Connecting Vatrer batteries via BLE to Cerbo GX - Success!

Been meaning to post about this for a while. Got my Vatrer 200Ah LiFePO4 talking to the Cerbo GX in the shepherd's hut last month using pretty much the same approach — ESP32 acting as a BLE bridge, then the custom driver package on the Cerbo side.

Took a bit of faffing with the Venus OS Large image to get the driver to install cleanly, but once it clicked it's been rock solid. Battery SOC, cell voltages, temps — all pulling through into VRM. Proper job.

What I will say is don't bother with the cheap no-name ESP32 boards. I wasted an afternoon on one before switching to a decent unit and the BLE connection actually held.

Few things worth noting for anyone trying this in the UK:

• Venus OS Large is your friend — don't attempt this on standard Venus OS
• Serial number format on Vatrer packs can vary between batches, which affects device discovery
• Keep the ESP32 within about 5 metres of the battery if you're in a metal-clad hut or van

Victron deserve credit here. The fact that the platform is open enough to allow community drivers without bricking anything is genuinely rare. Cerbo GX isn't cheap but the flexibility justifies it in my setup.

Anyone else running Vatrer packs this way? Curious whether the 100Ah versions behave differently over BLE — the cell balancing data seems a bit inconsistent on mine and I'm not sure if that's a firmware thing on the battery or a parsing issue in the driver.

Would be good to compare notes.

@BatteryTim interesting approach — been down a similar rabbit hole with the narrowboat setup, except I went the RS485 route after the BLE bridge kept dropping out every time the inverter kicked in. Interference was a nightmare.

Curious whether you're seeing accurate SoC figures or just voltage-based guesstimates dressed up as SoC. That's where I got burned with a cheap BMS integration — looked great on the dashboard, told a completely different story under load.

The ESP32 solution is clever but I'd want to know what happens when it crashes at 2am and your heating's running. Does the Cerbo GX fail gracefully, or does it start making bad decisions about the system?

Not trying to rain on it — genuinely curious if you've stress-tested the failure modes.

@BatteryTim ran the same ESP32 BLE bridge trick on my van build last summer — works a treat until the ESP32 decides it's had enough and just... stops. 🙃 Worth adding a watchdog timer in the firmware or you'll be crawling under your bed platform at 2am wondering why the Cerbo's gone blind. @Spider curious whether the RS485 route was actually less faff overall, because "simpler" and "narrowboat" rarely belong in the same sentence in my experience.

@FETFan the ESP32 stability issue is real — I had the same dropout problem on the boat until I pinned the watchdog timer properly and made sure the BLE scan interval wasn't thrashing the heap. Worth checking your partition scheme too if you're running anything close to the flash limit.

One thing nobody's mentioned: the Vatrer BMS broadcasts slightly differently depending on firmware revision. I've got two 200Ah units and they enumerate with different characteristic UUIDs. Took me an embarrassing amount of time with a BLE sniffer (nRF Connect on Android does the job) to realise they weren't identical.

The Cerbo side via the dbus-mqtt path is solid once you've got clean data coming through — VRM picks it up without complaint. Happy to share my ESP32 sketch if useful.

@AshChild good shout on the watchdog timer — that solved half my dropouts too. The other culprit I've found is BLE congestion when simultaneously charging from solar and the EV charger kicking in; the ESP32 seems to struggle when the Cerbo is polling aggressively during high-current events.

Solved it by throttling the GATT notification interval on the Vatrer side — bumped the connection interval to 100ms rather than the default 7.5ms. Dramatically reduced the reconnection storms.

Worth noting for anyone running a similar setup: if your Cerbo is on firmware 3.x, the VRM portal now flags BLE-bridged devices differently in the device list — don't confuse the "no data" warning with an actual comms failure; it's often just the portal's heartbeat timeout being overly aggressive.

@BatteryTim interesting timing — I'm literally in the middle of setting this up for my shepherd's hut right now. Got the Cerbo GX already mounted but still wrestling with whether the ESP32 bridge is the right long-term approach.

Quick question for the thread: is anyone running this on a permanent 24/7 basis, or does the ESP32 tend to need babysitting? My hut is quite remote so I can't just pop over to reset things if it drops.

Also wondering whether the BLE signal degrades much through the hut's insulated timber walls — the Vatrer battery is going in a separate external box about 2 metres from the Cerbo. Would a longer antenna on the ESP32 help with that, or is 2 metres well within range regardless?