Door/tail open battery drain

[caseyjay]

I tried the OBC battery test - 13.5v when driving, 11,5v when I come to a stop but oddly restarted and drove again. Came home and did the 5 mins with main beam on/engine off test, now drops to 10.4v and no start.

Am guessing I've been lucky so far it's not stranded me already.

Now I need to take a trip this weekend and will be away > 1wk. Normally I'd buy online but not going to receive it in time.

Either I buy local now - Fulmen/Exide
or
I go with my battery charger/leads and wait until I can get a 'better' brand.

What would you do? It's my first BMW, normally I'd buy Bosch for my Audis, not sure of Fulmen? Any views?

thx

[TiAgX5]

Originally Posted by caseyjay

I tried the OBC battery test - 13.5v when driving, 11,5v when I come to a stop but oddly restarted and drove again. Came home and did the 5 mins with main beam on/engine off test, now drops to 10.4v and no start.

Am guessing I've been lucky so far it's not stranded me already.

Now I need to take a trip this weekend and will be away > 1wk. Normally I'd buy online but not going to receive it in time.

Either I buy local now - Fulmen/Exide
or
I go with my battery charger/leads and wait until I can get a 'better' brand.

What would you do? It's my first BMW, normally I'd buy Bosch for my Audis, not sure of Fulmen? Any views?

thx

Driving with a dead battery will cause alternator/regulator failure.

A new battery will be 12.7 to 12.9v (100%), 12.2 is 50%, 11.7 is 0% (dead!). Charge the battery overnight, turn on headlights for 30 secs, then check voltage.

Many BMW owners replace the battery when the result of above test shows 12.2 (50%). This increases alternator/regulator life & avoids false trouble lights.

[caseyjay]

Originally Posted by trader4

You mean it has 11.5V when the car is idling, but not moving?

No I had the IBC on test 9 and 13.5v showing when driving, but when I turned everything off it dropped to 11.5v.

Have tested more today and regularly holding 13.4-13.6v when running so am hoping alternator is ok.

Not too sure about my battery charger though - only has 2 settings - 0-20Amp (marked for bikes) and 15-60Amp (marked for cars). Had it charging overnight on 15-60 and only reached 12v this morning so guessing dead cell.

Will check date on battery.

Is this something I should replace immediately or can it wait a week of further usage whilst awaiting delivery...?