Jkbms v6. 2 app can't connect to inverter bms

Had this exact issue a few months back on my boat setup. The v6.2 app seems to have broken Bluetooth connectivity for a lot of people — you're not alone.

A few things worth trying:

• Force close the app and clear the cache before reconnecting. Sounds obvious but sorted it for me initially
• Check whether your BMS firmware is actually compatible with v6.2 — there were some mismatches reported where the app updated but the BMS was still on older firmware
• Try rolling back to v6.1 if you can find the APK. I kept a copy after reading about these issues elsewhere

The main culprit I've seen discussed is the app's new pairing protocol not playing nicely with older JK hardware revisions. If your BMS is a earlier production run it may just not handshake properly with the newer app version.

Also worth checking — are you running Android or iOS? Android seems worse affected from what I've read. On my emergency backup system at home I've got a separate dedicated Android tablet just for BMS monitoring, and I had to pin the app version to stop auto-updates causing exactly this sort of headache.

Has anyone managed to get v6.2 working reliably with the older 200A JK units? Curious whether it's a universal problem or hardware-specific. Would be useful to know which BMS revision people are running when they hit this — might help narrow it down for everyone troubleshooting.

Ran into something similar on the narrowboat last spring — turned out the v6.2 update had quietly changed the Bluetooth pairing protocol and my older BMS board wasn't speaking the same language anymore.

Worth checking if your BMS hardware revision is actually compatible with v6.2. Mine had a sticker on the board with a firmware version — anything below a certain threshold and the app essentially ignores it.

@KevWatson57 has covered the app-side fixes well, so I'd add: try the JKBMS PC tool via USB instead. Ugly interface but rock solid — got mine talking again through that, then pushed a firmware update to the BMS itself, and suddenly Bluetooth clicked back into life on the app.

Also double-check you haven't got the Victron app running in the background simultaneously — had a bizarre conflict there that took me an embarrassing amount of time to diagnose.

Great thread, this. I had the same headache with my van setup a few weeks back. What finally cracked it for me was going into my phone's app settings and clearing the Bluetooth cache completely, not just the app cache — they're separate on Android. Also worth checking whether your BMS firmware and the app version are actually matched up; JKBMS have been a bit inconsistent with compatibility between hardware generations lately. @RiverSoul makes a fair point about the v6.2 changes — I'd also add that if you're on Android 12 or above, you may need to manually grant Nearby Devices permissions as these aren't automatically enabled after an update. Sorted mine straight away once I did that. Good luck!

Worth adding — had this exact faff with my garden office setup last winter. What sorted it for me was clearing the app cache completely rather than just force closing. On Android: Settings > Apps > JKBMS > Storage > Clear Cache.

Also check you haven't got another device already paired to the BMS — it'll only hold one Bluetooth connection at a time. Caused me no end of grief before I realised my old phone was still "connected" in the background.

If none of that works, the v6.1 APK is floating around on the Victron community forums — rolling back fixed it for a mate of mine with a Fogstar battery setup until a proper patch lands.

Good shout from @NorfolkCamper on clearing app cache — that's fixed me before too.

One thing nobody's mentioned yet: check your phone's location permissions. Sounds completely unrelated, but Android requires location access enabled for BLE scanning to function. I've watched people tear their hair out for hours over this.

Also worth checking — if you're running a Victron system alongside the JK BMS, the VictronConnect app can occasionally hog the Bluetooth adapter, particularly on older Android versions. Force-close VictronConnect completely before attempting to pair.

My van setup runs a JK 200A BMS with Fogstar Drift cells, and I had this exact grief after the v6.2 update. Rolled back to v6.1 via APKPure — problem gone instantly. Not elegant, but it works until JK pull their finger out and push a proper fix.

Right, so before everyone goes down the cache-clearing rabbit hole — has anyone actually checked whether the BMS firmware itself is compatible with v6.2 of the app?

Because I had a nightmare with my boat setup last month and it turned out the app update effectively requires a minimum BMS firmware version. The Bluetooth stack changed, apparently.

Worth checking:

• What firmware version is actually on your BMS?
• JKBMS's site has a compatibility matrix (buried, but it's there)
• You may need to flash the BMS firmware via USB before the app will handshake properly

Took me three evenings to figure this out. Three. Evenings.

@NorfolkCamper — did your garden office unit need a firmware update too, or did clearing cache actually resolve it fully for you?