2015 RXV Lithium Build vs Drop In's

[wingnut2000]

So I have a 2015 RXV that is stock except for tuning by Bob and 20.5" wheels so it runs about 27-28mph. I think I have done enough research on drop ins to know which battery I would need to support my cart as far as amperage draws and all.

I am interested in building a pack out of the Nissan modules and I have a very general idea of what I need to do. I think it is 7 leafs or modules I would need to combine together and then add a BMS. I have a voltage reducer already installed on the cart and I assume I can still use it the same on a lithium build to run my lights on. The BMS is basically for charging the cells properly correct?

Some of my questions are

how do I know what BMS to get?

how do you change the charging parameters? via mobile app? on the charger itself??

Im not sure what the amp draw specs are on the leafs?

Pretend I know nothing about batteries and the electrical system in the RXV's when answering. lol which is probably almost true.