Battery Draining Need Help!
#1
Battery Draining Need Help!
Ok so, bear with me. Recently my car has been draining the battery after setting for only a couple days. It’s been about 3 years since the last battery so I thought I might have been the battery, I replaced it and it’s still doing the same thing. Before I got it, that fans have been wired to run when the ignition is on, and an aftermarket radio was put in. Since I’ve gotten it, I put in after market combo lights, replaced the fans with rx8 fans (1 was locked up) and that’s all electrically speaking. I would like to trouble shoot it and figure out what’s causing it but I have no idea where to start....idk if they have common wiring issues, or just a place to start in general, thanks for any help!
#3
RX-7 Bad Ass
iTrader: (55)
9 times out of 10, it's aftermarket electronics. Bone stock cars don't usually have problems. I have seen messed up pop up headlights that get stuck and the motor is still running trying to move the headlight, that's about it on a stock car. Most likely something aftermarket is a problem or something dumb like Resterof said, a light that is staying on or something.
Humble Mechanic has a good how-to on finding parasitic draws -
Dale
Humble Mechanic has a good how-to on finding parasitic draws -
Dale
#5
My nearly bone stock FD with > 7 year old battery will start without issue after 3-4 week hibernation.
This was a fun video to watch to demonstrate how much aftermarket wiring could be removed
This was a fun video to watch to demonstrate how much aftermarket wiring could be removed
#6
Wow mine will set for about a week and be dead. I checked to see if there was any draw on the battery and it measured 0.15 amp, can anyone confirm if this is normal? Or should it be 0.00? On the videos they were saying a 2-4 amp draw would kill your battery
#7
Original Owner
iTrader: (1)
I've never measured the dark current on my '94, but during the winter it sits for extended periods in a garage that has no electrical service, so no trickle charger. The battery (Optima Red Top) slowly discharges but will still start the car after a few weeks. I found that the battery lasts longer if the factory alarm system is not activated.
The '94 factory service manual at page G3 says that dark current should be 20 mA (0.02 Amps) or less.
The '94 factory service manual at page G3 says that dark current should be 20 mA (0.02 Amps) or less.
Last edited by Retserof; 04-08-21 at 10:54 AM.
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#8
I've never measured the dark current on my '94, but during the winter it sits for extended periods in a garage that has no electrical service, so no trickle charger. The battery (Optima Red Top) slowly discharges but will still start the car after a few weeks. I found that the battery lasts longer if the factory alarm system is not activated.
The '94 factory service manual at page G3 says that dark current should be 20 mA (0.02 Amps) or less.
The '94 factory service manual at page G3 says that dark current should be 20 mA (0.02 Amps) or less.
#11
Original Owner
iTrader: (1)
Yes, with the meter set to measure at that 10 amp range, the car should be drawing at or below 0.02 amps. However, when a meter is set at the 10 amp range, 0.02 amps is probably too small a value to measure very precisely. Instead, can you set the meter to a lower range, say 1 amp, or better yet, does it have a milleamp (mA) range?
On the other hand, if you now are seeing a dark current of 0.15 amps with the meter set at the 10 amp range, the meter is precise enough to tell you what you need to know -- that the car's dark current is excessive. Something is drawing too much power from the battery. As Dale said, it is probably aftermarket electronics, or the dome light or rear hatch cargo light.
On the other hand, if you now are seeing a dark current of 0.15 amps with the meter set at the 10 amp range, the meter is precise enough to tell you what you need to know -- that the car's dark current is excessive. Something is drawing too much power from the battery. As Dale said, it is probably aftermarket electronics, or the dome light or rear hatch cargo light.
Last edited by Retserof; 04-08-21 at 10:16 PM.
#13
Sucker for Punishment
50 mA is generally considered parasitic. Keep unplugging fuses until you find your culprit. Leaving the key in will draw more amperage ei: Leaving key in all winter is sure to kill the battery... at least in my car.
I did end up measuring draw on my FC with and without key at some point. It was a measurable difference but I can't remember the exact numbers.
I did end up measuring draw on my FC with and without key at some point. It was a measurable difference but I can't remember the exact numbers.
Last edited by Rotary Alkymist; 04-10-21 at 10:41 AM.
#14
~17 MPG
iTrader: (2)
There's a lot of good advice in this thread, once you know how to measure current you simply pull each fuse one-by-one until you find which fuse (or fuses) make the drain stop. Even if you don't understand what gets powered by that fuse, keep good notes and others here might be willing to help walk you through the wiring diagrams.
I once helped someone check for drains 10-15 years ago and the little orange light near the ignition key threw us off the trail because it was drawing current when the doors were open. Try closing the doors while testing.
I once helped someone check for drains 10-15 years ago and the little orange light near the ignition key threw us off the trail because it was drawing current when the doors were open. Try closing the doors while testing.
#16
Full Member
iTrader: (6)
Once you've pulled fuses and identified the circuit that has the draw, you can also check relays on that circuit as they can fail or rust up causing a draw.
I had a short on the room fuse circuit and a battery drain problem ever since i owned the car. Turned out the audio relay in the front relay box was corroded inside and was the source to all my problems.
I had a short on the room fuse circuit and a battery drain problem ever since i owned the car. Turned out the audio relay in the front relay box was corroded inside and was the source to all my problems.
#17
Once you've pulled fuses and identified the circuit that has the draw, you can also check relays on that circuit as they can fail or rust up causing a draw.
I had a short on the room fuse circuit and a battery drain problem ever since i owned the car. Turned out the audio relay in the front relay box was corroded inside and was the source to all my problems.
I had a short on the room fuse circuit and a battery drain problem ever since i owned the car. Turned out the audio relay in the front relay box was corroded inside and was the source to all my problems.
#21
RX-7 Bad Ass
iTrader: (55)
I think it's engine ECU and auto trans ECU at a guess. Typically PCM = Powertrain Control Module.
Dale
Dale
#24
Original Owner
iTrader: (1)
Cluster? Have you already tested and eliminated all the easier things -- glove box light, dome/door lights, rear hatch light, and then the power antenna and your aftermarket radio? (if your car is pre-'94, there was a Mazda bulletin about faulty glove box light switches that wouldn't turn off.)
#25
Cluster? Have you already tested and eliminated all the easier things -- glove box light, dome/door lights, rear hatch light, and then the power antenna and your aftermarket radio? (if your car is pre-'94, there was a Mazda bulletin about faulty glove box light switches that wouldn't turn off.)
also found out I had a stripped antenna wire being held into the antenna port with a drywall screw, that was new to me lol
and idk if I’m just dumb and not seeing it, but I don’t even see a glove box light. It may have been removed prior to me?
Last edited by ecurbd02; 04-14-21 at 01:56 PM.