After completing the pilot project upgrade on my personal car, here are some random thoughts and info for the bruteforce 24-30kWh upgrade.
Here are the two battery management systems. Nissan refers to these boxes as LBCs, (Lithium Battery Controller) The top is from the 24, bottom 30.
Serial 24: 293A09RB3A
Serial 30: 293A04NR5B
They are mechanically very similar, but you cannot use the 24 LBC with a 30 Busbar. There are people on the forums who tried this, and supposedly it will short the module, since a pin or two are not the same. It would be good to document this later on, since it takes quite some time to do a busbar swap, but I am playing it safe this time.
Oh, and the 30 box speaks kind of the same language, but pairing it with an 24 vehicle control module will result in a whole can of worms in the form of DTCs and turtle mode, since the bootup handshake afaik is different. This is being worked on by multiple people, so this will change soon.
Speaking about busbars, here is the rear stack of modules.
These are 30kWh modules, identified as "16B70 04###". You can also see the busbars, along with the tiny sensoring and balancing leads. These will only shunt 9mA, so it is OK for them to be such a tiny diameter. I am pairing the 30 cells with the 24 busbars.
Funfact, the 24 pack has 2/3 temperature measurements on the outside edge of the cells, but the 30 pack has temperature measurements directly on the busbars. Measuring it directly on the busbars will for sure result in higher and more responsive temperature measurements, so I guess that is why the 24 pack also "measures" colder than 30/40 packs.
Another thing I dediced to play safe was the contactors
The contactors had slightly different serial numbers, but they probably would have been interchangable. Didn't feel like this was the correct time to gamble
Getting the 30kWh cells to fit presented a few minor problems. First, the rear stack's support beams wouldn't fit onto the cells. The cutouts at the end had to be made oval instead of round to fit the stack. Nothing a saw can't fix.
Then, the mounting holes for the rear stack did not align properly with the bottom shell
So I had to lift out the rear stack again (heavy!) and carefully file the holes to the proper shape. After that the bolts could be installed.
After everything was swapped over, I installed the hybrid 24/30 pack into the car, and it happily booted up with the lovely startup sound. After having the 12V battery disconnected the car always goes into miles/Fahrenheit mode, minor annoyance
I will now do a shakedown of the car before diving into correcting the instrument-cluser with the CAN-bridge.