Stachi:
So how does the battery in my vehicle get charged then. The alternator and regulator does it, right?
Actually, I don't see any dis-advantage to using a jump-box, but I have never had any issues with jumper cables and two cars. I suspose that if both batteries were borderline, then the alternator might get a whipping, but is it possible that if you asked anyone whose car was in questionable shape, that they might have provided a jump. (People who carry jumper cables often do so because their vehicles are about one step from the grave yard. I know that when I did, it was because my vehicle was a piece of crap and often would not start anyway. Now that I have a decent vehicle, the cables hang in the garage. These same people often do not have a clue of the proper way to get or give a jump.)
Also, I think that when the vehicle is at idle, the alternator will put out a lower voltage. If correct, this will result in lower current, not higher.
In addition, as far as the jumper box, I see two possible concerns.
1. You do need to maintain them and make sure they are kept charged.
2. They are intentionally kept small, light (and cheap). This is as if you were trying to start your car with half a battery (cranking current wise, not voltage wise). That tends to limit the available time that you can run a starter, especially when the jumper box is cold from the trunk (like it usually is when someone needs a jump.) Why would I keep it in the trunk?
Because I have a good battery charger (actually 2) with an engine start function sitting in the garage at home and so the jumper box is worthless there. By the way, that same cold temperature tends to help protect the alternator from excessive heat rise.
TerryMSU
