The towee could carry an additional battery. Probably not hard to link it with a cable to the tower.

RV trailers like that are coming to market, seems like a good solution. e.g.

https://pebblelife.com/

https://www.evotrex.com/

https://www.aboardrv.com/

An additional perk for these is you now have a large battery to power appliances in the trailer.