How I Swapped out my Ecotric 20" fatbike 810LED and controller.

harryS

Well-Known Member
This might apply to other Ecotric models that use the 810LED display. The18Amp controller paired with mine (20" folding fatbike) is limited to the LED analog display and can only support three PAS levels. On the fatbike, the first PAS level just seemed stonger than I wanted, so I replaced the controller and also the LED display. I've got several other bikes using the KT36/48SVPR 20A sinewave controller with the LCD3 display and LCD1 display, so that's what I put in.

The swapper has to consider the connectors for throttle, PAS sensor, speed sensor, brakes, motor, motor sensors, and power.

1) Power is straight forward. Both the KT and Ecotric use red and black for power. I matched them.

2) Most modern motors use heavy yellow, blue, and green wires for the motor phases. Both the KT and Ecotric use bullet connectors and I matched the colors.

3) The motor's sensor connections consist of six wires, but the Ecotric only uses five of them. The red and black are power. Yellow, blue, and green are position sensors. The white is not used by the Ecotric controller, but it is a motor speed signal. This will be a headache because the KT controller is a different style connector. The left image show the Ecoctric after I cut off the connector from the motor. The middle image shows the KT plug, which is a 2x3 connecttor and a matching connector. These are often used in ebike kits. You can buy this connector. Probably take six weeks from China. See link at bottom.

39846 39847 39848

The KT connector's six wires will match by color to the six wires on the Ecotric motor cable. One could splice directly without using connectors, but I chose to use a matching connector off of another motor I had. The right image above shows the white connector spliced into the Ecotric motor cable.

4) KT controllers can calculate the bike speed if you put in wheel diameter and supply a speed signal. That signal happens to be built into the 20" fatbike motor cable's white wire, and if you connect it to the white wire on the above connector, you're all set. A few other parameters need to be set in the LCD setup for this to happen, but I'll not get into that. If your bike motor doesn't have a speed signal, there is a separate connector (shown in the middle picture) that you connect to an external speed sensor ( about 8-10 dollars on ebay).

5) For my KT controller, the throttle connector is a JST female plug with red/black wires for power/ground and blue for the signal. The Ecotric throttle cable will have a JST female plug with red/black for power/ground and white for signal. You will have to swap it out for a male JST plug and match the functions.

6) For my KT controller, the PAS connector is a JST 3 pin male plug with brown/black as power/ground and signal was yellow. The corresponding Ecotric connector uses a JST male 3 pin plug with red/black as power/ground, and signal is green. Again, swap it out for a female plug and match the functions.

For the last two connectors, note that one could trade the female and male connectors on the throttle and PAS cables, and not have to go find new JST connectors. One could also trade them on the controller side instead of the sensor side. If you did that, then it would be easier to put the old controller back in, except that we did cut off the motor sensor cables. I have a junk box full of old JST connectors, and you can also buy them on ebay. I also have a kit of empty plugs/pins with a crimping tool to make my own, but my success rate in making them is like 20%.

7) My KT controller used brake connectors that matched the Ecotric. Whew.

I think that covers it. This took me about a half day to implement. I've wired up a number of ebikes, and unless you buy the controller, throttle, display, and PAS sensor as a complete kit, the colors of the wires and the gender of the connectors is all over the place, So I was used to having to match connectors and functions. Fortunately, the colors of the wires used in the motors is somewhat standardized. I've found that the three thick blue, yellow, and green wires can always go together, and the thinner red, black, yellow, blue, green and sometomes white all can be paired. Other ebike hobbyists disagree and say they rarely match. Maybe I've been lucky.

I didn't talk about the LCD display, because you have to buy a controller and LCD display together.I never wire up the lights either, so I just ignored them.

Ebay link for the 2x3 motor connector.

Ebay link for 3 pin JST's. I

One benefit of the controller change is that I did get rid of some cable slack, so it was easier to pack the new controller and cables back into the controller compartment.

The new controller allows me to also use 48V, if I wanted to do so, but I don't. Bike goes up to 20-21 mph on 36V and feels strong enough to me. I'v e had it up to 25.8 mph on a 52V battery.
 
Last edited:

harryS

Well-Known Member
This is another alternative to the six pin connector. Still gotta wait for delivery though.


Edit. Link changed because original seller out of stock. I ordered a set for myself. They have to be as shown in the picture, or they won't fit the Ecotric cable.
 
Last edited:

harryS

Well-Known Member
It occurred to me that a better approach by Ecotric owners would be to swap the new controller connectors to mqtch what's on the bike, so they could go back to the Ecotric controller easily. Get a six pin connector for the new controller, and wire it to fit the motor six pin. Swap genders if needed on the PAS and throttle, and line up the wires by function.

I have several of these PSWpower sine wave controllers, so it made more sense for me to make the bike fit the controller.
 

Cal000

New Member
I cant wait for my controller and display to come in I went with the kt-lcd8s
I'll probably just splice the wires directly together
 

harryS

Well-Known Member
Let me know if the colors on your ecotric throttle and PAS sensor match what I described. PAS sensor is the short one going to the round assembly on the pedals, Throttle goes into the harness with the display and brakes.

The first two are three wire olugs. Display is 4 wire. Brakes are two wire.
 

StanAnderton

New Member
I was very pleased to find this post! I bought the Ecotric 20" fat bike with the 48v 13ah battery which has the S900 display. I really like it, but as soon as my wife took it for a spin, she wanted one too! The vendor was out of stock so I bought her the 36v version. She does not like it because PAS 1 is too fast for her. I am sure she could get used to it, but she doesn't want to. Well, I ordered a new controller and display so momma will be happy. I searched and searched for information to help me decide what to buy. I guess everyone assumes that everyone else knows all about controllers and displays and how they work and how important it is to choose wisely... but this old guy, likes to REALLY know before laying the money down. A few days later, I now feel comfortable with my choices. We shall see...

How did you, harryS, deal with the wiring harness? I would imagine the 810 controller does not use the same wiring as your new display. I am thinking I will just have to zip tie or wrap the new wires to the existing harness. And what did you do with the 810? Did you remove it? Cut the wires or?

Thanks again for the post!
 

harryS

Well-Known Member
The wiring harness had to be unwrapped, and the old 810LED is removed and tyhe new display is then wrapped in. It's a bit tedious.

The 810LED is a 4 wire cable, and most LCD displays are 5-wire, so there's no labor savings in trying to keep the cable and splice the new LCD and its connectors to the ends.

You will also want to cut down the display cable to minimize having to stuff excess cable into the bike's controller cavity. I took the opportunity to also shorten the PAS sensor cable and throttle, as I was replacing their connectors to match my KT controller.

As I realized earlier, most Ecotric owners will probably want to change the connectors on their controllers to match the bike, rather than change the bike connectors.
 

StanAnderton

New Member
That certainly makes sense, changing connectors and pruning the excess wire. I noticed a lot of excess sloppily crammed in the controller cavity.

I haven't looked closely at all at what it will take to unwrap and re wrap the wiring harness, but that is the only thing that really makes sense. Being retired I do have a bit of available time. LOL!

How do you feel about the expanded functionality that you now have? From all I have read, the KT controllers are the most feature rich. How do you feel about the Ecotric foldable? Certainly less expensive than most, and seems to suit what I want.

Thanks for your reply. I am looking forward to this project... and not just to make my wife happy. ;-)
 

harryS

Well-Known Member
I've converted several regular bikes with electric motors, and I've found the KT controllers with LCD3 display work pretty well. I knew that the 20A and 17A sinewave models would fit in the box behind the pedals. Although I feel the LCD3 is a better display, able to display watts, ambient temperature, and battery voltage, I am using the LCD1 for its smaller size. All it shows is PAS level, speed, and trip meter. Since the LCD3 is the same price, it's a better choice.

When you get your electrics in, ask any question if anything is unclear.