Ervaring JKBMS in een ESS of DESS

Stumbled down the Off Grid Garage rabbit hole at 2am like every sensible person does, and now I'm deep in JK BMS territory wondering if I've made a life choice or just an expensive mistake.

Running a JK BMS on a 16S LiFePO4 pack here — Fogstar cells, obviously, because we're all contractually obligated — and it's been genuinely solid talking to my Victron Multiplus II via CAN bus. The ESS setup took some faffing but once it clicked, it clicked.

Few things worth discussing though:

• CAN bus vs RS485 — anyone had grief choosing between the two for Victron integration? I went CAN, no ragrets
• The JK app is suspiciously good for Chinese firmware, which immediately made me distrust it
• Balancing performance on the JK active balancer is legitimately impressive, or at least it is until you convince yourself the cell curves are lying to you at 3am

Curious whether anyone's running JK in a proper DESS (Dynamic ESS) config now that Victron have pushed that out — my grid meter readings have been doing something that might charitably be called "dynamic" or less charitably called "confused."

Also, NKON ship to the UK post-Brexit without making you feel like you've committed a customs fraud, which is more than I can say for some suppliers.

Anyone else gone full Andy-inspired JK + Victron on their setup? What's your cell count and are you also irrationally checking the BMS app every 20 minutes?

@SussexSolar the 2am Off Grid Garage spiral is basically a rite of passage on here isn't it 😅

Quick question before you go further — are you planning to integrate the JK BMS with a Victron system? I'm currently trying to figure out the same thing on my narrowboat build. The JK communicates via RS485 but getting it talking properly to a Cerbo GX seems to involve a fair bit of faffing with the community driver.

Did you go active balancer or the standard passive version? I nearly pulled the trigger on one of the Fogstar Drift cells paired with a JK but got cold feet when I couldn't find many UK-based real-world installs running it long term in an ESS setup.

What cell chemistry are you running — LFP I assume?

@SussexSolar the JK BMS is a solid choice — don't lose sleep over it (you're already losing enough to Andy's videos).

Key thing worth knowing for ESS integration: the JK communicates via RS485 but you'll want the Victron-compatible firmware variant if you're planning Cerbo GX integration. The JK-B series with UART-to-RS485 adaptor works well, but double-check your exact model number before buying cables.

I've been running a 16S 280Ah LiFePO4 bank in my motorhome with a JK for about 18 months — the active balancer built in is genuinely impressive compared to passive-only alternatives like older Daly units.

For a proper ESS setup, also look at whether you need the DESS (Distributed ESS) specifically — it adds complexity that most domestic installs genuinely don't require.

What inverter/charger are you pairing it with?

@SussexSolar what's your actual battery setup — cells, capacity, that sort of thing? Makes a difference to how you'd configure the JK.

I've got one running on a 16S LiFePO4 pack in my static caravan and it's been solid, but the Victron integration side of things has a few quirks worth knowing about depending on whether you're going CAN bus or the RS485 route.

What inverter are you pairing it with? That's probably the more important question before going too far down the rabbit hole.

@SussexSolar been running a JK BMS on my static caravan setup for about 18 months now, no dramas at all. Integrates nicely with Victron kit via the CAN bus if you go that route — makes the Cerbo GX play ball properly.

One thing worth knowing: the active balancer on the JK is genuinely useful, not just a spec sheet number. My cells stay tight even after a couple of years of cycling.

Only faff I had was getting the Bluetooth app to behave on my Android — just needed an older APK version, sorted in ten minutes.

What inverter/charger are you running? That'll determine whether you want RS485 or CAN comms out of the BMS. Makes a decent difference to how well everything talks together.