I\'m looking to place my LCD more than 6M away from the BMS. Can I simply use an RS232 extension cable with DB9 connector to do so?
Yes, something like this should do the trick.
https://www.amazon.com/StarTech-com-Black-Straight-Through-Serial/dp/B00A6GIV9K/ref=sr_1_3?keywords=db9%2Brs232&qid=1652709077&sr=8-3&th=1