"CWLee" wrote in message
m...

Using a handheld voltmeter, at the battery on my car, I get a reading of
around 12.5 volts. When I use the same voltmeter at the cigarette lighter
socket and at the accessory outlet, I get a reading of only around 4.5
volts. (The latter reading jumps about a volt if the engine is running.)
Why aren't the readings on the cigarette lighter socket and the accessory
outlet pretty much the same as at the battery? (Both the cigarette
lighter socket and the accessory outlet work just fine to recharge my
laptop computer.)

Enlightenment appreciated.


Assuming the sockets work as you say, you may have a bad connection of your
voltmeter test probes at the point you are trying to measure. The voltage
should jump a volt or two with the motor running as it takes more voltage to
charge the battery than what it is normally.

I have also seen bad connections on the wiring that measured the normal
voltage, but under load the voltage would drop. That is not your case.