terente
New here
Hi all,
I'm troubleshooting a 36V 18Ah pack from a Forza Viela Nero (Dutch brand, Bafang-style mid/front hub motor) and could use some input from people who've dealt with OEM UART BMS units.
The pack
History
Found the pack fully dead — all cells around 1.5V. Replaced all cells with new ones. Pack now reads correct voltage on the cell groups, all balance wires verified in sequence with a multimeter, no wiring errors.
What I've measured
So the buck is healthy, the cells are healthy, the wiring is verified, and the BMS still doesn't wake up. My conclusion is a dead BMS, but I'd welcome a sanity check.
Questions
I'm aware I can test this by feeding the bike directly from the cells through the dock's power pins with the signal pins disconnected, fused, and briefly. Planning to do that, but interested to hear if anyone already knows the answer for Bafang-style controllers on OEM packs.
Photos of the label, BMS, dock connector, and buck board available on request.
Thanks in advance.
I'm troubleshooting a 36V 18Ah pack from a Forza Viela Nero (Dutch brand, Bafang-style mid/front hub motor) and could use some input from people who've dealt with OEM UART BMS units.
The pack
- TurnLife TL-36V18Ah-L8, 648Wh, 10S
- BMS: Power core DXB31C-1020U-1052 (10S / 20A / UART), made by Tianjin D-powercore
- 4-pin JST from BMS: red, green, black, blue — VCC, TX, RX, GND
- Separate small board with 8-wire ribbon to the LED level indicator
- External SL8036 buck converter (47µH inductor, 47µF/50V caps), VIN from B+, VSS to P−, VOUT feeding the BMS
History
Found the pack fully dead — all cells around 1.5V. Replaced all cells with new ones. Pack now reads correct voltage on the cell groups, all balance wires verified in sequence with a multimeter, no wiring errors.
What I've measured
- No output on P− with the new cells installed
- No voltage on the UART connector's VCC/GND pair
- LED level indicator does nothing when the button is pressed
- Buck converter: with its ground on P− (as originally wired), no output — expected, since P− is floating while the BMS is in protection
- Rewired the buck's ground temporarily to B− → clean 5V on its output. So the buck is fine.
- Even with a guaranteed 5V fed into the BMS, no signs of life: LEDs stay off, no output on P−
So the buck is healthy, the cells are healthy, the wiring is verified, and the BMS still doesn't wake up. My conclusion is a dead BMS, but I'd welcome a sanity check.
Questions
- Anything left to try? Is there a wake-up sequence for this family I might be missing — a charge pulse on C−, an ignition pin, something on the 8-wire ribbon? I've tried applying charger voltage to the charge port with no result.
- Sourcing. DXB31 is no longer in D-powercore's current catalog. Has anyone found these as spare parts, or successfully ordered a single unit from the factory? Their current 10S range includes DXB61B (10S, UART, 20A) — does anyone know whether the UART protocol is consistent across their models?
- Generic replacement. The big question: does a controller like this actually gate power delivery on a valid UART handshake, or does it just use the data line for SOC display? If it's the latter, a JBD/Daly 10S would solve everything and I'd only lose the on-pack LEDs. Has anyone tested this on a similar OEM Dutch/German e-bike pack?
I'm aware I can test this by feeding the bike directly from the cells through the dock's power pins with the signal pins disconnected, fused, and briefly. Planning to do that, but interested to hear if anyone already knows the answer for Bafang-style controllers on OEM packs.
Photos of the label, BMS, dock connector, and buck board available on request.
Thanks in advance.
