Noticed something nasty with the charge controller setup in my previous post. I really should have thought of this, but the 100V voltmeter is not isolated. It will connect your high voltage pack negative to your 12V negative, which is your vehicle ground. Not cool. In fact so not cool, that it seems to have killed at least one, probably two 12V lead batteries I used in the vehicle as the aux battery.
So, lesson learned, again, always check your pack isolation after you install anything that connects to it. Check voltage between both positive and negative ends of you high voltage and the vehicle chassis. If you see the pack voltage or something like it, you have a problem. If you get some fluctuating, small voltage, you probably don't have a problem. Note that with a brushed motor, you can end up having dust from the brushes build up and create a short, so it's not a bad idea to check even if you don't install anything new.