Link a charger and a timer
If your charger merely sends energy into the battery 100% of the time, you will soon have a ruined battery. If you are careful, you can instruct a timer to turn on the charger for 30 minutes per day, then you can go play hockey or fish through the ice and forget about your poor lonely motorcycle dozing in the dark until March ... well, April ... thaws the snowbanks and warms your heart again.
Depending on your battery and your charger, my guess of 30 minutes per day may be too generous or too stingy. Experiment and check the voltage daily until you get the charging interval about right.
I wish I had thought of this stunt years ago when all the chargers were quite simple-minded. I spent a lot on batteries over the years, and I guess I am still doing it. My 1965 Super Hawk needs a battery, but it ain't getting one until I get it running properly (with a battery that belongs elsewhere and doesn't quite fit).
Good luck, and stay warm, even if you need to visit Florida to do that.