After parking my car whilst away for 4 weeks came back and the battery was completely dead. Not even warning lights on the dash. AA guy came and measured only 3 volts across the battery terminals. After starting ok with his booster pack he tested the battery and charging system and after leaving it running for 15 minutes he pronounced the battery ok. I have never had this before with previous cars that have had batteries much older than 18 months. The car has start/stop system (which I usually turn off) so the battery is quite a large high capacity type so shouldn't drain so quickly to such a low level. I am always careful to turn off the interior lights and entertainment system completely before I leave the car for more than a few days. If any members have ideas on what else to check it would be much appreciated. Also I thought that home trickle chargers could not be used with these EFB batteries used on cars with start/stop, but the AA guy seemed to think it was ok. The charger I have is a Ring Smartcharge 4 amp, the small electronic type about the size of a cordless phone.

Does your car have sat navigation? I'm sure I read on here about versions with sat navigation and or rear parking sensors having a battery drain. I seem to have in my mind it was if you manually switched your entertainment system off rather than it just going off itself when keys out and a door opens.

I'm quite possibly getting mixed up though

Thanks Allan for your reply, I don't have satnav but my car has factory fitted rear parking sensors.

I did a search around on here before I posted but didn't find anything

Alot of the battery drains on newer fiestas can be solved with a firmware update!

Thing to note, with a 100mA drain, a 60Ah battery will be flat in ~4 weeks. I've been trying to find the drain caused by an alarm/immobiliser but can't seem to find typical values. I have this prob with my camper-van which isn't used much suggesting that the alarm/immobiliser must be ~100mA which seems high. 10mA I could believe.