Roboboard top. This has 2 x 20A
H-bridges for pulse-width-
modulated wheel motor drives
as well as 2 shaft encoder inputs
with 12-bit counters for each,
plus a bunch of extra I/O...
It runs on a 12v, 55Ah battery

This shows some of the MOSFETs

More MOSFETs and a couple of fuses