Dead battery after two weeks...normal? - 986 Forum - The Community for Porsche Boxster & Cayman Owners

Ricochetron · 02-08-2010, 06:27 AM

That's a lot of good info to check. Once I get the optima battery I will have things checked out.

To answer preious questions, The car is completely stock with 9k miles. When I had the car delivered to the house (too much snow when bought) we had to leave the car running in the trailer to assure it started when it made it to the house (15 minute trip). We alreaedy knew the factory battery was bad and a new battery was on order. When I got the new battery, I trickle charged it to full charge then installed it. I then started the car and ran it for appx 15 minutes. The car was put back in the garage and two weeks later it was at 4 volts. There had to be a major draw somewhere or the new interstate battery was a dud.

Since the original battery was bad and the car probably required several booster starts, do you think the alternator was damaged in the process of jump starting?

70Sixter · 02-08-2010, 09:00 AM

Could be alternator/regulator if it discharges while driving.

Interstate batteries are good quality and warranted. If it is defective you should get a new one be reimbursed.

I routinely plug my Box into the battery maintainer when I park. I never know when I'll drive it next. Certainly if not run for a even a week it should be on maintainer.

Batteries hate recharges from low state of charge and will last longer if kept charged.

Ricochetron · 03-07-2010, 03:21 PM

Ok, I just installed a new Optima 34R battery with adapter plate. Battery is full of charge. Before connecting the negative cable, I checked the parasitic amp draw and found a whopping 1.2 amps. The 07 987 is completely bone stock. I unplugged the front boot light to get an accurate reading, (doors closed, everything in the off position.)

Is this what I should expect? No wonder why my earlier new Interstate battery went down to 4 volts in two weeks, ruining the thing.

vath2001 · 03-07-2010, 05:43 PM

Step 2: With the amp meter hooked up, start pulling fuses. Pull a fuse, check the meter and re-install the fuse if no change to the meter. That will narrow down the circuit.

jcb986 · 03-08-2010, 05:50 PM

Disconnect the front and rear trunk lights and then check your amps. Guys have had the switch go bad and these little lights will run down your battery if left on.

stephen wilson · 03-09-2010, 06:47 AM

Did your air bag light come on after the battery died? I left the lights of my 06 on, now I have a fault showing. I presume I'll have to have the dealer reset it?
Thanks,
Steve

SStiebers · 03-09-2010, 01:31 PM

I agree about the fault. Mine went dead when someone set off the alarm and it died, i had a lot of faults and resets, you might want to make sure everything that has to has been reset. also the light switch, i did have a bad one. Other than that i store mine from october to REAL SOON i hope, and i only start it every couple of weeks and it is fine. These cars do not draw much if anything.