Multiple batteries mysteriously dying?

aviper4u · Postby **aviper4u** » Sat Nov 05, 2011 12:03 pm

hello peeps,

my cars chewing batteries while sitting in the garage.

had the car for two years battery lasted 1.5 then started dying every few weeks (drive at least on weekends) went and got new battery under warranty same issue after a few weeks again..... looks like theres a gremlin sucking the juice????

anyone had this before ?
its a NB8B (2000 build)

thanks

Postby **Okibi** » Sat Nov 05, 2011 12:49 pm

Anything electrical modified?

Old Dude · Postby **Old Dude** » Sat Nov 05, 2011 2:04 pm

Sounds like something is not shutting down

aviper4u · Postby **aviper4u** » Sat Nov 05, 2011 2:39 pm

just added aux in to stock head unit though issue was occurring before that anyways.

so hooked up a multimeter to test draw and seemed to isolate draw to the "room 10a" circuit.

time will tell if this has worked

thanks guys

Hjt · Postby **Hjt** » Sat Nov 05, 2011 3:41 pm

Something appears to be sucking the juice, in the mean time d/c your red battery terminal when your not using the car. Save the power ;)

Tedsmx5 · Postby **Tedsmx5** » Sat Nov 05, 2011 8:00 pm

I use a battery switch from Bias boating to disconnect the battery when not in use, that solved all my problems,
Ted

aviper4u · Postby **aviper4u** » Sat Nov 05, 2011 8:14 pm

yea i unplugged the room fuse and the draw is all good now, though there is no head unit power

upon further research its the head unit that seems to be drawing the power.......

anyone know what that "room 10a" circuit runs?

as for the battery switch sounds like a plan though you need to setup the audio, time etc everytime

kris · Postby **kris** » Sat Nov 05, 2011 9:41 pm

In my old Audi somehow the alternator was draining the battery. I never understood how, or looked it up to try and figure out how, but it was something about negative charging? Could be an idea?

aviper4u · Postby **aviper4u** » Sun Nov 06, 2011 7:30 pm

need to do some further tests though anyone know what a stock NB8B current draw is meant to be when sleeping?

i guess it has to be something as the ECU, clock, trip meter and any other memory needing feature requires juice........

Locutus · Postby **Locutus** » Mon Nov 07, 2011 9:44 am

have a dig at the wiring diagrams in the NB8B workshop manual

Mr Morlock · Postby **Mr Morlock** » Mon Nov 07, 2011 9:57 am

You have to get the car checked by an auto elect- wiring diagrams are not going to tell you anything- they do not show faults. If power is being drawn the battery will suffer. You can use a trickle charger but this is not of course fixing the root cause. I always switch off the interior light just in case the door is left ajar but it is hardly likely this is your solution. You should be able to leave the car for at least a month and still be able to start it.

manga_blue · Postby **manga_blue** » Mon Nov 07, 2011 11:03 am

Room 10A is usually the interior lights and the stay awake power to the ECU (Pin 1A). So there should always be a draw through the Room fuse to keep your ECU ready - not sure how big tho but probably pretty small.

4sfed5 · Postby **4sfed5** » Mon Nov 21, 2011 5:09 pm

maybe your alarm has been hooked up to that also and it's died....

alarm installers have a bad habit of grabbing any power wire they can find to hook an alarm onto

Locutus · Postby **Locutus** » Mon Nov 21, 2011 9:37 pm

Mr Morlock wrote:You have to get the car checked by an auto elect- wiring diagrams are not going to tell you anything- they do not show faults.

i've got no idea what you've been smoking, but you can't be more wrong.

all you need are electrical diagrams and a multimeter to find an electrical fault.

Robbo · Postby **Robbo** » Fri Dec 02, 2011 1:52 am

You appear to have the same problem I had. My battery went flat after a week or so of non-use. Turned out the alarm was the culprit. Now have the MX hookd upto a trickel charger. Good Luck.