Battery and charging
What is a pure sine wave inverter?
An inverter converts direct current from a battery (12 V, 24 V, or 48 V) into 120 V alternating current like a wall outlet. A pure sine wave inverter delivers current as clean as the grid's or cleaner, safe for any device; a modified sine wave inverter is simpler and can cause trouble with motors and some appliances.
Pure versus modified sine wave
Grid power has a smooth, sine-shaped wave. A modified sine wave imitates it with steps. Lights and simple chargers usually run fine on it, but motors, fridge compressors, pumps, and some electronics may overheat, hum, or fail.
With a pure sine wave inverter, every appliance runs as it would on the grid. That is why it is the recommended choice for refrigerators, computers, and sensitive equipment.
How to size one
Continuous power (W) must cover everything you will run at once. Peak power must handle motor startup: a compressor can draw several times its normal load for a moment.
The inverter stores no energy: backup hours depend on the batteries and their capacity. Many home inverters also recharge the batteries when grid power is available (inverter-chargers).
What to check before you buy
- For fridges, air conditioners, or computers, choose pure sine wave.
- Add up the watts of everything that will run at the same time and leave room for startup surges.
- Size the battery separately: it determines how many hours the backup lasts.
Guides to help you choose
Frequently asked questions
It may work, but the compressor tends to run hotter and noisier, which shortens its life. Pure sine wave is recommended for refrigerators.