Flat battery!!

[mildwin]

Had to call breakdown because my car (fiesta auto 1994) wouldn't start, was told it needed a new battery. For a week it was fine, then for a couple of mornings it needed a few more revs to get it started, after 10 days my new battery was flat too! Car wouldn't start so had to get breakdown again, jumpstarted it but now dead. mechanic says alternator is fine & he can't find what could be draining the battery. Says I must be leaving something on but there is nothing obvious I can see. Have not been driving at night so have not had headlights on, interior light is not on, glove box doesn't appear to have a light & boot light only goes on when boot is opened. So what on earth could be the problem with it?? Any ideas much appreciated, is there anything that we have missed? May seem silly but if interior light bulb has blown but switch was in the on position would that drain it, even if there is no light coming from it? Not saying that that is the case, just clutching at straws!!

[spaced]

are you sure your boot light is not coming on when the door is shut? double check. Could be the alarm or immobiliser.

We had the same problem with one of our cars on the fleet, battery kept dying, RAC could not find the fault. It was later found to be a loose brake pedal. When the car was left overnight the brake pedal would slightly sink, causing the brake lights to come on and stay on all night.

[mildwin]

Thanks. Its not the same problem you had as the brake lights are not coming on. I will recheck the boot light but do not think it was that. Would the mechanic not have checked that anyway? It was 10 days between having the new battery & the battery going flat again. Could there be anything else draining the battery other than lights on?

[ugly_bob]

not sure specifically.
I had a Fiesta a few years back with a manual immobiliser switch. If I didn't switch it, the battery would be dead in the morning.

[homer75]

I would suspect the alternator - there may be a diode fault which is draining the battery. Unplug it when leaving it overnight then reconnect it in the morning and see if that cures the battery drainage. If it does then you need a new alternator.

[mildwin]

Mechanic says the alternator is fine, he has checked it. He thought it was going to be a drain somewhere but he can't find one!

[mildwin]

Have rechecked boot light & it is NOT on, only comes on when opened.

[kwicky]

It might be too simple a solution but is your alternator belt slipping?

[pianoman81]

i know its not advice really but i used to have a fiesta 1993- had it for 12 months, nothing went wrong,then all of a sudden it always seeemed to have electrical problems, loose connections here and there- battery flat, numerous alternators, starter motor etc etc, so if you manage to get this sorted and i hope you do, get it sold as youll just be throwing money at it from here on in- its suprising what you can buy for less than �1000.
good luck though.

[mildwin]

I'm not a mechanic, in fact I just about manage the petrol & oil!! I wouldn't know if a belt was slipping or anything like that. I just go by what my mechanic has told me, which is that the alternator is fine. Guess he would have checked that the belt was ok too?? Will let you all know what the outcome is, hopefully something easy & inexpensive to fix!!

[mildwin]

Mechanics just been again & turns out it IS the alternator! Any ideas how much??