I recently had the BMS on my 2020(I think around there) LBX die, I looked online and a replacement BMS was
260$
plus shipping and tax, which seemed kind of absurd. So instead I bought
this
BMS for $73 plus shipping and tax. It barely fits inside the stock battery compartment but with some squeezing it works just fine (my battery is a stock 32ah, idk about the new batteries with the upgraded capacity). There is only one problem with a new BMS, it does not talk to the Sur Ron controller the way the old one does, but apparently, it does not need to. The secondary plug NEEDS TO BE PLUGGED IN but does not need to be connected to a BMS on the inside. If the plug is not plugged in then the power is limited, but when it's plugged in it works exactly like normal but more powerful. I do not know why this is but I assume the bike has some way of identifying if it's plugged in to both plugs. Installing the new BMS took me about an hour and a half but I work on batteries a lot so I knew what I was doing, if you have any questions DM me on Reddit and I am happy to help you out. This new BMS also outputs more power (100 amps vs 90 amps), and you can customize everything: charging voltage cutoff, low voltage cutoff, power output, temperature cutoff, and you can monitor the state of charge and change these setting all via the phone app and provided Bluetooth dongle which you can leave plugged in inside the battery. I have purchased multiple BMSs from this company and they are all high quality and well built, there is no need to run them below spec, I have one that is going on 3 years of age and running at max amps on my 4kw ebike. Overall, if you have some battery skills and want to save close to $200 dollars, use this BMS instead of a replacement stock one. (The power is equivalent to a BMS bypassed Sur Ron but you get all the benefits of a BMS). I hope this helps some of y'all!
TLDR: New BMS has Bluetooth, more power, and more features, and is around 200$ cheaper then a replacement one