HVC Breaker Board used as an LVC power cut-off from the battery pack to controller test ride went well.
2 x 6S Zippy 4000 mAH Lipo Batteries from HobbyKing
2 x LVC boards
1 Breaker Board
Cute 100 Rear 201 rpm for 135mm drop out
KU63 15A Sensorless or Hall Sensor Controller. Good to about 15S/63V I think.
For this to work I wired the LVC 5V, signal, and ground from an LVC board (what you normally would wire into your throttle) to the Breaker Board LVC 5V, signal, and ground. In fact, it was pretty easy to modify one of the jumper cables Methods provided to do this. You can pop the pins out with a little flat jewelers screwdriver by pressing down the tabs that hold the pins in their slots. Then you can arrange them in the other slots so the 5V, signal, and ground all match up when you plug in the cable from the LVC to the Breaker board. Also for this to work you have to hook up the battery connections to the side of the Breaker board marked "Charger," because in this usage they are the "Source" of power, and then you hook up the "Battery" marked side of the board to your controller, because it is being fed the power. I think Methods said that his gut feeling was that it would work okay to something like 30 amps/100 volts this way., but that he hadn't tested it. With my BMSbattery.com KU63 controller, I'm only at 15 amps and 50.4 volts pack voltage max off the charger, so well under this estimate.
My test went well but use this idea at your own risk.
On the test bench the LVC triggered the Breaker board very accurately withing 0.1 volts of 3.0. With very little load, the battery cell that triggered it recovered to 3.05 after. Reset button worked fine to reset the board. On the road under heavy load, the breaker triggered as expected and the cell recovered to well over 3.20 volts. On the flats with a small load (a quarter throttle), the cell recovered to 3.15 volts after the Breaker was tripped. This is perfect. Thanks Method, for the well thought out thresholds you chose.
If I hit the breaker under a heavy load, I have the reset momentary button sticking out so I can reset and save a bit of juice for later if needed. My cell recovered to around 4.35 volts when I tested it under heavy load, so there's a bit of energy left in the pack that can still be used without killing the cells too bad. Like the last hill home or something
Here is a picture of my pretty little pack. What I like about this approach is that I can throw the pack into my trailer as a back up battery without having to wire a throttle cut-off cable all the way up to the controller. Or, I can build a second little pack that can be thrown in a back pack as a spare. When its time to switch, there is only the power cable to have to unplug and plug in again. For bikes that have the batteries attached full time, I don't see any reason for doing this as you just need the throttle retard cable.