350 watts or 500 watss

JoannaLIN

New Member
Anyone have questioned about why we'd like our ebike to go 350 watts or even 500 watts? How much power do we really need? Is there any power vs time profile that we can study?
 

Kaldeem

Active Member
I don't believe it's about being power hungry per say. But in Amp Hours (AH) and Watts the more powerful the motor, with a powerful battery increase the range at which they can be used. Or something like that. Here's an article that helped me understand it better to make a smarter choice on buying a bike.

https://www.electricbike.com/watt-hours/
 

Chris Nolte

Well-Known Member
Watts is part of the equation when determining time, or range as it's often referred to. Basically you have Watts, Volts, Amps, Amp Hours and Watt Hours.

When speaking of a motor they are rated at Watts which is how much power the motor can consume so for a 350Watt motor to consume 350 Watts it would draw approximately 10 amps from a 36v battery. A 36Volt 10 amp hour or 360 Watt Hour (36vx10ah=360Wh) battery is capable of sustaining a 350 Watt draw for one hour.

Not to add confusion, but the other item to note is just because a motor is rated at 350W doesn't mean that it will only operate at 350W. The Bosch motor although it can be rated at 350 or 250W is capable of approximately 550W at peak power. Some motors operate much more efficiently than others though. Some motors produce more power then heat and really that's the name of the game. Mid drives will generally operate more efficiently as they can utilize the bikes drivetrain.
 

biknut

Active Member
I've changed my thinking since my son bought a 350w Neo Carbon. Before that I would have said get the most powerful motor, but now I have to rethink this.

Most eBikes are limited to 20 to 25 mph. My sons 350w Neo Carbon blasts to the 25 mph limit, so now I thinking what's the point of a bigger power hungry, and heavier bike that's limited to the same speed anyway? Hills might be a factor, is the only thing I can think of, but his bike has no problem with the hills near us.

As long as there's an artificial speed limit, might as well get the smallest motor that gets the job done. My Bomber is the fastest factory eBike on the planet, but the difference in acceleration to 25 mph isn't a big enough deal to worry about.
 

biknut

Active Member
There is the thing some seem to have discovered with Specialized: if you make a small wattage motor work hard, it can overheat.

I believe that's probably an inexcusable design flaw. Although most eBikes are protected with a thermal overload, how many owners are actually complaining about it tripping on their bikes? I don't really know the answer to that question, but it doesn't seem prevalent. Sounds like a good polling subject.

I do know that with fractional hp motors such as air conditioning condenser fan motors, and also blower motors, it's been a common type of failing in certain models of motor that the manufacturer will get the thermal overload calibration wrong, and every one of those motors will be unreliable, and considered a lemon, while another brand with exactly the same spec motor, will never have a problem. Of course the bad motors don't last long in the market, but I've seen it happen more than once in the last 30 years. If that can happen with motors they've making for well over 50 years, I can see how manufacturers with less than 5 or 10 years experience could be making the same mistake.
 

Chris Nolte

Well-Known Member
I believe that's probably an inexcusable design flaw. Although most eBikes are protected with a thermal overload, how many owners are actually complaining about it tripping on their bikes? I don't really know the answer to that question, but it doesn't seem prevalent. Sounds like a good polling subject.

I do know that with fractional hp motors such as air conditioning condenser fan motors, and also blower motors, it's been a common type of failing in certain models of motor that the manufacturer will get the thermal overload calibration wrong, and every one of those motors will be unreliable, and considered a lemon, while another brand with exactly the same spec motor, will never have a problem. Of course the bad motors don't last long in the market, but I've seen it happen more than once in the last 30 years. If that can happen with motors they've making for well over 50 years, I can see how manufacturers with less than 5 or 10 years experience could be making the same mistake.
For a while I was riding an old Gen 1 250W classic Bosch powered bike I imported from Germany before the US ones became available and it over heated sometimes. It was modified a bit though ;). The gen 2 250W Bikes don't have that issue though. Tina from Haibike lent me a bike for the week while I was at Eurobike and I rode it really hard without a issue. I think it really comes down to how it's engineered. I won't claim to understand it fully, but although I know it's not an easy task, some brands have been successful of getting serious power out of these smaller motors.
 

Bud

Member
How do you know if your motor overheats? What is the sensation.? I find sometimes when I am charging home, which is 5 miles, mostly uphill, that the motor will cut out and then come back on. I had been thinking that this was an engine cut-off triggered by a fault in one of the brake levers or some other connection problem. Maybe it is overheating due to the sustained effort. Usually 20 minutes or so. Thoughts?
 

biknut

Active Member
How do you know if your motor overheats? What is the sensation.? I find sometimes when I am charging home, which is 5 miles, mostly uphill, that the motor will cut out and then come back on. I had been thinking that this was an engine cut-off triggered by a fault in one of the brake levers or some other connection problem. Maybe it is overheating due to the sustained effort. Usually 20 minutes or so. Thoughts?

What you describe is exactly like what happens when your motor overload trips. The motor stops running, and after a brief cooling off period it starts working again like nothing happened.
 

Lenny

Well-Known Member
How do you know if your motor overheats? What is the sensation.? I find sometimes when I am charging home, which is 5 miles, mostly uphill, that the motor will cut out and then come back on. I had been thinking that this was an engine cut-off triggered by a fault in one of the brake levers or some other connection problem. Maybe it is overheating due to the sustained effort. Usually 20 minutes or so. Thoughts?

overheating problems are almost always with direct drive gearless motors.
At higher RPM, you have significant core and impedance losses. Under higher loads, let's say a steep hill, the motor draws higher currents but the RPM is quite low and if the system doesn't have venting or excellent thermal compound, the system shuts off to prevent itself from frying.

In the case of geared motors, set of gears are used to reduce higher RPM of the rotor to wheels. As a result, a steep hill doesn't strain the system as much. Of course, geared motors may not last 10K miles but keeps the weight low and reduces thermal problems.

A long steep hill, higher rpm, minimal pedaling = motor is not happy. Sometimes, motors make slight rattling sound at low rpm and higher loads. Always pedal when going uphill on a gearless motor E-bike.
 
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jcasad

New Member
I ride a city commuter type electric bicycle with a 250W motor @ 36V. The performance and range has been fine for the flat terrain I ride in typically. However, I have made some longer rides with some long, 3 mile, moderately steep uphill grinds and found the motor shutting down on the thermal overloads. I weigh 190 pounds and feel that the smaller, 250W, motor is overworked and overheats on long climbs. When it stops I sit by the side of the road for about 10 minutes allowing it to cool and reset itself, and off I go again. I have also found that shifting down and setting the pedal assist at its lowest setting avoids some of the thermal shutdowns. I am in the market for an electric bike with a larger motor that will not have to work so hard.
 

DWEBiker

Active Member
what's the point of a bigger power hungry, and heavier bike that's limited to the same speed anyway? Hills might be a factor, is the only thing I can think of, but his bike has no problem with the hills near us.
Rider weight
 

jcasad

New Member
Rider weight
I'm sure that's part of it. A larger motor (350 watts) won't use any more power when ridden on the level then a 25o watt motor, at the same weight, but will have reserve power when climbing hills, and won't generate as much heat. Smaller motor works harder and runs hotter. Thanks for your input.
 

GatorBob

Member
Santa Fe's steep grades around my home pose no problem to my 2015 Pedeco Interceptor III's 500W geared rear hub motor with (edited) 48V10W battery. You can pay $350 for an optional 48V15W battery. If you take longer rides on hills, it might be worth it. I'm 86, weigh 165 and my bike weighs in at 60.
 
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jcasad

New Member
It's beginning to look like the general consensus is that a new bike with a 500watt motor is the answer. Thanks everyone. Pedeco seems to be a good choice too.
 

Ann M.

Well-Known Member
@jcasad you can search Court's reviews by motor size on the other side of the EBR site. There are a whole lot of bikes with 500 watt motors that will give you the power and range that you need and the reviews give you an idea of that variety and performance; its a valuable tool. Once you see a style and brand that catches your fancy then check out that manufacturer's website for additional bikes.
 

J.R.

Well-Known Member
It's beginning to look like the general consensus is that a new bike with a 500watt motor is the answer. Thanks everyone. Pedeco seems to be a good choice too.
ProdecoTech has really upped their game this year with many models now with a 600w geared motor and large Samsung batteries.