Planning on using a diesel or gasoline powered generator to recharge your batteries in a collapse scenario is a really STUPID idea. See below for a common sense applications of mechanical leverage and advantage. Young humans using mechanical leverage are RENEWABLE ENERGY back up generators
Here's an idea:
Ride one of THESE inside a large wheel that generates electricity.
Now that's a REALLY cheap generator that DOES NOT use fossil fuel POISONS. When you are in a hole, you are supposed to stop DIGGING!
There will ALWAYS be energetic types (while they are young, of course
) available to generate electricity after the collapse of civilization. That is, until the big homo sap die offs occur...
But let's take this in chronological order, shall we? There are STILL over 7 billion of us around, and a HUGE chunk of that population is young and will soon work for food.
It's gonna be REAL HARD to find distillates after the collapse, comprende amigos? Please discard your irrationally optimistic views of back up fossil fuel generator help for you and yours. They are NOT going to work in a collapse for more than a few months.
When the common people, post collapse and well into the global warming caused vicious weather, FINALLY do the math on cause and effect from fossil fuels, you can expect a lynch mob to visit you if they get wind that you are STILL using fossil fuels...