Gas Gauge solution for 10S5P battery pack

dtluigi

Other Parts Discussed in Thread: BQ78350, BQ76930, BQ77910A, BQ77PL900, BQ34Z100

My question is about the solution to take in order to precisely track battery status of 10 Series and 5 Parallel battery pack.

I am going to use the new TI solution BQ78350 + BQ76930 but my question is: obviously I should use 5 devices of the BQ76930 for each parallel string, but how many gas gauges?!?

Could it be sufficient to use one only BQ78350 (in I2C connection with all the BQ76930) for all the strings or should I use a BQ78350 for each parallel string?

Best Regards

Luigi

over 10 years ago

0 Damian Wilczyński over 10 years ago

Intellectual 285 points

Luigi,

Do you considered BQ77PL900 + BQ34z100 or BQ77910a + BQ34z100?

Best Regards,

Damian

0 dtluigi over 10 years ago in reply to Damian Wilczyński

Intellectual 595 points

Hi Damian,

thank you for your interest to my question.

BQ77PL900+BQ34Z100 seems to be a more expensive solution and even no low-power; BQ77910A seems no longer supported by TI.

0 Jörg Selig over 10 years ago in reply to dtluigi

Prodigy 231 points

Hi Luigi,

are you certain that you want to have separate strings? Or ist it an option to connect the parallel cells in each row and form just one string. The cell voltages can be supervised by just one 769xx in that case. In my humble opinion, this is a very common design.

Kind regards,

Joerg

0 dtluigi over 10 years ago in reply to Jörg Selig

Intellectual 595 points

I found the solution of parallel cells as the most used...perhaps as it is the cheaper one...and therefore I am doing the same!

Thank you for your reply.

0 dtluigi over 10 years ago in reply to dtluigi

Intellectual 595 points

Do you know how many cells (maximum) can I connect in parallel for the BQ78350?

0 Doug Williams4811 over 10 years ago in reply to dtluigi

TI__Expert 6470 points

There is no fundamental limit. However, if you will be counting coulombs and measuring current above 32.7A, then it will be necessary to use the current scaling feature in the gauge. In that case resolution of current measurement will be degraded accordingly, For example, if you scale up by X10 then you can measure up to 327A, but resolution will ony be 10mA instead of the default 1mA.

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Gas Gauge solution for 10S5P battery pack