i am happy to share what i have learned and delighted as well about PBP3 doing what needed to be done
pictures and pcbs are probably off the table due to being the property of the customer but things learned along the way in PBP are fine
i don't know about cars, isn't that CAN ?
my project has a 4 cell (4S2P) Li-ion pack with an integrated 'pcb' which contains the protection stuff and the aforementioned fuel gauge, about 80W/hr so closer to a laptop than a car
the battery 'pcb' is by the vendor
i had many concerns about the thresholds and possible protocol issues which i feared may necessitate using the I2C hardware but at the end of the day the I2CWRITE worked fine, voltage thresholds and levels were well beyond points to cause worries
in fact the i2c buss is shared with several other chips, a DAC and phillips LED blinker and all are playing nicely together
the main hurdle that cost the most time was discovering the address ('control') (dec 22), discovering how to set batt as slave (as it could be master) which 22 also accomplished

next the battle over corrupt SMBus data was won by good old trial and error, i found that i needed to slow way down (by means of OSCCON (is intosc)) to 2MHz** and then all was rock steady
trouble was that 2MHz turned out to be impractical overall (and BTW PBP does not have DEFINE OSC 2 and i needed DEFINE for many things) so i wasted a bunch of time compensating for that until i simply made everything 8Mhz and then in the GOSUB to ReadSMBus switched the OSC to 2 at the start and back to 8 before RETURN,
worked a treat!
now i just send
i2CREAD pSDA, pSCL, bFGAddr, bSMBC, [bTemp0, bTemp1]
where bFGAddr is dec 22, bSMBC is hex 11 (sorry about mixed types) and the 2 bytes get put into a word which gives me ...
RunTimeToEmpty
this word contains minutes which are dynamic and based on all the historic goes inna goes outta so as i vary the load the minutes go up and down, how cool is that ?

i can read the batt temperature, current in, current out, voltage, remaining runtime at an arbitrary current by writing something to another register, theoretical total capacity as per original setup and on an on

way more stuff than i need and kudos to TI for all this tech and kudos to MEL for these great tools that make it simple

**PS
as i recall, contrary to my expectation slower than 2Mhz was not better it started to get flaky again at 1, so 2 was the sweet spot, the I2CREAD routine is not a speed demon so i suspect the data rate is in the 10's of kHz, i did not scope it and measure it