Hi im new can anybody help

[wibblewobble86]

Hi I'm new to ebikes and was wondering if it would be possible to switch the rear hub motor on my bike any help much appreciated thanks in advance

 

[saneagle]

Generally, all motors can be switched around, as they all work the same in principle. You won't get more power just by changing the motor. Why do you want to change?

 

[wibblewobble86]

Generally, all motors can be switched around, as they all work the same in principle. You won't get more power just by changing the motor. Why do you want to change?

I'm looking to upgrade to a 1000w in the rear hub. Currently running 250w

 

[geoff967]

Completely illegal unless you register as a different category.number plates insurance etc

 

[wibblewobble86]

Completely illegal unless you register as a different category.number plates insurance etc

I'm not asking anybody to break any laws . My bike is already fitted with lights and indicators and I'm upgrading the disc brakes to hydraulic kind and putting better tires on before I do the motor and controller so I can't see a problem to change the class?

 

[AGS]

What motor do you currently have?

I would be surprised if it is only capable of 250 watts even though that’s what it says on the label.

It‘s not normally the motor that’s the limiting factor. It will be the controller and battery.

 

[wibblewobble86]

 

[Az.]

I can't see a problem to change the class?

Try to find insurance.

 

[AGS]

That looks like a Bafang H550W to me.

Here is the current Bafang workbook. I think your motor is about half way down. It shows the real power ratings.

https://www.bafang-e.com/Uploaded/Labels/202308100327283621.pdf

 

[wibblewobble86]

That looks like a Bafang H550W to me.

Here is the current Bafang workbook. I think your motor is about half way down. It shows the real power ratings.

https://www.bafang-e.com/Uploaded/Labels/202308100327283621.pdf

The wheel is the same but with a 250w motor inside of it. It's 250w at 36v that's all I know I can't really find much info about the bike. This is the controller

 

[AGS]

It just has a 250 watt engraving on it to make it European compliant.

The H550W is rated at either 750 or 1000 watts dependant upon the winding. And they can be run higher if you are careful to keep the temperature at an acceptable level.

The controller and battery limit the power to the motor. You have a 15 amp controller and a 36 volt battery, so 36v x 15A = 540 watts from the battery.

Although the controller is probably configured to run lower than that.

The bottom line is that your battery and controller are the limiting factors, not the motor.

Best to keep the motor because it has all of the correct labelling to make it UK compliant. You don’t really want a motor that is stamped 1000 watts, otherwise it will become a police magnet.

 

[wibblewobble86]

It just has a 250 watt engraving on it to make it European compliant.

The H550W is rated at either 750 or 1000 watts dependant upon the winding. And they can be run higher if you are careful to keep the temperature at an acceptable level.

The controller and battery limit the power to the motor. You have a 15 amp controller and a 36 volt battery, so 36v x 15A = 540 watts from the battery.

Although the controller is probably configured to run lower than that.

The bottom line is that your battery and controller are the limiting factors, not the motor.

Best to keep the motor because it has all of the correct labelling to make it UK compliant. You don’t really want a motor that is stamped 1000 watts, otherwise it will become a police magnet.

Thank you that is really helpful information so basically I just need a new battery and controller with a display that I can change the settings on right?

 

[AGS]

Thank you that is really helpful information so basically I just need a new battery and controller with a display that I can change the settings on right?

Yes but be careful you can easily overheat your motor if you feed it too much power, especially if you are doing a lot of hill climbing.

It may be a good idea for you to research oil cooling and temperature sensors. You may not need them, but you should gain an understanding of how increasing power increases the temperature inside the motor.

Some people just slap on a big battery and controller then wonder why their hall sensors keep blowing and their windings burn up.

You don’t want to blow your motor because it will be expensive to replace being built into the wheel.

I use a motor simulator (link below) when I’m building a bike so that I understand how far I can go so it doesn’t all go up in smoke. Your motor should be comparable to a Bafang G60 in the simulator.

Motor Simulator - Tools

Our ebike motor simulator allows you to easily simulate the different performance characteristics of different ebike setups - with a wide selection of hub motors modeled, and the ability to add custom batteries and controllers and set a wide variety of vehicle parameters you'll be able to see...

ebikes.ca

My most powerful bike runs at 7500 watts, so I monitor my temperatures closely and have alarms set to warn me if they are getting too high. I can abuse this motor easily and get the temperature to rise rapidly. This bike is road registered and insured.

 

[Saracen]

I'm looking to upgrade to a 1000w in the rear hub. Currently running 250w

100% UK ILLEGAL

 

[Saracen]

I'm not asking anybody to break any laws . My bike is already fitted with lights and indicators and I'm upgrading the disc brakes to hydraulic kind and putting better tires on before I do the motor and controller so I can't see a problem to change the class?

Adding things does not make it legal

My opinion is NO one should offer illegal advice to help someone commit a crime

 

[AGS]

The requirement is to have a motor that is UK compliant which the OP has because it has the necessary engraving and label.

He can run any controller he likes so long as it is configured to run within all of the other UK requirements.

It then becomes the OPs own responsibility if he chooses to configure that controller outside of UK compliance.

 

[jamesporritt]

My opinion is NO one should offer illegal advice to help someone commit a crime

What if I wanted advice about how to build a time machine to kill Hitler?

 

[saneagle]

You should change the battery to a 48v one capable of delivering 30 amps or more, then get any decent 48v controller you want. If you want to pedal, get a KT 22 amp one, otherwise any one you want. Those two things would increase your power by 90%. With a 48v battery and 22A controller, your bike will still be legal as long as you set it to 15.5 mph. If you put a 100w motor in it, there's a chance your bike could be seized by the police, especially if someone grasses you up after they see you riding around at over 20 mph without pedaling.

 

[Benjahmin]

I agree, keep the motor, as marked it is UK legal. There will be those who tell you otherwise but, so long as it has a manufacturer/supplier label/engraving stating 250w, it is legal.
Check you battery maximum current rating. This needs to be equal to or better at least 10% larger than your controller maximum current rating.
If your battery will take it, I would get a 17A KT dual voltage controller and display. This will give you a 36v max power of 612w.
Later, when your battery is up for replacement, you could get a 48v battery. The controller will automatically reset to new voltage. At 48v this will now give you 816w.

It's current that does the damage to motors. You'll only have increased the maximum by 2A which the motor should take. So long as you configure the new controller to UK speed limit you will be fully complying with UK law.

You could go for a 22A controller giving 1056w @ 48v but then batteries capable of delivering this are expensive. On my recumbent I have a 22A controller (9 mosfets) but have set the maximum current to 17A. This way everything stays nice and cool and well within operating parameters and the battery does not get a hammering.