[Battery Drain culprit found?] Urgent - car won't start...

Thanks guys, looks like I'm going to have to spend the afternoon doing some diagnostics. I've taken the bus to work but have got the afternoon off to sort things out.

Within range I have a Maplin, an Argos and a Halfords.

Suggestions on purchases?

1. A multimeter
2. A jump starter? or a batter charger? If the former, is this powerful enough?
http://www.maplin.co.uk/p/maplin-jump-starter-digital-500a-150psi-compressor-n63nk


Any tips on diagnostics once I get the car running? I'm a complete novice at this.

Moving back into Oxford in 2 weeks... why couldn't this have happened then huh?
 
Get the car started then check the alternator as mentioned above. Probably can take the battery back too now you know that's not the fault, if they will accept a refund that is, or at least you may be able to trade it against an alternator or some other parts.
 
I had the alternator lead off my starter motor by accident and no warning lights from the charge cycle on the alternator.

Just total electrical shutdown. Sounds like either the charge cable from the alternator is disconnected or broken or more realistically the diode pack in the alternator is shot allowing AC current into the battery and then when not running allowing a considerable drain to earth from the positive side which is permanently connected through the terminal on the alternator.

Need to get the altar or checked both for charge rate but also DC/AC content.

:cry:
 
Ok so the multimeter reads 11.6 volts on the battery, which I understand means it is under the required power to start the car. So a symptom of the problem is definitely the battery.

Can anyone confirm what setting I need to put the multimeter on to test the battery? This thing has 4 sockets and 28 settings :( and a terrible instruction manual for a novice.

Once the battery is charged I will of course see if the alternator boosts it.
 
If the battery has gone flat overnight then that's a value you would expect. It needs to be charged fully before it's worth checking it's output.
As for checking the drain, plug into the highest rated socket marked A (there will probably be 2) - making sure it's not the V that you've just used, then put it inline to see the drain. I can't help with what should be normal but pulling fuses should show which circuits are draining. If the alternator is faulty then unplugging it would show up.
 
Ok so the car starts with a charged battery - reading 12.65 now. When I attach the multimeter when it is running, it shows 14.32 which does suggest the alternator is running fine.

Unfortunately I cannot for the life of me work out how to get a drain reading on the multimeter I've got, it just shows 0.00 all the time unless I'm doing a voltage test...
 
The battery will always read 12.6 V once charged, to get an accurate reading you have to disconnect and leave for a few hours. As it is new though I am sure it won't be far off that. The alternator is outputting fine from that reading.

Make sure your black lead is in the COM port, and the red lead is in the highest current marked A port - it won't be the same as the V that you've been using. So if a 3 port meter use the other one and if 4 check the max current.
Make sure the selector is set to DC A (Solid line, dashed line - not wiggly line) with 10 for the scale. You should then be able to get a reading. If you take the +ve post off and put the multimeter -ve on the +ve post and meter +ve on the +ve lead it should work.
 
I'll give that a ho shortly, just off for a 20 mile drive now.

Is it normal for the remote central locking to die (on both keys) after removing the battery for a while?


Thanks for all the help guys.
 
Scooba_Steve said:
The battery will always read 12.6 V once charged, to get an accurate reading you have to disconnect and leave for a few hours. As it is new though I am sure it won't be far off that. The alternator is outputting fine from that reading.

Make sure your black lead is in the COM port, and the red lead is in the highest current marked A port - it won't be the same as the V that you've been using. So if a 3 port meter use the other one and if 4 check the max current.
Make sure the selector is set to DC A (Solid line, dashed line - not wiggly line) with 10 for the scale. You should then be able to get a reading. If you take the +ve post off and put the multimeter -ve on the +ve post and meter +ve on the +ve lead it should work.
Click to expand...

I've tried this now, it still reads 0 irrespective of whether I try it on the positive or negative side - even YouTube videos have not helped. Maybe my new multimeter is faulty? Would be just my luck :headbang:

This is the multimeter:

http://www.all-sun.com/products/EM8900_d.jpg

I've tried it in Com/10A and A and set to 6 o'clock.

The voltmeter part of it still works fine... the battery read 13.2 after a short drive, although 15 minutes later this has dropped to 13.02.

I've decided I'm going to give up for now and resign myself to a commute via bus until I work out what I'm gonna do...
 
You've got to leave the battery for a few hours to see it's charge state, preferably without being connected. Unplug one terminal and leave it overnight.

You could probably get away with using the car with this method; i.e. every time you turn off disconnect the battery. Bit of a PITA but better than the bus!

You want the +ve multimeter lead plugged into the 10A socket and the dial on 2A to start with.
-ve mulimeter lead to the +ve battery terminal and +ve lead to the +ve cable.
You're essentially connecting it in series rather than parallel to measure voltage.

Though if you have used it on A and the load was greater than 2A you may have blown the fuse.
 
So a friend came over and we used another multimeter to test it.

With the glovebox light disconnected, the draw was 0.9 amps. I understood from reading around the subject of parasitic drain 3 amps or something is the likely culprit, but doing some maths just now and 0.9 amp draw would reset drain almost 1/5 of the battery in the time my car sits overnight.

We disconnected every fuse in sequence and the only one that changed it was the immobiliser fuse (number 10) which had a draw of 0.5... I'm assuming the immobiliser will be drawing battery anyway, but this is maybe a problem?

Would be really useful to know if there's anything else I can do or do I now need to take it to a dealer/specialist to have them look at the immobiliser? Why do I feel like this is the most expensive thing that could go wrong :headbang:
 
Just a thought, but might be cheaper in the long run, to take it to an auto electrician, that's their job, unlike some dealers etc i know,who are just guess what's wrong artists... Then hopefully you'll be ready rock and roll again... :thumbsup:
 
Most dealers don't even guess, they just replace parts until the problem goes away, their diagnostics process is shocking.

Some sound advice though, £40-£50 for an hour or two from an auto electrician is probably worthwhile.
 
Thanks for the suggestions. My dad works in the motor trade and has a few people that might be able to look at it, so I'll drive up to Lincolnshire this weekend and leave it with them for a week.

Good job I still have my old car at his place!

Just wish I had these problems closer to people who could help out...

Back to the E92...
 
When I had parasitic drain problems with my E85 I ended up taking it to my Main Dealer after days of trying to diagnose myself.
Turned out it was the Gaptech Module......how they even found it I don't know.
Worth disconnecting any 3rd party aftermarket devices if you have any connected.......good luck and hope you sort it soon. PITA I know.
 
It will no doubt change with model and age of battery. But for info my Tracker takes about 3 weeks to flatten the battery. The good news is it text me before it dies. That would put current draw at at the 10-15 milliamp range. If you are reading 500 milliamps then that seems high to me.
 
I have this tool:
http://www.ebay.co.uk/itm/BGS-Tools-Digital-Current-Tester-For-Car-Automotive-Fuse-Contact-63520-/381114592477

So I can have the display on the dashboard and see from outside the display in the closed car.
I bought it for my BMW E39. After closing the car - around 20 minutes waiting until the car is "sleeping".
Changing it to the next fuse every day (or hour) - you can find the fault.
The same is an auto electrician doing.
 
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