12v Battery problem

[swamptheng666 0]

Toyota Avensis 1991. Does anyone know what the expected current drain should be - parked-up all lights off and locked? My neighbor complains that her Battery (fairly new) keeps going flat.

I put an ammeter between the earth lead and -ve Battery terminal and it settles to around 80ma. Seems a little high to me but i don't know what to expect (it has a standard alarm/locking system). About 70ma of the current goes through 15A 'Hazard' fuse located in the box under te bonnet.

All the best

 

Simon

[FROSTYBALLS 3,526]

Split into new topic and moved to the Avensis club.

[Mooly 204]

80ma sounds about at the top end of what I would have expected, particularly for an older car without sophisticated electronics that might be powered up 24/7. 

I would flip the problem around... 80ma draw should not cause a problem if the car is used a few times a week and sees the engine running for a decent length of time.

There are a lot of unknowns here. If the car hasn't been used much then the Battery charge will have got lower over an extended time period and that could impair the Battery such that it is down on capacity. It would be worth checking the charging voltage as well.

Also look and see if there is any non original kit fitted such as a different audio system.

You would have to look further at what that 70ma through the switch is doing. Does anything else electrical not function when that fuse is pulled? which would indicate it supplies other things beside the hazard circuit.

 

 

[Exvec 89]

 

[Konrad C 974]

The first fuse I would try is the 'dome' fuse in the engine bay, then check the current draw after. Obviously it's any item that still receives power, when the key has been removed. Some functions go through the dome fuse, so this will narrow if the fault passes through that fuse. 

[swamptheng666 0]

Yes, cheers. Can't see much current going through that

On 3/20/2021 at 6:27 PM, Mooly said:

80ma sounds about at the top end of what I would have expected, particularly for an older car without sophisticated electronics that might be powered up 24/7. 

I would flip the problem around... 80ma draw should not cause a problem if the car is used a few times a week and sees the engine running for a decent length of time.

There are a lot of unknowns here. If the car hasn't been used much then the battery charge will have got lower over an extended time period and that could impair the battery such that it is down on capacity. It would be worth checking the charging voltage as well.

Also look and see if there is any non original kit fitted such as a different audio system.

You would have to look further at what that 70ma through the switch is doing. Does anything else electrical not function when that fuse is pulled? which would indicate it supplies other things beside the hazard circuit.

 

 

Thanks. What you say makes sense to me. According to the manual I looked at and a circuit diagram, it's hazards and indicators (and anti-theft ECU). Not much going through dome fuse. I'd like to try disconnecting the anti-theft circuit but haven't found a way yet. I'm wondering if there's a dodgy relay switch sticking open - some clicking noises on passenger side front dash. All the best.