Strange loss of battery power... - 986 Forum - The Community for Porsche Boxster & Cayman Owners

Cebu · 12-30-2014, 04:06 PM

I left home for a couple of weeks and when I returned home my Beater Boxster would not start. The battery was almost completely dead, the courtesy or headlights didn't illuminate. The factory radio still had the flashing red light blinking.

I had propped my frunk lid open just in case the battery did die and would be able to charge it to life again. It turned out my son who was house watching did me a favor and shut the frunk lid.

Question:
I don't see any courtesy light in the frunk space. Would propping the lid cause a drain in the battery? I have gone through periods longer than this before and not have a problem with the battery discharging.

I was able to supply 12V to the cigarette light receptacle and provide enough current to pop my lid. I searched all over for the manual release without luck. I'll save that project for another day. Once I charged the battery overnight all seemed well in todays ride. I will not charge the battery tonight and see if it starts tomorrow morning.

Thank you in advance!

amitmishra4 · 12-30-2014, 04:54 PM

The frunk light is programmed to go off after a short while of leaving the bonnet open (don't know specifically how many mins but probably less than 30) so that was probably not the reason for the battery drain. How old is your battery? Batteries lose capacity over time. Also was your car locked and alarm system on?

Also, the car goes into a battery saving mode if not started for a week or so after which the remote and other accessories don't work until the key is inserted in the ignition and turned on.

Cebu · 12-30-2014, 05:17 PM

My battery was replaced a few months ago when I replaced my alternator. Where is the frunk light located? Perhaps I have something obstructing the view.

I read about the battery saving mode but I had no power even when I had the key turned in the ignition. I even tried applying power to the fusebox as shown in this video I found. https://www.youtube.com/watch?v=ueTM60piA6k - No luck.

Quote:

Originally Posted by amitmishra4

The frunk light is programmed to go off after a short while of leaving the bonnet open (don't know specifically how many mins but probably less than 30) so that was probably not the reason for the battery drain. How old is your battery? Batteries lose capacity over time. Also was your car locked and alarm system on?

Also, the car goes into a battery saving mode if not started for a week or so after which the remote and other accessories don't work until the key is inserted in the ignition and turned on.

particlewave · 12-30-2014, 05:41 PM

Joe B · 12-30-2014, 05:42 PM

Common problem. These cars have a lot of drain on the batteries. If I leave mine for more than a week or so, I disconnect the negative wire from the battery, or I hook up my C-tek charger. Just don't latch the frunk with the battery disconnected (I remove the catch; 2-10 mm head bolts).

Cebu · 12-30-2014, 06:06 PM

This sounds like my HD Roadglide

for my bike I use a trickle charger. What is your opinion with the Boxster? Use a trickle charger via the cigarette lighter receptacle? Thank you for the response and tip on the latch removal.

Quote:

Originally Posted by Joe B

Common problem. These cars have a lot of drain on the batteries. If I leave mine for more than a week or so, I disconnect the negative wire from the battery, or I hook up my C-tek charger. Just don't latch the frunk with the battery disconnected (I remove the catch; 2-10 mm head bolts).

Cebu · 12-30-2014, 06:13 PM

particlewave, thank you for the photos. I guess mine never illuminated as I never even noticed it was there. I just checked mine and it does not light up. Same with the rear trunk, no light. I'll check to see if I have a blown fuse. I guess that rules out the frunk light causing the problem. I've had it opened many times and it must have had a blown fuse when I first got the car or I blew one when messing around with the other projects.

Quote:

Originally Posted by particlewave

san rensho · 12-31-2014, 10:40 AM

Check to see what the at rest current draw is on the battery. Disconnect the neg lead to the battery and use an amp meter between the lead and the negative post to measure the amperage draw. It should be about .04 amps.

If the draw is too high, remove fuses one by one until the amperage falls and thats the circuit with the problem.