Mystery 12.5 amp Parasitic Battery Drain

[efil4ynot]

About two months ago the key was accidentally left on while cleaning out the Cruiser and the battery went dead. I put it on the trickle charger overnight and recharged it. However, ever since I have about a 12.5 amp draw on my battery that drains it down within hours. The auto parts store scanner thing said a bad voltage regulator so I replaced the alternator and that didn't fix it. Over the last few weekends I have pulled every single fuse/relay that I can and the draw persists. I also unplugged the ignition switch in case that was bad and there was no change. There was an unused aftermarket alarm/remote start that a PO installed, I completely removed that. I have the National Luna dual battery setup, and completely took that and the secondary battery out of the loop.

At this point the only thing that I know that could be left is the starter since (I think) that is the only wire left connected to the positive battery terminal. Seeing how it is kind of a pain to get to the starter I figured I'd seek some advice before pulling the intake manifold to get to the starter. So, does anyone have an opinion as to whether or not they think a faulty starter could be causing this? I've never heard of a bad starter doing this but this is the last thing that I can think of. It does crank/start just fine once the battery has been recharged. Also, no codes. Oh, and I did see a 2 amp drop in the draw when I disconnected all of the positive wires that go from the positive battery terminal to the fuse block but there was still about a 10.5 amp draw.

Thanks in advance for any help.

 

[od4x4]

I am sure someone else with more experience will answer, but if you have disconnected everything except the starter and you still have the drain... well then it looks like someone will be replacing their starter soon.

I wold be pretty concerned about the 2A draw on the main fuse block. That is not insignificant at all.

And lastly, I would assume that you have double checked your readings and don’t just have have a meter reading in the wrong scale. I only mention that because my neighbor bought a cheap meter and in was reading in milliamperes when on the amp setting.

 

[efil4ynot]

Yeah, the draw on the fuse block bugs me too but I'm going to focus on the big one first. And, yes, I did double check the meter readings. That was actually my very first thought when I took the amp reading.

 

[joshAUST]

Doesn't the starter motor cable run to that rectangular box that clips onto the positive battery terminal?
From memory it does but I could be wrong, so sorry if I am.
I'm pretty sure you can disconnect if from there, at the base of the box, once you take off one side cover - the one facing the windscreen, you can see 4 or so connectors.
I'd be disconnecting the starter from there, as mines currently getting a replacement starter motor installed, and its a lot of work to get to it - under the inlet manifold.
If it is the starter, its probably worth replacing the welsh plugs (cheap) and possibly knock sensors (expensive), and sensor harness,at the same time, if its got a lot of miles on it.

 

[hj 60]

Down to zero with only a small light is a batterie killer, maybe it also dies stand alone?
Battery indication in Volts: below 12.4 is bad!
12.6+V 100%
12.50V 90%
12.42V 80%
12.32V 70%
12.20V 60%
12.06V 50%
11.90V 40%
11.75V 30%
11.58V 20%
11.31V 10%
10.50V 0%

 

[efil4ynot]

Doesn't the starter motor cable run to that rectangular box that clips onto the positive battery terminal?
From memory it does but I could be wrong, so sorry if I am.
I'm pretty sure you can disconnect if from there, at the base of the box, once you take off one side cover - the one facing the windscreen, you can see 4 or so connectors.
I'd be disconnecting the starter from there, as mines currently getting a replacement starter motor installed, and its a lot of work to get to it - under the inlet manifold.
If it is the starter, its probably worth replacing the welsh plugs (cheap) and possibly knock sensors (expensive), and sensor harness,at the same time, if its got a lot of miles on it.

Actually, that cable is the only one that doesn't go through the plastic box. I unplugged all of those (which all run to the fuse box) which is how I got to determine/speculate that it's the starter. What I'm not sure about is, since that cable goes into a wire loom and then disappears between the engine and the firewall, the cable only feeds the starter and nothing else. I'm hoping that is the case. But again, I've never heard of this being a symptom of a bad starter.

Down to zero with only a small light is a batterie killer, maybe it also dies stand alone?
Battery indication in Volts: below 12.4 is bad!
12.6+V 100%
12.50V 90%
12.42V 80%
12.32V 70%
12.20V 60%
12.06V 50%
11.90V 40%
11.75V 30%
11.58V 20%
11.31V 10%
10.50V 0%

Thanks but I've tried that as well, a few times actually. I've had the battery completely disconnected for four days and it held it's voltage just fine.

 

[bigredmachine]

starter could have an internal fault and be grounding itself out. can you disconnect the hot lead to the starter and recheck your draw? also when your checking the parasitic draw you may need to wait up to half hour for all the computers to go to sleep and you should see a drop in voltage, and key away from teh car so the key oscillator isnt sending a signal to the car

 

[efil4ynot]

Well, that's kind of the thing. Once I've disconnected the other four wires that run through the plastic box and to the fuse box, that cable is the only thing left on the vehicle that is connected to the positive battery terminal. If I disconnect it then the battery is completely disconnected.

I actually read on identifix.com that the computers run for 120 minutes after the key is turned off. I'm hoping that the 2 amp draw that I found to the fuse box over the weekend is just that, although 2 amps is still a lot.

 

[Julian Stead]

Yes, fairly normal for a starter motor to fail in this way. Good on you for finding it, so simple that it is easily overlooked. If you shut all doors and push the bonnet switch down if fitted, then lock it, this should shut your computers down quicker, usually within 15 mins if you have sat nav. 100mA was the highest we would allow, that would be about 2/3 weeks to drain the battery.

 

[efil4ynot]

Ha, you said bonnet.

But seriously, thanks for the info. It looks like everything is pointing to the starter. I probably won't get to it this until weekend and will post my results afterwards.

 

[bigredmachine]

I actually read on identifix.com that the computers run for 120 minutes after the key is turned off.

that is true but most likely everything should go to sleep within a half hour. we had a problem car at work the the regional fts had to come out and check for a parasitic draw and it took about 90 minuets for everything to go to sleep. newer car usually take longer so i would think that you would be good with the 30 min timeline

 

[Julian Stead]

American - Hood. Uk - bonnet. I do try and get the terminology right.

 

[efil4ynot]

Yeah, I always think it's fun hearing the terminology in other parts of the world. Worked on my old man's TR6 with him and quickly got used to referencing the bonnet and the boot when looking for help online.

 

[Julian Stead]

Now that is a car I liked, a TR6. Worth a lot of money these days.

 

[efil4ynot]

So, now I'm officially stumped. Last night I went to disconnect the starter wire from the positive battery terminal only to find that I missed checking the positive lead from the battery to the alternator. After checking various configurations, what I came up with is that if either the alternator wire or any of the three plugs on the left (not the small one on the right) that go from the plastic box on the battery to the fuse box are connected to the battery, then I get a draw of 11.5 - 12.5 amps. So.... that's where I am now. Any ideas/suggestions?

 

[dogdaysindurham]

@efil4ynot I wonder if you have a bad diode(s) in the alternator. I would go to a shop that specializes in alternator rebuilds to do the testing.

 

[2001LC]

Couple of things may or may not apply.

• Headlight switch needs to be in off position. In auto it draws some current.
• We've had a problem with DVD players drawing current. Check to make sure no light is on any player. Make sure to check for draw even if no light on. Note: it's hard to even see if it's on unless in the dark. See: Snowy in my signature for overhead and The Redbaron for headrest DVD's. Darn draw reportedly came back on Snowy.
• IIRC there is a purge of evap system at some time after shutdown. Sorry don't recall how long after. OM makes reference about normal to hear a noise sometime after shut down for this. It also draws.
• Any aftermarket stuff is always suspect. We think of these rear and headrest DVD's as factory installed, they are not. There fuses are not in any box, they are line fuses hinden. One is hot all the time one is switched with the key.

 

[Julian Stead]

Disconnect the battery, disconnect the alternator and tape it up, reconnect the battery and try. Alternator is a lot more common than a starter motor to cause a drain.

 

[cruzerDave]

I'd try to find an infrared camera, or if you have the coin and inclination buy one;
https://www.amazon.com/Seek-Thermal...d=1513196823&sr=8-1-spons&keywords=flir&psc=1

That much draw should be generating some heat in the wiring which the FLIR can see with surprising accuracy (once the engine & rig are totally cool). I know that shops that do boiler work usually have those cameras as well, not sure who else but they are fun to play with

 

[dogdaysindurham]

FLIR and Seekthermal have a relatively inexpensive one that connects via the USB port on the Android or Apple phone.

I have a Seek Thermal Compact (first gen.) and it's really neat toy (was a kickstarter backer). Affordable Infrared Thermal Cameras It's between 250-500 for one of these units.

FLIR second gen ones are nice also. FLIR ONE and FLIR ONE Pro | FLIR Systems Between 200-400 for one of these units.

The resolution and distance of view isn't amazing, but for checking drafty windows or what cruzerDave is suggesting very cool.