Another way to think of it is this... If you take a jumper box which is a battery in a box, that's rated at 900 peak amps, and 200 continuous, you have effectively hooked up 200+ amps extra. Do you think a jumper box will burn up your bikes electronics?

I mean a jumper box like one of these.


A dead/weak battery should be slowly recharged to hopefully prevent damage to the battery and condition it somewhat. I fast charge on a weak battery will cause problems with the plates inside and lead to more problems. Really you just need a new or stronger battery as someone else said. Or possibly a thinner oil, again as someone else brought up.

 

I've read numerous sources including the instructions with my bike jumper cables that warn against using a running auto to jump start a bike as it can fry the bike electrical system. Car should always be off. Is that because the car's charging system is putting out too many amps or is it because of spikes?. Darn if I know but i don't do it .

I have used an 1150 max amp portable jumper box to jump our bikes with no apparent ill effects.