Parasitic battery drain

[hiker]

Hi all I have VS Statesman Series 3 V8 I have a problem with a parasitic battery drain of 1.3-1.4 amps I have pulled every fuse,relay,disconnected an after market security system,disconnected the alternator,the ABS module,cruise control,and pulled out various multi pin plugs under the bonnet but with no result.Does any one have any ideas on the cause of this? It does not effect the running of the vehicle in any way. If I drive anywhere and park for more than30 minutes I have to disconnect the battery or sluggish or no- start when I return. Any help or suggestions would be most appreciated. Thanking you all in advance.

 

[vc commodore]

Here's the youtube video I used to find my parasitic draw with my VY...

Other people will come along with another 60 different ways, so will leave it upto you which one you use

 

[Jeda]

Exactly what VC said. Check your glovebox light though first.

 

[chrisp]

Hi all I have VS Statesman Series 3 V8 I have a problem with a parasitic battery drain of 1.3-1.4 amps I have pulled every fuse,relay,disconnected an after market security system,disconnected the alternator,the ABS module,cruise control,and pulled out various multi pin plugs under the bonnet but with no result.Does any one have any ideas on the cause of this? It does not affect the running of the vehicle in any way. If I drive anywhere and park for more than30 minutes I have to disconnect the battery or sluggish or no- start when I return. Any help or suggestions would be most appreciated. Thanking you all in advance.

How good is the battery and the charging system?

If it has a parasitic load of 1.3A ~ 1.4A and is going close to flat if parked for 30 minutes, something is wrong with either or both. A good battery will have a capacity of about 60Ah, so it should hold a 1.4A drain for about 42 hours. So, to be flat, or sluggish, after 1/2 hour means it is (a) draining much more than 1.4A, (b) the battery is way down, and/or (c) isn’t be recharged properly.

For reference, a battery is considered faulty once it loses 20% of it’s labelled capacity, so, when a 60Ah battery gets down to 48Ah, a battery tester will indicate it should be ‘replaced’. But even a battery at that level will tolerate a 1.4A draw for a day or so.

I’m not doubting the parasitic draw, but I believe you also have another issue too (battery or charging system).

Also, if you do replace the battery, don’t let that parasitic drain flatten it. Slowly and deeply discharging a battery is probably the best way to ruin it.

 

[Skylarking]

Exactly what VC said. Check your glovebox light though first.

open its working... closed its not working... open its working...
seems similar to an indicator lamp

 

[Skylarking]

@hiker, fully charge and load test your battery with it out of the car.

If it tests good, reinstall the battery and then remove all fuses and disconnecte all non fused modules including the alternator, and if you're still getting a draw, you'd have a wiring problem (a 9 ohm resistive short to ground, about 12W)...

If that's the case, time to check the owners manual for a 12W lamp abnd then chech that any such lamps work correctly. If no lamp is stuck on, then you'll need to labouriously check all wiring looms.

If you dont get a draw with all fuses and non fused modules disconnected, then its not a wiring fault so systematically insert fuses one at a time chack for draw after each action. Then connect non fused modules (if any) and lastly connect alternator...

 

[hiker]

@hiker, fully charge and load test your battery with it out of the car.

If it tests good, reinstall the battery and then remove all fuses and disconnecte all non fused modules including the alternator, and if you're still getting a draw, you'd have a wiring problem (a 9 ohm resistive short to ground, about 12W)...

If that's the case, time to check the owners manual for a 12W lamp abnd then chech that any such lamps work correctly. If no lamp is stuck on, then you'll need to labouriously check all wiring looms.

If you dont get a draw with all fuses and non fused modules disconnected, then its not a wiring fault so systematically insert fuses one at a time chack for draw after each action. Then connect non fused modules (if any) and lastly connect alternator...

Hi Skylarking, at the beginning of my problem I thought it was a dud battery and as that battery was under warranty(20 months old) I took it back to the supplier and they said it was borderline but they gave me a new battery which I installed ,all good for a day or so then back to the flat battery so I used a multimeter and found the current draw problem and I have carried out what you have described above for no result .Thanks for your suggestions.

 

[vc commodore]

@hiker, fully charge and load test your battery with it out of the car.

If it tests good, reinstall the battery and then remove all fuses and disconnecte all non fused modules including the alternator, and if you're still getting a draw, you'd have a wiring problem (a 9 ohm resistive short to ground, about 12W)...

If that's the case, time to check the owners manual for a 12W lamp abnd then chech that any such lamps work correctly. If no lamp is stuck on, then you'll need to labouriously check all wiring looms.

If you dont get a draw with all fuses and non fused modules disconnected, then its not a wiring fault so systematically insert fuses one at a time chack for draw after each action. Then connect non fused modules (if any) and lastly connect alternator...

The youtube video I posted recommends removing one fuse at a time to test for the drain.

And yes, the battery test is a good idea

 

[hiker]

How good is the battery and the charging system?

If it has a parasitic load of 1.3A ~ 1.4A and is going close to flat if parked for 30 minutes, something is wrong with either or both. A good battery will have a capacity of about 60Ah, so it should hold a 1.4A drain for about 42 hours. So, to be flat, or sluggish, after 1/2 hour means it is (a) draining much more than 1.4A, (b) the battery is way down, and/or (c) isn’t be recharged properly.

For reference, a battery is considered faulty once it loses 20% of it’s labelled capacity, so, when a 60Ah battery gets down to 48Ah, a battery tester will indicate it should be ‘replaced’. But even a battery at that level will tolerate a 1.4A draw for a day or so.

I’m not doubting the parasitic draw, but I believe you also have another issue too (battery or charging system).

Also, if you do replace the battery, don’t let that parasitic drain flatten it. Slowly and deeply discharging a battery is probably the best way to ruin it.

 

[Skylarking]

The youtube video I posted recommends removing one fuse at a time to test for the drain.

And yes, the battery test is a good idea

Removing one fuse at a time or all fuses at once and then putting one at a time back in while checking the current draw really makes no difference (unless your inclined to mix up fuses and pu5 wrong ones in incorrect positions)…

It’s just to be methodical and know what is fused and what is not fused, how the BCM works w.r.t turning stuff on and going into sleep mode, etc…

Modern cars can be a PITA while old and simple cars are so much better in a lot of respects.