Video Diagnosis?

[Alimages]

VIDEO0028 - YouTube

VIDEO0034.3gp - YouTube

VIDEO0032 - YouTube

VIDEO0033.3gp - YouTube

Can anyone help with diagnosing the fault on my bike? If you have a look at the video links you will see that as I apply full power the whole system shuts down. Off and on again brings it back to life until full power again. My guess is the Battery Pack? Also, Am I checking the charger correctly by just putting one probe of the multimeter inside and one outside? Any suggestions greatly received.

 

[Ultra Motor]

VIDEO0028 - YouTube

VIDEO0034.3gp - YouTube

VIDEO0032 - YouTube

VIDEO0033.3gp - YouTube

Can anyone help with diagnosing the fault on my bike? If you have a look at the video links you will see that as I apply full power the whole system shuts down. Off and on again brings it back to life until full power again. My guess is the Battery Pack? Also, Am I checking the charger correctly by just putting one probe of the multimeter inside and one outside? Any suggestions greatly received.

I would guess BMS in battery pack...is this home built?

 

[Alimages]

Home fitted. Elifebike.com Kit.

36V 10AH Headway 38120 LiFePO4 Battery Pack - Elifebike Online Store

 

[Deleted member 4366]

The reason why it cuts off is because the battery cannot supply enough current, and so the BMS shuts down - like it's supposed to when your battery is flat. Normally this would happen at about 31 -33v for a 36v Lifepo4 battery, depending on how much current you draw from it. 38v is too low for a charged 36v battery. It should be about 40-41v off the charger, so clearly something is wrong with the charger. To get an idea of the current being drawn: What motor and battery do you have? If it's a 48v battery, then the problem is that your charger isn't charging it and it's flat. If it's a 36v battery, then there must be more than one problem.

 

[Deleted member 4366]

Just found the history of your problems. I didn't realise that these were related. It's possible that there's a short or other similar problem in the motor side of your controller. Would it be possible to show the voltage (like you did before) but at the same time as opening the throttle slowly so that you can see how much voltage reduction there is before it cuts out?

 

[Alimages]

Thanks for the input. I will try and get a chance to do a check and video as you have suggested d8veh. It might be a couple of days before I do. I'll have to get home before it's dark as I currently have no electrics in my garage at home due to building work.

Ultra Motor, I was thinking it was the BMS possibly myself. Just to be clear, are you suggesting that the reading should be around 32V on my 36V Lifepo4 before the system should shut down? I think the battery charger might be faulty as well because it refuses to charge the battery any more than its current state. If I put the probes of the multimeter inside and out of the female jack plug from the charger it doesn't seem to read any voltage. Does it need to be connected to a battery before it will supply any power?

 

[Ultra Motor]

Thanks for the input. I will try and get a chance to do a check and video as you have suggested d8veh. It might be a couple of days before I do. I'll have to get home before it's dark as I currently have no electrics in my garage at home due to building work.

Ultra Motor, I was thinking it was the BMS possibly myself. Just to be clear, are you suggesting that the reading should be around 32V on my 36V Lifepo4 before the system should shut down? I think the battery charger might be faulty as well because it refuses to charge the battery any more than its current state. If I put the probes of the multimeter inside and out of the female jack plug from the charger it doesn't seem to read any voltage. Does it need to be connected to a battery before it will supply any power?

Follow d8veh's advice. You could bypass the BMS for a test to check whether it is that causing the issue.

 

[NRG]

I would have thought the charger would have had the o/p voltage on its terminals without load, the ones I have certainly do. Is the fuse OK?

Regarding the cutout, when you open the throttle does the motor try to start? Does it give a little stutter just before it cuts out?

 

[Alimages]

Fuse in charger is ok. As for the motor, it will run fine at 1/2 throttle for quite some time. It only cuts out quickly if you apply full throttle.

 

[NRG]

Seems the fault is more to do with the battery side of things then. Can't understand why the charger is not outputting a voltage, if the battery could be fully charged it would help the diagnosis.

 

[Alimages]

I am getting the charger checked by an electrical engineer just to make sure I am not being stupid.

I have learned an interesting point about dealing with a supplier on mainland China. They have been surprisingly helpful so far in their replies. Not helped by my limited electrical knowledge and their slightly broken English. Nonetheless they have made a reasonable effort so far to help me diagnose the problem. The interesting bit was when I sent him the link to the YouTube videos he informed me that he was unable to follow the link to any videos. I had to send him a series of still frames by email instead. I assume this is all due to the infamous "Great Firewall of China"? I didn't realise their Government was still so touchy about free internet access.

Anyway, I hope that it's as simple as the charger being at fault and the meters on the battery and throttle are just rubbish. The BMS might just being doing it's job and saving the battery from discharging too much? I will keep you informed and hopefully will manage a voltage test on video tonight while gently increasing throttle instead of quickly going to full power.

 

[Alimages]

Just a quick update. I know it's been a while but I've finally had time to sort the problem with my bike. It turned out just to be a faulty charger. Basically the battery wasn't ever getting a full charge and was always on the point of the bms cutting in to save it from dropping to a dangerously low level.

Anyway, i'm back on my bike and loving it. Thanks for all your input.

 

[mike killay]

Thanks for telling us this.
Whilst the mechanical side of our bikes is well understood and bike shops can help, the electrical side is still a mystery to many of us.
Somehow we need to get all this sort of information together in one place, not only for ourselves but for newcomers who can have a good browse and get to know something about e-bikes