery volts ÷ 0.85 efficiency.
- Surge can be 2× running watts for a second or two.
- 12V 100Ah ≈ 1,000W; 12V 314Ah ≈ 2,000W; one 24V 100/200 ≈ 2,000W.
- For 3,000W, use two 24V packs in parallel or a 48V system.
1. The current is the limit
| Inverter | 12V DC current | 24V DC current |
|---|---|---|
| 1,000W | ≈98A | ≈49A |
| 2,000W | ≈196A | ≈98A |
| 3,000W | ≈294A | ≈147A |
These are running currents at 85% efficiency. Add the inverter’s surge rating for motor and compressor starts; a 2,000W inverter may pull close to 4,000W for a moment.
2. Which model fits which inverter
| Model | Continuous | Practical inverter | Note |
|---|---|---|---|
| 12V 100Ah | 100A | ≈1,000W | A 2,000W inverter will exceed the BMS under load |
| 12V 314Ah | 200A | ≈2,000W | Good match for a 2,000W inverter |
| 24V 100Ah / 200Ah | 100A | ≈2,000W | Same current, less cable loss than 12V |
| 2 × 24V 200Ah parallel | 200A total | ≈4,000W | Within 1S4P; check cables and fuse |
For a 3,000W inverter, one 24V 200Ah is not enough at 100A continuous (about 2,560W). Use two 24V packs in parallel, or move to 48V with four 12V models in series.
3. Surge and low-voltage cutoff
Motors, pumps and compressors can draw two to three times their running current at startup. The inverter’s peak rating, the BMS surge rating and the cable voltage drop all matter. A long, thin cable can make the inverter see low voltage and shut down before the battery is empty.
4. Cable, fuse and idle draw
- Size the cable for the surge current, not the running current; keep the run short.
- Fuse at the battery positive and check the fuse rating against the cable.
- A 2,000W inverter may draw 20–40W idle; switch it off when not in use.
- Use pure sine wave for motors, fridges and electronics; modified sine can overheat some loads.
Common questions
Can I run a 3,000W inverter on one 24V 200Ah?
Not at full load. One pack is 100A continuous, about 2,560W at 25.6V. Use two packs in parallel (1S4P) or a 48V system, and check the surge and cable size.
Will a 2,000W inverter run from a 12V 100Ah?
It may start a small load, but at full load the inverter pulls about 170A, above the pack’s 100A continuous rating. Use the 314Ah or a 24V pack for a 2,000W inverter.