andrew911

I believe this is called the Porsche Charge-o-mat. I have a battery drain problem, and am trying to isolate the draw. If I can fix my car and use the Porsche battery maintainer that plugs into the cigarette lighter, does the red light on the wall outlet adapter ever go out when the battery is fully charged? Not clear in my instruction booklet that came with it.

In the past I've had battery maintainers that a charging light would go off at full charge, then come one for a few seconds every 10 minutes or so since things like the clock and radio memory use a little power, but they wouldn't charge constantly. My red light stays on all the time now I think because of the relatively high draw, but then again I don't know if it Porsche charger light normally would go out, or if its designed to just stay on all the time.

Thanks!
Andrew

JW Hubbers

The red light in mine stays on all the time.

Cheers,

JW

The Eagle

Hi Andrew, I'm using that kind of charger since two years now; the red light goes out when the battery is fully charged. I know this for sure 'cause the red light is always out when return to my car the next day. I bought the charger at the same time that I bought a new battery.
PS; I've got my doors locked and the alarm is set.
Greetz
The eagle

AndrewM

Andrew,
I read the instruction booklet on mine cause I had the same question. The light on mine stays on all the time. (to let you know it's hooked up, according to the manual) I don't think that little LED light takes up much power.
Drew
89 C4
86 930

Drew_K

I've used the same charger for at least a year, and the red light does go out once the battery is sufficiently charged. It will come back on when necessary. For example, if the battery is charged (light off), and I open the door the red light comes back on.

I don't have the manual for mine, but I remember it saying that the red light comes on when charging and goes out when the battery is fully charged.

ThomasC2

My red light goes out as soon as the battery is full. It goes on for a minute or so if I open a door or similar.

andrew911

I confirmed that the red light on the porsche battery maintainer only comes on when the unit is actually charging, and goes off when it reaches a full charge status- I opened my door as mentioned in a prior post from Thomas, and the red light comes back on for a couple of minutes after the door is closed and the interior dome light goes off.

My conclusion is all cars have some small drain (clock, battery memory, etc), but if your red light stays on continually after a day or so, your drain is enough to keep it charging wereas a car with no abmormal drain will reach a range of full charge, and only cause the red light to come on periodically to bring the charge back up to that range when it dips below.

Thanks for your posts! Now that I know I have isolated my large drain by pulling the #1 fuse (HVAC), and checked that my battery is holding its charge (the red light is out on the maintainer whereas before it was on all the time),I just have to figure out how to fix that, but I'll post that sepeately...

Thanks-
Andrew