BnB,

Why do you have to jumpstart so often? Maybe you should invest $60 in a new battery at AutoZone. I just bought one this week, after another Exide failed. I will never buy an Exide again.

If you jump to another car, you can't hurt anything if you don't have its engine running because you would just have the nominal voltage of the battery, not the voltage generated by the alternator.

Probably the open circuit of your charger is so high is to make up for the voltage drop under starting current load.

P E H