Alternative to a RV battery?

[exjay]

Found the deepcycle RV battery that came with my TT is bad and will not hold a charge at all and will need to be replaced. My question is what is an alternative to this battery since all I need it for is to actuate the brakes in the event of a disconnect? We store the TT at home and utilize tge TV to run the electric jack and plug into the house when prepping for a trip also we do not do any boon docking camping. Will a smaller/lighter12v 7ahr battery work or simillar? Im more worried about overcharging a smaller battery vs the full size RV battery. Just seeing other options avail since I can get these batteries for next to nothing via a friend. Thx