MG-Cars.info

Welcome to our Site for MG, Triumph and Austin-Healey Car Information.

Parts

MG parts spares and accessories are available for MG T Series (TA, MG TB, MG TC, MG TD, MG TF), Magnette, MGA, Twin cam, MGB, MGBGT, MGC, MGC GT, MG Midget, Sprite and other MG models from British car spares company LBCarCo.

MG MGF Technical - flat battery

The battery on my 1998 vvc went flat when the car stood unused for a week. I had a new battery fitted and the same thing has happened. Either my new battery is duff or I have a cuurent leak.

Any experience or comments would be welcome.
Wil Wilkinson

Lots about this subject in the archives.
David Clelland

This is a not uncommon problem with more than one possible cause. Your battery will not be duff.
See the archives

Sticking MEMS relay, boot light switch, Chaffed wires (behind centre console or from boot lid).

Jon Baker

My bet would be broken wires shorting out in the boot causing the boot light to remain on after closing. Another prob caused by the same fault is the alarm can trigger when opening/closing the boot lid when the alarm is armed (you should be able to do this without firing alarm).

Have a look at the wires on the left hand side boot hinge, you will probably have to peel the tape back to see - IIRC there are 5 wires in there.

HTH

Steve

Steve P

Hi Will,
Yes my 2004 model has a similar problem. Does your battery have a charge indicator on it? I noticed that mine was showing 'green'when I parked up overnight, but by morning was showing 'black', indicating that there was a current drain.
I put a multi meter in series with the battery (Just disconnect one of the battery leads and put the meter in between) It was reading nearly 0.7 amps when the engine had been switched off. This fell to 0.04 amps after 15-20 minutes. This is to keep the MEMs powered for regulating cooling fans etc after engine switch off. At this discharge rate it would take 68 days for the battery to be completly flat.
I opened and closed the boot, doors etc and I could see the current going up and down as I did it, so no problem there with bulbs staying on.
I reconnected the battery and drove into my garage, but by the morning the charge indicator was showing black again.
What I suspect is that disconnecting and reconnecting the battery is freeing a sticky relay (on the MEMS?)which is not happening after the timeout period.
As I have a warranty I am taking it into the main dealer who will put the car on Testbook. I'll let you know what happens.
Graham
GrahamH

Well, the main dealer could not find a problem. Firstly they said it was my audio equipment as it was drawing over 0.5 amps, but a reference to the handbook showed that this was normal for 30 minutes after switch off (its a Blaupunkpt by the way). So I had to pay £81.00 and no fault found.
Moral of the story? Do it yourself!
GrahamH

Just to add to the confusion, I had a spell of losing charge, not fixed by a new battery. I could measure a definite current flowing with everything turned off. It eventually stopped doing it, and has been OK since, touch wood!
M Cunningham 1

This thread was discussed between 10/04/2007 and 14/04/2007

MG MGF Technical index

This thread is from the archives. Join the live MG MGF Technical BBS now