This allows the battery to be charged from an AC power source such as a generator or the utility. When an inverter is used in a back up power system the battery charger is a key feature of the inverter. If a significant amount of the power being delivered to your battery is coming from a generator, battery charger size may be very important. Having a charger that is too small will require running your generator for too long under a low load to achieve a proper charge. It is most efficient to use your generator to its maximum capacity so you can minimize the running time.
Efficiency varies from model to model and according to the relative load on the inverter.
True sine wave inverters are usually less efficient than modified sine wave inverters. Overall efficiency may be similar due to the energy lost in the harmonics of a modified sine wave, especially when running motor loads. Generators Generators and inverters are an ideal match. An inverter operates small loads like lights and computers more efficiently than a generator. Large, intermittent loads like pumps, power tools and microwaves are also perfect for an inverter, but expensive to operate with a generator.