There are about 350 Elec-Trak devotees, lots of techies dedicated to keeping the ET's going. Like me, the majority prefer lead-acid storage batteries (you fill 'em with distilled water) along with AGM's. See the Trojan site, I know a place for a good price. They provided enough weight for me to plow snow with Ag tires, no chains.The place where I work got into solar powered energy. They have several acres of open land, and decided to install solar panels to power the machinery. After installing all those panels on all that land, they generated enough solar power to run almost one whole machine out of the 50 or so that they have!
Cheers, Jack C