On board pallet jack charging

I have a 389 Pete and I bought a van trailer recently and then decided to use it for seed corn deliveries. The trailer used to be a reefer and was converted so it has a corrugated floor In it. I bought a power pallet jack due to easier use and I also needed the wide single wheel at the base of the next for turning on the corrugated floor. This jack works good but it doesn’t have a battery pack onboard and doesn’t have any sort of charging system on board it either. So the previous owner had it set up using two 12v group 31 marine batteries and they are tied together (one hot to the ground of the other) to create a 24v system for the jack. Then it has one ground and one hot cable running from the pallet jack to the batteries. It works well but I need to find a way to charge this with ease without having to take them out to charge individually on a 12v charger. Being only 2 batteries I imagine it will die sooner than most pallet jacks. So I wanted to try to do an on board charging set up. At first I thought a simple 2 bank 10amp NOCO marine battery charger/maintainer. Simple enough on the pallet jack side however it has a 120v plug in that powers the NOCO. So I’d need to wire up a power inverter. So then I thought instead of spending that much money for an inverter plus the noco and all necessary hardware and wiring, I thought what if I just charge the batteries using my truck? So I have a tarp cord for an auto tarp on a hopper bottom that is wired to my battery box where my main cables for the truck connect. So I thought maybe do some sort of pass through on the front? To use the alternator of my truck through those cables to recharge these 2 batteries while I drive empty and plug it in at the front of the trailer. But how is the question? I don’t want a large box portruding inside the trailer to possibly get damaged by a load. I thought for the pallet jack maybe I could mount a battery shut off switch wired into the jumper wire that goes from one battery positive to the other battery negative in order to shut that connection off. Making it two 12v batteries. Then I’d have to I guess run some battery cables to each battery and most likely use a 4 prong plug maybe? To keep these 2 batteries separated at the male plug coming from the jack in order to prevent any issues when switching back to a 24v system after charging. But I’m trying to see if this idea would even work? if it would overcharge or not? What set up for a plug inside the trailer should I use? I’m assuming people have done this kind of thing before to charge their jacks on board without buying those massive and expensive underbelly pallet Jack chargers