The fast method for 12V:
Watts ÷ 10 = DC amp current demand
For example, a 1,000W inverter (and supplying 1,000W to AC devices) divided by 10 = 100A of battery current required - this is a rough, rounded-up way of calculating inverter/battery current demands.
The detailed method & different battery voltages:
Watts ÷ battery voltage ÷ 90% (or 0.9) = DC amp current demand
For example, a 1,000W inverter divided by 12.8 (a lithium battery's nominal voltage is 12.8V) divided by 0.9 (90% - inverter efficiency rating) = 87A
For 24V: 1,000W ÷ 25.6 ÷ 0.9 = 43A
For 48V: 1,000W ÷ 51.2 ÷ 0.9 = 22A
Using the above, if you're looking for a TITAN Lithium battery to power your 12V inverter, we recommend:
- Our 80Ah & 100Ah for 1,000W inverters
- Our 120Ah for 1,500W inverters
- Our 150Ah & above for 2,000W inverters
- For anything above 3,000W, we recommend at least two 150Ah in a parallel connection or a higher voltage inverter & higher voltage batteries, or batteries in series
Important to note:
- Inverter efficiency depends on voltage and the quality of the product - 24V and 48V inverters typically are 92-95% efficient.
- Inverters can output up to double their rating for short periods of time - a 1,000W inverter can supply 1,000W continuously but could output up to 2,000W for a short period if required.
- Watts does not change - 1,000W AC is the same as 1,000W DC.
Need to calculate Watts instead?
Watts = Volts x Amps
