Wondering which battery tender you all use for the 2017/2018 and above models, it has the smaller AGM battery. I put my supposedly "intelligent" battery tender on my 2018 GT a few months ago and something made me need to start it yesterday and ....stone dead, nothing. Checked the battery voltage, 3.4 volts. Used a Ctek Zafir 100 charger for a few minutes and that brought the voltage up, but ordered a new battery from BMW as we have a two day ride coming up and do not want battery issues in the middle of nowhere. The wife unfortunately destroyed my Oxford Optimate charger a while ago by helping clean the garage and bumped a battery that was charging, the leads shorted out and she stands there looking dumbfounded and says "somethings burning" Grrrrr, Goodbye one charger. Anyone use the Ctek range of chargers?