Battery gone flat - AC related?

[newsh]

Been using the AC the last couple of days, I noticed when I walked away from the car the fan cut in, later on it had stopped so didn’t think any more about it.
Went down the shops earlier, when I came out 5 mins later there wasn’t enough juice in the battery to start the car, when I switched off and withdrew the key there was a clicking, chattering noise from under the dash on the driver’s side.
Same story with the AC switched off..

One of the lads brought me down a spare battery and the car fired straight up.

Any clues what it might be?

I guess first job is to check it’s properly charging!

[John.]

Could using the AC just be coincidental ?...…… maybe the after-run relay under the dash is dodgy?

……...a good battery would still crank the engine after 5 mins of the fan running though. As you say, check charging system first.

[newsh]

I know the AC switch activates the first stage of the fan, so perhaps the relay is dodgy.

With a fully charged battery there’s no clicking from under the dash.

Charging seems to be good according to the voltmeter.

I’m going to leave the spare battery in and see if it stays up overnight.

Maybe my old battery is on the way out and the hot weather and after run fan action has finished it off.
I’ve got it on the smart charger to see if it recovers.

[orsum]

My battery was going flat over about two weeks. Now that I removed an old tracking unit that I found in the rear side panel of the boot the battery seems to be holding its charge.

Dropping a full battery charge in 5 min seems to be a bit more than a slight drain.

Guessing its the battery that's at fault.

[newsh]

Yes I think the battery must have just died.

[piotr]

Just do the battery drain test to be sure that nothing is staying live on the car John