Porsche Enthusiasts Club Forum

Any advice greatly needed please. Ive had my battery checked & my alternator, both are brand new & fine, however my battery power last a little over a day of no use before I need to use my jump pack on it, the only things I have in the car non standard are an Alpine active sub woofer behind the driver seat which has both a switched live & a permanent live ( no idea why ?) and an ipod which is connected via the USB port on the stereo unit, this doesn't charge until the radio is live. The boot light goes out when I close the hatch, so its not that & the interior light goes out when I shut the doors, so its not that. I know that the flashing LED's on the door pins draw some current, but surely not this much ?? & I know that these cars don't like to sit around for long before the battery goes flat, but ive had more than a day or so out of the battery in the past. its slowly driving me mad, so advice greatly appreciated, cheers, Tony

Have you taken the sub out for a couple of days to check if it's that? That would be a huge power draw if it's not turning off fully.

No I havnt, ive been avoiding doing that as I very neatly tucked it up behind the carpet & its a real faff to get to, was hoping that there may be another cause, but may have to bite the bullet, ive had the amp in the car ever since ownership, however I did pick up an identical unit in better condition & just swapped them over, but don't know if the drain coincided with this swap over or not ??

Check the lights in the glove box go out with door shut, along with the under bonnet light as well!, they can drain a battery overnight!

+1 for glove box light, take the bulb out and see if it's that

Check and clean the door light switches, especially if you can hear a relay clicking

Cheers guys, didn't think of the glove box light, !!, the under bonnet
light only illuminates when the headlights are on though doesn't it ? I've got no clicking from the relay by the doors.... Well not on this car anyway, I do on the mk1 mr2 I have, but I can leave that for months & it will start every time !!

Possibly a bit late, but often a sub will have an inline fuse in the 12v supply wire that might be more accessible? Pull that instead of digging the sub out maybe

Does the sub stay on at all when the car is turned off? There should be 5 connections to the sub:
-Remote wire (the switching wire)
-Permanent Power (this should be a pretty thick wire)
-Ground wire

Does your HU turn off with the ignition of the car?

What brand is the battery and what size is it?

As for checking for a short take off the battery negative lead and insert a multimeter in series between the two on the current setting. With the windows down and the door shut see what the reading is. If it is above say 0.2A
-Take out the fuses one by one until you find out when the voltage goes down.

Where in Herts are you?

Hi Chas, thanks for taking the time to reply, yes the HU turns off with the ignition, the Amp does indeed have 3 wires, a perm live, switched live & an earth, I have exactly the same set up on my MR2 with no undue side effects like with the Porsche, battery is Yuasa, unsure of size but its the one recommended in the Halfords, book for the 944 & has been tested as working perfectly, it comes with a 5 year guarantee & was replaced only last year, alternator was also replaced last year & working perfectly. I'm in Hoddesdon, Herts if this helps, as for multi meters I'm at a loss as I have no idea how one works I'm afraid cheers, Tony

If you need a little help I'm in Waltham abbey

Hey that would be really kind of you thank you, I'm good at wielding spanners etc & do my own mechanics, but multimeters are as alien to me as kitchen equipment . what day were you thinking ? & how do I let you know my address etc ?, cheers, Tony

Pm sent