750 watt vs 500 watt motor

[DragNLady]

It just occurred to me to ask Rad for some insight into this, and this is what they said: . . . . . . The difference between the two motors is purely in the programming, as the motors themselves are the same make. The Canadian models are just programmed to not exceed 500 watts, with the pedal assist levels also offering more gradual wattage increases as well. This allows them to get slightly more range than the US models, although it isn't necessarily noticeable for the average rider.

The actually performance differences are typically just seen in extreme circumstances, as 500 watts is plenty of power for most circumstances. Additionally, there are limitations even with the 750 watt motors. For longevity purposes, we do recommend keeping the motor at or below 500 watts when tacking steep or exceedingly long hills, as that will help to ensure that the motor isn't strained beyond its capacity. Because of this, I would typically recommend the Canadian model as performance will be similar but you won't need to worry about the additional cost and headache of getting it across the border.

 

[DragNLady]

So the speed controller that I have been talking about looks very similar shape in this photo.
(It is attached in between the rear wheel and seat post)
If connectors are the same, there's a high chance that you can use the 35A aftermarket controller that was meant for Rad Rover.
Here's the review of Bolton kit. https://electricbikereview.com/forums/threads/radrover-controller-display-upgrade-kit.27089/

If I were in your position, I would definitely get a 500W Canadian version first, then decide whether you want to get a 750W version controller from Rad or Bolton 35A upgraded kit.
Even if you get the Bolton kit, it's $219 ($291 Canadian) including the new display and controller.
(Link Removed - No Longer Exists)
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Thank you Timpo, I really appreciate all your help!!! Your suggestion of buying the new controller - is that just to make it go faster? If so, that is not something that is important to me. The ONLY thing that is important to me is that I might damage my 500w bike by pulling a trailer with my mother, (and exceeding the maximum weight allowed), and I wondered whether a 750w bike would be advantageous.

 

[rich c]

It just occurred to me to ask Rad for some insight into this, and this is what they said: . . . . . . The difference between the two motors is purely in the programming, as the motors themselves are the same make. The Canadian models are just programmed to not exceed 500 watts, with the pedal assist levels also offering more gradual wattage increases as well. This allows them to get slightly more range than the US models, although it isn't necessarily noticeable for the average rider.

The actually performance differences are typically just seen in extreme circumstances, as 500 watts is plenty of power for most circumstances. Additionally, there are limitations even with the 750 watt motors. For longevity purposes, we do recommend keeping the motor at or below 500 watts when tacking steep or exceedingly long hills, as that will help to ensure that the motor isn't strained beyond its capacity. Because of this, I would typically recommend the Canadian model as performance will be similar but you won't need to worry about the additional cost and headache of getting it across the border.

You might check your manual, but in the past they told owners not to ride at full assist under heavy load. Especially on hills. Their reply seems to say they are still using that train of thought. For me it would imply your plans may result in an issue of running at too much load. Edit; Found this in a 2016 manual, can't say if the recommendation is still the same.
"When climbing hills reduce the power output to 500 watts or less. This can be accomplished by pedaling with the bike
while in pedal assist modes 1 or 2."

 

[GregGritton]

Thank you Timpo, I really appreciate all your help!!! Your suggestion of buying the new controller - is that just to make it go faster? If so, that is not something that is important to me. The ONLY thing that is important to me is that I might damage my 500w bike by pulling a trailer with my mother, (and exceeding the maximum weight allowed), and I wondered whether a 750w bike would be advantageous.

Given that the 500w and 750w motors are exactly the same, you won't be more likely to damage the 500w motor by pulling the trailer. If anything, as others and Rad Power Bikes mentioned, limiting the motor to 500w means less chance of damage to the motor. It is the heat buildup from running at high wattage for a long time that damages motors, and running 500w maximum reduces that chance.

 

[AHicks]

The ability to control the level of assist while in PAS 1 would be among the other features of the Bolton kit......

 

[Justin Fischer]

Have you considered a Voltbike? https://www.voltbike.com/voltbike-yukon-750-2018.html

 

[Deleted member 4210]

Thank for your help, but as I previously said, I will only be riding on flat terrain, NO hills at all.

Even on flats , it's a poor choice for towing. Get something with a geared hub drive and 60 nm of torque.

 

[Alex M]

Even on flats , it's a poor choice for towing. Get something with a geared hub drive and 60 nm of torque.

My thoughts exactly.

About Bolton kit - its ability to control output on PAS1 is not really "on the fly", as I understand. To change max wattage on PAS1, you must enter the programming stage of KT LCD3/8, scroll through several screens and set the parameter.

 

[Off road all day]

I'm not sure about how you feel about it, but when I point my bike at the opposite side of a busy intersection and tell it to go, I want to get to the other side as quickly as possible.

For that reason, given a choice between 500 and 750 watt motors, this is a no brainer. When adding a trailer to the decision, that makes it even more of a no brainer.

When acceleration or hill climbing is no issue, lets's say the 500 watt motor pulls XXX amount of power at 10mph (due to the factors in play at the moment).

Same identical bike, same identical factors in play as the earlier 500 test, but with a 750 watt motor at 10mph, still pulls XXX amount of power as it's doing the same amount of work the 500 was doing. The 750 watt motor is only using 500 watts! Kinda like the throttle isn't open as far as it was on the 500

The difference between the 2 is the increased amount of power available with the 750 - when or if you want it, and yes, when the 750 is going faster or pulling harder than what is available with the 500 it WILL be pulling more power. In simplest terms, 750 watts vs. 500.

You will have more power but decreased your range by %33

 

[AHicks]

My thoughts exactly.

About Bolton kit - its ability to control output on PAS1 is not really "on the fly", as I understand. To change max wattage on PAS1, you must enter the programming stage of KT LCD3/8, scroll through several screens and set the parameter.

No not something you would normally do on the fly (while moving). The bigger point was that it IS POSSIBLE to set/adjust, where the Rad controller is locked down - not possible.

If somebody where familiar with the process to adjust (path through the menu's) , it could be done in 2 minutes. Not like you need to take anything apart. More like pulling off to the side to get/keep out of everyone's way for a minute, to allow you to make the appropriate key strokes.

 

[AHicks]

You will have more power but decreased your range by %33

ONLY if you are using that full 750 watts! If you are pacing a 500w bike side by side, with an identical load on an otherwise identical 500w bike, your 750w will go just as far as the 500w.

 

[Off road all day]

I am assuming you're new to ebike?

My Juiced CrossCurrent Air was rated at 350W, that was nominal power, the max power was somewhere around 750W.
A lot of bikes that are rated at 500W can push over 900W max.

Something to consider though, battery & motor themselves aren't the only factor. The speed controller is important too. I switched my speed controller (left the motor and battery stock) but made a pretty big difference.

If you're new to ebike... Are you familiar with sound system?
I'll give you an example. What if you get a 15 inch Alpine Type-R subwoofer and all the powerful speakers?
But if you end up getting some cheap amplifier, your subwoofer won't be able to perform at its full potential at all.

Ebike is kind of like that. Some people worry about getting a powerful motor (subwoofer) and battery, but sometimes forget about the speed controller (amplifier). My bike for example, had a crappy speed controller (amplifier) so it made a big difference.

The motors can handle far more than their rated for, you only have to increase the controller output. Now you have a new issue. Make sure the BMS is rated for the maximum output and remember the greater the amp draw on your battery the shorter the life span.

 

[AHicks]

Timpo, if the 2 otherwise identical bikes are pacing each other with identical loads placed on both of them, they'll both be using the same amount of power. Makes no difference what either motor is "rated" for, especially in the case of the 2 Rads running physically identical motors.

I think we both agree the "rating" on many of them is open for much debate and is not the point here.

What we "should" also see, is that when it comes to an uphill sprint using these otherwise matched bikes, the 750w bike should get to the top before the 500w bike does. At THAT point, the 750w will have used more power than the 500w did. -Al

 

[Skypilot]

I am planning to buy a trailer to pull on my bike. The weight of the trailer and person will be 200 pounds. I will only be pulling the trailer on the rail trail, flat terrain, no hills, no streets to cross. I will be getting a RAD City Step-thru with 48v and 14 amp. and a direct drive hub motor. Will a 750 motor make a big difference as compared to a 500watt motor? It will cost me $400. more for the 750 watts. Is it worth it? If so, how will the 750 watt outperform the 500? I know the watt hours are the most important aspect of choosing a bike, but I cannot find that much information on whether a 750w motor would be that much better than a 500w motor. What advantage would a 750 motor give me over a 500 motor? Thanks!

Water analogies are useful when thinking about electricity.
Voltage is like water pressure. Current (Amperes) is like the volume per second of water flowing through the pipe. Resistance is analogous to pipe inside diameter; higher voltage will force more current through a given amount of resistance, but the resistance gets hotter and may fail (controller motor windings, or wiring) if excessive voltage is applied. Controllers are like valves and can only pass so much current or withstand so much voltage before failing. Pipe wall thickness is like maximum voltage rating: too much pressure (voltage) and things break.
So: a 52V nominally rated battery can push more current through the resistance of the system (motor, wires, controller) than a 48v or 36 V battery. This can be helpful in later phases of your ride: when the battery is,say, half discharged, a 52v battery can push more current than a lower-voltage battery, for better performance at that point.
Power is current times voltage (flow times pressure). It’s power that does the work, not merely the Voltage or the amperes, but the product of the two. Watt/hours is equivalent to the reservoir of power to do the work. Therefore: for maximum performance you need:
A) a high voltage, high current battery that has a high watt-hour (voltage x ampere-hours) capacity rating, a motor that can handle the maximum desired power (so, 750 W is potentially more muscular than 500 W, and with a high-voltage, high-current battery, the motor will be able to provide peak power to handle those hills), and a controller that can handle the required voltage and peak current to supply the motor with maximum rated peak and average power. The usual weak sisters are the controller and battery, so scrutinize them for the required specs. It’s great to have a 750 W motor, but if your battery/controller combination can only supply 36 V x 20 A = 720 W at full charge, and 25 V x 20 A = 500 W when drawn down some, performance will be more anemic than expected, and that 750 Watt motor won’t be doing the work it was rated to do.

 

[Captain Slow]

Geez for a Canadian drag racer I would have thought a Biktrix model with 1,000 watts or more would be appealing