NMC is a great battery. I figure since the bigger names are using it, then it must be good for us too.
We have found that these cars respond really well to a little more volting. The controllers don’t seem to be bothered by it until you get up to 96v, and yes, they will need the high voltage spoof to get past the startup check.
If you are going to do all this work, I would try to target 22s, and charge to 4.0 and see how it does. If you need more, you can go up to 4.1.
parallel 4 cells will get you around 100ah. (88~90v)
The video I recently watched shows that your bricks are indeed bolted together. You just need to plan best to arrange the cells.
Hanging one cell on the end of your 19 cell brick will get you 4) 5s group, then a smaller 8 cell (2s brick) off to the side will get you up to 22s.
If length is an issue, you could trim 3 off your 19 to get a 4s pack, then you need to package all 5 of your bricks(20s) somewhere and build another 8 cell pack (2s) as a little floater.
You would also need to find another charger that will get this pack up to 89v.
You thought this was going to be easy?
You build is even more complicated by being island isolated.