To power the tank I took apart a DeWalt LiIon adapter https://www.ebay.com/p/Dewalt-Dca1820-20volt-Max-Battery-Adapter-for-18volt-Tools/6030009643?iid=273258375426&chn=ps and used the tool foot for the battery, only bringing out the B+ and B- wires, so there is no battery management here.  I took it outside the first time I tested it fully prepared to run away, but every thing went fine mostly.

I had built the H-Bridges with tip 102's and tip 107's and used two ti DC-DC converters.  Apparently I made an unwanted solder bridge somewhere because one of the motors would only run in one direction, but it was enough for me keep going with it.

Boards have been made and shipped, so I'll test out the L298P and see what kind of results I get with that.

I also saw this as a good opportunity to begin to learn solidworks, so if everything goes well I will post all of the drawings, assuming that solidworks licensing agreement is not as restrictive as NI Labview.  

Best i can tell there is no restriction on the files so long as i dont remove the water mark.