r/VanMoofSelfRepair

Hi everyone,
I’m trying to repair a VanMoof S2 battery with a Darfon E4C0E-001 BMS. I’ve reached the point where I think I need someone who has actually reverse engineered this board.
History
Bought the bike as defective.
Bike showed Error 27 and Error 29 before opening the battery.
Battery pack measured 3.75 V total when I first received it.
I slowly recharged the cell pack directly (NOT through the bike) using a current-limited lab power supply.
The complete pack is now at 30.5–30.7 V.
Cell condition
All series groups measure correctly.
Every group has a plausible voltage.
No group appears completely dead.
Total pack voltage remains stable at ~30.6 V.
Measurements
Fuse
LF30A fuse has continuity (~0.5 Ω)
Temperature sensors
NTC1 = 8.61 kΩ
NTC2 = 8.61 kΩ
Both appear normal.
Outputs
Measured:
B+ to B− = 30.6 V
P+ to P− ≈ 0 V
CH+ to CH− ≈ 0 V
Neither discharge nor charge outputs become active.
MOSFETs
The board has four power MOSFETs marked:
9581GP
No obvious signs of damage.
Controller
Main MCU:
Microchip PIC18F46K80
I cannot find any obvious logic supply around the MCU.
Communication wires
Connector has:
P+
P−
CH+
CH−
Blue
Green
Yellow
White
Orange wire labelled “PRESENT”
Measured against B−:
Blue = 0 V
Green = 28.8 V
Yellow = 0 V
White = 0 V
PRESENT = 0 V
Visual inspection
No burnt components.
No obvious damaged traces.
Back side of PCB has no components.
My questions
Does anyone know the actual function of:
PRESENT
Green wire
Blue
Yellow
White
Is there any documented wake-up/reset procedure for the Darfon E4C0E-001?
Does this BMS permanently lock itself after a deep discharge?
Has anyone reverse engineered the PIC firmware or communication?
Is there any known method to recover this BMS without replacing it?
Has anyone identified the internal 3.3 V / 5 V regulator or the gate driver on this board?
Any schematics, boardviews, reverse engineering notes or repair experience would be hugely appreciated.
Thanks!

Have an S3 & X3 and trying to figure out if it’s possible to move them overseas from US to UK.

Shipment/moving companies don’t seem to want the batteries that large in their containers, and I don’t think I can bring the two raw batteries in my carry-on at their size.

I think shipping them may not be doable either. Any ideas, thoughts, experience, or other options I’m not thinking of?

Trying not to have to sell them, but may be my only choice.

Even contacted a shop in the UK to ask if they’d sell me just batteries on arrival and they refuse(d).

I have an S3 that works great and an X3 that has been deeply discharged. For testing purposes could I swap batteries between bikes? I’m deathly afraid of screwing up something on my S3. Am I likely to cause any new problems doing this?

UPDATE TO ADD:
I am perfectly comfortable pulling the batteries and all of the physical stuff, just not sure if the bike will recognize it as a mismatched battery / control unit and make something bad happen.

Hello,

I’m unlucky enough to have purchased an S5 pre-bankruptcy, and the seemingly inevitable has happened: my bike’s motor no longer works. It holds a charge just fine and powers on, but the motor does nothing regardless of the selected power level.

I took it to the Rybit shop in SF. They were nice enough to take a look, but don’t have the ability to service S5/A5s any more and couldn’t identify the issue. They told me the following:

“We have tried a new wheel and a new motor cable ( after first ensuring the original motor cable was fully plugged in ), neither resolved the problem. There is an Error 90, modem comms issue, which we really do not have a known resolution for. Possibly, repairing or replacing the Main ECU could resolve the issue. We do not have any known, new, functional Main ECU's in-house.”

I’m turning to Reddit now in a last-ditch attempt at finding a solution. If anyone has any suggestions on a fix or is located in the Bay Area and can help, I’d be grateful!

Hi,

I recently bought a second hand VanMoof s3 it has been particularly registered in my name but I am unable to fully access the ap as the bike is showing error 5 and 6 individually flashing. The battery is not the issue as I repaired it and is reading 40v. I think the bike needs a reset to delete the error codes but a hard reset by pressing the tube underneath and the handles doesn’t work. Is there another way of clearing the error codes or something else to get the bike working

As in title, my X3 no longer has a smooth boost function. It surges and is inconsistent. The hub is fine as I switched that out with a spare and the same thing happens. Has anyone experienced this and if so what was the issue? Boost button failing? Smart cartridge? Other? TIA

Hi, our S3 has the following issue. Has anyone experienced this before?

🔴 Issues:

• Error codes 6, 17, and 20 permanently displayed – immediately after startup, even while stationary
• No motor assistance, no Boost
• No speed detection (always 0 km/h in the app)
• No lights
• Bell and all system sounds are very quiet, but they still work
• Reset and battery restart make no difference

✅ Initially still working:

• Bluetooth
• App connection
• Firmware displayed correctly
• Battery charge level displayed correctly
• Kick Lock movement detection
• Alarm (but very quiet)
• Charging shown correctly in the app, but the charger LED alternates between green and red

Troubleshooting already performed:

• Replaced the main battery with another original battery → bike worked perfectly for 2–3 hours
• After unlocking the bike, error codes 6, 17, and 20 suddenly returned along with the other symptoms
• Previous battery showed the exact same errors and, about 2 weeks later, could no longer be charged; the bike then became completely unresponsive

Current situation with the second battery:

• After two days, the bike became completely dead again
• Won't charge, won't start, won't connect to the app
• Initially, when the charger was connected, the alarm would sound quietly and the skull icon appeared on the display

Possible causes (according to ChatGPT):

• Smart Cartridge (internal power supply / communication path): 55% probability
• Power Board (ECU / central ride power supply): 45% probability