K9 usage with 4s4p banks

HowTo
,
1

I’m a Newbie to lithium systems design.

I have two banks of 12v, made up in 4s4p configuration. I wish to monitor each cell, and protect each battery. Output is to be contactor controlled by the BMS.

Is the K9 suitable for this configuration? I see it has 16 inputs.

Thanks for any advise

4s4p configuration
4s4p configuration862×448 115 KB

2

Hi boatsparks,

I don’t think K9s would be a great fit for your proposed configuration, they can monitor a string of cells between 3S and 16S, and you need more K9s for more strings. In other words, you can’t have the voltages in the K9 go 0V, 4V, 8V, 12V, 0V, 4V etc. as there is a negative difference that will damage the K9.

Instead you could consider:

  • Paralleling up cells into groups of 4, then 4 in series, and monitor that 4S string with a K9
  • Moving to a higher pack voltage i.e. 16S for 51.2V

What are your thoughts on the above? Could you tell us a bit more about how you will be using the pack?