Bike Speed

[rgh]

Hi. could anyone tell me please what speed an e bike would go using a 1,500 watt motor with a 10AH battery.

 

[NRG]

You've just asked 'how long is a piece of string'....what voltage, what RPM motor, type of motor, what current, weight etc.

You'll get a reasonable answer by plugging in those values into the CA bike simulator here:

ebikes.ca Hub Motor and Ebike Simulator

 

[banbury frank]

Hi rgh The Voltage off the battery affects the speed the 10 AH is the capacity off the battery the bigger the AH the more range


Frank

 

[rgh]

Thanks nrg and frank. so what your saying is even if it was a 20AH you would still get the same speed as the 10 AH but not range.?

 

[banbury frank]

rgh

we quote 10 miles flat out no pedalling with a 20 stone rider with a 10AH battery 15 miles with 15 AH 20 miles with 20Ah You can double that if you are say 12 stone and help with some light pedalling

We always Quote worst case scenario so the customer is happy if he gets more range

I have one customer 12 stone and fit he just circled the isle off Wight 65 miles and still had battery left

We no longer sell 10 AH as the range was never enough Now even the 15 AH is only jut enough that's why we now sell a 20 AH all our bikes are Customer driven

Frank

 

[Deleted member 4366]

Thanks nrg and frank. so what your saying is even if it was a 20AH you would still get the same speed as the 10 AH but not range.?

Correct.
Also. there's not many 1500w motors. Most are 500w run at 1500w. If you have a meter that shows how muuch power is coming from the battery and it shows 1500w, then that would be enough power to sustain about 23 to 25mph for a normal bike, but to get that speed, the motor has to be designed to reach that speed with the voltage supplied. My BPM motors are rated at 500w, but will draw 1500w up a hill; however, top speed is only about 22mph because they reach their maximum speed, and at that speed, they'll only draw about 500w. On the other hand, I have a 450w GNG crank drive that has no speed limit because it's power goes through the gears, and you can always change up a gear, so it will maintain about 25mph with about 1200w showing on the meter, but can accelerate to 40mph down-hill.

 

[Miles]

........ All our bikes are customer driven.

.. :d .......

 

[rgh]

Thanks for your replies and answering my question d8veh.as it was the speed I was most concerned about. with not knowing much about e bikes I always thought that the bigger the battery such as 36v and 48v gave you more speed than say a 24v. as it would the speed I need when getting one of these bikes. so if the bike I quoted with the 10AH and 1,500watt motor will reach a speed of say 25/28 mph then that would do me

 

[Deleted member 4366]

If you had a 24v 15mph 250w bike and put a 48v battery and controller on it, it'll try and go twice as fast to 30mph, but the motor can't hansle the power to go that sat, so it would get hot and burn.

Your basic idea about different voltages affecting speed is correct, but it also depends on the design speed of the motor. By winding the motor stator with different number of turns, the makers can get the motor to run at different speeds for the same voltage. The end result is that the motor will spin at so many rpm per volt. The user can then decide what speed it'll reach by choosing the appropriate voltage battery and controller. Obviously you need a lot of power to actually reach high speeds. Power = volts x amps, but as you know, if you push too many amps through a wire it gets hot unless its thick wire. Therefore, more powerful motors are generally bigger.

 

[NRG]

The motor will be wound to provide a set RPM at a set voltage, given the same wheel size a 24v motor can be wound for the same rpm/speed as a 36v one. So for more speed you can do either of two things (or both!) choose a higher RPM motor for your wheel size or overvolt the one you have. Motors have a constant Kv which sets the RPM / Volt, if you know the Kv you can estimate the speed. Remember that doubling the speed of a bike will required quadruple the power so the battery and controller will need to be upto the task.

 

[rgh]

ok Thank you both for your help