Looking to replace BMS in Xiaomi EF1 Qcycle bike

[NovelRoman]

Hi there, I'm looking to replace the BMS from the battery and can't find anyone selling it. Has anyone ever found the part ?

I got another bike working, swapped the battery but none of the bike is working anymore :/

It sounds like the bike controller is also faulty?


Thanks a lot !
Roman

 

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Hi Welcome, how did you conclude the battery pack bms and or controller are faulty.

To benefit from the collective wisdom in here lay out the problems you have encountered and any events leading up to any fails.
Pictures of the controller/label and the display will help, there are 100's of different bikes out there..

How many wires/contacts connect your battery pack to the Bike?? If you battery pack is complicated with extra communication wires/connections - well that can complicate things .. best case is a simple 2x load connections only

What voltage will your fully charged battery hold? and is your charger outputting a suitable voltage?

does anything turn on/light up when you attempt to start the bike?? is any voltage supplied to the display?

Sorry have to ask, is the battery switched on and has the fuse (if fitted) blown?

 

[amberwolf]

Hi there, I'm looking to replace the BMS from the battery and can't find anyone selling it. Has anyone ever found the part ?

What is the specific part?

Remember that we only know what you show us and tell us, everything else is only a guess at what you have there.

Also, what specific tests were done to determine the BMS is faulty, and what were their specific results?

FWIW, most people trying to replace a BMS are not solving their problem (and potentially setting themselves up for a fire) as they usually have failed cells in the battery that the BMS has turned off output / charge ports to protect the cells from damage that can lead to a fire.

I got another bike working, swapped the battery but none of the bike is working anymore :/

What other bike? What other battery? Do you mean that now the other bike doesn't work either (blown up by wrong battery, perhaps)?

Specific details and order of events is required to provide useful help to you.

It sounds like the bike controller is also faulty?

What specific tests have been done, and what were their specific results?


The less you tell us, the less useful feedback we can provide.


Also, your thread title doesn't reflect the actual post; I recommend you edit the subject of your first post to match what you want to do in this thread.

 

[NovelRoman]

Hi and thanks a lot for your replies.

To be more precise :

I had a Xiaomi EF1 : bike 1 + battery 1 that suddenly stopped working (no more LCD or power). Battery still charging and showing level of charge.

I got a new exact same Xiaomi EF1 : bike 2 + battery 2.

I wanted to use the bike 1 with the battery 2 : burned the battery 2 (now smells burn). Same symptoms as battery 1.

So I assume controller from bike 1 + battery 1 BMS + battery 2 BMS are burned.
Kind of silly of me, I thought those things were protected from other dead components.

I didn't open anything yet because of fire risks etc. I was investigating if it was even possible to replace those parts.

Ifixit shows pictures of the BMS and it doesn't seem to have any fuse.

Bike controller sells on aliexpress but not the battery BMS.

That's where I am right now, going to ride my muscle bikes ...

 

[fill]

Hi and thanks a lot for your replies.

To be more precise :

I had a Xiaomi EF1 : bike 1 + battery 1 that suddenly stopped working (no more LCD or power). Battery still charging and showing level of charge.

I got a new exact same Xiaomi EF1 : bike 2 + battery 2.

I wanted to use the bike 1 with the battery 2 : burned the battery 2 (now smells burn). Same symptoms as battery 1.

So I assume controller from bike 1 + battery 1 BMS + battery 2 BMS are burned.
Kind of silly of me, I thought those things were protected from other dead components.

I didn't open anything yet because of fire risks etc. I was investigating if it was even possible to replace those parts.

Ifixit shows pictures of the BMS and it doesn't seem to have any fuse.

Bike controller sells on aliexpress but not the battery BMS.

That's where I am right now, going to ride my muscle bikes ...

Plugging in new battery #2 into dodgy bike #1 resulted in the battery BURNT??? and smelling bad??
That alone indicates a problem with the cables or connections between the battery mount and the system, and perhaps the controller itself.
If so your battery bms protection should have kicked in???

what voltage readings do the batterers provide, if you dont have one a basic multi meter is an essential tool and can be picked up for less than a posh coffee. and do the batteries accept a charge?- smelling bad due perhaps to proximity to a shorted out wire frying its sleeving in the battery mount is not an indication of a failed battery or bms. LOW voltage readings and a failure to charge are..

Battery fuses when fitted tend to be automotive spade types.. (edit and inside the case)

As long as your bike uses no superfluous battery comms you can employ any suitable bms for your pack size and config. If it does employ battery comms Its possible that its one of the worst auto bricking type designed to create battery sales opps..

 

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Also plugging in 'bad batteries' into new bike#2 and not getting power is not a conclusive dead battery test without first checking battery contacts for arcing damage that could prevent a clean connection.