Thread: 18v powertool battery to start quad

If the generator on the bike isn't working, it wouldn't run for long without a charged battery, if you get more that 5 mins from the bike after a jump start, the generator should be working. Speaking as someone who was an electrician in a previous life, I can say that there are all sorts of ways and means for doing what you are trying to do.
But the two most pragmatic things that have already been suggested are:

1 Small solar panel and regulator.
2 Emergency jump starter pack.

Not a silly idea to go with both. for the emergency jump starter, you could wire a cigarette lighter socket plug onto your bike, this would make it easy to plug in for jump starting. These starter packs can also run a spotlight quite well so it isn't like a PLB that is useless until it is useful.

I wouldn't persist with jump starting from an 18V Makita battery. In due course it may ruin your bike electrics and or the battery.