250Watt whats it really

[flecc]

If I were the supreme ruler of the UK, there would be no power limit, but there would be strict speed limits

There's obviously widespread dissatisfaction on this issue since some years ago the European Parliament debated it. Their conclusion, which was forwarded to the EU Commission as a recommendation, has much in common with your view. They recommended removal of any power limit with reliance on a strict speed limit, leaving the power necessary entirely to designers.

The Commission, 28 ex politicians, one from each member nation, rejected the proposal. It seems they thought the sum of their knowledge of the subject superior to that of the 705 MEPs, many from the top cycling and pedelecing countries.
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[Bonzo Banana]

Any bike that's limited to 15.5mph is a 250w bike because that's how much power you need to ride that fast on a flat road.

Nobody cares about torque and how much power is used to go up hills, which is why early 250w bikes gave 40nm of torque and now they give 110nm. We all know that's three times the power, but they're still 250w bikes.

When you hit someone on your bike, the energy you impact them with is half your mass times your velocity squared. It doesn't matter how much power your bike uses to go up a hill because you will never impact with more energy than you would on the flat when your speed is restricted.

If I were the supreme ruler of the UK, there would be no power limit, but there would be strict speed limits tiered according to mass so that light bikes could go faster than pedicabs and delivery vehicles and I would allow the use of independent speed controls.

That's what I find confusing according to the 15194 standard it has this;

4.2.14 Maximum power measurement — Measurement at the engine shaft The maximum continuous rated power shall be measured according to EN 60034-1 when the motor reaches its thermal equilibrium as specified by the manufacturer

Looking at 60034-1 it's a pretty standard way of measuring duty cycles and continuous power as used on other products. Bosch for example sell the same motor as 250W or 350W depending on market but wouldn't the testing of the same motor be identical so why is one 250W and the other 350W. Same with other manufacturers, in other markets it appears a motor rated as 500W is now 250W in the European market. Why is the same motor not getting the same results?

I just don't get how the same physical motor can have lots of different wattage ratings.

So much easier to focus on the controller and how it controls power and wattage. I mean a Bosch controller is using something like 20-22A at 36V at continuous max power, easy to measure, easy to understand. Everyone can make simple comparisons with other ebike controllers.

A direct drive hub motor can operate from 200W to about 2500W with a suitable controller. Is it ok for a controller to limit output to 250W on the flat and unrestrict to 2500W on a hill? I just don't get the logic behind the legislation if its really allowing unlimited current for hill climbing. There is nothing in the certification about un-restricted power for hill climbing though. The graph on typical power characteristics is this which I accept is for flat ground;

 

[saneagle]

That's what I find confusing according to the 15194 standard it has this;

4.2.14 Maximum power measurement — Measurement at the engine shaft The maximum continuous rated power shall be measured according to EN 60034-1 when the motor reaches its thermal equilibrium as specified by the manufacturer

Looking at 60034-1 it's a pretty standard way of measuring duty cycles and continuous power as used on other products. Bosch for example sell the same motor as 250W or 350W depending on market but wouldn't the testing of the same motor be identical so why is one 250W and the other 350W. Same with other manufacturers, in other markets it appears a motor rated as 500W is now 250W in the European market. Why is the same motor not getting the same results?

I just don't get how the same physical motor can have lots of different wattage ratings.

So much easier to focus on the controller and how it controls power and wattage. I mean a Bosch controller is using something like 20-22A at 36V at continuous max power, easy to measure, easy to understand. Everyone can make simple comparisons with other ebike controllers.

A direct drive hub motor can operate from 200W to about 2500W with a suitable controller. Is it ok for a controller to limit output to 250W on the flat and unrestrict to 2500W on a hill? I just don't get the logic behind the legislation if its really allowing unlimited current for hill climbing. There is nothing in the certification about un-restricted power for hill climbing though. The graph on typical power characteristics is this which I accept is for flat ground;

View attachment 52232

You're looking at the measurement method. Instead you should look at the requirements to pass. Also, You can't measure rated power at the output shaft or anywhere else. You can only measure output power, but there is no specification for how much it must be.

 

[Linfitter]

It's possible that linfitter has damaged his motor with overheating. What is the exact swx motor do you have linfitter?

It came with the Kudos King bike that is all that I know

 

[Linfitter]

It's your battery that's knackered, not your motor.

My 36 volt battery registers 41.6 volts on my multimeter when fully charged

 

[Nealh]

Voltage doesn't mean it is A1 , I have a 14.5ah battery that is the same but because of age and usage the voltage sags terribly, one should use a meter rigged up to see what is occurring with the voltage to see how stable it is.