Battery drain. Ideas?

[Dark_Rider2k3]

First off for the small few that don't know:

1992 Mazda MX-3
1.8L BP swap and ATX to Kia MTX swap.
Rockford Fosgate amp (I think 1,000 watt or something) (to power dual 12" subs) and Soundstorm Labs 4 channel 500w amp (to power speakers).

I am also running 3 "Glo-shift" gauges. Voltmeter, Wideband AFR, Oil pressure.


First off, when the car is on and running, I am showing no less than 14 volts from the voltmeter. However, when off it's usually around 10-11 volts.

I had the battery tested and it shows fine. The Alternator showed fine as well.

My question is, how do I go about checking wiring? What are your ideas for my wiring.


Here are some rough sketches of my aftermarket wiring:

------Oil pressure 12V switched---\
------Voltmeter 12V switched-----L------------ [FUSE PANEL SWITCHED 12V]

------Oil pressure 12V constant---\
------Voltmeter 12V constant-----L------------ [FUSE PANEL CONSTANT 12V]

------Oil pressure ground---\
------Voltmeter ground-----L-------------[GROUNDED TO BOLT ON FRAME]


Wideband O2's wiring goes to the same fuse/ground as the oil pressure and voltmeter, just soldered together.

The amps connect to a splittler that goes to the battery (so it's like [BAT +]----------------< (where the < is the split for both amps), and ground near the seat belt bracket for the rear seat belts. They are also on a power wire to the head unit that keeps them off when the power is off.

So my question is how do I figure out what is draining the battery?

Thanks!!!

[Newfie_dan]

you are going to need an ammeter to test for the drain, I am not 100% sure how you wired the amp, it should be positive wire to the battery directly using a splitter is not a big deal but just be aware that the amp wiring should always be run through a rubber firewall grommet that is easy to test if its the drain just unhook the power wire for it from the battery and see if the battery drains or not. The rest of the wiring sounds ok from what I gathered. Once you have that checked then proceed to checking for draws by removing the fuse inserting the ammetere leads into both sides of the fuse holder and checking the draw. That will help you narrow it down to what circuit is causing the draw.

[Nd4SpdSe]

Battery drain on a non-running car should be about 0.01amps. Easiest way to test is disconnect the positive battery terminal and hook a multimeter between the the terminal and the post, put the meter on amps of course. Don't turn on the car with your key otherwise you'll blow the fuse, the meter usually only has a 10amp fuse. Now from there literally pull each fuse one by one, and if that's not the case, try disconnecting some things like your system (or just pull the fuses on those too for ease) until you've isolated the problem.

The trick is that some vehicles take some time before everything goes to sleep, my Xterra takes 45minutes before the BCM shuts off.