troubleshooting about ebike motors

Discussions related to motors other than hub motors.
This includes R/C motors, botttom bracket, roller and geared drives.
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userBike   1 µW

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troubleshooting about ebike motors

Post by userBike » Sep 21 2022 3:10pm

Hello guys. I have seen bike kit's .Unfortunately they are not very clear and do not clearly explain the performance you could get. If I want a bike to travel a daily distance from my house to work of 40 km round trip (unfortunately I live far away) at a decent speed (something like 35 km/h minimum) would I need a 12, 24 or 36 volt motor? 150, 250 or 300 W of power? And for a reasonable daily battery charge, how many amps should I have?

Thank`s a lot.

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ebuilder   10 kW

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Re: troubleshooting about ebike motors

Post by ebuilder » Sep 21 2022 6:42pm

userBike wrote:
Sep 21 2022 3:10pm
Hello guys. I have seen bike kit's .Unfortunately they are not very clear and do not clearly explain the performance you could get. If I want a bike to travel a daily distance from my house to work of 40 km round trip (unfortunately I live far away) at a decent speed (something like 35 km/h minimum) would I need a 12, 24 or 36 volt motor? 150, 250 or 300 W of power? And for a reasonable daily battery charge, how many amps should I have?

Thank`s a lot.
I see its your first post and welcome to the community.
I will coach you a bit if you don't mind. The framework of your question is much too broad for a substantive reply.
A suggestion and only that is....give us a bit more a description of your vision of what kind of ebike you would prefer.
A high power ebike? Low power and low cost? How big a bike? Fat tires? Narrow tires? Moped style?...or my bicycle style you plan to pedal?
Do you have a preference on hub drive versus mid drive?

From there a general recommendation can be made. Type of bike affects power due to weight and tire rolling resistance. Do you have an eye on a particular bike for your build or are you planning to buy an ebike?

userBike   1 µW

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Re: troubleshooting about ebike motors

Post by userBike » Sep 22 2022 9:51pm

ebuilder wrote:
Sep 21 2022 6:42pm
A high power ebike? Low power and low cost? How big a bike? Fat tires? Narrow tires? Moped style?...or my bicycle style you plan to pedal?
Do you have a preference on hub drive versus mid drive?

From there a general recommendation can be made. Type of bike affects power due to weight and tire rolling resistance. Do you have an eye on a particular bike for your build or are you planning to buy an ebike?
@ebuilder more than buying an electric byke, what I want is to buy an installable kit for an electric byke in @commerce.
I have a normal city bike with narrow tires. It´s a rather light bike. What I have seen and what is most available are 24V motors with 300 or 350W. In first case appears : 2750 RPM / 17 A. 350 W motor it´s instead: 2800 RPM / 15.5 A. All I want to know is what speed can I reach in each case and how many kilometers can I travel on a single battery charge.
I would appreciate this info but the site is not clear about it.

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ebuilder   10 kW

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Re: troubleshooting about ebike motors

Post by ebuilder » Sep 23 2022 6:08am

userBike wrote:
Sep 22 2022 9:51pm
ebuilder wrote:
Sep 21 2022 6:42pm
A high power ebike? Low power and low cost? How big a bike? Fat tires? Narrow tires? Moped style?...or my bicycle style you plan to pedal?
Do you have a preference on hub drive versus mid drive?

From there a general recommendation can be made. Type of bike affects power due to weight and tire rolling resistance. Do you have an eye on a particular bike for your build or are you planning to buy an ebike?
@ebuilder more than buying an electric byke, what I want is to buy an installable kit for an electric byke in @commerce.
I have a normal city bike with narrow tires. It´s a rather light bike. What I have seen and what is most available are 24V motors with 300 or 350W. In first case appears : 2750 RPM / 17 A. 350 W motor it´s instead: 2800 RPM / 15.5 A. All I want to know is what speed can I reach in each case and how many kilometers can I travel on a single battery charge.
I would appreciate this info but the site is not clear about it.
Site isn't clear because what you are asking isn't perfectly quanifiable.
Even the type of type of tires you put on your city bike and what you inflate them to will affect battery capacity and speed traveled relative to motor wattage. If you weigh 300 lbs or 120 lbs, that will substantially affect your watt-hr's as well. Live near a shoreline?...and ride all the time into a 20 mph wind? You can add a lot to your battery capacity as well.

So the reason you struggle finding this data is because there are too many influencing factors to be absolute about precisely what battery size and motor size you will need. I presume on a city bike, you are going to ride bolt upright. It takes a lot more power to propel a bicycle with rider sitting straight up. Are you tall? More power. Do you want the motor to do all the work? More power. Are you a hard pedal-er? Less power.

I will tell you in general where I come down on this. Very few people lament having too much power on an ebike. Why is that? Because its there when you want it and you don't have to use it. What is the penalty of building a bike with more power than you need? Cost and weight. Big motors and batteries cost more and weigh more.

In general for the type of bike you want, I would suggest a 500-750 watt rated hub motor...front or rear hub motor wheel position...preferrable rear wheel because more bicycle/rider weight is over the rear wheel and a 48v 15 amp-hr battery size minimum. If you post a picture of the bike you have in mind we can speculate on how well the battery will fit. You could even mount the battery to a rear rack...or buy such a battery if that is your preference.
Hope that gives some insight.

userBike   1 µW

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Re: troubleshooting about ebike motors

Post by userBike » Sep 28 2022 8:41am

Thanks @ebuilder, I'll follow your advice.

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