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what kinda of watts can you get out of the rad motor

Started by jonnycat69, April 25, 2022, 08:52:04 PM

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jonnycat69

so I have a Rad mission.  I know most of all the Rad bikes come with a 500watt motor but can you push out more from the motor? if so what can you do to it to make sure that the guts don't blow up on you? is there metal gears for the motor? and can you really go faster then 20mph. has anyone did any test on pushing more then 500watts out of the motor.

FortunatelyTheMilk

Peak or sustained? I've gotten 1500W peak with fresh charged cells and a 35A controller. With the 35A controller it'll push out 800W as long as the battery can sustain it.
The reduction gears are plastic. I've done 3000km with that controller without motor issues.
Top speed is about 40kph/25mph, higher speeds would require a high kV motor, or higher voltage batteries.

Ddaybc

I've done a lot of research on the Rad motors. All of the hub drives are 500 watt motors regardless of whether they are sold in the USA as 750 watt versions, the EU as 250 watts or here in Canada as 500 watts.

It means that under normal use they can handle 1000 watts all day long without issue. If I remember right they are rated as 1000 watts nominal and 1600 watts peak. So they can handle 1600 watts for short periods of time like a hill climb type of thing. Of course I won't debate what "short periods of time" can mean as it will mean different things to different people depending on their reference points.

If you wish to see what the real world can offer then, on this forum, look up posts by Altema where he tried to burn out a Rad hub drive and was unable to. Unfortunately I don't know how to look up specific posts so I don't have the link for it.

The important thing to recognize is one can safely apply double the wattage the motor is rated for.

As for the "plastic" gears they are actually nylon and/or teflon. This type of gear has been used for decades in the automotive industry and in the correct application have proven their strength and reliability. I've also found a site when the plastic gears were replaced with metal ones. They are very expensive to make and are a lot louder. They also don't give a performance or durability benefit.

JimInPT

Quote from: Ddaybc on April 26, 2022, 09:31:11 AMIf you wish to see what the real world can offer then, on this forum, look up posts by Altema where he tried to burn out a Rad hub drive and was unable to. Unfortunately I don't know how to look up specific posts so I don't have the link for it.

I remember that post, and Altema has confirmed several times that he was unable to burn out the stock Rad motor after trying to do so with up to 1600w for sustained periods of time.  (The motor used was surplus after a motor swap, so he was willing to find its limits to destruction, but never did.)

Here's a link to another one of his posts with a lot of detail about these motors where he reiterates the extra power is no problem: 
https://www.radowners.com/index.php?topic=726.msg3576#msg3576
Shucks Ma'am, I'm no "Hero Member", I just like to wear this cape.

Brandon

It's likely more of a current limitation out of the battery or thermal conditions in the motor. Most Li-Ion cells, depending on internal resistance, are rated for 0.5C discharge (or less). That means about 1A per string of cells. Since the RadMission battery is smaller and less parallel, you can't get as much current out of it. You'd need the larger battery.

Additionally, I think there is less thermal mass around the RadMission motor, which means less heatsinking. Since it's a Permanent Magnet motor, you really want to keep the magnetic material under its thermal limit or you get permanent degradation of the binding material and then less magnetic field. So it's more of an aging and power degradation rather than a wire/heat problem.

bajen25473


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