Berlingo 1.9d battery keeps going flat?

[tmm]

Hi
My berlingo 1.9d 2004 battery keeps going flat, tried another battery and that went flat. The battery light come on when i 1st put the ignition on, but is not coming on when the car is running so i am assuming its not the alternator.
The car has been fine up until now. The only other thing that has been changed on the car recently is the alternator belt but i have checked this and it tight enough.
So now i,m looking for suggestions please.

[Peter.N.]

Connect a voltmeter meter across the battery with the engine running, it should read about 14.4 volts, much less and your alternator is duff.

Peter

[tmm]

Thanks Peter
Done a few tests today.
I checked the battery and its 12.62, then i checked the battery with the engine running and that read 14.48, I then turned all lights on,blower, wipers and rear demist and the voltage was 13.28, I then cranked the engine over and the battery went down to 10.80 while turning until it fired up and then it went back up to 14+ volts.
Do these seem fine to you Peter?

[spider]

The drop seems a bit much.

It could be a weak battery (internal short) which would flatten it. The way to test this (although not always practical) is to disconnect it and if it does go flat when disconnected then its at fault.

Seeing as you've tried a few batteries then I doubt its that. other causes are a continual current drain or a low alternator output, bear in mind it is charging as you said if its going to 14/15v but how much is it charging ? if its only putting out 1A or so ( ! ) then it will not help.

You could try one of the usual outlets for a free battery (and more importantly alternator) check, an induction ammeter can be used to check the output current.

Its rare but its not unknown for diodes in the reg/rec to go short circuit which could flatten the battery from what I remember, the thing with this is it may behave normally(ish) and the excitier will still function hence the light behaving properly.

Is worth checking the main battery / alt leads (both ends) and engine earth leads for corrosion etc, Clean them up as required.

[Peter.N.]

I don't think a voltage of 10.8 while cranking is at all bad, the starter is drawing several hundred amps and the battery has some internal resistance, I have known it drop a lot lower than that.

13.28 does sound a bit low but if you have only just started the car the alternator is also charging the battery, try doing this test again after its been driven for a while.

Peter

[addo]

You can try disconnecting and insulating (temporarily!) the wires to your alternator.

[wheeler]

It would be perfectly acceptable for a battery to drop down as low as 9v on cranking.
You really need an ammeter on this to check the current draw at rest, after about 3 minutes when the BSI shuts down there should be a reading of around 0.04 amps.

[tmm]

Hi
Would this 1 do the job? as i have this.
http://www.screwfix.com/p/lap-mas830b-d ... 600v/75337" onclick="window.open(this.href);return false;

[Peter.N.]

Yes, that should be OK, it also has an 'Amps' range so you could check for battery drain. For volts you connect it across the source, for amps in series i.e disconnect a battery lead and connect the meter between the two connections you now have.

As already mentioned it could be an alternator fault that is discharging your battery. Remove the battery lead, connect the meter between the battery terminal and the lead set to the amps range. First stop the engine and wait a couple of minutes for everything to shut down, connect the meter and check the reading, it shouldn't be much more than about 50ma = .05amps, if it is probably the first thing to disconnect would be the alternator, see if it makes any difference.

Peter

[tmm]

Not sure if im doing this correct.
I set the multimeter on as seen in diagram i then took the neg lead from battery with everything switched off in the car, i placed the red lead from meter to the neg lead that goes to the battery then placed the neg lead on multimeter to battery neg terminal and the meter read 0.00.

This is how i have the meter set?

[ekjdm14]

Not sure if im doing this correct.
I set the multimeter on as seen in diagram i then took the neg lead from battery with everything switched off in the car, i placed the red lead from meter to the neg lead that goes to the battery then placed the neg lead on multimeter to battery neg terminal and the meter read 0.00.

This is how i have the meter set?

Yeh that looks/sounds right, lead is in the correct socket etc, have you checked the fuse in the meter? it could already have been blown in the past if someone overloaded it. Or it could have blown the fuse when you connected it, if the battery goes flat quickly it's possible you have a draw over 10a... (you could test this theory by substituting the meter for a 10a or less blade fuse i.e. connect the fuse between Battery neg & earth lead see if it blows.)

[Peter.N.]

It should be reading something, as suggested you may have blown the fuse, on no account should you connect the meter across anything on the amps range as it has virtually no resistance. Does it read OK on the volts range across the battery?

Peter

[old-un77]

0.00 looks suspicious to me too.......

find a 12volt headlight bulb and connect it to the +ve battery lead and the battery post( or earth lead and car) and remove lead leaving the bulb in series, after the bsi has closed down, any decent glow to the bulb will show a leak.........60watt/12volts = about 5 amps.......
Bob

[tmm]

It should be reading something, as suggested you may have blown the fuse, on no account should you connect the meter across anything on the amps range as it has virtually no resistance. Does it read OK on the volts range across the battery?

Peter

Yeah the volts across the battery is reading fine Peter, i have checked the fuse in the multimeter and it seems to be fine,
ritch

[tmm]

Not sure if im doing this correct.
I set the multimeter on as seen in diagram i then took the neg lead from battery with everything switched off in the car, i placed the red lead from meter to the neg lead that goes to the battery then placed the neg lead on multimeter to battery neg terminal and the meter read 0.00.

This is how i have the meter set?

Yeh that looks/sounds right, lead is in the correct socket etc, have you checked the fuse in the meter? it could already have been blown in the past if someone overloaded it. Or it could have blown the fuse when you connected it, if the battery goes flat quickly it's possible you have a draw over 10a... (you could test this theory by substituting the meter for a 10a or less blade fuse i.e. connect the fuse between Battery neg & earth lead see if it blows.)

Fuse in the meter is fine as i have just checked it.