I usually use the original charger to charge them to 36 volts and then I use my Astro 109. I charged them at 5amps and they seem to take it with easy. The pack is a 10S1P.
New pictures of the truck. Now it has a 3695/MicroCar, Hacker ION-X motor and 2 36 volts packs in parallel. I will make a video of the truck running with the 16/65 gear and then I'll make one with the 22/65.