These cars don't kill batteries over night. Something else is wrong ! You are avoiding what could be the most obvious and simplest issue. Start with a fresh battery... ! The more you understand the make up and function of a battery the more you will see that this is a common issue not only in our P cars. I have multiple cars hooked up to tenders. Just recently this was going on with an old hot rod I have. Sure enough it was a bad battery. Not saying this is your issue, but it is the simplest first order of attack in eliminating and figuring out the problem.

 

weird, is right. i file this peculiarity on my list of "joy of ownership" items lol..

along with things such as spoiler re-bleeds and replacing accumulators

 

I feel you on that one. I have my CTEK charger mounted to the garage wall, and I have quick disconnect leads with the plug easily accessible from out the side of the battery cover. Anything more than 3 days and I pop the hood and plug it in. Mine will go nearly flat in 7 days easily. More if it's super cold.

 

Well, got a ride to and from work today. Left the car on the trickle charger all day so it fired up and just came home from getting a new battery. We'll see how it goes. The last one was purchased in November and I didn't really have any issues until mid-late December.

Problem now is that I'm paranoid about having issues and won't know when they'll show up until I go to start the car one day.

Kind of thinking about rerouting that emergency release cable then putting a kill switch on the negative terminal. The only issue there is that I would either have to leave my trunk open (if I was going to be somewhere for a while and disconnected the battery) or use that cable regularly.

I already moved my tools and jack into the car behind the passenger seat, so at least next time I can pull the wheel if necessary!

 

Get one of these, some decent gauge wire with stripped ends, and some jumper cables. If battery dies plug this in, attach jumpers to another car, open hatch, jump car with cables in proper place. I have two of these, one in the car, another in my garage. The fuse box PowerPoint has never worked for me! Don't try to jump the car with this, it'll just pop a fuse and leave you stranded...

https://vetco.net/products/cigarette...FdaCswodFgQHvQ

 

Reading this thread has had me worried. I have been in Mexico with my 02 TT sitting in the garage at home. Well just went out and it fired right up. If your car won't start after a week you got problems.

 

Thanks I might check that out. Yea, I was mainly trying to get the hood to pop open since I was using the new battery to provide power, so I could swap out the old one. Went down and checked the battery with a multimeter, still reading fine.

Yea, I think there is something else going on, maybe the alternator is bad, or as mentioned by someone previously, the ignition is going out. Not sure really. Thought I had it after the car started fine without the trickle charger for about 4 or 5 days, even with not starting it for over 24 hours, then it just wouldn't start.

 

Please update us on status after new battery is installed.

 

FYI, my car sat fro 1 month with no battery tender and fired right up. I have a 10 month old duralast H7 AGM battery.

 

I installed it the night I posted on the 24th. So far it's starting up like a champ. When I returned the battery, there was a crack in the case. No leakage of any kind but maybe it was damaged. So far I've been going down and checking the battery with a multimeter every so often to see how the charge is holding up. So far so good.

Just checked it (8:18 pm, last drove around 5-5:15pm or so) and it's at 12.68. When I got home and checked, with the car running, headlights on, cd player going, and front windshield defrost going full it was at 13.47 and with all that stuff off and the car running, it was at 13.81.

That's what I have in there right now, and what was in there when I was having issues. Hopefully it was just damaged but we'll see. Like I said, going to continue to check it periodically and if I notice a significant decrease, I'll throw it on the trickle charger then start looking at the alternator or maybe ignition.

 

Glad to see your on the right track. Seems as though it may have been just a common battery issue. Your recent readings are correct for a healthy battery. Your past symptoms may have been that of a sulfated (dead cell) battery. In that case it is common to get a healthy voltage reading after a charge but after usage the battery heats up and disconnects cells. Thus causing the battery to drain itself.
Use your tender through the cig lighter and run the cord fattened in front of sill plate. This will not cause any paint or seal damage.
Hopefully problem solved !
Enjoy your car !

 

Here's hoping! Thanks for the help and suggestions everyone. I'll keep an eye on the charge for a while to make sure this isn't a fluke. It would be nice to have my car stable again, seeing all these upgrade threads while you're dealing with simple problems isn't fun. haha

 

I just did a motor last year , car came in with a bent rod, never seen it before. after a few weeks of investigating I found a corroded ground from battery to body. does your oil gauge read less then 1.5 bar at idle? is your V read out on the dash around 13 or less?
if so, check your grounds...

 

Thanks for the suggestions, I'll have to take a look at the oil gauge tomorrow morning but the battery read out is just below 14.

So far I've still be going out to the garage every night and checking and the battery is sitting around 12.6x after sitting in the garage for a few hours. Once it was 12.5x but later that night it was at 12.68.

 

That's not the issue then.