Battery OEM Toyota or OEM BMW

I was told to replace the small battery in the back with an OEM battery from Toyota (oddly much cheaper). Problem solved. So far. :)

For about a month I have owned a 2016 REx whose 60 Ah battery is supposed to get 72 miles. This week I fully charged it and have been commuting four four days without topping up. Today the REx kicked in with the trip meter at 73.3 miles. This was a mixture of city traffic jams and short bursts on the carriageway, mostly with the air con on and mostly in Comfort mode. So I'm pretty pleased.

I am still on my original battery in my 2007 335i w/ 87k miles.