CycloTricity Stealth 48V/1000W problem - battery or motor?

strober

Just Joined
Jun 18, 2018
2
0
I'm an owner of a CycloTricity Stealth 48V/1000W E-bike that has been used for 1748 km/1086 miles without any motor or battery problem. After last charging it simply does not work :( No warranty so I have to fix it on my own. I'm very thankful for any help to locate the source of the issue (Is it battery, motor, controller or something else?)

Issue described (with video):
Bike can be turned on without problem on the LCD controller. Whenever motor power is triggered regardless if by the assistance-button or by pedals, the motor only runs for a maximum of 1 second or less and LCD goes black and bike acts if its turned off. After this has happened I can turn the bike on again from the LCD controller and replay the same scenario. See the video I recorded for a demonstration of issue:

I'm not good with electronics but still was able to measure the output connector on the battery with a multimeter to about 54V. What I think is suspicious is that if I turn battery switch to "off" my multimeter shows 51V on the battery output connector. Should it not be 0V if turned off?

The battery is Cyclotricity of type 48V/16Ah with USB output, On/Off switch, 4-LED Battery status indicator with button, and an output connector.

Many thanks in advance for any help in trouble shooting this!
 

vfr400

Esteemed Pedelecer
Jun 12, 2011
1,439
248
Basildon
You need to do some tests to find out what's wrong. If the LCD has a flat connector disconnect it, bridge the red and blue wires and bridge the white and yellow ones so only the black is not connected. If the bike works like that without the LCD then the LCD is faulty. Lift the back wheel and turn it by hand. If it's stiff, unplug it and see if it loosens up. If neither of those tests show anything, you have to check your battery and motor wires for a short circuit.
 

Andy-Mat

Esteemed Pedelecer
Oct 26, 2018
322
55
72
I'm an owner of a CycloTricity Stealth 48V/1000W E-bike that has been used for 1748 km/1086 miles without any motor or battery problem. After last charging it simply does not work :( No warranty so I have to fix it on my own. I'm very thankful for any help to locate the source of the issue (Is it battery, motor, controller or something else?)

Issue described (with video):
Bike can be turned on without problem on the LCD controller. Whenever motor power is triggered regardless if by the assistance-button or by pedals, the motor only runs for a maximum of 1 second or less and LCD goes black and bike acts if its turned off. After this has happened I can turn the bike on again from the LCD controller and replay the same scenario. See the video I recorded for a demonstration of issue:

I'm not good with electronics but still was able to measure the output connector on the battery with a multimeter to about 54V. What I think is suspicious is that if I turn battery switch to "off" my multimeter shows 51V on the battery output connector. Should it not be 0V if turned off?

The battery is Cyclotricity of type 48V/16Ah with USB output, On/Off switch, 4-LED Battery status indicator with button, and an output connector.

Many thanks in advance for any help in trouble shooting this!
Firstly, a quick check would be if you knew of someone with the same style of battery, that you could try out, to confirm that the fault is in the battery, as I think it could be....
But I assume that the battery is fully charged, then I would think it should show about 56 volts unloaded (can anyone here confirm that please), which means that 54 volts could be an indication that a cell or some connection in the battery, has some extra resistance, which, once a load is applied, causes the battery voltage to collapse and the battery safety electronics then simply "turn it off!"
Your description might indicate something like that!
I feel that you might need a bike "battery Doctor" to have a look at it.....
If it turns out to be a cell, it may also be an indication of a need to have all the cells replaced as they all need to be carefully selected to be as close in all repsects to each other as possible! There is usually electronics to do that to a degree, but once cells are failing, then the electronics will not be able to "do anything useful, other than switch off!"
You do need professional, hands on, help.....
My guesswork help might be far from true reality.....hopefully.
The only other thing I can think of is that an internal fuse, or fuse holder or the switch or something, may have corroded or has a loose connector, but its a long shot.....
Do please remember that Li-ion batteries have large amounts of energy in a small space, an accidental short can cause explosions or fire, or both. A rank amateur should never open us such a battery, even the experts have safety masks and clothing!
Replacement batteries need to be from a good manufacturer and have been "graded" so that all the cells are very similar in characteristics....I personally have only Panasonic, a good balance between price and quality.....Unknown Chinese makes do not get built into my bike!!
But I am not suggesting that you yourself do anything at all inside the battery, other than to pay for the repair of course! :)
best of luck
Andy
 

Nealh

Esteemed Pedelecer
Aug 7, 2014
7,301
2,763
55
West Sx RH
48v 13s will have a max charge of 54.6v, 54v is 4.15v per cell which is fine if all the 13 groups are in balance.
The fault is more likely as Dave has said so carry out his tests as in #2.
 
Last edited:
D

Deleted member 128

Guest
I'm an owner of a CycloTricity Stealth 48V/1000W E-bike that has been used for 1748 km/1086 miles without any motor or battery problem. After last charging it simply does not work :( No warranty so I have to fix it on my own. I'm very thankful for any help to locate the source of the issue (Is it battery, motor, controller or something else?)

Issue described (with video):
Bike can be turned on without problem on the LCD controller. Whenever motor power is triggered regardless if by the assistance-button or by pedals, the motor only runs for a maximum of 1 second or less and LCD goes black and bike acts if its turned off. After this has happened I can turn the bike on again from the LCD controller and replay the same scenario. See the video I recorded for a demonstration of issue:

I'm not good with electronics but still was able to measure the output connector on the battery with a multimeter to about 54V. What I think is suspicious is that if I turn battery switch to "off" my multimeter shows 51V on the battery output connector. Should it not be 0V if turned off?

The battery is Cyclotricity of type 48V/16Ah with USB output, On/Off switch, 4-LED Battery status indicator with button, and an output connector.

Many thanks in advance for any help in trouble shooting this!
The 51V could be there because of capacitance in the controller, what do you measure after (say) an hour or more?
Also, what is the voltage doing while the motor is briefly running?
 

bongo

Just Joined
Feb 18, 2019
1
0
hi i have only just joined the group so i hope i am not butting in
the fact the motor jerks trying to move, then cuts power would lead me to think you have hall sensor problems, shorting the motor,
most motor assemblers use 7 core awg wire discarding the white in the hub using the other colours connected to the halls this is the case with cyclotricity, anyway sorry to but in
 

strober

Just Joined
Jun 18, 2018
2
0
Hello all! Thanks for your help troubleshooting.
I ordered a new battery for £500 ... it didnt help :) so now I got two! But I'm totally fine with that.

I then opened the control box and tried to measure if something was shortcut or looked for melted components.. nope. But It was strange that when turning the electricity on, the input + - voltage connectors slowly raised from 15V to 53 V... in maybe 5 minutes. After I try to start the bike the voltage dropped to ~15V again and slowly raised to 53V within a few minutes. This made me think something is wrong with some component in the control box, but I didn't have the skills to measure what component was failing.
So, I decided to order a new control box for £80 and that actually fixed the problem!
Now the bike works again and I'm happy! =)

If anyone is interested in the "broken" controller box, let me know. Maybe its easy to fix if you know how :)
 

Andy-Mat

Esteemed Pedelecer
Oct 26, 2018
322
55
72
Hello all! Thanks for your help troubleshooting.
I ordered a new battery for £500 ... it didnt help :) so now I got two! But I'm totally fine with that.

I then opened the control box and tried to measure if something was shortcut or looked for melted components.. nope. But It was strange that when turning the electricity on, the input + - voltage connectors slowly raised from 15V to 53 V... in maybe 5 minutes. After I try to start the bike the voltage dropped to ~15V again and slowly raised to 53V within a few minutes. This made me think something is wrong with some component in the control box, but I didn't have the skills to measure what component was failing.
So, I decided to order a new control box for £80 and that actually fixed the problem!
Now the bike works again and I'm happy! =)

If anyone is interested in the "broken" controller box, let me know. Maybe its easy to fix if you know how :)
This sounds like a poor (high resistance) connection, between the battery connector on the controller, and the point you measured the slowly rising voltage.
The point of high resistance will usually get very hot too. Do not burn yourself, wet the finger first and only touch for a very short time each point of connection.
A so-called "dry joint", a soldered connection may also be the problem, or a burnt out resistor or other component.
There are many possible reasons.
If you know anyone with a camera that is sensitive to IR, may see it. Even some quite normal phone's camera, in total darkness, may show the hot spots, depending upon the way/how good the IR filter works!!!
Some cameras have a night vision setting, my Sony video camera has that, it shows hot spots really clearly!!
Best of luck.
regards
Andy
 

vfr400

Esteemed Pedelecer
Jun 12, 2011
1,439
248
Basildon
Change the parameter P5 to 0 or 1 to get instant showing of voltage on the display. If you have it on the normal high number, like 15, it shows a moving average with a longer time constant.

15V is normal when the battery is switched off by the BMS. It's not real voltage. Its just a bit of leakage through the discharge MOSFETs. If you try to take any current from it, it'll immediately collapse to zero.

Most likely your problem was a blown MOSFET in the controller, which caused a short to ground, so as soon as you switched on, the BMS in the battery detected over-current and switched off.
 

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