[COLVERT]

Originally Posted by alanaslan

This can happen because if you have a pump running when the alarm is set the voltage sensor with in the alarm will pick up power consumption of the pump. surprised it lets you set it at all. Though if it is not sensitive to pick up the discharge when it is fully charged as the battery voltage goes down the amperage drawn will increase the good old V=IR equation you would have been taught at school. Also you should never charge the cars battery is connected to the car. You can blow the diode pack in the Alternator by charging the battery whilst it is still connected to the car. So nothing should should be live when charging the battery.

Whenever I've needed to charge a battery I have never dis connected it from my car or other family members cars for over 40 years now without any problems.

It's the same if you jump start one car from another and leave the donators car engine running. It won't hurt the alternator diodes.

The alternator or charger put around the same voltage into the cars circuitry. The diodes are built to take this. ( approximately 14.4 volts. )


If what you suggest is true the roads would be littered with cars with damaged alternators after a jump start.

( It's a bit of a wives tale that just won't go away.-----)