Quote:
Originally Posted by Moopai
I see different ones offered from Ctek, is there a specific one you recommend? Do you connect the charger to the battery next to the engine or the one in the trunk? Thanks
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I use a Ctek MXS 5.0 (see link below), as do many others from another forum I’m on. It has settings for small and large 12 Volt AGM and non-AGM (flooded lead acid) batteries. AGMs charges to a slightly higher voltage (300 milli volts) than non-AGMs.
It also has a “Recondition” setting, but it’s only used on non-AGM batteries to help prevent stratification. AGMs are not prone to stratification.
Ctek is the rebranded charger/maintainer sold/provided by Mercedes, Porsche, Ferrari and others.
https://smartercharger.ca/collection...s/ctek-mxs-5-0
Pg. 282 of my 2023 BMW Owners Manual states:
“Only connect battery chargers for the vehicle
battery to the jump-start terminals in the engine
compartment.”
I’ve confirmed that the small Li-ion battery's “battery controller” receives voltage from the charger/maintainer; however, I did not measure directly at the Li-Ion battery's output terminals to confirm it was charging. If I ever find those terminals I will measure and update.
Edit: I just re-read your post. The battery "next to the engine" in the M850i is the small Li-Ion battery located in front of the passenger side firewall. Do not connect the charger there. Only connect the charger to the jump-start terminals.