Re: Onan 5500 dedicated starter battery setup ...

Not a great solution, but for years I kept a second bank of two 6v batteries in a plastic tote and hooked them up to the house batteries once we got to camp. It was a pain--metaphorically and actually. The first hassle was loading them into the truck bed and unloading them and connecting them when we got to camp (and then doing the reverse when we left). Even more "pain" came when my wedding band touched the nose of the trailer and completed the circuit from the trailer (ground) to the wrench in my hand to the positive lug on the battery. That was pretty dumb, but it was even dumber when Derwud did the exact same thing on my trailer exactly one year later. We have matching his & his scars. Lame.

Anyway, the power those extra batteries provided was pretty perfect. It wasn't an elegant solution, but it worked very well on that trailer since we didn't have room for more batteries on the tongue.