I am planning to build an electric bike powered by a 12S LiPo battery, and I am trying to decide how I should implement monitoring of the individual cell voltages. Manufacturers like TI provide a decent selection of chips for battery monitoring which include balancing functions, although I will not need this functionality as I will connect the battery to a balance charger when not in use. With MCUs being available for ~$1 with plenty of ADC channels, it seems tough to justify spending $7 or upwards on a TI chip when I could implement basic ADC reading and communications on a MCU (not to mention I could easily implement some kind of differential signalling to run over long wires in the vehicle, where the I2C or SPI native to the TI chips would require some kind of buffer).

I would like some seconds opinions on this. Is there any other sort of advantage to off-the-shelf battery monitor chips I should be aware of, other than convenience (and perhaps peace of mind in that if I roll my own solution, I have to make sure my code is reliable in every situation)?

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    \$\begingroup\$ Probably the only thing is safety. If you use a Micro, you are going to have to implement a lot of redundancy (watchdog timer, multi-channel reading, reliable PCB connections, make sure your code is perfect) to make sure you charge safely and appropriately. I'm sure you are well aware of how volatile Li-Ion/Li-Po batteries are. The extra money you are paying for the IC is paying for this redundancy/safety - in the form of secure circuitry and a test/verified/approved control system, depending on the architecture of the chip. \$\endgroup\$ – DSWG Sep 11 '18 at 2:10
  • \$\begingroup\$ @DWSG This is not for charging, solely for monitoring the voltages in my application. But I agree, the off-the-shelf chip will have been through lots of professional testing and intense failure analysis beyond what I could do. \$\endgroup\$ – Billy Kalfus Sep 11 '18 at 2:16
  • \$\begingroup\$ The big problem using MCU is that you can't connect the ADC inputs to the cells: you'll need a voltage translator (which has a cost). The best thing about AFE (Analog Front-End) chips is that they provide the measurement of each cell voltage directly in digital format, usually via I2C comm. \$\endgroup\$ – Diego Sep 12 '18 at 12:11

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