Help! Replace Pedal Assist Controller with Throttle

tomlain

1 mW
Joined
Jun 17, 2021
Messages
10
Hello fellow ebikers!
I have just bought my first ebike and would like some advice on upgrading the controller.
I would like it to go 35km/hr on flat ground.
Max range 20km would be fine.
The bike has 27 inch wheels.
I weigh 80kg.

The bike is an Estate City:
www.estatebikes.com/product-page/men-s-e-bikes

It has:
• A brushless 250W motor, 36v.
• Battery is 7.5Ah, 270Wh.

The current controller is:
• DC36V
• Current 14amp
• Dual Mode
• Brakes low level
• Booster 1:5 6km/h
• Pedal assist.

I have attached photos.

I would like to replace the controller with a 36V 350W one that has throttle control and a LCD display (get rid of pedal assist). I have been looking on ebay and found the following:

https://www.ebay.com.au/itm/393031265151

Would this work with my bike?
Or, is there another that would be more suitable?

Kind regards,
tomlain
 

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This is a better controller/display, in my opinion, It's a KT controller with LCD display.
https://www.ebay.com.au/itm/363357617945?hash=item5499cd3f19:g:boAAAOSwj61cuBjg

Either will work. I have a controller similar to the one you showed, with the same display. I never liked it and took it off my bike. I use it as a tester.
 
Hi docw009,
Thanks for reply.
Do you think that the ebay one I linked would work?
The KT controller says it is for a sensor controller. Do I need a sensor or sensorless controller?
What speed do you get with your KT controller?

So many questions, so much to learn!

Tom
 
tomlain said:
Hello fellow ebikers!
I have just bought my first ebike and would like some advice on upgrading the controller.
I would like it to go 35km/hr on flat ground.
Max range 20km would be fine.

• A brushless 250W motor, 36v.
• Battery is 7.5Ah, 270Wh.

You're going in the right direction with the controller, but unfortunately you have to upgrade your battery to meet your requirements, for two reasons.

Your current battery, 36V7.5A is likely a 10S3P configuration, based on common available cell capacities. That would be 2500mAh cells (2.5 x 3 = 7.5).

The cells could be 25Rs, but highly doubtful (since the battery would have Samsung plastered all over it), and likely generic cells. The cells might be capable of 5A or so, so 5 x 3 = 15A continuous if you're lucky, but just enough to meet the demands of the current 14A controller.

If you upgrade the controller alone, you will kill your battery. But, even if your battery could handle it, you wouldn't meet your speed goal, since you need more voltage.
36.jpg

The spec from the link says the bike goes 25km/hr, which obviously involves pedaling, as do the range figures, but assuming it can go 25 on its own power, then you need at least 50V to get up to 35.
35/25 * 36 = 50.4
That means at least a 48V battery, which is 54.6V fully charged, but more likely 52V
52.jpg

You will have more stored energy in the new battery, even if you stick with 3P, because of the additional series cells, but that energy will be more than offset by the added wind resistance from travelling at the higher speed. If you are riding throttle only, then you will decrease your range even more.
 
Thanks for the detailed reply E-HP!
Well, if I kill the battery, then I will have to replace it with another (better) one down the track :)
Do you think that ebay controller would be able to go faster than 25km/hr?
It shows a wire/wires that are labelled 'Adjustable speed controller'. Not sure what this means. Any ideas?

https://www.ebay.com.au/itm/393031265151

I have contacted the seller, but they aren't able to give me an answer.

Tom
 
tomlain said:
Do you think that ebay controller would be able to go faster than 25km/hr?
It shows a wire/wires that are labelled 'Adjustable speed controller'. Not sure what this means. Any ideas?

https://www.ebay.com.au/itm/393031265151

No, you need higher voltage for higher speed at your current speed levels. As you encounter more wind resistance, you need additional power too, so if power was the limiting factor, not voltage, then it could help. However, your choice of a controller that CAN run at 48V gives you an upgrade path for when you kill the battery and replace it. Plus, most controllers that are rated for 48V will also work at 52V.

The controller you selected though, may have less power than your current one. Right now you have 36V @ 14A, and the one you linked is 36V @ 13A. The 250W vs 350W rating is related to how much the controller can be run at continuously, so even though it says 350W, you really need to look at the specs to see what the other limits are. Search for one with 36V/48V and an amp rating higher than yours if you want more power now and ability to go up in voltage in the future, after you kill your battery (which I guess is a legitimate way to go, since you'll replace the battery eventually).

I believe your next threads will be about wiring the controller up, and figuring out the hall sensor wiring etc., which people here can help you with. Later you may post about your bike cutting out under full throttle, and people will tell you it's due to voltage sag, which will be your indicator that you're battery isn't up to it and starting to die. All part of the process, but you'll learn a lot moving from your factory bike into the DIY world.

Good Luck!
 
Thanks E-HP, much appreciated. I'll have a look for higher amp rated controller.
The problem, which many others seem to have faced, it that I can ride much faster than the controller will assist. I generally cycle unassisted (to work) at about 34-35km/hr on level ground. But I want this bike to be able to give me a bit more grunt and not cut out at 25km/hr when I am tired and riding home from night duty. 25km/hr jus seems too slow :(
 
I have another question. I have rung the manufacturer about weather my hub is geared or not. They couldn't tell me :|
Is there a way to tell by looking at the hub?
 
tomlain said:
I have another question. I have rung the manufacturer about weather my hub is geared or not. They couldn't tell me :|
Is there a way to tell by looking at the hub?

It's almost definitely a geared hub, which is why I chose a comparable geared hub in the graphs above. Direct drive would be noticeably larger in diameter.
 
Think I'll go with this one:

https://www.aliexpress.com/item/4000324036199.html?spm=a2g0o.cart.0.0.77d93c004qLZUR&mp=1

15Amp.
36V-60V 350W(15A)
Available undervoltage: 19V, 29V, 39V,

A bit more current for a bit more speed. Allows for upgrades. What do you think?

I'll post some pics of the finished project :)
 
tomlain said:
Think I'll go with this one:

https://www.aliexpress.com/item/4000324036199.html?spm=a2g0o.cart.0.0.77d93c004qLZUR&mp=1

15Amp.
36V-60V 350W(15A)
Available undervoltage: 19V, 29V, 39V,

A bit more current for a bit more speed. Allows for upgrades. What do you think?

I'll post some pics of the finished project :)
I can't tell from the pic what connectors the existing controller has, so you should make sure to check if it's setup for hall sensors (and not sensorless), before pulling the trigger on the controller. I'm assuming you don't want pedal assist and just throttle, correct?
 
I unplugged the wiring going to the rear hub and it has 9 pins. I'm thinking that 2 are positive and negative, 3 are the three phase lines, and the remaining 4 are hall sensor?

I have taken a photo (attached) of the wires that run down to the rear hub from the controller on my bike. The yellow, blue and green lines on the left should be my 3 phase lines. Leaving the black plug:
* black and red for power to the rear hub, then
* blue, green, yellow, white hall sensor?

I have enlarged their picture which shows the hall sensor plug having a black and red wire going in, then blue, green yellow and white wires. I am hoping this will correlate :)

Do I assume that the 1:1 accelerator is the throttle?

The 'lamp' plug only has one wire coming from it. I have a headlight with 2 wires. Any ideas of how this will work?
 

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Looks like it will probably work. You may need to change out the connector for the hall wires. Can't tell about the lights until you get it and can check out the voltage on that connector. Looks like it has a self learning function to figure automatically set up the right hall configuration.
 
What was the result?
I jave an Estate folding ebike and want to do same.
 
okz00k said:
What was the result?
I jave an Estate folding ebike and want to do same.

The linked controller doesn't appear to support PAS, which suited the OP. The five levels on the LCD must set speed limits on the throttle.

BTW, I had an S866 display. The buttons felt too cheap to me. It didn't work anyway. Was able to return it.
 
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