battery draining constantly

[chris290582]

can any of you nice helpful knowledgable people give me any clues as to why i m getting a dead battery every day and the batterys are becoming so flat they wont accept a charge.
this is a project im putting back together and every day i go to see it the battery is f**ked.
any help much much appreciated.
chris.

[modfather]

have you tried a new battery

[DaveMayGTT]

Also make sure that nothing electrical is being left on. Exactly the same happened to me, took me a while to realise that my fan to the air vents had developed the ability to stay on after keys are removed from ignition.
Funny french wiring!

[UnstableCable]

Also make sure that nothing electrical is being left on. Exactly the same happened to me, took me a while to realise that my fan to the air vents had developed the ability to stay on after keys are removed from ignition.
Funny french wiring!


I had a simular problem with the battery draining over night, turns out the fog light switch was left on and was draining the battery even though the fog lights wernt connected! :scratch:

[Spooky]

When the battery is fully charged, get a voltmeter across the terminals and see what the cranking voltage is.

You should be seeing a constant 12-14v once its fired up.

Check the condition of the earth straps and add more if necessary, too many earths won't do it any harm.

If the battery is new and reliable, I would then suggest trying another alternator :)

[chris290582]

have you tried a new battery

yeah i have even put a bigger bat on and it killed that too

[chris290582]

When the battery is fully charged, get a voltmeter across the terminals and see what the cranking voltage is.

You should be seeing a constant 12-14v once its fired up.

Check the condition of the earth straps and add more if necessary, too many earths won't do it any harm.

If the battery is new and reliable, I would then suggest trying another alternator :)

ok, im going to the car tommorow so i will borrow a volt meter and try that. also go round all the switches and fans & lights make sure they r all off.
thank you for advice

[Ian S]

Do you leave the car for long periods between driving it?

How long a does charged the battery last?

As mentioned, have you checked to see the alternator is charging?

If you can, take off one battery terminal and use a multimeter to measure the current being drawn with everything switched off.

Multimeters eviscerate at car style currents, so don't try it with the engine running or starting, etc.

There should be no milliamps. But in your case there probably will be.

You will then need to trace the thing(s) that still drawing current.

It might be the security system. It only needs to be a tiny current to flatten the battery in 2 weeks.

[chris290582]

Do you leave the car for long periods between driving it?

How long a does charged the battery last?

As mentioned, have you checked to see the alternator is charging?

If you can, take off one battery terminal and use a multimeter to measure the current being drawn with everything switched off.

Multimeters eviscerate at car style currents, so don't try it with the engine running or starting, etc.

There should be no milliamps. But in your case there probably will be.

You will then need to trace the thing(s) that still drawing current.

It might be the security system. It only needs to be a tiny current to flatten the battery in 2 weeks.
ok, the battery is dead the next day, the car doesnt get driven it is just getting put back together after engine on subframe being out and put back in

[Ian S]

That's quite a bit of current then. Possibly too much for a multimeter.

Maybe you pinched and cut through a wire as you fitted the engine back in?

Or connected +ve wire to earth by mistake?

[SCHWARTZ]

My battery does this also, thought it eas the alarm or amps so disconnected them bit still went flat. Do you get a blue spark when you connect the batt earth as this could mean a short somewhere or something is constantly on and drawing current.

[chris290582]

many thanks for all your advice, im very grateful and you have given me a some stuff to check now , i will be seeing the car over the weekend and let you know the outcome.:agree:
chris

[markey b]

silly suggestion, but how about not keeping the battery connected at the mo

[chris290582]

ok, ive been to the car and jumpstarted it off a pack, let it run for 25 mins and turned it off so the battery got some charge in it.
the volt meter read with the engine off and keys out of the ignition at the battery 11.35.
does that mean that there is something drawing 11.35 volts from the battery with every thing off? ive left the multi meter where i can see it through the windscreen and went through every switch and light on the dash and the number didnt move off 11.35.?
any ideas on that guys? im goin again tommorrow, so a couple of things for me to test would be nice to try and fix this problem.
chris.

[IANMM]

no mate thats just showing the voltage at the battery :)

[chris290582]

no mate thats just showing the voltage at the battery :)

oh ok, but the battery keeps going flat by the next day and i dont understand it. im just throwing anything up in the air hoping to get some light shed on this.

[Ian S]

You need to measure it with the engine running to see if the alternator and wiring are OK.

Should be about 13.6 volts with engine running.

Voltage is the difference between one point and another for current to potentially flow.

The higher the voltage, the higher the potential.

If current flows, the voltage often drops.

When you switch an item on, that allows current to flow from the battery, through the item and back to the battery.

Actually what's happens is that electrons are released from a stored 'compressed' state within the battery, pumped 'backwards' into there by the alternator. Once released those electrons run forwards around the circuit from one battery plate to the other going through the item or 'load'. In so doing, the potential for further flow has been reduced, so the voltage has dropped.

A 'load' has a resistance to flow. The lower the resistance, the more current flows.

[chris290582]

You need to measure it with the engine running to see if the alternator and wiring are OK.

Should be about 13.6 volts with engine running.

Voltage is the difference between one point and another for current to potentially flow.

The higher the voltage, the higher the potential.

If current flows, the voltage often drops.

When you switch an item on, that allows current to flow from the battery, through the item and back to the battery.

Actually what's happens is that electrons are released from a stored 'compressed' state within the battery, pumped 'backwards' into there by the alternator. Once released those electrons run forwards around the circuit from one battery plate to the other going through the item or 'load'. In so doing, the potential for further flow has been reduced, so the voltage has dropped.

A 'load' has a resistance to flow. The lower the resistance, the more current flows.
ok, i read that a few times and understand now about the current and flow of electrons.
im going to go back to the car tommorrow and see what the reading is with the engine running.
is it possible that the alternator is wired incorrectly and constantly drawing power or something?

[Ian S]

is it possible that the alternator is wired incorrectly and constantly drawing power or something?Maybe. That will be ruled out if the voltage is 13 or so.

If the battery is drawing a lot from the alternator, the voltage will be a downa bit until the battery has charged.

So if it was just over 11V then goes up to only 12V with the engine running, the alternator may still be OK.

If it doesn't go up at all, or goes down, then there's a fault somewhere.

We can only make guesses as to where.

First things first though.

[chris290582]

Maybe. That will be ruled out if the voltage is 13 or so.

If the battery is drawing a lot from the alternator, the voltage will be a downa bit until the battery has charged.

So if it was just over 11V then goes up to only 12V with the engine running, the alternator may still be OK.

If it doesn't go up at all, or goes down, then there's a fault somewhere.

We can only make guesses as to where.

First things first though.

ok, much appreciated, iw ill do some more work tommorrow and report back with the volt meters readings and anything else which may help me on my quest to beat this fault :)

[chris290582]

done some fault finding today and may have found the problem.
with the relay that is on the passenger side that has the horn connectors from it, i put the volt meter on the battery with the relay in and its reading was 11.35. with the relay removed it was 11.92.
the engine was off when i did this test and it was the only thing drawing a charge without engine running.
maybe a wiring fault to that relay somewhere.
with the engine running the voltmeter read at the battery 13.89.
would the 0.57volts be enough to drain the battery overnight? if so i think i have found the problem.

[IANMM]

done some fault finding today and may have found the problem.
with the relay that is on the passenger side that has the horn connectors from it, i put the volt meter on the battery with the relay in and its reading was 11.35. with the relay removed it was 11.92.
the engine was off when i did this test and it was the only thing drawing a charge without engine running.
maybe a wiring fault to that relay somewhere.
with the engine running the voltmeter read at the battery 13.89.
would the 0.57volts be enough to drain the battery overnight? if so i think i have found the problem.


hmmm i wouldn't of thought that the relay would cause a draw like that as in theory the horn would be sounding if the relay was in a closed position.....(i assume your horn is working? ) the problem you have is with the age of the cars over the years the loom has been cut into so many times a problem quite literally could be anywhere....not also taking into account the natural aging of the wiring....

you really want to find out the current draw not the volt drop.....have you got or know anyone with a clamp meter?

[chris290582]

hmmm i wouldn't of thought that the relay would cause a draw like that as in theory the horn would be sounding if the relay was in a closed position.....(i assume your horn is working? ) the problem you have is with the age of the cars over the years the loom has been cut into so many times a problem quite literally could be anywhere....not also taking into account the natural aging of the wiring....

you really want to find out the current draw not the volt drop.....have you got or know anyone with a clamp meter?

the horn doesnt work the compressors broken on it, unfortunatly i dont know many mechanically minded people or for that matter people with job specific tools.
the wiring had been cut at where the engine loom should connect to its o.e connector and put on a choc block the problem may be there.

[IANMM]

have you put your tester on the horn to see if the "broken" compressor is drawing anything.....or is it disconnected?

simple test would just be to pull the relay out as your horn isnt working it wont make the blind bit of difference :)

[Sparkie]

if the compressor is ok.....

remove the drivers side indicator lamp and the bumper. - under the headlamp is a three pin connector - make sure its not burned out.

i had this happen and the horn and fog lights didnt used to work. - fog lamp indicator on the dash glowed half brightness.