OK. I have a handful of other quality chargers but they are not with me at the moment so I have the following issue (or non-issue). The Viking microprocessor smart charger seems to work well on big and small batteries. It works on regular flooded, AGM and gel. On my ATV with a five year old AGM battery it maintains the battery in float at 13.1 - 13.2 volts. Didn't really give the low float voltage a thought since I'm at my remote retreat with solar and don't float anything long term up here. I put it on my R1250GSA with a three month old AGM battery and it maintains that battery in float at 13.5 - 13.6 volts. MY ATV cranks over just fine but I can't understand why it would float at .4 volts lower. Initially I was thinking I should get a new battery but I saw a review on Youtube of the charger and it was floating his snowmobile AGM battery at 13.1 volts. Do the BMW factory batteries have a higher resting state of charge? I though they were Yuasa AGM batteries just like my ATV. I really don't want to spend $60 on a new battery if mine is fine but on the other hand I need a reliable starting ATV or I could get stranded after dark in Griz country.