What the hell is draining my battery?

**WHITCHY** · 09-03-2006, 05:44 PM

Can someone please help me figure out what is draining my battery?
I just put a microtech in my AE86 and used all the wiring it came with for a direct bolt up, I just had to cut the charge system wiring from my old loom and add that in. I did this no worries and had the car running and the charge light would come on when the ignition was on but the engine wasnt running and it would turn off when the engine started so i figured everything was fine. Then a few days ago the charge light just stopped coming on all together, and my battery became drained over night.
I grabbed a multimeter and unplugged all the new wiring i have added in and I am still getting a reading that started at 1.38-1.38 and then as i disconnected more things it raised to 1.39-1.40. I have removed all the fuses from my fuse box and that didnt change anything, but when I removed the big 80A fuse from the little black box that hands off the +ve terminal it read 0.00.
So my question is what things run off this fuse?
the things currently NOT plugged in are: alternator, microtech, coil, stereo, driving lights, power windows, wiper motor. and it is still getting the 1.39-1.40 reading.
Where do I look now?

Thanks heaps to anyone who can help me out with this!
Cheers.
-Whitchy-

**Cuzzo** · 09-03-2006, 05:51 PM

have you got an alarm? i guess you would have checked that already. may be your battery is just f**ked.Or It might need to be topped up with distilled water.

**psychofox** · 09-03-2006, 05:52 PM

This reading you are talking about - is it resistance or current or voltage??? Where are you measuring this mystical figure between?

All the accessories that are connected directly to the battery on your car will have a small current drain when they are not on (microtech, stereo, etc.). Not a heap but if you have a dodgy battery it can be enough to kill it.

**WHITCHY** · 09-03-2006, 06:03 PM

Yeh I have an immobiliser, but I have had that for about a year and its never given me any probs! The battery isnt that old.
I dunno what the reading is? I have the dial turned to a DCA section and on the 20m mark, the red plug in the 10ADC plug and the black in the COM plug. I don't know shit about multimeters, I just asked a mate how to use it and what readings I should be getting. I am getting the reading by disconnecting the +ve terminal and putting one probe on the +ve terminal on the battery and one on the disconnected +ve terminal.
Cheers.
-Whitchy-

**slide86** · 09-03-2006, 06:32 PM

Originally Posted by WHITCHY

I am getting the reading by disconnecting the +ve terminal and putting one probe on the +ve terminal on the battery and one on the disconnected +ve terminal.
Cheers.
-Whitchy-

What you have done here is put the multimeter in series to measure CURRENT DRAW in AMPS. this is the correct way to look for current draw, so you are on the right track.
looks like you have bout 1.5 amp current draw. WAY TOO HIGH, should be bout 0.05 to 0.10 amps.

I would suggest you leave the multimeter hooked up this way and start disconnecting more things. as you disconnect each thing, keep checking the multimeter. Watch to see if the amps goes down. then you will know what is drawing the current.
Sounds like to got all the major stuff off tho....
I think the 80A fuse runs all the accessories? so anything that would be on with ignition swith on. (correct me if im wrong tho)
Try
- interior lights
- the light in the hatch area?
- brake lights or park lights
- dash lights
Thats all i can think of now, you will have to just keep looking. electrical sucks....i know!

**WHITCHY** · 09-03-2006, 07:47 PM

well please don't bother -ve repping me, I will do it myself!
hint to anyone checking for wiring probs like I was, MAKE SURE YOU CLOSE YOUR DOOR BEFORE YOU CHECK READING!!!!
turns out the battery drainage was from a relay being hooked up wrongly, no idea how it happened, I can't remember touching the relay but its all good now!
Thanks for all the suggestions! and massive thanks to Joel (TurboRA28 for his phone support!