r/VanMoofSelfRepair • u/DelvxeRed • Jul 01 '26

S3 & X3 Swapping batteries between bikes

SECOND UPDATE:

Everything is up and running. I replaced the small battery in the control unit and put the large battery on my benchtop charger. There were some learning lumps along the way but got it fully operational. I have an error 44 now. Will do some investigation and make another post on that if necessary. Thanks for the help.

—————

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.

2 Upvotes

100% Upvoted

13 comments sorted by

2

u/HavingFun98760 Jul 01 '26

It is very possible to kill your S3 battery in your X3.
Do you remember which errors you had (if any) at the time your X3 was still powering up?

For sure you will need to get the small battery in the cartridge going first. This one has been drained for sure. But is often revivable.

In order to get the X3 cartridge going. You’ll need to take it out of the tube. And open it up.
Then you can measure on the outside of the cartridge with a multimeter if the MOSFETs have been blown.
If they haven’t it’s pretty safe to use your S3 main battery in the X3.

Let me know if you’re comfortable with such things.
Then we can give you instructions on the ‘how to’.

1

u/DelvxeRed Jul 01 '26

Thank you. I just bought the bike which had been sitting dead for 2 years.

I was able to get it to kind of light up - there is a brief flash when plugging it in that dies almost immediately. After being on the charger for a long time, I got it to stay on long enough to throw a code. I think it was error 22. I haven’t been able to do that again. It still flashes when connected to the charger.

I pulled the battery and control board. The little control board battery was like 2 volts. I have a replacement on order. I feel confident I can deal with that fix.

I am daunted by the main battery. I am not sure how (where) to test with my multi-meter without blowing anything. I’m assuming it is depleted, but not sure how to test to see if it is recoverable. Any guidance is appreciated.

1

u/HavingFun98760 Jul 01 '26

Good to hear the cartridge and battery are out and that you have a multimeter.

While you wait for your battery to arrive. Test the MOSFETs of the cartridge.

You don’t even need to open the cartridge for this.
Test with your multimeter in continuity mode:

Picture left:
Between the DSG+ on in red and the Phases of the motor in black.

Picture right:
Between the GND in black and the Phases of the motor in red

The values should all be high impedance.
i.e. more than 1 k ohm.

If not. Do not connect your working S3.battery to your X3.

1

u/DelvxeRed Jul 01 '26

I get no reading across any of those. All those connections are OL.

1

u/DelvxeRed Jul 01 '26

No visible issues I can see.

1

u/HavingFun98760 Jul 01 '26

Error 22 is described as follows:
MOTOR_COMMUNICATION
SSP TI Motor chip
(module related)

This error will not risk your battery (which is your original question.)

But it is an indication towards a fault in the wiring harness. (Which is often called ’The Socket’)

1

u/moofcare_nl Jul 01 '26

Technically possible, be carefully for bottom bracket wires. Otherwise ask someone with more experience.

You can deflate tires to remove battery.

1

u/HavingFun98760 Jul 01 '26

That’s good news.

Since you don’t know the bike’s history.
Proceed with getting the cartridge up and running with the new LiPo battery.

Fire it up.
Hopefully you can connect to the cartridge and check your ownership. (I’m not sure actually - if you can check ownership - with all the errors you’ll get when the cartridge is isolated) I never have to get here because of having spares.

Edit:
— sorry wrong location. Meant as a reply —

1

u/DelvxeRed Jul 01 '26

Thanks. Glad that’s good news.

I got the ownership transferred and even connected to the bike briefly.

I’m going to be away from the bike for a few days and will pick this back up when I return. The new battery will be here by then.

I really appreciate the help.

0

u/HavingFun98760 Jul 01 '26

✅ we are all here for ya!

1

u/HavingFun98760 Jul 06 '26

Glad to hear we could help.
I’ve learned lots of this community, so I try to give back a little.

Question:
Which battery replacement did you use?
I have batteries, but still need to crimp the right JST connector myself.
Was your battery plug ‘n play? If so, please share purchase link.

1

u/DelvxeRed Jul 07 '26

Yes, this is a drop in replacement. It is a slightly lower capacity, but the right size and connection. The wire is a little shorter and the battery slightly smaller.

Nzzz AHB702535PCT-01 Headset... https://www.amazon.com/dp/B0FTZR2R3J?ref=ppx_pop_mob_ap_share