Battery drain woes.

[science 0]

So I'm getting a constant 0.158A battery drain and I'm trying to find out what's draining it?

There are two fuses for the alarm (7.5A and 15A) and a 20A fuse for the door/window control module that seem to be drawing power.

 

Removing just the 20A fuse for the door/window module brings it down to 0.070A

 

Removing just the 15A fuse for the alarm brings to it 0.113A

 

Removing both the 20A door module and the 15A alarm fuses bring it down to 0.030A, which I'm guessing is acceptable???

 

Removing both the 20A door module and the 7.5A and 15A alarm fuses gives 0.013A, which then drops to 0.003A with the radio fuse out.

 

Is my door/window module knacked or my alarm or both???

Edited August 16, 2015 by science

[fendervg 30]

You might have a short somehwere. Pick the circuit with the biggest drain and trace the wiring back or unplug any components on that circuit. Radios and alarms will always draw a bit of power, I would have thought the window control module would not draw any when not in use. Did you check the wiring that goes from the door to the body at the hinge to make sure there's not a break or worn insulation there?

[dr_mat 0]

I believe the door/window module is a common problem with current leakage as they get older. I think it's because there's a timer in there that allows you to operate the windows up to a short period of time after the car has been turned off, so it gets a permanent live.

 

To do the maths, take the Ah of your car battery e.g. 64Ah, take around 60% of this, and divide by the current you are reading:

 

64 * 0.6 / 0.07 A = 548 hours, or around 22 days.

 

The biggest issue is that the battery degrades steadily if it's not kept fully charged, so although you will survive ok with a drain like this as long as you use the car weekly for a decent run, the battery will lose capacity and within a couple of years you'll need to replace it.

 

I'd been replacing batteries every couple of years for half a decade until I got a trickle charger to keep it topped up ..

[science 0]

You might have a short somehwere. Pick the circuit with the biggest drain and trace the wiring back or unplug any components on that circuit. Radios and alarms will always draw a bit of power, I would have thought the window control module would not draw any when not in use. Did you check the wiring that goes from the door to the body at the hinge to make sure there's not a break or worn insulation there?

Ah yeah, that could be it! Had a couple of times when the fuse kept blowing but then been alright after a drive. I'll have a look, Cheers

 

 

I believe the door/window module is a common problem with current leakage as they get older. I think it's because there's a timer in there that allows you to operate the windows up to a short period of time after the car has been turned off, so it gets a permanent live.

 

To do the maths, take the Ah of your car battery e.g. 64Ah, take around 60% of this, and divide by the current you are reading:

 

64 * 0.6 / 0.07 A = 548 hours, or around 22 days.

 

The biggest issue is that the battery degrades steadily if it's not kept fully charged, so although you will survive ok with a drain like this as long as you use the car weekly for a decent run, the battery will lose capacity and within a couple of years you'll need to replace it.

 

I'd been replacing batteries every couple of years for half a decade until I got a trickle charger to keep it topped up ..

 

Just squeezed a new 76Ah battery in, so that should help.

Do you think removing the timer circuits from the module could help?

[Wullie 1]

I had a similar problem which turned out to be the actuators in the door (Mine was the passenger side). Disconnected the plug and the drain stopped. Having it disconnected didn't seem to make any difference to the operation of the windows. Seemed to have happened with a few other people as well.

[dr_mat 0]

To be honest, though putting a bigger battery in does give you more time before it dies it will still ultimately fail.

Lead acid batteries are just not designed to be left anything other than fully charged, it's the one and only thing that routinely kills them.

[science 0]

To be honest, though putting a bigger battery in does give you more time before it dies it will still ultimately fail.

Lead acid batteries are just not designed to be left anything other than fully charged, it's the one and only thing that routinely kills them.

It killed my Optima battery but I had a good deal on a new 100 type battery. It just needs to see it through the next couple of weeks and then I can start taking things apart to find the root cause.

Shame I can't hook up the trickle charger where the car is, maybe a solar panel would help?

I had a similar problem which turned out to be the actuators in the door (Mine was the passenger side). Disconnected the plug and the drain stopped. Having it disconnected didn't seem to make any difference to the operation of the windows. Seemed to have happened with a few other people as well.

What the the actuators for?

[dr_mat 0]

Couple of weeks and you'll be fine. Solar chargers are almost useless in the UK, unless you literally coat the entire roof in PV cells...

[fla 9]

Solar panel chargers are only good for maintaining the level not to charge the battery. Current outputis too low.

[fendervg 30]

Actuators for central locking? You can close your windows by holding the key turned in the lock.

[dr_mat 0]

Solar panel chargers are only good for maintaining the level not to charge the battery. Current outputis too low.

 

And in my experience they can't even do that unless they are pretty large and you park the car in full sun. (And it's sunny...)