Carrera Crosscity 790 LED Display Problem.

Tortus

Pedelecer
Sep 22, 2023
49
2
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..
Like you say its a minefield.
Is this something like the stuff you bought?
Apart from the cable is just a 1 to 4
 

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Tortus

Pedelecer
Sep 22, 2023
49
2
I'm not fussed about throttle and lights, I just want it to run without buying the wrong bits.
Cheers
 

Tortus

Pedelecer
Sep 22, 2023
49
2
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.

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.
Cheers I do appreciate your time and knowledge, shame I don't live in the same area.
I have found this, it says its a KT790 like the one I have but it has a light, will that matter?
 

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saneagle

Esteemed Pedelecer
Oct 10, 2010
7,005
3,241
Telford
Cheers I do appreciate your time and knowledge, shame I don't live in the same area.
I have found this, it says its a KT790 like the one I have but it has a light, will that matter?
There are two types of those control panels that look the same. One is digital and uses comms down two data wires, the other is analogue and uses an analogue signal to set the PAS level. When they have lights, they have the same number of wires.
 

thelarkbox

Esteemed Pedelecer
Aug 23, 2023
1,252
385
oxon
Like you say its a minefield.
Is this something like the stuff you bought?
Apart from the cable is just a 1 to 4
Similar though different brand.

NOT RECOMMENDATIONS OF PRODUCTS OR SELLERS LINKS ARE JUST EXAMPLES...

i did a quick ebay search for kit close to what i got, i went for the 17a version but the cheapest option would be a 15a..

ebay 15a kt controller . I cant tell if its square or sine wave, both work, but square wave is more basic and can result in a 'rougher' signal ?? louder motor? Im just paraphrasing what i have read??? apparently sine wave controllers are 'better' more sophisticated and a bit more expensive ??
ebay KT headsets, the cheaper led displays wont display config settings for change.. so if you want to change or set any settings like wheel size max power etc you want a lcd headset
edit @saneagle 's advice carries Much more weight than mine.. as i said i have 1 controller purchase on you.. ;)
 

Tortus

Pedelecer
Sep 22, 2023
49
2
I think I will give this a go, fingers crossed.

And this.

They don't have the 1 to 4 or 1 to 5 cable in stock in the UK so I will get one off eBay.
£64.00 for both.
Could be £64.00 down the drain I suppose but I cant get the 790 display anywhere and the like for like controller is £80 to £150 on eBay.
Thanks again both of you who have helped.
I need a rest now my brain is fried.
Cheers
 
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Nealh

Esteemed Pedelecer
Aug 7, 2014
20,981
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West Sx RH
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..
Woosh don't sell kit parts unless you own one of their bikes and need spares for it.
 

Nealh

Esteemed Pedelecer
Aug 7, 2014
20,981
8,565
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West Sx RH
I think I will give this a go, fingers crossed.

And this.

They don't have the 1 to 4 or 1 to 5 cable in stock in the UK so I will get one off eBay.
£64.00 for both.
Could be £64.00 down the drain I suppose but I cant get the 790 display anywhere and the like for like controller is £80 to £150 on eBay.
Thanks again both of you who have helped.
I need a rest now my brain is fried.
Cheers
You can't go mixing and matching controllers or displays from different brands as the firmware and protocols are different and simply won't work correctly.
You have to buy the controller and display form the same seller , the only exception is with KT brand stuff nearly all of it is compatible though some resellers have differing connectors (but this is rare).

Buyinh direct form china sellers is easy and often far cheaper then uk or eu sourced parts. KT are by far the easiest and by far most accessible end user parts to buy anywhere fromthe world.
Most of us use Aliexpress shops/sellers or Topbikekit, some of us have been buying stuff from these suppliesr for donkeys and have few issues.
 

Cadence

Esteemed Pedelecer
Feb 23, 2023
276
207
I think I will give this a go, fingers crossed.

And this.

They don't have the 1 to 4 or 1 to 5 cable in stock in the UK so I will get one off eBay.
£64.00 for both.
Could be £64.00 down the drain I suppose but I cant get the 790 display anywhere and the like for like controller is £80 to £150 on eBay.
Thanks again both of you who have helped.
I need a rest now my brain is fried.
Cheers
I can confirm that the above two items will work together - I have bought and fitted them myself. However, make sure that you get a 4 or 5 to 1 cable from Yosepower as the brake cut off plugs are reversed compared to some others (male rather than female).
If you get the controller sold for their 350w rear motor it is 18Amax current and needs a 4 in 1 cable. The controller for their front motor is only 15A max and includes output for a front light, so it will need a 5 in 1 cable. The C500 display will work with either.
 

Tortus

Pedelecer
Sep 22, 2023
49
2
Hi bit the bullet and bought all KT stuff from AliExpress.
I bought a 17a sinewave controller with 1 to 5 cable, LCD5 display and a throttle.
Hope this all works together, it should.
Not bothered really about the throttle but would be a plus if it did.
Many thanks for all your help and I will keep you up to date when I get it.
 

thelarkbox

Esteemed Pedelecer
Aug 23, 2023
1,252
385
oxon
Hi bit the bullet and bought all KT stuff from AliExpress.
I bought a 17a sinewave controller with 1 to 5 cable, LCD5 display and a throttle.
Hope this all works together, it should.
Not bothered really about the throttle but would be a plus if it did.
Many thanks for all your help and I will keep you up to date when I get it.
Is the controller light enabled?? if not it might be prudent to get a 1 to 4 cable too from ebay or amazon so you can return if necessary.

The 1 to 5 cable has more pins including a low current light circuit at the controller end

If the controller has no light feature advertised and no 2 prong red julet connector exiting the controller intended to power a rear light, it will require a 1 to 4 cable with fewer connecting pins.

I got a light enabled controller so thats why i also got the 1 to 5 cable.. ( my fixer upper bike had a front light fitted...and its feeble..)

google for "kt lcd5 manual pdf" for the 20-30 page manual detailing the configuration parameters.
And dont be daunted by it. Now i got my Bsc in computer science from the local university here in Oxford, and the first time i glanced at my lcd3 detailed manual (last night) i was confused.. These things are set up like commercial controllers. But its a learning experience, and if really stuck ive read posts in here where the experts rattle off p and c parameter values as if they were nuts n bolts. so in the famouse words of Douglas Adams 'Dont Panic'

EDIT you may not need to touch any config parameters its not afaik a 'everyone needs to do' thing
but reading the manual is a good way to spend the delivery time, wish i had done so myself now..
 

Tortus

Pedelecer
Sep 22, 2023
49
2
Is the controller light enabled?? if not it might be prudent to get a 1 to 4 cable too from ebay or amazon so you can return if necessary.

The 1 to 5 cable has more pins including a low current light circuit at the controller end

If the controller has no light feature advertised and no 2 prong red julet connector exiting the controller intended to power a rear light, it will require a 1 to 4 cable with fewer connecting pins.

I got a light enabled controller so thats why i also got the 1 to 5 cable.. ( my fixer upper bike had a front light fitted...and its feeble..)

google for "kt lcd5 manual pdf" for the 20-30 page manual detailing the configuration parameters.
And dont be daunted by it. Now i got my Bsc in computer science from the local university here in Oxford, and the first time i glanced at my lcd3 detailed manual (last night) i was confused.. These things are set up like commercial controllers. But its a learning experience, and if really stuck ive read posts in here where the experts rattle off p and c parameter values as if they were nuts n bolts. so in the famouse words of Douglas Adams 'Dont Panic'

EDIT you may not need to touch any config parameters its not afaik a 'everyone needs to do' thing
but reading the manual is a good way to spend the delivery time, wish i had done so myself now..
Yes I bought the controller with the 1 to 5 cable as a package then the display they said would work and also the throttle. Like I said I probably wont use the throttle or the light as well. Separate lights are cheap enough anyway.
Nothing straight forward or standardised. I'm sure in years to come it will get more straight forward and easier.
I bought the bike originally to do up and sell but my profit margin has just shrank to zero. Only good thing is if I get it running I can advertise it as good for 50 to 60 miles with the 2 batteries I now have for it.
I have built 2 ebike's before this both with 1000w Voilamart conversion kits and I like them just to tootle round and go on trails through the woods. They both do 30 mph but after a while you come to your senses and about 15 to 20 mph is fast enough. Only thing is the torque is not super on a rear gearless hub drive.
Cheers
 
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thelarkbox

Esteemed Pedelecer
Aug 23, 2023
1,252
385
oxon
Good to hear, you should be sorted..budget smudget eh? think of the fun you will have scrapping your knuckles etc...
Next time you will be better prepared too ;)
 

Nealh

Esteemed Pedelecer
Aug 7, 2014
20,981
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Quite a few of the KT's have a light output, though one can't run very powerful lights off them as they are only rated for about 1a power. For powerful lights one needs to tke direct fused supply via the battery/controller v+/-.
 

saneagle

Esteemed Pedelecer
Oct 10, 2010
7,005
3,241
Telford
1 of my 2 bikes.
Specialized.
Nice bike, but there are two things you need to sort out: The motor is installed upside down. You need to rotate the axle 180 deg, which brings us to the second problem that your bike might fix that on its own because you forgot to install torque arms.

Also, I don't know whether it's just the photo, but your front brake doesn't look right unless it's a hydraulic one that the photo makes it look like a cable one. Does it work OK?

The motor in your other one is upside down too.
 
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Nealh

Esteemed Pedelecer
Aug 7, 2014
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And both wanting /waiting to be confiscated by plod.
 

Tortus

Pedelecer
Sep 22, 2023
49
2
Nice bike, but there are two things you need to sort out: The motor is installed upside down. You need to rotate the axle 180 deg, which brings us to the second problem that your bike might fix that on its own because you forgot to install torque arms.

Also, I don't know whether it's just the photo, but your front brake doesn't look right unless it's a hydraulic one that the photo makes it look like a cable one. Does it work OK?

The motor in your other one is upside down too.
Are you saying the cable exit point should be the other way up?
Yes it is a hydraulic brake on the front of one of them and that has a torque arm fitted.