battery discharging

[avants2turbo]

the battery on my s2 avant keeps discharging, its fine while driving, and the voltage meter on the centre consol reads 13v when the engines running, when i park up at nite, set the alarm and get to it in the morning and the car wont start, anything i should check?

[K Simmonds]

Could just need a new battery, would be the first thing I'd check.

[EspenW]

13v sounds sorta low. How much voltage at battery when engine is running.
Could be a short circuit somewhere. Test battery drain with the ammeter function on your multimeter

[Bosscat]

Flat Battery

Check the afterrun pump relay has not gone !!! - Had that - every morning - flat battery - bought a new battery - still flat in the mornings.

Eventually - what is that whirring noise with the engine off - changed the relay and hey presto !

Tis a thought !!!!!

Regards

Martin

[Rusty]

Should be closer to 14v when running, check the alternator output with a voltmeter. Check the battery when not running too.

[Flat on my back]

Should be closer to 14v when running, check the alternator output with a voltmeter. Check the battery when not running too.

Could try a new reg. from here

http://www.woodauto.com/Component.aspx?Ref=VRG46410

Or a standard one is VGR4641.

[HPmuirt]

Do the old alternator/battery/wall test.....

Park in front of a wall preferrably when it is dark, start the engine and turn on the headlights. Then rev the engine - if the lights get brighter then you have a flattish battery but your alternator is fine.

If the lights do not get brighter, turn on the rear demist, the fan, the aircon, the main beam and the fogs and repeat.

If the lights still don't get brighter when you rev, you either have a super efficient alternator which is making full current at 800rpm (quite possible) or a dead VR.

This also works on the voltage gauge but is more fun with the lights

Cheers n

Si

P.S. I agree with the others, you should be seeing 14V with the engine running.

[Acidburn]

i'm seeing just over 13 with the engine running and at nights 13, same on two alternators.

Btw si, did you mention that at the herts meet you had problems with alarms when you left the car at airports and it draining the battery, how did you solve this?

[HPmuirt]

Btw si, did you mention that at the herts meet you had problems with alarms when you left the car at airports and it draining the battery, how did you solve this?

T'was a two part solution: -

1. New 78A/h battery

2. Do not park at the back at Pink Elephant at Heathrow! Seriously, when I had a flat battery the chap in the office walked over with a booster that they have permanently on standby. When I asked if he did this often.....

He said 'all the time now that the fully laden 747's bound for India take off from the nearest runway'

'Huh' says I 'seriously?'

'Yup' says he 'they now take off from the runway just the other side of the fence and use full boost which produces so much noise and vibration, all the car alarms go off'

As he said that, an Indian 747 came past on full reheat, turbos spooling, all the passengers pedalling and double nitrous injection. As the incredible noise quietened down, I realised that all the cars down the rear of the car park had sirens and flashing lights going

Cheers n

Si

[Acidburn]

Yeah remember it was something like that, I was thinking of investing in one of them small solar panels and hard wiring it in with a cut off switch for when I use the car so I don't end up with a flat battery all the time.

My cars currently parked up with the battery unplugged as it ain't going anywhere anytime soon.