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What is the normal drain on the battery for our cars while parked?

Normal for both my Porsches is dead in under a week.

Ryan...that's not "normal". I can leave the 944 sit a good long while and it's fine. I used to be able to do that with the 968, but now it's draining fairly quickly. I haven't had a chance to troubleshoot it yet, but I'm eagerly awaiting anyone's response of what the "normal drain" should be. Something has changed with mine and it's dead in about a week too! I've resorted to a trickle charger, which I thought was going to be a pain to connect/disconnect all the time, but it's fine and gives me peace of mind that I can get in and the car will start!



- Darryl

Darryl, that was sarcasm, but I think it odd that both cars drain the battery like a hot thirsty kid with a small soda.



People have mentioned the ground being the culprit, but I have found nothing. Wish I knew...it is a pain.

I had a bad cell in the battery in one car and it would die quick if unused. Replacing all my battery cables on one car has resolved the sitting issue as well as numerous other issues in the other car.

I have similar problem...leave for a week (with new battery) and it drains dead



I need to run it at least three times a week to be OK. Can't find a short anywhere



It got to the point where I would unhook the new bat for extend periods.

I tested my 968 a while back when I was having a similar problem with rapid battery drain and took the following readings, thinking that one of the microswitches was faulty or misadjusted:



0.10 A - no key in ignition

0.13 A - key in ignition ("P" red light illuminated)

0.72 A - hood light only

0.71 A - trunk light only

0.69 A - interior light only



None of these should have been enough to drain my battery in a week. Even though the battery tested good at several shops I eventually replaced it and solved the problem. FYI, Sam's Club is now carrying a group 91 Interstate battery for $87.32.



Tom

a week is pretty short (pardon the pun) - sounds like a problem



3 weeks seems to be the "norm" - not sure why - i am very certain i have no shorts or aftermarket components abnormally draining - i have a new optima, and all new very pricey high quality cables - i don't even engage the alarm - still, a few weeks and it's too low to start the car

When I first bought my car, I was getting a flat battery within a week. I traced my fault to a sticking switch in the glove box.

No problems now (although I dont set the alarm as its locked up tight in the garage) even after 3 weeks without starting.

Maybe I just got lucky.

Maybe a relay is stuck. You can feel it. Because they are warm.

I have had it in the past. Check it with a "cold" car.

I just got mine out the shop where they spend several hours trouble shooting my drain. It was .500A when it went in and they got it down to .102A. The tech said .30A was my stereo system, but he could not find the other drain. He thinks it has something to do with the security system. Does anyone know if the Porsche trickle charger cuts off automatic when the battery is fully charged?

Try disconnect the dynamo. Maybe you got a worn diode inside.

This will give you the same symptoms. but it is hard to find because there are no fuses in this circuit.

I can easily go a month in both of mine, that includes keeping the alarm system on.



Kim

Quote:Try disconnect the dynamo. Maybe you got a worn diode inside.

I give up. What is a "dynamo"? Is it alarm related? One of my cars has the factory alarm and I have never used it in 10 years. My cab has a Clifford that has door lock control and motion detector but I don't use it in the garage. Both cars suck the battery dead in a week.

alternator

I have also left my car outside, unstarted, alarm on, for periods as long as four weeks and had no problem on the first start.

[quote name='Larry Currie' post='52571' date='May 15 2008, 08:46 AM']Does anyone know if the Porsche trickle charger cuts off automatic when the battery is fully charged?[/quote]



Larry,



Yes, the Porsche Tequipment trickle charger has a series of lights on it that indicate charging mode and "full". Once the battery is fully charged, it goes into a maintenance mode where it basically sends a quick pulse for feedback and then if necessary, will revert to charge mode. Otherwise, it's happy to just maintain a full charge. As I mentioned above, I thought it would be a pain to plug it in, etc. but I'm enjoying the peace of mind it gives.



I don't know if it's any different per se than any other trickle charger, other than it says "Porsche" and probably costs too much, but we're all used to that. I got mine from Sunset on sale for just over 100.00 IIRC.



- Darryl

I've had mine for years. It has only one red light on it, but I think it goes dim when in maintenance mode.

When I used to travel for a living, I would leave my car sit for up to 6 weeks.



Had no problems, and fired right up.

I use 2 amp Schumaker motorcycle battery chargers on all of my vehicles, wired with cigarette lighter plugs--$17.44 at Walmart.



Tom