Flat Battery
Moderator: martauto
when you've charged it up take your car and get a battery test done
on it at one of these motorfactor places they do em for free
as it could be either a knackered battery or you've a power drain on it
has it got an alarm fitted? as mine has a clifford one fitted and it drains
mine if it's been parked up for a week
on it at one of these motorfactor places they do em for free
as it could be either a knackered battery or you've a power drain on it
has it got an alarm fitted? as mine has a clifford one fitted and it drains
mine if it's been parked up for a week
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Middy26
- E30 Zone Newbie
- Posts: 32
- Joined: Wed Mar 30, 2005 11:00 pm
- Location: Swansea S.Wales
- Contact:
Sorry Jason mate i have no solution but i do know how annoying it is as my battery is doin exactly the same thing except mine goes flat in about 1-2 days 
at first i thought it was my sub and amp maybe id wired them in wrong and they were draining the battery but its not cos ive taken them out and its still goin flat 
hopefully its a common fault that someone knows about and they can put an end to our misery
Fingers crossed
Matt
at first i thought it was my sub and amp maybe id wired them in wrong and they were draining the battery but its not cos ive taken them out and its still goin flat hopefully its a common fault that someone knows about and they can put an end to our misery
Fingers crossed
Matt
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Andy_magic
- E30 Zone Camper
- Posts: 1121
- Joined: Tue Feb 22, 2005 11:00 pm
- Location: Cambridge
A common cause of this is the diode pack in the alternator dying.
The easiest way to check is to charge your battery up and fit it to the car, start it up to make sure the battery is really charged.
Switch off the engine, remove the battery negative cable and then just touch it against the negative battery post, there should be a slight spark, if you get a fairly decent spark something is drawing power that shouldn't.
Next, unplug all wires from the alternator and do the 'touch the wire against the battery post' bit again, if it sparks less you have found your culprit.
If you have a multi-meter, use it and see how much current draw is flowing with ignition off etc, make sure all doors are closed etc so no lights are on.. blah blah.
What can happen with alternators is that the diodes (think one-way valve) give up, allowing electricity to flow both ways.
With the engine running, the alternator charges up fine, with power flowing from the alt. to the battery, when the engine is not running, the faulty diode lets power flow back from the battery to the alt. and energises the coils inside it, flattening the battery in the process.
I have seen this problem many times, don't rush out and buy an alt. do the tests first as it could well be a dodgy alarm/stereo/amp/boot light etc.
Worth a go though
The easiest way to check is to charge your battery up and fit it to the car, start it up to make sure the battery is really charged.
Switch off the engine, remove the battery negative cable and then just touch it against the negative battery post, there should be a slight spark, if you get a fairly decent spark something is drawing power that shouldn't.
Next, unplug all wires from the alternator and do the 'touch the wire against the battery post' bit again, if it sparks less you have found your culprit.
If you have a multi-meter, use it and see how much current draw is flowing with ignition off etc, make sure all doors are closed etc so no lights are on.. blah blah.
What can happen with alternators is that the diodes (think one-way valve) give up, allowing electricity to flow both ways.
With the engine running, the alternator charges up fine, with power flowing from the alt. to the battery, when the engine is not running, the faulty diode lets power flow back from the battery to the alt. and energises the coils inside it, flattening the battery in the process.
I have seen this problem many times, don't rush out and buy an alt. do the tests first as it could well be a dodgy alarm/stereo/amp/boot light etc.
Worth a go though
Here something you might find helpfull. I don't know where you can buy this outside scandinavia...
It is called a Startloop. You just plug it in the cigarett-output and wait for a beep and turn the ignition. After starting the car... leave it in the cigarett-output until it beeps again. Now you got power on it to start the car next time you left your car standing. Picture below (so you know how it looks like).
It is called a Startloop. You just plug it in the cigarett-output and wait for a beep and turn the ignition. After starting the car... leave it in the cigarett-output until it beeps again. Now you got power on it to start the car next time you left your car standing. Picture below (so you know how it looks like).
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Brianmoooore
- E30 Zone Team Member
- Posts: 49358
- Joined: Mon Jan 10, 2005 11:00 pm
To sort this out you need a milliampmeter and a bit of logical fault finding.
Meter doesn't have to be anything fancy. Just needs to be able to measure up to abot 2A DC.
Meter doesn't have to be anything fancy. Just needs to be able to measure up to abot 2A DC.
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Mahmood
- E30 Zone Camper
- Posts: 1340
- Joined: Mon Jan 10, 2005 11:00 pm
- Location: People's Republic of Londonistan
Kenneth
Where do you get a startloop from?
I am thinking of buying a solar panel to slowly charge in the glorious sun
we have here in London.
Check it out:
http://www.maplin.co.uk/Module.aspx?Mod ... D=&doy=4m4
Where do you get a startloop from?
I am thinking of buying a solar panel to slowly charge in the glorious sun
we have here in London.Check it out:
http://www.maplin.co.uk/Module.aspx?Mod ... D=&doy=4m4