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Thread: Battery keeps draining.

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2012-10-12 15:09:12
Battery keeps draining.
So on my 99 se-l, ive been having a issue. The battery keeps draining after 1-2 days of sitting. And heres the weird thing, i think its the anti theft causing these issues for jump starting. Every time it drains, if i try to jump it, it sparks the battery jumpers, even melted a pair, but if i get enough of a charge and push the unlock button that stops, you can jump the car fine? Ive pulled the inhibitor relay and it lets me jump the car without fucking up my cables.

Ive tried 2 different batteries, the car is stock except cd player, and hid's, ive unlplugged the hid's from the battery and no issue. Car seems to charge fine i can go the whole day driving around, starting, lights on so i know its not the alternator, she charges fine. Its like there is a draw somewhere, but this damn inhibitor system is causing a shit load of issues for trying to jump the car and crap. Any ideas or anyone have similar issues?
2012-10-12 15:53:08
Any changes recently before you noticed this? How long have you had the cd player in there?
2012-10-12 17:16:48
Put it in when i bought it and had no issues, was all plug and play as well, and only other thing was the hid's, but i had unplugged them from the battery and no change. This is the second battery i have tried in it pulled it out of my 510, and if it sits more than 2 days its dead, sits a day you can tell its draining because it doesnt want to start as fast.

Its getting frustrating, the car had front end damage when i got it, so im wondering if a ground got fucked up or something? but the damn inhibitor on the alarm seems to fuck up the battery as well, because it wont let me jump it with the positive terminal on the battery, i have to take it off, and charge the battery. Then once the battery has enough of a charge i have to put the terminal on, and deactivate the alarm because it starts to go off, THEN it allows me to actually put the cables on with the terminal still on the battery, and not make the cables start to smoke.

Im really thinking somethings wrong with a ground to maybe the alarm sytem or a crossed wire. Its getting very annoying. I tried hooking it to the trickle charger and it wont even charge it, the thing freaks out when i hook up. I know its not the battery either since this is the 2nd one in there.

The one thing i hate about getting rid of another car for a car you dont know, my 200sx i knew every single thing on that car, this se-l im still learning what her weird things are. sigh.
2012-10-12 17:34:58
You can narrow it down for sure if you disable the alarm entirely and see if the problem still persists. If it does, something faulty in the alarm system components is probably not right..

Keep in mind that the alarm may be freaking out because of the low battery voltage. Not the first time I've seen this.
2012-10-12 17:58:35
here's what I do.

grab a beer. start drinking.

then grab a friend (metaphorically speaking), and get them to sit in the driver's seat. you put a multimeter on the battery on 20v. pull out fuses one by one until the battery drain stops. That narrows it down big time.
2012-10-12 18:14:48
Canx2k said it right, I do the same thing. I have a tester on the battery and I pull fuses till I see a change, that at least narrows down the search.

2012-10-12 18:21:23
You guys have the right idea, but monitoring amps is even better. Just make sure everything is off, just like it would be with the car sitting at night with the doors closed, and ignition key out. Note how much current is being drawn in that condition, and unplug your fuses one at a time while monitoring the current draw. You're probably going to have the driver side door open while pulling the fuses, so make sure that door light plunger is pushed in, so the dome light circuit is off.

2012-10-12 18:26:17
Google 'Dark current drain testing'

Flyin' Miata 1 800 FLY MX5s

This is a technique for tracking down battery drains that may be killing your battery when the car is parked. There is always some current flowing from the battery, even when the car is shut off. This is known as dark current and is what keeps radio memory and clocks going, as well as many alarm systems and cellular phones.

A typical allowable number for dark current would be in the 40-60 milliamp range. This can be measured by installing a milliammeter in series with the negative post of your battery. If you don't have a milliammeter, you can disconnect the negative cable and hook up a 12 volt test light between the removed cable and the battery post.

If the light lights at all with the doors shut and key out of the ignition, it will be enough to kill your battery.

If you do show either a milliamp draw over 60 or your test light lights, you must find the problem. To do this, leave your light or meter hooked up and start pulling fuses one by one. After you pull each fuse, look to see if the current draw has dropped or the light has gone out. Do not reinstall the fuses as you pull them. In other words, keep pulling without reinstalling 'til one of them makes your light go out or meter drop.

Once you have narrowed it down to a specific fuse, it's time to go to the wiring diagram or owner's manual to see what circuits are controlled by that fuse. Some common culprits are power antennas that don't shut off, alarms, power mirror switches, courtesy lights and radios.

Hope this helps somebody! Late breaking news! Just looked in the factory manual and Mazda calls for 20 milliamps of dark current for a Miata. The lazy man's way around hunting for battery drains is to use a Priority Start. This is a little box that straps onto the side of your battery and monitors its voltage. If the battery voltage drops to a preset level the Priority Start will disconnect the battery, leaving you enough juice to start. Doesn't require resetting, just open the door and the courtesy light drain will reconnect the battery for you. Great for cars that sit between weekends!

PS Don't forget, while pulling fuses, you either have to shut the door after pulling each one, hold the door switch in, or make sure that the courtesy lights are turned off.

Last edited by Chriscar on 2012-10-12 at 18-27-09.
2012-10-13 01:11:09
@Chriscar should sticky thst post; at a minimum add it to the manifesto...

Sent from my SAMSUNG-SGH-I747 using Tapatalk 2
2012-10-13 05:03:03
Agreed with chriscar... You need to isolate components. I would still recommend a buddy with a case of beers. Chris, was it you I bought a 93 sapphire blue nx from 10 years ago with rear panel damage?ive been away from hand forum for a bit and have forgotten most usernames..
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