John in CR
100 TW
It turns out that current with the brake on is a show stopper for my idea. Current draw with the controller on is a tiny 20mA, which is great, less than 1/8th of what I've seen with any controllers with the power potential of the Nuc 12F, however, with the ebrake applied (I use a throttle for the variable ebrake), the current jumps to 250mA.
On the bright side, we pulled a bonehead move and at some point during our program settings we put the turn off setting back to "Button" instead of "Switch". I did numerous On/Off switching with the mode set to "Switch", and it proved reliable with or without the display connect, which is good news.
For the DC/DC converter I'll have to switch the Negative, and Vasily told me to be absolutely sure to protect the Com line from seeing pack voltage using a diode, because high voltage there will wreck the controller. Just to be extra safe, I think I'll put 2 diodes in series. I don't know if a diode failure can be a closed circuit, but for a few cents I don't want to learn the hard way. I don't think I can switch a CA on at the negative side, since it needs a direct line to the shunt, so that means a switch for the CA unless I want to get fancy with a relay that opens and closes with the converse of a switch to use those other wires of the motorcycle key switch. I've never had a CA on a switch, so that will be nice to measure charge energy to calibrate myself with SOC at different at rest voltages of my battery packs. The only instrumentation on a number of my ebikes is a voltmeter, which I have gotten away with for 12 years due to my conservative DoD despite being only loosely calibrated. In 12 years I've hit LVC only twice, and both times was less than a mile from a charger and knew I was cutting it close. One of those was when LFP was down and we had a good headwind the last few miles that ate up the remaining capacity, but he towed me the rest of the way, so still only one "walk of shame" on a 50 mile outing in 2009 when I didn't properly factor in enough net increase in altitude and headwind for the return trip. Too bad I didn't have Nuc's back then as I would have had capacity to spare with the higher efficiency.
On the bright side, we pulled a bonehead move and at some point during our program settings we put the turn off setting back to "Button" instead of "Switch". I did numerous On/Off switching with the mode set to "Switch", and it proved reliable with or without the display connect, which is good news.
For the DC/DC converter I'll have to switch the Negative, and Vasily told me to be absolutely sure to protect the Com line from seeing pack voltage using a diode, because high voltage there will wreck the controller. Just to be extra safe, I think I'll put 2 diodes in series. I don't know if a diode failure can be a closed circuit, but for a few cents I don't want to learn the hard way. I don't think I can switch a CA on at the negative side, since it needs a direct line to the shunt, so that means a switch for the CA unless I want to get fancy with a relay that opens and closes with the converse of a switch to use those other wires of the motorcycle key switch. I've never had a CA on a switch, so that will be nice to measure charge energy to calibrate myself with SOC at different at rest voltages of my battery packs. The only instrumentation on a number of my ebikes is a voltmeter, which I have gotten away with for 12 years due to my conservative DoD despite being only loosely calibrated. In 12 years I've hit LVC only twice, and both times was less than a mile from a charger and knew I was cutting it close. One of those was when LFP was down and we had a good headwind the last few miles that ate up the remaining capacity, but he towed me the rest of the way, so still only one "walk of shame" on a 50 mile outing in 2009 when I didn't properly factor in enough net increase in altitude and headwind for the return trip. Too bad I didn't have Nuc's back then as I would have had capacity to spare with the higher efficiency.
