Originally Posted by def
I am not an expert but I too have long discarded my "trickle" style chargers in favor of what the industry now calls "smart" chargers. The old trickle chargers merely reduced the charge rate to a low current however, the charger still provided current to the battery even though the battery was full. This caused heat, gassing and eventual battery failure.
Nowadays, the smart chargers turn off once the full battery voltage threshold has been reached but monitors the battery and turns back on if the voltage drops below the threshold, keeping the battery full and thereby reducing sulfating and optimizing the battery output the next time you call for high current like during a cold start at 0 F.
In this maintenance mode, a battery can be left connected to the "smart" charger indefinitely, especially important if your vehicle has low parasitic drains required to maintain various ECU functions, clocks and other low level current loads.
Batteries like to be full and kept full. The good "smart" chargers accomplish this and thereby extend battery life.
There is no charger out there smarter than a human. Plug it in overnight every month or so and you can opt out of the whole discussion of charging algorithms, etc. Due to the frequent power outages we seem to have and the fact that I don't like the idea of attaching my bike to the grid when I'm not home I'll stick with my proven and safe strategy. I do have the bmw branded charger and new deltran tenders but I think it is foolish to trust them for long-term storage. At least take the battery out of the bike if you insist on doing that.