Fiido d2s with d4s components

SOURLEMONJUICE

Finding my (electric) wheels
Feb 13, 2025
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Hi guys

Qiuck question, I got second hand d2s which doesn't turning ON. As I will need to replace handlebar display and controller, I was thinking to order both parts for d4s to get little bit more features. To me motor on both ebikes looks identical, and other parts shouldn't cause any problems. Did someone tried to use those or upgrade d2s with aftermarket display and controller? Thanks
 

matthewslack

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Nov 26, 2021
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Ask Fiido via their website?
 

SOURLEMONJUICE

Finding my (electric) wheels
Feb 13, 2025
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Ask Fiido via their website?
I did, their support worker doesn't seems to be much helpful in technical questions. They said that the g20 display unit were never mounted on d2s, which is not true. Also they mentioned that the motor is different on d4s, by tech. specifications I found, they are identical..
 

thelarkbox

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Aug 23, 2023
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Hi and welcome, E-bike control systems have 'evolved' in a particular way. such that displays and controllers often share a specific communication protocol and format.
This changes from brand to brand and differences can even crop up within bike brands and model lines. SO the rule of thumb is if you need a new display - get it from the bikes supplier and only the one specifically for your bike. otherwise you are taking a gamble. Many who take the gamble end up in here and with no supplier replacement available get directed towards replacement controllers with paired displays. .
 

SOURLEMONJUICE

Finding my (electric) wheels
Feb 13, 2025
14
0
Hi and welcome, E-bike control systems have 'evolved' in a particular way. such that displays and controllers often share a specific communication protocol and format.
This changes from brand to brand and differences can even crop up within bike brands and model lines. SO the rule of thumb is if you need a new display - get it from the bikes supplier and only the one specifically for your bike. otherwise you are taking a gamble. Many who take the gamble end up in here and with no supplier replacement available get directed towards replacement controllers with paired displays. .
Hi, thanks for answer. I understand and totally agree with you. Anyway as I mentioned I would like to order both, handlebar display unit and controller for d4s. I wonder if anyone sees a potential problem in this. So, if someone could confirm for me whether the engines from both models are identical, in my opinion that is the only thing that could cause a compatibility problem
 

matthewslack

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Nov 26, 2021
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It is unlikely the motor will be a problem. Assuming both models are a 250W rated motor, they should use a standard 9 pin cable, and if they have the same wheel size, will be the same nominal rpm.

It is much more common to have issues with controller and display, but you plan to replace both as a set, so that should be fine.

However, I do NOT have first hand Fiido knowledge! Their customer service usually gets favourable reviews here, so maybe try again, you might get someone different/more knowledgeable!
 

SOURLEMONJUICE

Finding my (electric) wheels
Feb 13, 2025
14
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Hi and welcome, E-bike control systems have 'evolved' in a particular way. such that displays and controllers often share a specific communication protocol and format.
This changes from brand to brand and differences can even crop up within bike brands and model lines. SO the rule of thumb is if you need a new display - get it from the bikes supplier and only the one specifically for your bike. otherwise you are taking a gamble. Many who take the gamble end up in here and with no supplier replacement available get directed towards replacement controllers with paired displays. .
Both models are fitted with 36V , 250w brushless motor. Design are different, battery on d4s has slightly larger capacity, but that's all. In my opinion, a controller and display unit from d4s should work with a d2s motor without any problems. Please correct me if I'm wrong. Thank you
 

thelarkbox

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Aug 23, 2023
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I dunno, Probably ;) a half hearted google led me here which sells d2 and d4 motors but only pictures the d4 motor connecting wires which are not terminated in the familiar 9 pin socket ;( -

Since you have the d2 bike can you see if the motor is connected with automotive sockets as pictures in the d4 motor ad above? if so your probably ok, otherwise you may have some soldering/crimping ahead.

Worst case scenario 1x controller uses power output math for speed output and the other uses a extra sensor input from the motor so you may loose a speed readout ??
 
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matthewslack

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Nov 26, 2021
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Both models are fitted with 36V , 250w brushless motor. Design are different, battery on d4s has slightly larger capacity, but that's all. In my opinion, a controller and display unit from d4s should work with a d2s motor without any problems. Please correct me if I'm wrong. Thank you
See earlier post, but yes, sounds like you should be fine. Can never be zero risk, but no obvious red flags. Battery size does not matter.
 

saneagle

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Oct 10, 2010
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Hi guys

Qiuck question, I got second hand d2s which doesn't turning ON. As I will need to replace handlebar display and controller, I was thinking to order both parts for d4s to get little bit more features. To me motor on both ebikes looks identical, and other parts shouldn't cause any problems. Did someone tried to use those or upgrade d2s with aftermarket display and controller? Thanks
You can probably swap controller and display without problems as long as the motor has the standard 9-pin connector, and, more importantly, the battery only has two wires connecting it to the controller on both D2S and D4S. If either has more than two wires, it probably won't work.
 

SOURLEMONJUICE

Finding my (electric) wheels
Feb 13, 2025
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I dunno, Probably ;) a half hearted google led me here which sells d2 and d4 motors but only pictures the d4 motor connecting wires which are not terminated in the familiar 9 pin socket ;( -

Since you have the d2 bike can you see if the motor is connected with automotive sockets as pictures in the d4 motor ad above? if so your probably ok, otherwise you may have some soldering/crimping ahead.

Worst case scenario 1x controller uses power output math for speed output and the other uses a extra sensor input from the motor so you may loose a speed readout ??
I already checked all possible websites that are selling fiido parts, but there is lack of specs.. As you saying, the wires on the d4s photo from their website are not fitted in the terminal, anyway the wiring and colour coding are identical. Just swapping the pins in the terminal will do the job. Possible crimping or soldering is no problem, but in this case not required. I worried more about the speed sensor output. I contacted Fiido support again to send me detailed specs of both motors..
 

SOURLEMONJUICE

Finding my (electric) wheels
Feb 13, 2025
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You can probably swap controller and display without problems as long as the motor has the standard 9-pin connector, and, more importantly, the battery only has two wires connecting it to the controller on both D2S and D4S. If either has more than two wires, it probably won't work.
Hi, thanks for reply. Both motors have 3 wires beside the 9 pin connector. Can I ask why this should be a problem?
 

saneagle

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Hi, thanks for reply. Both motors have 3 wires beside the 9 pin connector. Can I ask why this should be a problem?
If the battery uses two wires, it's dumb, and so is the controller. If it has more than that, it normally means that the controller communicates with the battery. It can only communicate if it has the correct comms protocols and identifications.
 

thelarkbox

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Aug 23, 2023
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Hi, thanks for reply. Both motors have 3 wires beside the 9 pin connector. Can I ask why this should be a problem?
any thinner data wires Not the 2 x thicker gauge power wires from a battery to a controller would indicate a requirement for a battery /controller handshake similar to but infinitely more problematic than any display issues.

Motors generally have 9x connections 3 x thicker phase power wires( often blue green yellow), 1 x +5v logic level power supply (thin red wire) 1 x logic ground connection (thin black wire) 3 x hall sensor oututs (thin yellow blue green) and a speed hall sensor output - (white wire)/ or temp sensor output? sometimes a 10th connector.

The other 3 x wires are probably for connecting to a pas sensor fitted to the crank hence its similar placement.. I guess?
EDIT - xtra 3 wire connector could also be for brake or gear change sensor or even a back light? if any are situated in the rear motor area?

edit #2 if anything other than pas input and not a d2 feature only found on D4 bikes? simply not connecting should not be a problem
 
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Nealh

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Not being rude but have you first carried out the basics ?
Does the battery actually output correct voltage and does it take a charge ?
 
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SOURLEMONJUICE

Finding my (electric) wheels
Feb 13, 2025
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any thinner data wires Not the 2 x thicker gauge power wires from a battery to a controller would indicate a requirement for a battery /controller handshake similar to but infinitely more problematic than any display issues.

Motors generally have 9x connections 3 x thicker phase power wires( often blue green yellow), 1 x +5v logic level power supply (thin red wire) 1 x logic ground connection (thin black wire) 3 x hall sensor oututs (thin yellow blue green) and a speed hall sensor output - (white wire)/ or temp sensor output? sometimes a 10th connector.

The other 3 x wires are probably for connecting to a pas sensor fitted to the crank hence its similar placement.. I guess?
EDIT - xtra 3 wire connector could also be for brake or gear change sensor or even a back light? if any are situated in the rear motor area?

edit #2 if anything other than pas input and not a d2 feature only found on D4 bikes? simply not connecting should not be a problem
Thanks for explaining the wiring, anyway there is no extra 3 wires. By the 3 wires beside the terminal connector was meaning 3 thick phase power wires. I just double checked the controller/motor wiring and there is 5 wires (black, blue, yellow, red and green) on terminal and 3 phase wires, so total 8 for d2s. Also I checked photos of d4s controller and there is one white wire extra compare to d2s controller. So 9 in total (black, blue, yellow, red, green and white[speed sensor?]). That mean the motors are not identical and with d4s controller and display connected to d2s motor it would run but no speed reading...CORRECT?
 
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SOURLEMONJUICE

Finding my (electric) wheels
Feb 13, 2025
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Not being rude but have you first carried out the basics ?
Does the battery actually output correct voltage and does it take a charge ?
Hi, thanks for comment. I forgot to mention in firs post that the battery is fully charged and holding 41.8V over last few days. So battery is not the issue
 

SOURLEMONJUICE

Finding my (electric) wheels
Feb 13, 2025
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Bellow is answer from Fiido support when I asked for both motors specs.

D4S motor: motor~20 "CZJB90TZ rear 36V 250W rear left inner outlet, disc brake OLD 137 6S thread 36H 13G black with one speed gauge, wire length 800mm, maximum speed 31km/h 9-core ordinary wire, phase wire 3C head, Hall 2 8-piece flange nut with rubber sleeve

D2S motor: 36V 16 inch high-speed integrated wheel motor, equipped with 6-speed flywheel, all sub black color, disc brake variable speed, imperial thread, 145mm on gear, load speed of 25 kilometers per hour, right outlet, with internal speed measurement, ordinary nine core wire length of 710mm (excluding wire stripping)
 

matthewslack

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Nov 26, 2021
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Still sounds good to me.

I think the six speed flywheel means freewheel, and the other one is single speed.

If you can make sense of the wiring it should work.