Battery Trickle Charger

[korver]

Hello everyone,

I'm having a problem with a battery charger that charges via the cigarette lighter. Whenever I plug it in, my speedometer tips to 40 mph and the miles start advancing. Imagine if I left it in all night! I'm thinking there is a short somewhere or a grounding problem. Anyone have a similar problem or have any advice? Thanks.

J. Korver

[Wil Ferch]

Some cars have the cig lighter circuit active when the car is "off"....( these lend themselves to trickle chargers plugged in there)...and some cars have the cig lighter circuit dead when the car is off....anything plugged into it won't charge anything.

Porsche did it both ways depending upon model and year. Might want to post yours so you can get proper help from some of the folks here. I don't have a clue as to your particular problem,..have never seen such a thing.

- Wil

[Por_sha911]

Gosh, if you could just reverse the polarity, you could have a low mileage car in no time!

[korver]

It's a 1982 911 SC. Any ideas?

[David E. Clark]

Not much help here but you obviously have a short. You might try following the connection between the cigarette lighter and the speedometer with a short circuit finder like this one sold by our host. I've never heard of a problem like yours so I can't make a guess as to why it appears to the speedometer that the car is running. I guess us old guys with mechanical speedometers have one thing to be thankful for. Good luck!