I've got a couple of JK BMSs. The first one I got back when they were all the buzz here, and it is still a great BMS. After using a few JBD BMSs, the JK took a bit of getting used to, but I really liked it. The app is much better than the JBD, and the active balancing is game-changing.
I had to wait to buy the second one while they were revising the design to add heating. I finally got it, but when I hooked it up to my 8S 230Ah battery with my Schneider Inverter/Charger and SCC, there was some strange sounds coming from the Inverter/Charger during solar charging. It was kind of a hissing sound, a little like something arcing. I was afraid it was going to burn something out in my Schneider equipment, so I fell back to my JBD BMS that had been operational for a few months with no issue. I tried again later and made sure I could pin-point it to the BMS.
I found someone else here posted the same issue (Sorry, I can't find it now). I tagged
@Nami a couple of times, but he/she has never replied. I'm trying not to judge JK/Hankzor, but I've personally made the decision not to buy any more of the JK BMSs until I hear more information.
It is pretty sad for me, as I really thought that the JK was the BMS at the top of the list. Now.... I'm not so sure. The fact that I'm now seeing no one able to get any customer service pretty much seals it.