G-Bike City- Electric Scooter 48V dropping out

[powersupply]

Hi there!
I got me this (used) G-Bike City- Electric Scooter
http://www.shopgbike.com/products/city/indigo.html

And it has the issue that it sometimes does not accelerate!
As if it is hesitating.
And when I turn the throttle a few times, it suddenly kicks in.

It has a controller which I could not find anything on (even tried Alibaba)
Brush intelligent motor controller jdk 404R




The bike came with a spare mystery box and I was suprised to see it next to the controller (small silver box above controller)




Could it be the throttle making the problems?



The batteries are totally OK, all same level and have much power.

Could it be a short or a broken connection somewhere?

Has anybody a schematic from these bikes? I checked the *** Controller Information Links *** but could not find anything on 48V 750W, but I guess they are all very similar, right?

I am totally new to these exiting scooter ebike things, but do know some electronics.

Also, I am totally blown away by some of the mods/posts on these pages, amazing!

Any help/info is very much appreciated,

 

[amberwolf]

And it has the issue that it sometimes does not accelerate!
As if it is hesitating.
And when I turn the throttle a few times, it suddenly kicks in.

Could be batteries or a connection somewhere, in throttle or in wiring. If throttle is resistive rather than hall, could be a bad pot or have dirt in it.

It has a controller which I could not find anything on (even tried Alibaba)
Brush intelligent motor controller jdk 404R

Typical brushed motor controller, probably.

The bike came with a spare mystery box and I was suprised to see it next to the controller (small silver box above controller)

Probably DC-DC converter for your lights and stuff, possibly a control box for turn signals/etc, maybe other stuff. You'd have to trace the wires.

The batteries are totally OK, all same level and have much power.

What voltage are they at the moment you try the throttle, each time, both when it does not work and when it finally does?

The idea is to see what htey are under load.

 

[powersupply]

Could be batteries or a connection somewhere, in throttle or in wiring. If throttle is resistive rather than hall, could be a bad pot or have dirt in it.

I checked all battery connections, also under a 17A load, it's fine.
Yes, I remember scratchy potentiometers, maybe it's just that?

Typical brushed motor controller, probably.

I see, do those have 120 degree phases, too?

Probably DC-DC converter for your lights and stuff, possibly a control box for turn signals/etc, maybe other stuff. You'd have to trace the wires.

The wiring is a mess, no schematic on the bike, it has no manual and that G-Bike company is a bunch of criminals.
I opened the spare mystery box, please see attached. Considering high tolerance resistors, and the 48V label outside, could it be the charging unit?

What voltage are they at the moment you try the throttle, each time, both when it does not work and when it finally does?

13,3 V and around 12V under load.

The idea is to see what htey are under load.

Yes, that was the first thing I checked, but as mentioned that is all OK.
I checked the connections between the batteries, from the battery compartement to/after the fuse etc.

The weird thing is that when it drives, it drives OK, even under high load (uphill).
I had one time when I throtteled down briefly and when I tried to accelerate again, it hesitated. But that happend once, while from standstill it happens much more often.

Puzzeled.

Thanks!

 

[amberwolf]

Typical brushed motor controller, probably.

I see, do those have 120 degree phases, too?

No, brushed motors don't (usually) have any position sensors. If the motor has only two main wires from it it's probably brushed, but if it has at least three main larger wires and at least 5 smaller wires, it's brushless. Could be either on this type of scooter.

Since the label (which I didnt' see in the first viewing of your thread but do now) says "brush" but also says that about the sensors, the label is definitely a mishmash of conflicting information, at least for those two things (possibly others). That is also typical of this kind of stuff, unfortunately--that's why I recommend you manually trace out the wiring because any schematic you might find on it is probably wrong.

I opened the spare mystery box, please see attached. Considering high tolerance resistors, and the 48V label outside, could it be the charging unit?

You'd have to trace out the wiring. Probably is DC-DC for lights and stuff, like I said. Until you trace it out or measure voltages or both, you won't know.

I checked the connections between the batteries, from the battery compartement to/after the fuse etc.

Often it's nto just whether something is plugged in, but also whether it is crimped or soldered properly, and also whether any wires might be broken inside the insulation.

Last week I fixed a friend's Kawasaki motorcycle that had had intermittent problems with electrical stuff every time he made a right turn. This was because the idiot at the shop he'd last taken it to for a speedo cable fix had tied down the wiring harnesses very tightly to fixed points on the frame, not to the places they originally went to, and with no loops for flex as the handlebars have to turn. So it ripped the conductors open inside the insulation on two of the wires to the keyswitch, which I had to splice to fix the problem.


I can't even list all the times I've fixed stuff that was intermittent from poor crimps or nonexistent solder on contacts, where the actual pins made perfect contact but the wire was just sitting in the back of the connector pin.

The weird thing is that when it drives, it drives OK, even under high load (uphill).

That eliminates batteries and makes it much more likely it is a connection problem.

 

[powersupply]

On
http://www.shopgbike.com/products/city/indigo.html
under 'Tech Specs' it says 750Watt Brushless Hub Motor, but that's for the newer models.
Mine is 2 years old and maybe brushed as you suggested.

Will check the motor wiring and measure the mystery box tomorrow, good ideas you had.

Yes, those crimping issues are really bad. But worse are the unleaded wires/cables they use here in the US (and China).

Nerarly all cables I encounter here, be it in my car or other equipment have plain copper (or copper clad aluminum) wires in them.

And with this bike, they use copper contacts/wires on silver plated terminals, which is an invitation for disaster, corrosionwise.
Many were corrorded green already, washed it all off first thing.

Anyhow, back to the initial question, of why this bike sometimes does not start, I will try to check the thorttle tomorrow, in a weird way, I hope to find it broken...

Could it be a bad switch from the brake?
Looking at some schematics, there is a brake switch (for the brake lights), but it also goes into the controller and probably disables the power output to the motor.

Wish I had some sord of schematic to go on....

Thanks!

 

[dogman dan]

Not so likely to be the brake switch. It has to close a circuit to engage the controller shut off function. More likely an intermittent bad contact in the throttle wiring, or the wiring to the motor itself.

If brushed, it could also be a sign that the brushes are wearing out. Brushed motor will have only two big power wires into the hub in most cases. Brushless has three big wires, and possibly 5 smaller ones.

 

[powersupply]

I have never seen such a balant disregard for prevention of galvanic corrosion!

As if they deliberatedly try to fault the machine.

Nearly every single connector beneath the controller had different anodic indices, be it gold plated to copper, silver plated to copper, or grey stuff (probably an alloy) to gold plated. And even copper to iron (fasteners)!

No wonder these things don't last long!

Green, yellow, brown, you name it, any oxidation from the chemistry books was there.

And not a single (tin) plated copper wire, all pure copper.

Add to that the salt and humidity present in SoCal, and yes, youv'e got a time bomb.

And these people charged over $1200 for this!

UNBELIEVABLE!!!

After seeing this I took apart all connectors and cleaned the pins.
As mentioned, some connectors were burried beneath the controller.
Had to remove it of course.

Used dielectric grease an glue to to seal it off.

At least it does work now!

Thanks all for your suggestions/help.

 

[powersupply]

The mystery box was indeed a 48V to 12V converter!

Another question:

Do the control boxes (in general) manage the charging of the batteries or is it done just by the charger itself?

thanks!

 

[powersupply]

Hi all,
just an update, I found the charger for it and it has been a great experience this e-bike riding!

In comparison to a real motorcycle, this is a quiet and slow ride, and you have much more time to take in the enviroment around you.

I found shops and places I passed often and didn't know they existed.

Anyhow, great thing!

Thanks for your input!

 

[tronics]

Hi All, sorry to bump this thread from the dead but I'm in EXACTLY the same position as the OP; I just got a used G-bike City from a friend and it's in need of some love...

...it has exactly the same problem as you described powersupply - sometimes you turn the throttle and it does nothing and only jumps in to life after the 4th or 5th twist, and again, it fine once you're in motion, but again, say stop at a set of lights, damn thing won't move.

Did you just solve it by cleaning all of the contacts? I was considering cleaning all of them, then using Deoxit Gold. Please let me know if that was the fix!?!?

Also, I have an issue with the key.

I don't have one. The friend gave it to me as they were getting rid of their storage unit and they told me the key should be in the ignition. I drive all the way there and no key and they have no idea where it is. I called a few local locksmiths but the general consensus is don't hold out much hope. Apparently with the chinese electric scooters, it's complete pot luck as to whether you can key something for it and most of them have quoted $200 with no guarantees.

Any ideas?

Finally, I know it was in storage for at least a year and the battery is going to be at least 3 years old. I was told by a guy that used to sell them that he would upgrade them to L-ion but he let his contacts slip and has no idea of a good source.

All I know is it seems to be 48v in a 4 x 12v config and the extended battery is apparently 22ah.

Again, any help great appreciated!!!!

 

[tronics]

*BUMP*

Sorry peeps, just would really love to get some feedback from anyone on the above post.

Halp!