Trying to get past speed governor on electric bike.

Hello, I bought an electric bike conversion kit and converted my own bike. However, despite the kit being advertised as around 35mph, it seems to have a speed limiter that kicks in at 26mph. It's a 2000w peak controller, brush-less 3 phase motor. At 26mph, I get a constant 1200w so I know I have the power to go faster and the rated rpm of the motor is 540 so I'm not close to my limit there. There are no speed wires I can cut, I've looked and I have tried changing the wheel diameter in settings with no luck.
To me it appears the only solution is to place a arduino between the 3 hall sensor wires of the motor and the controller to somehow trick the controller that I'm moving at half the speed that I actually am.

Does this sound like the right way to go about it? Anybody have a arduino function in mind that I can use to achieve this?
I was gonna hook up each hall sensor to a analog input and use a function to register every 2 rotations as 1.
Does anybody know if doing this may affect motor performance/function?
Thanks for the help.

Does that kit contain brakes handling 35 mph? Already 25 mph is quite some speed for a bicycle. You even want to go faster. In some countries the speed limit for electrical bikes is 15 mph.

The bike has brakes. I bought a high quality fat bike used with shocks, 4.5 inch wide tires and disk brakes with larger rotors than stock. Here is a link for the bike I'm using but mine has a larger disk brake in the front.
http://www.bikesdirect.com/products/motobecane/fat-bikes/fatbikes-boris-brut-sprung.htm

I'm aware of the legality of the speed, here it is 28mph. However, I ride this mostly in places that the speed limit doesn't apply and having a speed limiter takes away the point of having a 2000w motor and giant brakes.

Good luck. I don't feel like supporting this experiment anyway. I've got the same kind of brakes on my present bicycle.

Railroader:
Good luck. I don't feel like supporting this experiment anyway. I've got the same kind of brakes on my present bicycle.

Thanks, I guess.

Do you know that air drag at 35 MPH is 2 times what it is at 25? That may be the biggest part of your problem.
Air drag increases with the SQUARE of speed, twice as fast, four times the drag. If it takes 1200W to go 26MPH, to go 35 would take 35 / 25 = 1.4 squared = 1.96 times the torque + 1.4 times the RPM, so 1.96 times 1.4 = 2.77 times 1200 = 3293W.

Lift the motor driven wheel from the ground and apply full throttle. Does it show a speed greater than 26mph?

JCA34F:
Do you know that air drag at 35 MPH is 2 times what it is at 25? That may be the biggest part of your problem.
Air drag increases with the SQUARE of speed, twice as fast, four times the drag. If it takes 1200W to go 26MPH, to go 35 would take 35 / 25 = 1.4 squared = 1.96 times the torque + 1.4 times the RPM, so 1.96 times 1.4 = 2.77 times 1200 = 3293W.

Thanks for your input. I'm currently being limited to 26mph. I'm not sure if this system is actually capable of going 35mph but I know it can go faster than 26mph.
I've been talking to customer service about this issue and they make it sound like there is no speed limiter. But that doesn't make any sense. Advertised max rpm of the motor is 540 rpm which equals about 50mph on 26inch fat tires and I'm only pulling 1200w at 26mph. I've seen the power display show 1800w or more when accelerating many times. As for the batteries, at the moment I have 4 interstate sla1075 connected in series. https://www.globalfirecontrol.com/media/uploads/product/bba29be30944b7059f9f93c662d0c079.pdf
max discharge current of the battery is 80A, 50A continuous so the battery should be more than enough.

mikb55:
Lift the motor driven wheel from the ground and apply full throttle. Does it show a speed greater than 26mph?

Yes, it shows 33mph and stays there. With max rpm of the motor being listed as 540 it should be higher under no load.

Your device is likely imported into your country. The speed limiting will be a requirement for that importing to be done. The people you bought the thing from are not aware of the importing restrictions.

Paul

There are no speed wires I can cut...

...between the 3 hall sensor wires

What? No speed sensor? Hall effect speed sensor?

A [u]type-T flip-flop[/u] (or a J-K flip-flip flop wired as a type-T) will cut the pulse rate in half.

05silgto:
Yes, it shows 33mph and stays there.

Does that not suggest it is not speed limited to 28 mph? That sounds fairly close to 35 anyway.

DVDdoug:
What? No speed sensor? Hall effect speed sensor?

Not needed. It is a brushless motor, the speed is what you send to the motor (though the motor may have Hall sensors built in).

Paul__B:
Does that not suggest it is not speed limited to 28 mph? That sounds fairly close to 35 anyway.
Not needed. It is a brushless motor, the speed is what you send to the motor (though the motor may have Hall sensors built in).

The motor does have hall sensors built in. When you hit around 26 mph, the watts seem to drop and stay around 1200. The controller is 48v 22A continous, 45A peak. I wonder if the controller gets too hot by the time I hit 26 and limits current.
Doesn't seem to make sense, my friends electric bike hits 28mph and is a 1300w peak reduction geared motor. Geared motors should accelerate better but have a lower top speed. I accelerate way faster than him but my top speed is limited. I do weight 50lbs less than him though.
Maybe the controller just limits current at that speed. I'm gonna borrow my friends 52v battery soon and see if I notice a difference.

Hello, I recently made my bike into an ebike. The top speed of the bike is lower than I like. Not 100% sure yet if it is due to lack of power or a built in speed limiter. I already bought some expensive 48v lithium batteries. I was wondering if it is possible to take 3 step up boost converters, connect them in parallel in order to boost the batteries to 52v or higher.
Something like this is what I have in mind currently...

If it can be adjustable on the fly with a micro-controller, would it be rise to have the voltage of the batteries be adjusted continuously while in use to try and maintain 52v longer than normal?

Not 100% sure yet if it is due to lack of power or a built in speed limiter

I would determine the actual limiting factor before buying parts.

You cannot connect voltage regulators in parallel, as they “fight each other” to control the output voltage.

jremington:
I would determine the actual limiting factor before buying parts.

You cannot connect voltage regulators in parallel, as they "fight each other" to control the output voltage.

Gotcha, thanks for your reply. I'm gonna contact the manufacturer and see what they say. Not sure if I will get a straight answer or not. I don't mind burning out my current controller trying this and then upgrading to a 60v controller. The question is are there any possible voltage restrictions on a brush-less motor with hall sensors?

The motor data sheet should state the permissible operating conditions.

jremington:
The motor data sheet should state the permissible operating conditions.

There doesn't seem to be a motor data sheet, at least that I'm aware of. It's a cheap unbranded Chinese hub motor.

I opened up the controller and saw it had 63v capacitors. I'm probably going to order a more op beefy 60v controller and Just limit the max amps through the display. The controller seems to have a way to hook up your own motor temp. sensor. I think I'll do that and just monitor those temperatures closely if everything seems to check out with the seller.

Hello, I'm trying to connect dc boost converters in parallel to go from about 48v to 60v. I need to supply about 2500-3000 watts.
I saw this video on YouTube where the guy uses resistors before connecting the converters together in order to enable load sharing. It appears using resistors slightly lower the current which lowers the voltage. Here is a link to said video.

The problem with this is that 1000w resistors are expensive and unreasonable.
Is there another component I can use to slightly lower voltage to achieve the same effect that is more reasonable in this application.

This is going to be for a ebike, I want to boost the voltage of my battery packs.

Doesn’t sound a great way to get increased performance but hey ho.
You don’t need 1000w resistors , just work out what value resistance you need then , I^2R to work out the power to be dissipated . If you loose 1000w across the resistors then you’ve lost any power you gained.

Really you need to upgrade your speed controller /motor/battery , probably cheaper and will work