I come from the tuner world and .. well JDM is a popular product I have typed those letters a few times.
My battery packs are DIY 8S2P 48V. One string of 8 has alot of heat compared to the 8 I got from Docan in February. So I ordered 8 more of those to replace the 8 I got direct from china last year. I am sure they are only Grade B based on no QR stickers, no documentation.
Yes, the Growatt has a balancer of some sort. I believe people just call it the inverter balancer. I can set parameters that are really supposed to handle all the battery needs and the BMS is merely a backup device to avoid issues. However, I am not having a very easy time of getting the Growatt parameters set to something that avoids inverter shut down. SA is showing 0 volts at the battery all the sudden and the inverter shuts down for 30 seconds. My poor computer has improper shutdown 20 times in the last 15 days.
I mostly got the JDB for the compatibility to the SA software and Pi. I have 2 Daly BMS ( 200A and 250A ) now, but both are new in the box still. I had no idea that Daly was so run down by this forum and I just figured I avoid trying them and posting issues only to read the negative responses I would likely get back. Seems the Daly with 485 ( 250A which is 16S ) can communicate with the SA software, and I might try later on. I need to build a 2nd MPPT setup so not all is lost have lots of spare parts.