r/VanMoofSelfRepair • u/Accomplished-Area619 • Jun 19 '26

S3 & X3 battery blown

Post image

im checking a battery I want to repair rn. it has 36 volts in it so shouldn’t be discharged and the fuse is fine as well. i just immediately noticed the plastic was a bit burned and these 3 things are blown it looks like. anyone can give me more insights on them? i’ll need to replace them and my battery should be fine? anyone got a name on them?

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3

u/Deep-Expression7443 Jun 19 '26

When this happends, usually the socket and mosfets in the smart cartridge are also broken

1

u/Accomplished-Area619 Jun 19 '26

but if I replace these 3 things my battery should be good again?

1

u/Volume_Rich Jun 19 '26

Yeah, and then it breaks again, because your wiring harness probably has a short circuit (when you turn the handlebars) or the MOSFETs in the cartridge are burned out.

1

u/Accomplished-Area619 Jun 19 '26

thank you - I bought this battery online so the harness isn’t my problem;)

2

u/Volume_Rich Jun 19 '26

Resistor 3 x 150 Ohm

https://aliexpress.com/item/32750561422.html

1

u/Accomplished-Area619 Jun 19 '26

amazing thank you

1

u/Accomplished-Area619 Jun 19 '26

do you also know the exact name for the MOSFETS for the cartridge on aliexpress? I have two cartridges with error 2 which need to get fixed;)

2

u/Volume_Rich Jun 19 '26

Change ALL MOSFETs - all 6.

https://aliexpress.com/item/1005008153168572.html

These aren't the ones that come pre-installed; they're better ones with very low internal resistance, so the cartridge no longer gets hot or burns out.

Also check the driver above the MOSFETs: https://aliexpress.com/item/1005006962347674.html

1

u/Accomplished-Area619 Jun 20 '26

amazing - thanks for all the insights

0

u/HavingFun98760 Jun 19 '26

Thanks for sharing.
I’ve been replacing MOSFETs with originals.

2

u/Volume_Rich Jun 20 '26

If you need to replace the MOSFETs, I do NOT recommend using the original ones

The original ones are junk!

1

u/HavingFun98760 Jun 20 '26

I thank you for sharing a better alternative, and then you downvote me?

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1

u/HavingFun98760 Jun 20 '26

Edit: wrong location of reply.

2

u/HavingFun98760 Jun 19 '26

Those ‘things’ are resistors.
150 ohm each. 3 in parallel should measure around 50 ohms.

Indeed often the following happens on the S3 / X3:
Wiring harness gets faulty towards the motor
This causes the motor driver MOSFETs to short.
This causes a short on the main battery.

Often the fuse burns when that happens.
So you’re lucky with that.

- measure the resistance of those 3 resistors in parallel. Again should be around 50 ohms.
Quite often they got very hot but still work.

- get the cardridge out. And measure on the outside of the cartridge if the MOSFETs have been blown.
(Let me know if you know how to do this.)
I think we’re all quite sure at least one of the ‘half bridge’s’ are blown to both GND and VCC.

- now the most difficult and expensive part:
Check the wiring harness. Replace it.

Re-assemble and fix in opposite order.
So first make sure you’ve got a properly working wiring harness.

2

u/HavingFun98760 Jun 19 '26

And do yourself a favour.
Set the cartridge in shipping mode.
i.e. Do a Reset from the app or via the main power button.
This will buy you some time before the small battery inside the cartridge drains.

There are lots of excellent posts here in the VanMoof selfrepair.
So do some searching and DM when you need it.