I have one of these BMS units. Just installed it a week ago and working through its functionality.
I alway hate when a board has conflicting markings - such as a separate place to solder P- and C-, but they tell you to put both wires on the C- tab. Why?
I use that same phone APP and it occasionally cuts out and I have to re-connect the bluetooth, but it does not lose any data in that case. The BMS must have on board memory because it saves the number of cycles the battery has seen, fault data, and capacity info. The app asks for a lot of permissions, but it uses GPS location data to calculate your speed and distance so it can take a guess at the remaining distance your battery can go. You can pull up individual battery cell voltages in use to see voltage sag at max power and other info. It has a cool lock feature where one tap on the screen on the Lock icon turns off the output power. Nice for when you just run into a store and don't want anyone accidentally hitting your throttle. But I can imagine that you lock the BMS and then your phone dies and now you can't get it unlocked until you charge your phone. Guess I need to finish hooking up my USB port on my battery!
I have not loaded up the computer software, but it looks more powerful than the cell phone APP. You can change a lot form the phone and could save yourself by having a higher LVC and then if you really need, you can change it on the fly to a lower value to limp home. For my LiFePo4, the LVC is 2.7v. I would like it to be a little higher, but in reality it will only be at 2.7v under sag and the resting voltage will be higher. Balancing may or may not work well. I don't see any current flowing when it reaches its cell overvoltage cutoff. My charger is a standard no-name charger, but I do see 1 amp of current on other packs and BMSs when it is in balancing mode at top of charge. I can't feel any hot resistors, but they are under an AL cover plate and are small 50ma ones, so they may be working. My pack is a large 48v 45AH, so I don't expect balancing miracles. It does have a setting where I can tell it to turn on balancing at a specific voltage. I set it at a low 3.4v and when the first cells hit that voltage, a Chinese character appears next to them, so perhaps that cell resistor is turned on and reducing the current from that point until the first cell hits HVC.
Overall I really like its functions and being able to check individual cell voltages while riding really makes it a cool piece of tech. I just have to figure out how to wrap everything up so that I still get bluetooth signal but have a waterproof and protected pack. Any ideas? Also, how would you mount a USB port on a battery so that it is waterproof? I was thinking to just put the USB circuit board in with the battery and have a micro-usb cord already plugged in. Then I can run just the cord out through a waterproof grommet/caulked hole in the pack. Do they make a waterproof cover for the end of a micro-usb cable?
This is very early morning with a 1 year old, so it may not be written well, but I will update if I have any issues.