Being short on battery power while dry camping,I removed the 12v battery which gave me 55 amp hrs .I replaced it with 2-6v batteries(in series)which gave me 235 amp hrs.I fabircated a custom vented battery box using heavy sheetmetal with a hold down bracket and rubber isolators for the batteries.I also added a solar panel (I fabricated my own stainless steel brackets so I didn't have to penatrate the roof) to keep the batteries charged.The factory pump encloser(plastic)at the front of the trailer cracked and was falling apart. I rewired ,soldered all connectors & used heat shink tubing.I fabricated an insulated heavy sheetmetal box for this & used liqiud tight electrial conduit for all the wiring.Our HI-LO is a 21ft.1997 Towlite.We tow with a toyota tacoma.