Comment by adrian_b

Power electronics shall never be connected to the "Internet".

Any such installations of solar panels, batteries and the like must be interconnected only in a private network without Internet access.

For remote monitoring and control a proxy mini-PC must be used, to which one should use an authenticated and encrypted connection.

For any competent person, this is trivial to do today, to ensure that even if some electronic device includes a backdoor for its vendor that backdoor cannot be accessed.

If there exists any kind of wireless connection provided by the vendor for a device, it must be disabled, e.g. by removing any internal or external antennas. Unlike wired connections that can be filtered externally, wireless connections cannot be secured.