Battery drain.... investigating
Discussion
My Tuscan has always been a bu66er for flattening batteries. It sits plugged into the Accumate all the time so its only a problem when it goes to the garage or is away for a few days.
So, I'm going to fix it!!
Plan is:
Disconnect positive cable from battery, then stick my multimeter between the +ve post of the battery, and it's cable.
At this point I'll disconnect the accumate - I'm hoping that doing it this way will mean I don't re-set the immobiliser etc. Doesn't matter too much either way.
Turn on the meter, I will start it off a high current setting and work down the way depending on what the drain turns out to be. The meter is fused but I'd rather not blow it! Given that I have a 72AH battery and it lasts maybe 5 days, I should be looking for a drain of the order of 750mA.
Then, start pulling relays one at a time(prime suspects?) and keeping an eye on the current. If there's no good from the relays, I'll start pulling fuses one at a time.
Anyone got any advice/ comments on this?
Which relays / fuses should I try first?
Is there any way to get to the fuse box without partially crippling myself by putting my spine right on the sill?? Been there before and it is not comfortable!
Cheers,
FT.
So, I'm going to fix it!!
Plan is:
Disconnect positive cable from battery, then stick my multimeter between the +ve post of the battery, and it's cable.
At this point I'll disconnect the accumate - I'm hoping that doing it this way will mean I don't re-set the immobiliser etc. Doesn't matter too much either way.
Turn on the meter, I will start it off a high current setting and work down the way depending on what the drain turns out to be. The meter is fused but I'd rather not blow it! Given that I have a 72AH battery and it lasts maybe 5 days, I should be looking for a drain of the order of 750mA.
Then, start pulling relays one at a time(prime suspects?) and keeping an eye on the current. If there's no good from the relays, I'll start pulling fuses one at a time.
Anyone got any advice/ comments on this?
Which relays / fuses should I try first?
Is there any way to get to the fuse box without partially crippling myself by putting my spine right on the sill?? Been there before and it is not comfortable!
Cheers,
FT.
Does the yellow charge light change to green on your Accumate? If it does not that indicates that the drain on the battery is more than 200ma. I seem to remember the current drain for a Tuscan is around 125 ma with alarm & immobiliser on so the Accumate should keeps pace with the battery discharge. Possible cause of high battery current drain could be the immobiliser, or the boot light staying on.
Yes, it does go green so the accumate does "catch up" eventually. The boot light is okay, was wondering about the interior light relay as it incorporates the delay timer (I think) which could cause problems.
I spoke to Carl at car and bike installations a good while ago, he said the immobiliser itself should be no problem but a faulty siren could be a cause.
Cheers,
FT.
I spoke to Carl at car and bike installations a good while ago, he said the immobiliser itself should be no problem but a faulty siren could be a cause.
Cheers,
FT.
Update:
Hooked up my meter as described above. This prevented the alarm going off until one of the crocodile clips fell off - got deafened when I reconnected it!
The current flowing with everything off was around 190-200mA. This is a bit less than I'd estimted but I guess the battery stops turning the engine over a good bit before it is fully discharged. Either way, at 200mA a 72 Ah battery would still only last about two weeks until fully drained.
I then got into the fuse pulling position, started with all the relays - no effect. Worked my way through the fuses, and eventually found that pulling each door ECU fuse dropped the current by about 85/90mA. With both out the remaining current was about 20mA. About 10mA of this seemed to be attributable to the ECU (I can't remember which one but I think it was####) so I guess the rest of the load was spread between one or more of the other fuses. I wasn't able to see much more than 10mA as I left the ammeter on the 10A setting.
If you try this, I would reccomend leaving your meter on quite a high setting as if you set off the alarm (as I did) and the siren and lights all come on there is a pretty good current flowing which could easily damage your meter on a more sensitive setting.
So, 90% of the drain is coming from the door ECU circuits. Is there a fault in them? Is this normal?
Problem not solved, but more illuminated!
Cheers,
FT.
Hooked up my meter as described above. This prevented the alarm going off until one of the crocodile clips fell off - got deafened when I reconnected it!
The current flowing with everything off was around 190-200mA. This is a bit less than I'd estimted but I guess the battery stops turning the engine over a good bit before it is fully discharged. Either way, at 200mA a 72 Ah battery would still only last about two weeks until fully drained.
I then got into the fuse pulling position, started with all the relays - no effect. Worked my way through the fuses, and eventually found that pulling each door ECU fuse dropped the current by about 85/90mA. With both out the remaining current was about 20mA. About 10mA of this seemed to be attributable to the ECU (I can't remember which one but I think it was####) so I guess the rest of the load was spread between one or more of the other fuses. I wasn't able to see much more than 10mA as I left the ammeter on the 10A setting.
If you try this, I would reccomend leaving your meter on quite a high setting as if you set off the alarm (as I did) and the siren and lights all come on there is a pretty good current flowing which could easily damage your meter on a more sensitive setting.
So, 90% of the drain is coming from the door ECU circuits. Is there a fault in them? Is this normal?
Problem not solved, but more illuminated!
Cheers,
FT.
I was thinking that it wouldn't be hard to fit a kill switch to the door ECU's
Then I realised you might have a slight problem getting out/into the car.
Kill switch (windows down), manally open and shut door, arm alarm (windows go up)...
...damn it still couldnt get into car.
Thats me out of ideas!
Then I realised you might have a slight problem getting out/into the car.
Kill switch (windows down), manally open and shut door, arm alarm (windows go up)...
...damn it still couldnt get into car.
Thats me out of ideas!
Yeah, wouldn't help!
I'll take a look at the encoders and ECUs to see if there is anything obvious, if that doesn't help I'll be buying one of these, and putting a switch for it under the service bonnet.
http://uk.rs-online.com/web/search/searchBrowseAct...
Cheers,
FT.
I'll take a look at the encoders and ECUs to see if there is anything obvious, if that doesn't help I'll be buying one of these, and putting a switch for it under the service bonnet.
http://uk.rs-online.com/web/search/searchBrowseAct...
Cheers,
FT.
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