The inverter can be changed to sine wave

When a pure sine wave inverter isn't necessary if you have electronic devices that use rectifiers to convert AC to DC, then you probably don't need a pure sine wave inverter. However, most electronic devices run just fine on a modified sine wave. How do you turn a square wave into a sine wave?

DC Power Input: The pure sine wave inverter is connected to a DC power source, such as a battery or a DC power supply. Pulse Width Modulation (PWM): The DC power is converted into a high-frequency AC signal using Pulse Width Modulation (PWM).

In summary, pure sine wave inverters are generally considered to be more suitable for powering sensitive electronic devices and appliances, while modified sine wave inverters may be a more cost-effective option for basic power needs. When Do You Need a Pure Sine Wave Inverter?

Devices without AC motors tend to work as expected with modified sine wave inverters, and any device with a rectifier cleans up that rough AC wave as it turns it into DC power. So lamps, TVs, and other devices are OK for modified inverter use. The major advantage of modified sine inverters is that they are less expensive than pure sine models.

Conventional AC power is produced by rotating machines (alternators) that produce a smooth alternation, like that of a pendulum. It is described mathematically as a “sine wave”. It is the ideal waveform for the transfer of AC power. An inverter is an electronic device that converts DC to AC through a switching process.

If your electronics don't fall into either of those categories, then it's extremely unlikely that a modified sine wave inverter will do any damage. So while a pure sine wave inverter is safe for use with a wider range of devices, the greater cost associated with pure sine wave inverters isn't always worth it.