Designing yet another BMS (yaBMS)

[hzcruiser]

Originally Posted by s/v Jedi

In the end I have decided to come back to the simplicity of the Texas Instruments INA219 but another version, the INA226. This version ticks all the boxes:

A small daughterboard should do the trick:


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This one can monitor 4 cell voltages but also reports back all the cell temperatures using an LM75 on the bottom. Without conformal coating they look like this:



And installed in the batt:



And in the web browser, I'm seeing:

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(The temperature on this chart is in Kelvin; SoC is not being updated until the batt has reached 100% SOC).

[hzcruiser]

Originally Posted by Dsanduril

Just curious, as I'm starting down the same road, have you looked at anything like Analog Devices ADBMS6817 (datasheet)? [...].

Is that a new chip? The full datasheet is not openly available, only a two pager summary; and there is no availability nor pricing on digikey nor mouser?

[Dsanduril]

Yes, seems to be a brand new chip. In the family of the 6804 Jedi mentioned. Since he said he’s busy sailing I figured it would give Analog time to actually produce. TI also produces some stack monitors that aren’t vaporware and I’ve wondered if overall they’re easier than building with analog signal devices and doing more configuration work.

[ronstory]

For those curious about the tried and true INA226, there is a decent Arduino sketch and very simple schematic using multiple modules, each with a different power supply. So could be a decent example and code to start with.

https://forum.arduino.cc/index.php?topic=647807.0

Just look to the bottom of the short thread for the corrected code.

[mimijane]

Hi,
I would look at the BQ76942. I'm thinking about hooking one up with an ESP32. I'd rather use a STM32 but stock levels are crazy !

Cheers,
Mark