Carrera Cross city e power problem

[Johnny8ball]

Hi there folks!
Just wondered if anyone could help me with my latest brainstorm
I recently acquired another Carrera Cross city e bike, having been using one for a while.
I transferred the battery from my old bike to the new one, as it came without a battery or charger.
The control unit on the handlebar lit up but as soon as I started to pedal the lights went out!
So I put the battery back in my old bike & to my horror there was no power at all..zilch!
I have tried swapping over the control units from inside the frame but to no avail.
I have charged the battery fully & the USB socket provides power, but doesn't power up the bike.
Any how I am currently up the creek without a paddle so to speak...any ideas please?
Would be greatly appreciated as I've spent all day trying everything but I'm stumped!

 

[vfr400]

You've probably blown the fuse in the battery. maybe the second bike had reverse polarity. You have to check where the wires go.

 

[Johnny8ball]

You've probably blown the fuse in the battery. maybe the second bike had reverse polarity. You have to check where the wires go.

Hi vfr 400..Thank you
Thought that might be the case but tried taking the battery apart earlier to see if I could access the fuse if there was one..
But I ran out of time as had to be somewhere tonight.
I will check it out tomorrow cheers for your reply..
Ps. I once had a Yamaha RD 400 & my mate had a VFR 400.
We exchanged bikes for a little blast up the road & my got off my bike & couldn't stop laughing : D : D....Nice reliable bike the VFR!!

 

[Andy-Mat]

Hi there folks!
Just wondered if anyone could help me with my latest brainstorm
I recently acquired another Carrera Cross city e bike, having been using one for a while.
I transferred the battery from my old bike to the new one, as it came without a battery or charger.
The control unit on the handlebar lit up but as soon as I started to pedal the lights went out!
So I put the battery back in my old bike & to my horror there was no power at all..zilch!
I have tried swapping over the control units from inside the frame but to no avail.
I have charged the battery fully & the USB socket provides power, but doesn't power up the bike.
Any how I am currently up the creek without a paddle so to speak...any ideas please?
Would be greatly appreciated as I've spent all day trying everything but I'm stumped!

Always, with any sort of power problem, measure the battery voltage with a known good multi-meter, check against another occasionally, and replace the battery if the results are not what you expect.
If you need assistance with any problem here, tell us that voltage value, and also mention the so called, "nominal Battery Voltage" as well, "just in case!"
If anything I, or any others here ask you is not 100% clear, simply ask for clarification from us.
When was the battery last charged on the original bike it was attached to?
Remember that there is a huge amount of "power" in a fully charged battery, and it is difficult to imagine, if the battery was fully charged, how in a few seconds, that power was dissipated, unless it is still available, but a fuse or other component has blown.
May I also say, as someone else here has already mentioned, never take for gospel that the same battery type and the same bikes, have the same polarity, particularly if one of the bikes (both?) are secondhand!!
Which is why all e-bikers need a digital multi-meter, and roughl how to (and not to) use it, unless they are rich enough to always give the bike shop the work!!
I have Scottish blood, and giving away money is simply against my breeding!!
Let us know how you get on.
regards
Andy

 

[Johnny8ball]

Always, with any sort of power problem, measure the battery voltage with a known good multi-meter, check against another occasionally, and replace the battery if the results are not what you expect.
If you need assistance with any problem here, tell us that voltage value, and also mention the so called, "nominal Battery Voltage" as well, "just in case!"
If anything I, or any others here ask you is not 100% clear, simply ask for clarification from us.
When was the battery last charged on the original bike it was attached to?
Remember that there is a huge amount of "power" in a fully charged battery, and it is difficult to imagine, if the battery was fully charged, how in a few seconds, that power was dissipated, unless it is still available, but a fuse or other component has blown.
May I also say, as someone else here has already mentioned, never take for gospel that the same battery type and the same bikes, have the same polarity, particularly if one of the bikes (both?) are secondhand!!
Which is why all e-bikers need a digital multi-meter, and roughl how to (and not to) use it, unless they are rich enough to always give the bike shop the work!!
I have Scottish blood, and giving away money is simply against my breeding!!
Let us know how you get on.
regards
Andy

Thanks for the heads up on this Andy..
I took the battery apart & changed the fuse, put the battery back in my original bike & hey Presto! She's up & running again.
Now all I have to do is go over the other bike with a fine tooth comb checking the wiring & components are all as they should be.
I guess it may be a bad connection or faulty component that made the battery blow the fuse? I'll keep you posted..thanks for your expert advice (*__*)

 

[vfr400]

If the MOSFETs in the controller are blown, you get a dead short across the battery. You can check them with a meter set to measure resistance. You disconnect everything from the controller, then measure between the black battery wire and each of the three thick motor phase wires, the resistance of each should be the same and around 7K. repeat with the battery red wire to the three phase wires. They should be the same as each other, but maybe as high as 14K.

 

[Johnny8ball]

If the MOSFETs in the controller are blown, you get a dead short across the battery. You can check them with a meter set to measure resistance. You disconnect everything from the controller, then measure between the black battery wire and each of the three thick motor phase wires, the resistance of each should be the same and around 7K. repeat with the battery red wire to the three phase wires. They should be the same as each other, but maybe as high as 14K.

Thanks very much vfr400
I'll be checking the bike over tomorrow & let you know how I get on with it (*-*)