Is this 50A Rated Controller adecuate for a 48V 2000W upgrade rear hub motor?

rafmartom

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Hi,

I am upgrading my ebike rear hub motor from 750W to 2000W , and I want to make sure I have a capable enough controller.
The batteries are rated 48V , for what I shouldn't be pulling more than 42.(some)A
I currently have a 30A Controller , but obviously I am going to dispose it.
So I am buying the upgrade one.


KT 50A Sine Wave .

But looking at the specs I can see that
①Brand :KT(KUNTENG)50A Controller
②Color :Silver
③Dimension :236 * 88 * 42 mm
④Mosfet :18 Mosfets
⑤Maximum current : 50±1A
⑥Rated current : 25A
⑦Rated voltage :DC48V / 56V-90V
⑧Speed set : 1-4.2V
⑨Brake input :Low-Level
⑩Low voltage protection :DC56±0.5V
⑪Cable length : all about 10-16cm
⑫Weight : about 550g



Rated current is 25A . It does 50+1A on peak. Is this really meant to be used in a 48V 2000W (setting it up to aproximately 42A maximum) ?

Also I am just intending to swap the controller in my ebike (no new Controller screen nothing else) . So I have the following screen

Yolin YL90T-H


Which checking the manual looks like it has the same commuinication port (the connector is made of 5 small cables lied horizontally)


Are they compatible?

Thank you
 
Hi,

I am upgrading my ebike rear hub motor from 750W to 2000W , and I want to make sure I have a capable enough controller.
The batteries are rated 48V , for what I shouldn't be pulling more than 42.(some)A
I currently have a 30A Controller , but obviously I am going to dispose it.
Is it 30A peak? Or continuous?
If it doesn't say, you can use a wattmeter and ride your worst-case route and conditions, and see what it really provides.

You may find that you don't even need an upgrade, because you may not be using the power you already have.


Rated current is 25A . It does 50+1A on peak. Is this really meant to be used in a 48V 2000W (setting it up to aproximately 42A maximum) ?
That means it can do 25A continuously. Peak is usually a few seconds, and not very often, or overheating, damage, or failure can occur. Some have protections to disallow longer usage at higher current, by rolling back to the lower rating, but many cheap ones don't. If it doesn't say, it's safer to assume it does not, and limit your high current usage as much as possible.

If you aren't sure, and you dont' have a way to measure current while riding and/or can't spare the attention from the road to do this all the time, you should get a controller that you are *sure* can handle the current required to do the job you need, continuously, all day, not peak.

Some thoughts:

what do you need the system to do for you, under what riding conditions?
If you take that data to the motor simulator at ebikes.ca you can use it (after a bit of learning via the instructions below it) to figure out how much power it will really take to do what you need.

it will also help you figure out how much battery you need to do it, for the range you need.


Also: What current is your battery capable of? If it is not designed for the higher output, youll have to replace the battery as well, with one that is more capable than what you need it for. As they age, they become less capable, so if you get one that can only barely do it now, it wont' be able to do it later as it ages.

The cheaper it is, the faster that will happen, and the less likely it is that it can *actually* do it even when new.



Also I am just intending to swap the controller in my ebike (no new Controller screen nothing else) . So I have the following screen
Which checking the manual looks like it has the same commuinication port (the connector is made of 5 small cables lied horizontally)
There's a lot of threads about this, the best of which is E-HP's, but controllers and displays are not generally intercompatible (different signals, comm protocols, data sent/processed, etc), so you should either verify that your display is a model that is compatible with the *specific* version of the specific controller you are buying, or buy the controller and display as a set at the same time from the same seller (not as separate items, but as a "kit") to be sure they will work together.

Many but not all connectors that are the same appearance will connect to each other and be wired the same. The ones that aren't wired the same can blow up both your controller *and* your display, *and* anything else that's connected to the controller at the time (motor hall sensors, throttle, PAS, etc). So you have to be sure of the wiring before connecting them. If they come as a kit they *should* be the same. If not...it's up to you to verify first, or replace after smoke. ;)
 
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KT's "rated current" is for determining what to call your bike power-wise, which as we know is meaningless nonsense. All of mine rise directly to their maximum amps when I call upon them, and they never get hot or misbehave except the couple of times they died young without previous issues.

48V x 50A is nominally 2400W, which should be about 2000W maximum at the wheel, and would be rated a "1200W" bike by prevailing commercial standards.

I've used 60A KT controllers before, so I know that's an obtainable version.
 
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I currently have a 30A Controller , but obviously I am going to dispose it.
If you're going to dispose of it anyway, and you have a soldering iron, you could always do a shunt mod to see how you like it at 40A.

 
If you're going to dispose of it anyway, and you have a soldering iron, you could always do a shunt mod to see how you like it at 40A.


Thanks for thatone.
I think I am going to order the whole kit of the hub motor , which comes with a Controller already

2000W Rear Hub Motor

●Construction:Gearless drive
●Rated Voltage (DCV): 48V
●Rated Power (W): 2000W
●Rated Speed(KM/H): 55-70km/h
●Rated Speed(rpm): 579-596RPM
●Torque(N.m): 90-95N.M
●Fork size(mm):190mm
●Installation: Rear
●Certification: CE
●Wheel Diameter (Inch): 20/24/26inch---Optional​
Controller detail:
●Maximum current: 60±1A
●Dimension: 185*108*57 mm
●Mosfets: 18 mosfets
●Weight: 1025g
●Rated current: 30A
●Rated voltage: DC48V-72V
●Speed set: 1-4.2V
●Brake input: Low-Level​

As it is stated , the motor does 2000W rated power (so I guess it can continually provide 2000W ) while the Controller does 30A constant. But I guess I can shunt mod it to push it to push 40A ( I dont want to get it to 42A as it may blow up the motor I dont know)

My current controller is rated 26+1A so I guess even with Shunt Mod I dont think it will do safely. So I will just do that first option.

Now to my head are coming 2 questions:
- What happens If the Controller cannot cope with the Amperage that the actual system is pushing ? (So say in the Screen I select 40A but the controller is rated at 30A , provided that I modified the shunt so I lose the electrical protection, will the controller blow or will it also blow other components such as screen, Pedal Asists stuff, Motor Stuff ...)

- What happens if I push the Motor to do an Amperage which is a little bit higher of what it is rated to?
To be on the safe side I am not gonna push it to 42A , I will do 40A, which will be a little bit less than the motor is rated (1920 W) . But if the Motor is rated 2000W but this is sort of a peak rating and It ends up fatiging or blowing? Will the motor blow or it will trip the connection with the Controller ? Will I be compromising the durability of the Motor by pushing it too hard? (say it is better to select 35A or even 30A ? )


Thank you
 
As it is stated , the motor does 2000W rated power (so I guess it can continually provide 2000W ) while the Controller does 30A constant. But I guess I can shunt mod it to push it to push 40A ( I dont want to get it to 42A as it may blow up the motor I dont know)

My current controller is rated 26+1A so I guess even with Shunt Mod I dont think it will do safely. So I will just do that first option.
Your original post said your current controller was rated at 30A. It’s probably better just to wait for the kit. I thought maybe since you’re replacing everything anyway, that you might want to experiment, for free (well 2 cents for the solder). Some folks like to tinker. Anyway, basically you monitor your motor and controller temps and learn how much you can push them, then exercise some self control.

I bought a cheap 80A controller, but it came delivered limited to 60A, so I shunt modded it, but accidentally overshot to 90A. I normally limit it to 70A for daily riding though (5kW which is plenty). My motor is rated at 1500W but I’ve put as much as 7kW through it, but I monitor the temps so I don’t damage anything. Plus adding Statorade keeps the temps down by a lot. The controller was really cheap, so I bought another for backup.
 
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What happens if I push the Motor to do an Amperage which is a little bit higher of what it is rated to?
Hmm, what happens right now when you put 1300w through your 750w motor?? (Or 1400W, if your current controller were rated at 30a)
You may find at lower power levels, your 750W geared hub will feel more responsive than a 2000w direct drive. What are you trying to get out of this upgrade?
 
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Hmm, what happens right now when you put 1300w through your 750w motor?? (Or 1400W, if your current controller were rated at 30a)
You may find at lower power levels, your 750W geared hub will feel more responsive than a 2000w direct drive. What are you trying to get out of this upgrade?

Thanks for sharing your knowledge.

I am trying to get as much top speed as possible. I use the ebike in a Main Road , for not very long (maybe 20 minutes a day), and it is full of Trucks, currently I can only reach about 22 MPH which causes a bit of a disturbance in the road, cars and Trucks have to be overtaking me.
At the same time, some days are really windy, so for the current setup I risk zig-zagging due to the wind.
So mainly top speed, but some more torque would be nice too.

I see the Statorade procedure


So would you drill in a brand new Motor (maybe I need to use the guarantee, I will try it for 2 Months then do this) ? Although I want to take the oportunity of then the Wheel has no Disk Brake Plate attached , so I may do it straightaway.

How often to apply Statorade? How many miles?

Also How do you monitor the temperature of the Motor?
Do you buy a Termometer Gun, use the motor for a bit then point it straightaway at it to check the temperature?
I am ready to tinker :)


Thanks again
 
I am trying to get as much top speed as possible. I use the ebike in a Main Road , for not very long (maybe 20 minutes a day), and it is full of Trucks, currently I can only reach about 22 MPH which causes a bit of a disturbance in the road, cars and Trucks have to be overtaking me.

So would you drill in a brand new Motor (maybe I need to use the guarantee, I will try it for 2 Months then do this) ? Although I want to take the oportunity of then the Wheel has no Disk Brake Plate attached , so I may do it straightaway.

How often to apply Statorade? How many miles?

Also How do you monitor the temperature of the Motor?
Do you buy a Termometer Gun, use the motor for a bit then point it straightaway at it to check the temperature?
I am ready to tinker :)
Good attitude! Thanks for defining your goal. Unfortunately, you'll likely need to go up in voltage to increase your speed. Something called back EMF stops an electric motor from spinning faster than it's rated speed for a given voltage, which in this case, at 48V, prevents the motor from spinning faster (the back EMF is equal to the forward EMF, so it's like it's hit the wall at that speed).

There are controllers with a feature called "field weakening", that changes the back EMF in order to allow the motor to spin faster, but that feature uses more current, so not a long term solution, but in your case, if you only need the speed for part of your trip, it may be a possible solution. Unfortunately, those controllers usually cost more.

There are cheaper controller that have what is called a 3-speed switch, where speed 2 is the normal speed, while 3 may implement field weakening or some other timing tricks to achieve a higher speed. This may work possibly work for you, but not all 3-speed switches function the same, so may take some hunting.

Here are some examples, not necessarily your motor, but I've tweaked the motor parameters to match your 22mph top speed for the base case.

You need about 400 watts to go 22 mph (black curve the the load). Battery power is 493W (compensating for losses, etc.).

G60.jpg

Raising the power from a 26A controller to 30A or even 40A results in no change to top speed, but does provide a bit more torque (blue line. increases acceleration or climbing power), and power (red line):

Compare.jpg
So, if speed is what you need, you'll likely need to up your voltage, which means a new higher voltage pack (60V in this example).

You may wish to play with the simulator and get familiar with how it works. It's very accurate, so one way to try before you buy.

Statorade will last a couple of years before you need to top it off. You use very little. Drilling a hole is one way to apply it, or opening the side cover of the motor is another. I drilled on my first motor, and opened the side cover for my second. I don't worry about the warranty. These motors either work when you get them or don't, and I haven't heard of many folks getting warranty work on them.

Monitoring motor temps requires a temp sensor in the motor, attached to the stator. Some motors come with them, but you can add a sensor as well. The main hurdle is adding the wiring. It's only a single wire, since ground is already present in the motor, but fishing it through the axle is the challenge. Monitoring the case temp with your hand isn't very accurate, but better than nothing, since adding Statorade allows the heat from inside of the motor to be transferred to the case, allowing the heat to radiate from the motor. Without it, there's no path for the heat to reach the case, so the stator could be really hot, while the case feel lukewarm.

While going to a 2000W motor and compatible controller may not necessarily get you a higher speed, it can. You have to know the motor constant or turn count of the motor to know for sure. A lot of cheap motors may not list their turn counts, but may list a speed (e.g. 30 mph), and a motor voltage (motors aren't rated for voltage, so when the voltage is listed, it is usually supporting other parameter, like 30 mph using a 48V battery). So, you could by a 1000W motor, with a higher speed constant, and get the results you want without going up in voltage. Again, playing with the simulator and changing motors may help you get closer to finding the right motor.
 
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