Rear hitch rack battery bank

I have a 22 ft Wildwood X-Lite backpack edition. The backpack means that Forest River put a fold down cargo carrier on the back. I can carry minimal weight back there with out causing sway. The sticker says 250lb capacity. It may hold 250lbs but 150lbs causes the trailer to handle differently. Storing heavier stuff under the front bed, filling front water tank, emptying rear holding tank, ect. will help but not worth the hassle. Maybe a heavier or longer trailer would handle the rear weight better but I think I would start with 2 batteries and build up from there checking for sway after each 2 batteries.