I have the same system, within a few days I had purchased a leisure battery, 85ah, cost me £45
Heavy for sure but can be used with the trolley, just make sure it has a carrying handle!
I tend to use mine as a mini van mount and work from the back of the hatch.
Bought 50m of non kink yellow hose plus hose reel, fine most of the time.
when I need the trolley I hook up the smaller battery and away I go!
Battery stays in the back of the car and I connect up the battery charger via an extention cable to the battery and let it charge up overnight.
The blend between the 2 batteries means I keep the smaller one fully charged
Ian