How much weight can my bumper support?

tkoden wrote:

When you add new batteries to the rear, any chance you can remove those batteries from the tongue, this will help with your weight? Unless you're spending a lot of money on HEAVY cabling, the two banks will not be working in parallel to drive large loads.

Yes, the plan is to remove the batteries from the tongue. The net would be 300 lbs roughly 150 off the tongue and 150 added weight on the rear.

So what you're contemplating is moving all of your batteries to the rear? I wouldn't do it because of the inertial moment mentioned previously and the cost. Having nearly all of the accessory weight of batteries, box, and carrier outboard of the frame might lead to severe sway events. Also, you'll need some big wiring to pull this off, probably 4/0, to keep voltage drop down and the effectiveness of a big bank. I don't know the specifics of the layout of your trailer, but I would look for a different mounting location.