I got the four harnesses done for the self-balancing skateboard.  Two for the battery chargers and two for actual skateboard.

I still need to add on the quick disconnects and figured out a clever color system for the disconnects that will be stupid proof for mis-plugging stuff in..  But I know if I give it to my brother, he'll still figure out a way.  Best of all, he is not color blind.

Klein Crimp Tool, expensive but worth it, I should have gotten one of these ages ago.

Half done part of the charger harness

Part of the wire mess

4 Completed harnesses

Skateboard Battery Harness, 2 24v 3.3Ah batteries combined to 1 24v 6.6Ah battery.  Slightly tweaked design from previous post.  Just need the quick disconnects added.

Battery Charger harness, able to hook 9 12v 3.3Ah batteries into.  Just need the quick disconnects added.