750 Watts

[Martinet]

I understand that wattage rating is a measure of continuous output.

Since 750 Watts is generally the road limit in the US, I would much rather have a bike equipped with a motor branded at 750 Watts with continuous measured at Death Valley conditions than one branded at 1000 or 1250 Watts.

As I recall the Go Swiss motor used to be rated at 250 Watts, 750 peak. 750 watts, peak 2250 would be about right for a super bike. If such super motor had outlines whereby a shop could cut out vents that even better.

 

[Ann M.]

@Martinet, the Bafang, BBSHD mid drive motor can be programmed to perform at continuous 750 watts with a much higher peak. The battery you use with it will impact the range & speed; however, this is all programmable too. The BBS 02 is a 750 watt motor but lacks the nice thermal sensor that the HD has which is handy for those of us who ride in hot, humid weather. It helps prevent overheating.

Also, take a look at a Golden Motor hub motor which has cooling vents on the motor. You can get the Magic Pie5 and a 36V battery to set the system to 750 watts. Or you can use a better, larger battery and program the motor limits to 750 watts.

 

[JRA]

My road bikes are 48v x 25a (1200w) and 52v x 25a (1300w). I rarely see that much wattage on my CA3 display which keeps a constant readout of watts going.

Times I will are getting the hole shot briefly, going all out for speed against headwinds and getting frisky on steep climbs. Because I use dd hub motors using too many watts creates too much heat as well as eating ah’s decreasing range.

For long road climbs I’ll set my cruise @ 350w and use the appropriate gear ratio to stay on top of the motor. Most rides I average 500w output but for the times I use it I’m glad it’s there.

I live in OR and the legal watt limit is 1000w so I’m over the limit but so is the ability of my crap car to exceed legal limits.
I just ride responsibly.

But for mtb use I am happy with a 52v x 15a (780w) torque sensing mid drive. While not as versatile as my hub bikes, for climbing steep gnarly single track with its range of gearing advantage it rules.

 

[rich c]

I thought the 750 was nominal. Peak is much higher.

 

[MisterM]

I understand that wattage rating is a measure of continuous output.

Since 750 Watts is generally the road limit in the US, I would much rather have a bike equipped with a motor branded at 750 Watts with continuous measured at Death Valley conditions than one branded at 1000 or 1250 Watts.

As I recall the Go Swiss motor used to be rated at 250 Watts, 750 peak. 750 watts, peak 2250 would be about right for a super bike. If such super motor had outlines whereby a shop could cut out vents that even better.

Bafang's Ultra mid motor is nominally 750w/1000w with 1500w peak. Can program as needed. Big 160nm torque

 

[gv1]

If you are concerned about street legal, I believe the best comprehensive guidance is California AB-1096 which starts: An “electric bicycle” is a bicycle equipped with fully operable pedals and an electric motor of less than 750 watts. I believe they consider 750W nominal as acceptable. Big motors, jail breaks, DIY are all great for the appropriate riding environment. Martinent is correct in assuming 750W nominal is the safest approach for road and street. European rules are strict and Bosch and Brose will stick with 350W because they do not want to spend more for the US market when many states are actually leaning to tight restrictions that may copy European rules. The US market should be encouraged to offer branded 500W and 750W nominal motors which will help establish a market standard that can universally accepted as a norm.

 

[Alex M]

My road bikes are 48v x 25a (1200w) and 52v x 25a (1300w). I rarely see that much wattage on my CA3 display which keeps a constant readout of watts going.

Times I will are getting the hole shot briefly, going all out for speed against headwinds and getting frisky on steep climbs. Because I use dd hub motors using too many watts creates too much heat...

Is it the current or wattage that generates heat in DD? When would it heat more - 48V*25A=1200W, or 36V*33A=1200W?

 

[gv1]

The SR Suntour ATS HESC hub motor with an external heat sink has 500w nominal, 80nm torque and excellent high demand long term performance. Heat sinks are not used enough on any size motor.

 

[Ken M]

You can measure the power being supplied to the motor at any time but it's nebulous to statically rate any motor's wattage. It's just mindless legislation because they lacked any technical background to even write the legislation. It's my understanding the original federal regulation came from Bush Sr. time frame and they just converted 1 HP to watts and thought that was a good number to go with. It was a butt pull.

Don't worry about buying a powerful ebike, even one with a peak actual drive wattage over 750 watts because the current regulations will never last. Police can't enforce a "motor wattage" rating as just one of the huge problems with the current regulations.

The mid-drive drive system manufacturers want to keep the current system because it's helps their marketing efforts (they are more efficient because of gearing at low speeds but for anyone that commutes at typically speeds over 20mph that gearing advantage actually turns into a disadvantage (only 25% of a mid-drive torque is delivered to the rear wheel if you are say riding on a 44T front 11T rear chain ring at 20mph so they simply are not as efficient as a hub motor at high speed - overall mid-drives and hubs tend to be about the same overall efficiency on faster ebikes used for commuting.