I agree. Adding another switch(i.e. BMS with discharge) to stop the board abruptly, when cell are reported imbalanced, is pretty dangerous. Detecting imbalanced cells or broken balance wire and stopping the esk8 gently would be a game changer.
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One more note.
@Pimousse is working on a more standardized ESC-BMS CAN messaging protocol, but it’s currently still in it’s early steps and there is quite a lot of work to do to develop it further, but I see this as a very good place to improve integration between ESC’s and BMS’ via the CAN-bus.
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On the line of expanding the number of temperature sensors.
I looked around on Digi-Key for different temperature sensors with either I2C or UART data interface and landed on Microchip’s AT30TS74 and designed a small breakout board for it shown below.
It has 3 I2C-address pins, so you can have 8 sensors on the same I2C-bus as long as you un-bridge/bridge the data pins on the bottom of the PCB accordingly, so the addresses don’t overlap.
It has good measurement resolution, accuracy, range and is able to work in low-power mode.
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What the benefit over simple thermistor ?
I guess those boards will be dispatched to different point of the battery meaning the wires length will be significant.
For such distances, I2C isn’t really a reliable protocol regarding EMI, is it ?
For instance, on my smartCharger I needed to re-route cables and shorten them the most I could to avoid having the OLED display flickering while charging.
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There is only one connection available for an external NTC temp. probe, but a forum user asked me if it would be possible to have 3 temp. probes in total. I then started to look at different options on how to expand the number of temperature sensors and ended up with either I2C- or UART-enabled sensors, which can be easily interfaced to the 4-pin PH connector, as it’s connected to hardware I2C- and UART-peripherals.
Very possible, but the bus can be driven at low speeds and if needed use stronger pull-up resistors for the I2C-signal lines.
Was the display flickering because of glitches in the I2C-lines or was it power supply related?
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The power supply is seperated and since it works flawlessly after just moving the data wires away from power wires, I can’t find other reasons than an EMI pollution of I2C.
It started flickering at 2A only ! The greater the current, the worse the flickering.
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Did you try different bus clock speeds and changing the pull-up resistor strengths just to see, if they had any effect?
EDIT: Also, I got some reeeels boiiiiiis
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Yes, I changed the clock speed, nothing better.
I didn’t change the HW (and didn’t want as it would have been a pain for production).
@rpasichnyk @hexakopter Does the future BMS integration only works with MetrPro? Or can I manually CAN forward it and get data from the BMS?
Just thought about that, I’m still on the old Metr module
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Getting stuff done. I made a little test firmware for the boards that helps me check that the major HW blocks are working ok. I’ve been planning on making a proper production tester in the future, if the project progresses into actual selling products state.
Unfortunately, I ran out of horizontal 13-pin JST-XHs, so I’ll order more for next week from DK. Pretty sure I can get most of the boards shipped next week, but no concrete promises.
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Hi, just read a big part of the posts here.
Are you very confident you can release a batch before like March?
And can you give me the dimensions? Couldn’t really find them.
You can prioritize my board last. My work is shipping me out to the Bay Area for the next two weeks so I won’t be able to get it immediately.
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Hope you get to ride with those bay area maniacs.
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I’m trying to figure out a way to bring my board but I can’t get around the battery limit for airlines 
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PCB XY-dimensions are 62.5x26.5 mm and mounting hole pattern is 57x21 mm.
Going to be very dependent on how the testing goes with the testers. If nothing major is found, then there is the possibility of going for the first PCB+assembly production test batch around Q1 of next year, but I can’t and don’t want to at this point give any promises that I’m not sure I can keep. I’m still working on this project as a hobby project.
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Update.
All the boards have been prepped, apart from @Friskies, but I’ll get that done tomorrow. I’ll contact the testers with payment details and get their shipping info in the next few days. I’m planning on using Paypal friends&family for the transactions.
I worked overtime this week and got sick on Wednesday. I’ve had fever coming and going in waves on the side of a throat infection, which is now turning towards a flu. Spitting and coughing up this nuclear yellow slime from my throat.
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Shit sorry to hear you’re not feeling well mate.
Excellent news on the boards!.
Is there an option to pay G&S if we pay a little extra to cover the fee?
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Great! very curious about it!
and take care of yourself too 
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Sure, the reason I mentioned I was planning on using the Paypal Family & Friends (F&F), was that there was the possibility that someone would rather want to use the Goods & Sevices (G&S) and they could inform me about it.
If you want to pay as a G&S you can select it in the “send payment”, or I can initiate the transaction as a “request payment” in which case it’ll always be G&S.
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I’m down to chip in a little extra for g&s
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