Voltage drop on battery

[gogsboy 0]

Been having Corrado problems pretty much since first week of ownership and not been about much to try and get things sorted out..

 

Battery not been keeping much of a charge, was tempramental as in sometimes it would keep charge for long enough and other times it wouldnt.

 

Had it off and got it tested as its a new battery, said all well with it but once again it was stone dead.

 

Took it for a run for about an hour and it was only upto 11.95, ran it again and it was up to 12.05, still well below.

 

So just checked it there where got back and its at 2.75 and its only been sat for a day, no lights left on, doors not even locked so no alarm system on and the boot light is not the culprit, also pulled the stereo fuse...

 

Any ideas what its most likely to be....some earth wire missing or...?

[DanVW 0]

Check your glove box light, I put my phone camera on record chucked it in there to prove it was why my battery was not lasting as long as it should! :lol:

[dr_mat 0]

Also make sure it's being charged by the engine .. what's the voltage when the engine is running? Should be 13-14V.

And at 12 V after a run, it's probably still only about 20-30% charged, which means you only get about 10-15 Ah, and it'll go flat really quickly .. Also note that you should let the battery "rest" for a while after it has been charged - the voltage immediately after a charge will be unrepresentatively high, so your 12.05 volts could be false..

[gogsboy 0]

Will check the glove box, was yours coming on randomly or just staying on period?

 

Mat, checked the charge and it was about 13.75 or thereabouts.

 

I did leave it a little while but you reckon the 12.05 could be a fair bit less than that?

 

Will I be able to get it upto full charge by running or will I need to get a proper charger?

 

Are there any particular earths that I should look out for being broken etc

[DanVW 0]

Hi Mate,

 

The glove box light has an on off switch on it, when switched on in my car it always stays on where as it should switch off when the glovebox door is shut!

 

So its currently switched off and I very much doubt I will ever get round to fixing the switch! As the glovebox is a right bas*ard to remove :lol:

[dr_mat 0]

You should be able to fully charge the battery from flat after a few hours running, yes, but if it's holding 13.75 volts with the engine running I don't think you have a problem with the alternator.

Suggest you get clamp meter or an ammeter and hook it up in series with the battery to see what current you're pulling from the battery when the ignition is off.

To lose all power from a (60 Ah) battery in less than a day implies a current of over 2 amp, which is fairly hefty leakage.

If you can get a live current reading with the ignition off, the next step is to run through the fusebox pulling fuses until the current drops down to less than a few hundred mA (2-3 hundred milliAmps seems to be "normal" for Corrados). You will be unlikely to get it lower than this, short of removing ALL the fuses ...

[craigowl 0]

I have seen that a diy ICE fitting can be the culprit.

As dr_mat says, though, do the fuse check to try and identify source of drain.

[gogsboy 0]

Not to sure about all this milliamps etc and what I am really meant to be doing to be honest.

 

I had suspected the aftermarket ICE as I noticed sometimes when you flash up, no power to it at times but a slight push of the key and it starts up, now not sure if that to do with ignition barrel/coil or whatever or the stereo wiring.

 

Anyway I pulled the radio/stereo fuse in the box and it still drained pretty rapid. Maybe there can be other culprits regarding ICE when the fuse doesnt come into it, is that possible.

 

Also meant to ask, the car had tracker fitted as new and suspect its still in their somewhere but not active, heard a story that these batteries need changing every so often and can be guilty?

[Cnut 0]

If the ICE is connected to an amp make sure that the remote turn on lead is connected else the amp will stay on with the ignition off!

[waynos 0]

had exactly the same problem! i had loads little faults though.my rear light had a hairline crack in it....this lead to water sitting inside of the light all over the wires etc, dunno if that what caused the drain.

 

i also changed the ignition switch and it has been fine ever since!

 

check your starter motor wires.

 

oh and your alternator, leave the car overnight and feel it in the morning, if its hot theres your problem!

 

hope this helps

[dirtytorque 0]

I had a similar prob.

I kept having to jump start every few days.

I suspected the alternator until I checked the output voltage at the alt when the car was running.It was about 13.5volts.

 

But when I went to the battery it was about 11 volts.

It was the cable between the alt and the starter.Cleaned joints up etc and now all is well.

 

Check their is no disparity between the output voltage of the alternator and the battery voltage when the car is running and that it is charging at a good voltage level.

 

 

My glovebox has a switch inside.If you knock it when you stuff sh!t in there then the light stays on.

Not good for the battery :)

[matt-the-mussel 0]

My 2.0 16v had a traker, and a battery that would'nt hold a charge! whip your glovebox out and have a rummage. I found a big lead acid battery that was pulling about 200 mA, combined with short runs and not being driven everyday = flat battery! No problems since I removed it. 8)

[gogsboy 0]

I had a similar prob.

I kept having to jump start every few days.

I suspected the alternator until I checked the output voltage at the alt when the car was running.It was about 13.5volts.

 

But when I went to the battery it was about 11 volts.

It was the cable between the alt and the starter.Cleaned joints up etc and now all is well.

 

Check their is no disparity between the output voltage of the alternator and the battery voltage when the car is running and that it is charging at a good voltage level.

 

 

My glovebox has a switch inside.If you knock it when you stuff sh!t in there then the light stays on.

Not good for the battery :)

 

How do I check the voltage at the alt exactly? Only thing I have done is checked the reading at the battery while its running and it was 13.75 or thereabouts.

 

Glovebox is empty so doubt it be that but worth a check, away from home at moment though.

[dr_mat 0]

If the voltage across the battery is 13.75 then the alternator (and all it's connections) are perfectly fine. You have something that is leaking current when the ignition is off flattening your battery (or you have a dead battery .. ).

[Riley 0]

Disconnect the earth lead from the battery.

 

run a wire from battery earth to one pin on an indicater bulb.

 

run a wire from the earth lead on the car to the other pin on the bulb.

 

You may find that it lights up better than your headlights :lol: if there is a drain.

 

If it does,then pull individual fuses until its no longer/very dimly lit.

 

Neil.

[dr_mat 0]

That's a nice way of doing it. I was trying to use an ammeter in circuit .. it's a bit cumbersome..

[Kaktus 0]

Hi Mate.

I also havea similar problem except mine drains over 2-3 days. It turned out to be the window/central locking unit behind the drivers seat in the side panel. I still have the drain though, not sure what is causeing the unit to drain my battery. As i checked all switches and connections. :(

Worth a show in your case aswell?