Carrera Crosscity 790 LED Display Problem.

[Tortus]

I have just joined and this is my first thread.
I hope its in the right place. If its been answered before could you please point me in the right direction.
I bought a Carrera crosscity with a faulty battery (so I was told)
After getting it home I put the battery on charge and it charged for about 4 hours and then the green fully charged light came on.
I thought I was on a winner as it wasn't the battery.
I plugged the battery in the bike and pressed the on button, power lights go from low to high then go back to low and the low battery light flashes.
The peddle assist light goes from low to high then settles on a steady low light.
After about 5 seconds all the peddle assist lights come on and flash.
I removed the battery and checked the voltage with a meter and the voltage is 41v.
Any help would be greatly appreciated thanks.

 

[saneagle]

It's just a guess, but I'm going to say that you have a problem in your motor controller.

First step is to get a voltmeter on the battery wires to see what happens to the voltage when you switch on. If it sinks rapidly, then your controller is faulty and need to be replaced.

There is also a possibility that the 790 has a problem, like water in it or wires pulled and shorting. You can eliminate that by disconnecting it from the controller and making a bridge between the red and the blue wires on the controller side connector with a paper clip or something like that. In that condition, the bike should still work with the pedal sensor as if you'd selected level 1. If it works OK like that, you need a new 790 and your controller is OK.

 

[cyclebuddy]

Here's the error code table for your King Meter 790 LED:



41v is low for a fully/freshly charged battery. It should ideally be between 41.5-42v.

 

[Tortus]

Thanks for the suggestions everyone.
The cables coming out the controller are the waterproof plug type that go to the display PAS etc so testing the wires is not an option or me knowing what the wire colours are.
When I got the bike I noticed that the whole stem had been turned round a few times making the cables and the wires very tight, so tight when I went to turn the steering the front brake came on.
I will check the display tomorrow and get back with my findings.
Thanks

 

[Tortus]

The battery was over 41v, I just rounded it up.
Thanks, I will get an accurate reading tomorrow.

 

[saneagle]

Unfortunately, you can't solve your problem without doing tests and measurement. The only alternative is to replace parts until it works.

You can monitor your battery voltage at the charge socket while you ride your bike or you can connect to the main connector, or you can open the controller and connect to where the battery wires are fixed.

With the controller open, you can figure out which is the power wire to the control panel, and which is the return power wire that switches on the controller, then you can bridge them there.

 

[Tortus]

This is the type of controller that's on the bike, I would imagine its a sealed unit looking at it.
It looks like I will have to get a matching controller and display.
Saw this on eBay and it looks similar and has a display that matches it sold separately. (Lishui).
Any thoughts?

 

[saneagle]

This is the type of controller that's on the bike, I would imagine its a sealed unit looking at it.
It looks like I will have to get a matching controller and display.
Saw this on eBay and it looks similar and has a display that matches it sold separately. (Lishui).
Any thoughts?

You can monitor the battery voltage on the charge socket while you ride your bike. The first thing you must do is eliminate the battery as the cause because it's expensive. If the battery is OK, it's very cheap to replace the controller and control panel, and you can get better ones than what you have. You don't want to spend £40 on a new controller and LCD, only to find that there's nothing wrong with the ones you have and you need to spend another £200 on a new battery.

 

[Tortus]

Bike wont do anything at all so unfortunately I cant ride it, I have 2 batteries now and just measured voltage on them 41.85v approximately on both.
Can you recommend a controller and display with waterproof connectors?
This is the motor if it helps.
Thanks

 

[saneagle]

Whichever controller you get, you'll have to change some connectors. Are you OK with that? Nearly all after-market controllers have two separate wires for the the battery, so you'd need to cut off your connector and join the wires by soldering or other means.

 

[Tortus]

Cheers Saneagle, I don't mind doing the battery cable its the other ones I didn't want to attempt.
The Lishui controller I posted before has these connections.

 

[Tortus]

Mine has these connections, the only thing different is The connector for the brakes, and display so I would also need a 4 to 1 cable to suit.
I think the only difference is the small multipin. mine has 6 pins where as the the other has 8 pine.
I assume the extra wires are either for lights or a throttle.
It would be nice to have a throttle

 

[Tortus]

1 to 4 cable.

 

[thelarkbox]

Cheers Saneagle, I don't mind doing the battery cable its the other ones I didn't want to attempt.
The Lishui controller I posted before has these connections.

the lishui controller has connections suitable for use with a 5 TO 1 CABLE , this provides an additional input for a 3pin pas sensor t feed into the controller. The Pas connector is the other end from the brake throttle and headset connectors. lights?

If you source a controller like this just source a 5 to 1 cable instead of the 4 to 1 you pictured above

fwiw the controller i have bought for a replacement on a fixer upper is one of these KT brand sine wave controllers paired with a kt lc3 display/headset (delivery took 2 weeks)

 

[Tortus]

Hi, thanks for the information but I want to avoid buying from AliExpress, Alibaba etc.
I would rather buy from UK sites but that is a bit of a challenge.

 

[thelarkbox]

Hi, thanks for the information but I want to avoid buying from AliExpress, Alibaba etc.
I would rather buy from UK sites but that is a bit of a challenge.

KT controllers and headsets cost a bit more, but have clearer and more config control I went bargain hunting and didnt save much in the process tbh the same kit is available via ebay and amazon i linked the ads since they both detail lots of options.
Try contacting whoosh who are a uk distributor and an active friendly helpful contributor in here..

 

[Tortus]

Thanks for the info thelarkbox.
My head is done in looking for compatible stuff. It would be much easier if you could just buy the controller, 4 to 1 or 5 to 1 cable and display from the came site.
So will my bike be able to have a throttle. Is this due to a different controller.
Will the motor be compatible with a throttle?
I take it the 5th cable on the 5 to 1 is for a light.
Thanks

 

[saneagle]

We don't know if your motor has a speed sensor in it so it might be better to buy the whole kit with speed sensor, brakes, pedal sensor and LCD. It'll be a bit more expensive, but at least it'll work. Throttle is optional.

Thanks for the info thelarkbox.
My head is done in looking for compatible stuff. It would be much easier if you could just buy the controller, 4 to 1 or 5 to 1 cable and display from the came site.
So will my bike be able to have a throttle. Is this due to a different controller.
Will the motor be compatible with a throttle?
I take it the 5th cable on the 5 to 1 is for a light.
Thanks

Fot those of us that are used to swapping controllers and buying stuff from China, it's really simple. It takes me 5 minutes to cut off connectors and solder whatever wires I need. The problem you have is that the controllers that have the same connectors as yours often have different wiring, so they don't work if you just connect them. The alternatives become complicated regarding all the different bits you need to get a suitable match for the controller.

Your motor might not have a speed sensor, as it doesn't need one unless you have a speed display. That means you can't use a controller with an LCD unless it has block connectors for the speed sensor, though for some of us, it's easy to open the controller and wire a connector for the speed sensor to it. The cheap controllers that have LED displays, like yours, normally have the block connectors and separate brake wires, and you'd need a motor cable to convert from 9 pin to bullets and block. If I had your bike here in front of me, I'd have it done in 20 minutes, but, unless you're going to put the time in to figure out how it all works, you wouldn't be able to do it. There is nothing that you can just buy, connect, and it'lll work other than the OEM controller and control panel.

 

[thelarkbox]

Thanks for the info thelarkbox.
My head is done in looking for compatible stuff. It would be much easier if you could just buy the controller, 4 to 1 or 5 to 1 cable and display from the came site.
So will my bike be able to have a throttle. Is this due to a different controller.
Will the motor be compatible with a throttle?
I take it the 5th cable on the 5 to 1 is for a light.
Thanks

TLDR I think i may be just the one ebike controller purchase ahead of you.. Im no expert just a bloke finding out myself.. Check and double check anything u order..

Yes.. And it is a bloody minefield.. i put in an aliexpress order for all the bits to fix a gifted wreak.. and the bl**dy throttle i bought has the same gender socket as the 5 in one cable.
so i either hack the wires or buy a redundant male to male lead for a further tenner.. ha.

Throttle wise motor compatibility isnt an issue the issue is eu/uk regs that suggest a throttle (speed control) is fine as long as its only applied when pedalling and without pedalling is limited to 4mph Im not a legal bod so dont take my word for gospel..

So distributors and sellers within the uk/eu that want to stay the right side of the law sell ebikes and their controllers with the 15mph speed limit and 4mph throttle limit set.
depending on the controller there may be hacks and firmware fixes that let you break this..
which is one of the reasons the KT range are popular..

Hence the attraction and 'safety' in buying a controller via china direct as it will be set for international use not eu uk usa or anywhere with regs.. I think an ebay front to a china seller will get you the kit you want ..

5th cable for lights yes, well it is on the cable i fitted today,(the wreak runs ) but i think? the 5th socket on my yosepower kit supplied 5 in 1 lead was for the pas sensor but my cable management solution on that bike has hidden the details so i cant confirm without disassembly ;( so that could be my memory playing tricks..

All i can suggest is anything you buy you inspect each and every socket gender and double check the same on any and all components you buy too. and if in doubt use sellers like amazon and ebay/paypal with no quible returns..

Be mindful NOT to buy scooter bits i think my dodgy throttle was for a scooter hence the socket gender issue so a cheap scooter controller may have all the wrong gender connections??

hope my story of limited experience buying 'julet' waterproof connection ebike controllers and bits is helpful..

 

[thelarkbox]

RE Motor sensors, just check the lead coming from the hub motor if it only contains the 3 power wires then its a sensorless hub, if however the three power wires are combined with an additional 6 sensor wires then the hub has sensors..