battery issue when leaving door open

[bluesky110]

hi all ,
just had aa out again to jump start my custom ltd lwb . side door was open for max 5 minutes while unloading - then wouldn't start . apparently only had 10volts stored . battery checked and fine - charging as it should . losing confidence in opening doors now dark nights and mornings are here .
could this be just a crap battery or common problem ?
I see a few questions about second batteries but surely battery should last for longer than that ??

[Altransit]

Faulty batteries aren't unknown, and if it's 3 years old or older, that's about the life these days.
It may be taking a charge and holding voltage, but it's capacity is probably down, especially of an open door for 10 mins is causing a 2.6volt drop.
Get it tested with a proper drop tester, which takes a high current discharge, voltage reading. If it doesn't recover after a 15 second high load test, it's no good for starting a van

[S60r]

Yes as above.... the oem Ford batteries are average.. if 10 mins has left the battery flat it is pretty useless. Time for a new one, perhaps worth going LED on all lighting to lessen the draw when you are loading, but a decent battery from eurocarparts etc will cure your problem. Once they have lost their charge they are never the same again.