Living of the grid and solar panels?

Set your lights on auto so that they aren't drawing power when you're not using them (or swap them out for candles or lanterns, which don't use power at all), and upgrade your appliances and computer to be energy efficient.

I do find computers take a lot of power. I had a couple of college roommates living off the grid, and the power was never functioning when they needed to write their term papers. I ended up having to take them to campus and having them write their papers on computers in the Student Union. I tried to fix this problem by putting multiple solar panels on the roof of their house, but since it was often cloudy or rainy (they were living in Windenburg), it didn't help much. Finally I added a few of the windmills that don't need to be upgraded to the roof, and that helped a bit (although they also need the wind). In general, my advice would be not to have a computer on an off the grid lot, or to find a work around, such as buying a laptop instead and taking your sim to the library for a few hours when they need to use it. My off the grid sims tend to be low level athletes, gardeners, cooks and artists, careers that doesn't need to use too much technology.

So weather affects them?
I didn’t think about upgrading the items! I did some research and found that the fridge is a big culprit since it’s on all the time, upgrading it helped alot it seems.