M8TJT manual states 40 mins using hardwired connection earth and ACC 12 volt utilising 9 amps, connceted via 15 amp unused fuse... for my case rear cig but dont have but is wired in car, so even driving 3 short journeys get a full charge
at extreme settings between 20 and 22.75 hours... i know the battery is expensive at first but i see it's value over 3 years and not having to buy another oem battery like i have once in last 10 years, 2 other times BMW and Mercedes Mobile
rescue replace the battery later after charging to be able to drive the car back home... i was very lucky there on those occasions, as they know all about your car and service agreement, so it makes me think they want to keep your loyalty..
After considering everything the Neo 6 is probably the best buy, both batteries are made by same firm Egen... same specs but i found this out 1 hour after my purchase for BV B-124...