I think running 8 of this pack would just work..
https://www.banggood.com/ZOP-Power-18_5V-7000mAh-35C-5S-XT60-Plug-Lipo-Battery-for-RC-Car-p-1753781.html?cur_warehouse=CN&rmmds=buy
2 batteries long , wide and high would measure 25,6 x 9,2 x 10,2 cm (LxWxH) and give 74 volt with 14ah giving a...