Fubarberry , 10 hours ago

Having generators together with the solar panels is completely normal.

From what I understand the trailers were supposed to provide backup power to cell towers, sporting events, etc. Solar can provide small amounts of “free” power but you lose it when it’s cloudy or dark. It also can’t meet high power demands for when a lot of power is needed. Normally these problems can be offset by having more solar panels and large battery banks, but that’s not a good option for a trailer mounted backup system.

A diesel generator can provide a huge amount of power in a comparatively small package, making it a much more reliable power source. You can provide backup power with just a generator (no solar), but you usually can’t provide enough backup power with just solar. For example, my local emergency services has a 200kw trailer mounted generator they can use if their main generators are down. A solar system capable of generating that much power would need to be at least 115 sq ft, and would require a ridiculous lot of batteries to make the power available consistently.

Any off-grid set up will usually combine solar and generators, they both have advantages. But a trailer mounted generator can easily be 100s of KW, which isn’t a feasible amount of power to have be portable with solar.