The overall plan for a BMS was to acquire it just after the balancing charger and just before the 40AH cells. There is an extensive thread in the endless-sphere forums from a couple of people working on an expandable BMS , and I see they are getting close to being able to sell the kits. Link here: http://www.endless-sphere.com/forums...416&start=1710

The main motivator was price and the ability to put it together myself and "tweak" it if I have to. I had hoped to set up a quick-connect to allow me to use it with either the 20AH battery or the 40AH battery by using some sort of connector system. It'll be a wiring mess at the top of the battery with the charger leads and BMS leads. I'd like to mount it on the back rack and have the LEDs function as taillights for the bike as well.

I did look at other BMS, and there are two fairly interesting "bolt on" solutions for the Thundersky cells as well as several others that look quite good, but I'm drawn to anything that requires I learn how to repair/troubleshoot. I believe in being able to fully repair and maintain anything like this so I don't have to rely on anyone else if things go south during a long trip.

Until I get it, I'll be carrying my multimeter and chargers with me everywhere. I'm pretty sure that as long as I don't use regen a lot until the BMS is installed that I will only have to make sure I don't discharge the cells too much between charging/balancing cycles. I'm also hoping that as long as I balance the cells during home-charges that I can use the 36v charger in the field to get me where I need to go.

Since the snow is just off the ground here, I intend to be doing short trips to test AH usage and charging behaviour during the day. The upcoming long weekend holds a lot of promise for a few day rides. The washer (last part I needed) just arrived in the mail, but I was up too late topping the battery off and I need sleep.