Phantom 4 I2C reading one chip only

[RiaanAspeling]

I've opened the battery and connected SDA, SCL and GND to the raspberry pi. The output of "sudo i2cdetect -y 1" is:

 0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f

00: -- -- -- -- -- -- -- -- 10: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 20: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 30: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 40: 40 -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 50: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 60: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 70: -- -- -- -- -- -- -- --

It only sees 40 and not 0b as most posts suggest. Has anybody had this issue?

[mefistotelis]

Looks like you connection is correct, then.

First tries:

• try turning the battery on, to disable pull-down used when battery is off,
• try running Pi GPIO Deamon to affect line impedance, ie. sudo pigpiod -s 2

If that won't help:

• Use piscope to check if BMS is talking to uC when the battery is on; if BMS says nothing - it just doesn't work. In that case, reset it, resolder or something - you need to make BMS talk.
• Find and remove the pull down on battery board. People often just cut the copper lines in a way which is easy to link them back later.