need help CFW scooterhacking for 52 volt battery

[Adridri]

hello good evening, I need help to adjust xiaodash with 52.80 volt battery. I have 3 batteries, the original battery of the xiaomi pro 2 a battery equivalent to the pro 2 in 7ah and a battery in the bag of 21ah /12v, for the connection it is good but for the bms emulation part I I don't understand how to put the right parameters between the number of cells, the total capacity, these parameters are the first time and I find no clear indication of how to do it, what a brief calculation if someone can enlighten me and give me the good parameter at re-entry

Battery :
https://fr.aliexpress.com/item/4000727761296.html
https://fr.aliexpress.com/item/4001055023026.html

the 12v 21ah battery makes the series connection between the xiaomi battery and the 42volt 7ah battery, so the 7ah 42v is in parallel, this allows you to have 52 volts for ~21ah

finally whether it's with xiaodash (I prefer xiaodash it avoids reflashing each time) or a cfw which can make the scooter work correctly, the problem is when going up flat it goes downhill too but going up I have the error 21 I don't understand why

Thank you in advance for your help