For anyone who’s confused as to how this sorcery could work, it’s due to the chemistry/physics of the battery. As batteries discharge, there is more crystal growth of the electrolyte. Crystals can store mechanical energy like a spring, while the electrolyte in solution absorbs energy. It’s like dropping a water balloon vs dropping a solid rubber ball.
It depends on the freezer. Some are “garage rated”, so they are designed to operate in a greater temperature range, while normally, they should only be used at room temp (plus and minus reasonable swings). Check your manual to see if it gives an operating range. I suspect that the more important factor is when it’s too hot outside for the level of insulation and compressor to keep up with, but too cold could be a problem