Winter storage for Gel batteries

Hello everyone, I’m putting my 2013 Gem E4 up for the Winter. I have new (this year) gel batteries and wanted to know what is recommended for Winter storage in an ambient temperature garage. Should I leave the battery charger plugged in all Winter or not at all, or …? Your thoughts please. Thanks

I store mine for the summer by simply fully charging batteries and completely shutting off power. It has worked well for 6 years for me with at least 6 months shutdown.