350w vs 500w geared hub motor

Bluespills

1 µW
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Sep 14, 2016
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I am a newb to e bikes, i had my first 250w ebike which was stolen, so now im looking to upgrade. It was capable of about 23kmh, and i would just like a bit more speed. I see on kits rated 350w and 500w both have top speed rated at 33kmh. Does anyone have experience comparing the two, and will 350 really get up to 33kmh?

Where i ride is almost totally flat with only very few small hills. I only weigh 60 kilos, but my bike is an older steel frame and is pretty heavy, maybe up to 20kg.

Thanks for any advice!
 
In my experience with 350w motors they will get you to about 38kph on the flat with you pedalling. In fact they will probly drive you to 50kph for a short time before dying a smoky death. The controller dishes out thepower so don't neglect to pay close attention to the one you choose. Some are limited to a legal speed.
The 500w motors I have seen and used (macs) are a big step up. Able to handle 1500w for a while and will cruise at 50kph on the flat no prob.
If you are used to the 250w limited, 350w unlimited will be a noticeable improvement and a 500w unlimited (on a say1500w controller) will be vastly superior.
Don't forget to look at the system as a whole not just one spec on one part
K
 
350w output power is enough to push you down the road at a little over 20mph. 500W of mechanical power will get you to around 25mph. The Mac is referred to as either 500 or 1000w. A Mac is quite comfortable to cruise at 30mph (which requires ~1000w of mechanical power and therefore ~1200w of battery power).

If you have a 250w motor, you may as well jump to a 500w. Bear in mind, the actual max speed is determined by the motor rpm, wheel size and supply voltage (not the rated power). The motor speed should be selected appropriately, according to the power rating and your requirements.
 
It gets very confusing. A 350w motor that has 350w max power will not go much faster than 30 kph with typical speed/rpm wind. Wind resistance means more speed needs more watts. This is not the motor limiting speed, it's drag limiting it. But if you give that same motor 750w it can go 40 kph. But 40 kph is pushing the small motors pretty hard. You can do this in mild climates, but not in the desert where I live. It may overheat if pushed too hard by heavy riders.

A 500w rated motor may have the same speed wind, but it can be pushed much harder and still get away with it in my climate. So 45kph is quite common when you give that 500w motor 48v. at 36v, 35 kph is typical.

If you want a system that can grow,, then get the 500w motor. you may choose to run it at very low power now for various reasons, your controller is weak, or maybe your battery is weak. But later on, you can upgrade to 48v and 1000w if you want, using the same motor.
 
Thanks for all these very helpfull replies. I'm starting to get a clearer picture. It sounds like 350w will satisfy my needs, but 500w sounds fun too.

So whichever motor i choose, it can be upgraded slightly within it's limits to increase speed. To be clear, this can be done by upgrading the controller with more amps, correct? Say the system is 350w motor, 36v battery, and 36v 12A controller... Then replacing the controller with 36v 18A will give a bit more more speed?

One more question is i have seen some kits where the controller specs list the amps just as one rating
36v. 17A

And another says
36v
Nominal 8A
17A MAX (1 sec)

Is there a difference between the two?

By the way, This is the set i am looking at if i go for 350w. (Sorry its in german but hopefully you can understand the specs)
http://www.ebay.de/itm/391519390739?_trksid=p2060353.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT
 
Firstly, the rating of motors (350w or 500w) has very little real world meaning. A Q100 is rated at 350w. Compare it with a Bafang CST that's also rated at 350w. The Bafang is double the size and just as efficient. Do you think that they'll give the same power and torque? Every motor is different. Luckily, there's a lot of guys with experience of all these motors, so it's better to define the performance you want and then ask for recommendations.

Hub-motors have a speed rating as well as a power rating. It's very important that you choose a motor that goes at a speed that matches your riding. For best efficiency, you need to choose one with a maximum RPM that's about 25% higher than your modal intended travelling speed. If there's a maximum speed you want to sustain, then you need a motor with a max RPM about 25% higher. You also need to be mindful of hill-climbing because a motor that runs fast will have very low efficiency when slow climbing. More power means that you can climb faster to avoid that, but small motors can't provide the torque to get the power.

Having said all that, I can tell you that virtually any small hub-motor that has a maximum rpm of around 270 to 300 rpm at 48v will give you what you want. You only need 14 or 15 amps which is what the small controllers give. If you want 36v, it would be better to go up to around 20 amps.

On the controllers, they normally print something about current. 17A max means exactly that. The controller will give no more. The rated current is normally 50% of the max, so a 7A controller is 14Amax. Generally, you can judge a controller by its size and the number of mosfets. 6 fet is around 15A max. 9 fets 22A, 12 fets 25A. You can adjust any of them +/- 30% by adding solder to the shunt to increase current or crimp the shunt to decrease it. The KT controllers can be adjusted a bit by software accessible through the LCD.

When you've chose a kit, post details here before ordering to get confirmation that it'll do what you want.
 
Is there a dimensional size difference between a 250W , a 350W , or a 500W geared Hub Motor ?

The Ebike has an aluminum "Mag" type wheel with solid spokes , and a machined out hub to fit the 250W geared hub motor . Would this wheel hub accommodate a larger Watt geared hub motor ?

If a 250W motor is too small to tow a Ebike trailer , would a 350W or 500W motor be necessary ?

:?:
 
Digging up an old post?

Power is determined more by the controller than the motor, but of course the motor will only take so much power before overheating.

Some motors like the MAC above have basically the same motor at different power levels, depending on what you need. The windings (or motor speed) internally may be different to keep the motor in its happy place at different power levels.

250 watts would need a 24v battery (which is too small for everyone here)
260 watts would need a 36v battery
500 watts is typically a 48v battery, but could also be a 36v battery at higher current.

If in doubt, and you don’t mind a little extra weight, go for the larger power. It’s not a huge difference, but most people find a little extra power better (except for me, I like lower power, I like to pedal, LOL).
 
I already tried a 500w geared hub very similar with Shengyi, worked fine with 9 MOSFET but the controller went hot in summer in a longer uphill, when i was using it at full power around 1000w (20A @ 50V). Now I would like to try the Shengyi DWG22, i hope to get 45km/h top speed, please advise about this model. Best would be for me to read well the engine chart see the torque. I understand that Bafang CST and Dapu are good choices, but these are hard to get and not cheap. Mac is quite pricey, I would rather pay a BBS02 750 at that price level.
 
Im not sure how this will work but will be running a 350w 48v MXUS using a 450w 48v to 60v (20a max) controller.
It equates to a 30% increase in push from the controller that is throttle controllable.

Turbo mode

I can set the speed / gear limit switch to med speed and run flat out staying safe (Im thinkin) then when I need / want more power can I change the speed switch to high and get the extra juice for short duration.

When the parts get here I will test if it actually does run quicker or if it runs about the same.
 
It depends which motor it is. MXUS make a lot of different ones. As I said previously, the 350w rating means very little. You can kill it with 250W or run happilly with 750w. It just depends how you use it. The important characteristic is the kV or RPM at any given voltage.

Say you had a typical geared one of 270 rpm at 36v. If you ran it at 60v, it would change it to nearly 500 rpm with a fully-charged battery. That means that it would be very inefficient below 20 mph, so would overheat and waste battery power. It wouldn't have the torque to get you into its efficient zone quickly; however, if you fitted it to a lightweight low-drag bike like a roadbike and pedalled hard below 20mph, it would give much more useful performance.
 
Chances are a 500w rated motor will not fit in the mag wheel you have. you need to replace the guts with the same thing, or if its not broken, just run it on more power than 250w.

I'm confident that your motor can handle more, up to at least 750w. So get a 36v 20 amps controller, and upgrade your power. It will stress your motor more, but not enough to kill it, since you have small hills, and are not a heavy guy.

For a real power increase, replace the whole wheel with a 500w rated motor, which can easily handle 1000w, a 48v 20 amps controller. The more speed you want, the more voltage you use. but your existing motor should be limited to 36v.
 
d8veh said:
It depends which motor it is. MXUS make a lot of different ones. As I said previously, the 350w rating means very little. You can kill it with 250W or run happilly with 750w. It just depends how you use it. The important characteristic is the kV or RPM at any given voltage.

Say you had a typical geared one of 270 rpm at 36v. If you ran it at 60v, it would change it to nearly 500 rpm with a fully-charged battery. That means that it would be very inefficient below 20 mph, so would overheat and waste battery power. It wouldn't have the torque to get you into its efficient zone quickly; however, if you fitted it to a lightweight low-drag bike like a roadbike and pedalled hard below 20mph, it would give much more useful performance.

My signature has bike details , I will be gently with it until I know it then will bring a IR temp gauge along and spank it and see how it handles the push.

When I find out how it does will start a thread titled ' the MXUS xf07's performance "

The Hub was advertised in 290 and 360 RPM versions. I expect to get the 290 hub as its coming on a 26 inch wheel.

I'm looking at it this way - More torque = less speed = longer battery distance.
 
Not sure how I missed the "towing a trailer" comment.

I consider 1000w the absolute minimum for towing on flat ground, 2000w for hills. You need 2000w, and a big heavy motor for that, if you are going to use hub motors to tow trailers up hills. ( and maintain 13- 15 mph, which hub motors need to avoid overheating)

Take a small geared motor, or even the larger ones, hook up a heavy trailer, and head up 8% grade for two or three miles, and you WILL melt the motor. Anything above 300 pounds total vehicle, trailer, and rider weight will be too much for that grade. You will slow to 8 mph, and in a mile the motor melts.

Best bet for towing, if climbing the hill very slow is ok with you, is a mid drive. Replace your whole thing with a mid drive, of about 700-1000w.
 
I had some XF07s, that I ran at 36v and 44v. They were around 270 rpm at 36v. The voltage didn't seem to have any effect on torque like it normally does, neither did increasing the current do much, so I spoke with MXUS about it. They told me that I most likely had the Chinese version with weak magnets and thin wire, as I bought them from a Chinese reseller. One of them managed something like 15,000 miles, so they were pretty reliable. I did a few tests and came to the conclusion that 36v and 19A got the best from those motors without too much risk of over-heating. They did get a bit warm when I tried 44v (12S) at 19A.
 
that's a lot of miles for a knock off of a knock off of a hub motor.

I have been researching batteries and found I can add 12AH of 7.4v or 11.1v RC to a 12AH 48v battery pack for a voltage output of 55.4v and 59v respectively.

With I can gain either speed or distance depends how the throttle is used.
 
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