> Hello wizards of electronics !
> I made great advances on my electric trike in the last few weeks, and my =
own
> battery build is rising in priority very fast!
>=20
> To keep costs down I am now considering to create a hybrid between my
> proposed cell level protection scheme (
> https://prezi.com/qibqej3sqqy1/open-source-battery/ ) and a more
> conventional BMS where one circuit monitors the whole pack.
> So I know there are BMS chips that can measure the voltage of series of c=
ells.
> I wonder how it is done? Maybe a charge sample moved around by a variety
> of FET?
> For a beginning I want to work with a 24S LiFePO4 (72V or full at
> 87.6V) But a flexibility of the circuit would be even better! I still wan=
t to
> bridge cells in or out of the circuit to protect them either from overcha=
rge or
> deep discharge! What I think is smart to avoid in this first iteration is=
 to have
> one microcontroller per cell level with all the communication hassle this=
 might
> imply!
> Thanks for all comments they are appreciated !

Linear Technology makes chips that monitor each individual cell in a string=
.. From memory they can be stacked beyond the number of cells an individual =
chip can handle. IIRC they have an I2C or SMB interface, which can be isola=
ted for big cell stacks. IIRC they were originally designed for laptop batt=
ery stacks, but I think they also talk about electric vehicle stacks which =
is why they have made the chips intelligent enough to go beyond the number =
of cells an individual chip can handle.



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