Where is the battery on a 1991 735i

OK...it was on under the back seat beside the driver. Easy job, took about ten mins to replace. Started it up for the first time in 3 months...ran rough as a badgers arse for a few mins and kep cutting out. But the idle smoothed out eventually.

Also had the battery warning light on and ABS and break circuit warning lights on while idling. I narrowed this down to a seized up alternator which I freed up with a large spanner, now it's running like a beauty. Amazing cars! Three months of sitting outside over a winter, and it more or less starts up and runs fine within

Hmmm, my 1990 GM/Vauxhall/Opel crap-box started up first turn of the key and run's just as well as it ever has after sitting for 4 months outside over the winter so I wouldn't exactly call your experience amazing, but then I wouldn't call the winter we've had a real winter anyway, except or today.

Top of front right wheel arch.