Front Hub Motor Suggestions (48V, 250-500W, Light, Reliable)

[Kevin Crawford]

Greetings everyone,

I've used a front hub eZee motor kit from Grin Cyclery for two years. I'm very happy with the kit, but have decided to swap my ebike conversion over to another bike. Since the new bike uses a different wheel size (700C, instead of 26") and I was also interested in trying a lighter motor, I decided to sell the eZee wheel, but keep the rest of the parts. A lot of folks seem to like the high-powered stuff, but I found that using my eZee at even 400W (with my 48V pack) was overkill.

In fact, as my battery pack started to wear out I dropped the current limit down to 5A (~250W) and even that was enough (I wouldn't want less than that, though). My experience is that the higher current just doesn't make my commute faster enough to make it worthwhile. It barely made a difference. It does make a noticeable difference in climbing, but I don't have enough of that on my routes that it's much of a problem. I like the additional speed that 48V vs. 36V provides. I'd like to ride in the 20-25 MPH range. I like to pedal while the motor is running, but I like that the motor is doing most of the work.

The new bike is a Specialized Sirrus Sport. It has an aluminum fork and rim brakes.

So, what I want to do is buy a new motor (or wheel) that will work with my eZee controller, that provides at least similar performance as my eZee motor did in the 250-350W range, but in a lighter package, so geared is preferable. It must be safely compatible with 48V. Reliability is paramount. This isn't an experiment and I'm not looking to push any limits. I need to get to work on time. I want to be able to bike in at least moderate rain without problems. And the longer the motor lasts, the better.

I was sold on buying one of the "Outrider" motors that Grin used to carry, but they're sold out now. So something like that would be a good baseline.

One name I see a lot is Bafang. http://www.szbaf.com/en/components/component/motor/fm-g02350dv.html looks like a possible candidate. What doesn't make sense to me is that there is another motor on their site that looks exactly the same and has exactly the same specs but has "250" in the name (for 250W apparently, even though it is claimed to work to 350W just like the other one). I also don't understand why some of their motors are listed as disc compatible, but not rim compatible. These motors are also about the same weight as the eZee. Might there be another suitable option besides the 2.4 kg Outrider that is considerably lighter? If all else fails I'd be OK with getting another eZee, but it just seems to be more motor than I need.

Any advice is greatly appreciated! Thank you very much!

 

[motomech]

It's just as well the Outrider is O. of S. From the reviews I have read, it's performance has been a bit of a disappointment.
I believe is a clone of a MXUS 2.3 Kg. geared mini, I motor that I have been abusing for years and 1000's of miles. Unfortunetly, it is a little difficult(but not impossible)to order. It has to be ordered from the factory or from Alibaba.

Usually, I would be hesitent to agree to the idea of going to a smaller motor, while going to a bigger wheel. The 700 will require more torque to get it turning. But since you are happy running such small currents, a mini should be fine.
Actually, with such low power levels, I think you would be happy with a 2.0 Kg. Q100H, also called the Cute. You would want to go with the "260" motor-speed version, same as your Ezee(for the same top speed). I have been using the Cutes for several years and they are reliable enough, but not water-proof(This is only a problem in very deep water). Besides, these are $100 motors and if it would help you sleep at nite, you could order a spare motor to go with your new motor/wheel ASM. It is very easy to swap out motor cores with the Cutes.
Since you are "dialing-in" currents, I assume you have a Cycle Analyst plugged into a Grin/Infineon controller. Although this will work fine with a mini, I would probably sell it with the EZee and go w/ a controller that offers PAS. Even a cheap genaric controller w/ PAS works very well with a low-powered system. The new Sine wave w/ "torque imitation" from BMS Battery is very nice. And since the Cutes have 16 Poles(like your Ezee), they are very quiet and combined w/ a sine wave,pretty much dead silent.
You can order the Cutes from BMS Battery or E Life Bike. Get the spoke wrench because the spokes will be loose(but the whl. will be true).
Can't help you w/ the Batt. When my Grin Flat-pack died, I tossed it and went to Lipo.
If you need to order a battery, I would look at what BMS batt. offers, especially the ones w/ Panasonic sells. You could combine the motor/whl. order with the batt order and perhaps save a bit on freight.
If you get to the point where you want to know what the freight will be, you can "dry order" the parts to see that.

 

[Kevin Crawford]

I just edited my post to make it more brief on the suggestion of another member.

Thank you very much mototech. Great information. Someone from Grin told me they weren't planning on getting more Outriders. Now I might know why.

I had heard of Cute before but haven't looked into them much, but will now! I don't need the motor to be waterproof - just good enough to not have problems with most rain. Maybe putting on a thin layer of waterproof grease between the chassis and the motor cover as I did with my eZee will help.

Yes, I have a Cycle Analyst V3. I bought it mainly for the current-limiting, but also love the auto-cruise feature. I had considered PAS before, but I like my relatively simple setup - I don't even use the speedometer cable anymore, and went as far as to unsolder all of the cables from the CA that I don't use. I just twist the throttle to max, hold it there for 2 seconds, and let auto-cruise take over. If I need to move at a lower speed (which I do for the brief periods I'm on a side path) I just cut off the throttle. My commute doesn't have a lot of stopping, so this works fine.

Can you elaborate on why you suggest PAS?

Thank you again.

 

[Kevin Crawford]

Well, I've just spent quite a bit of time looking at Cutes (Q100). As far as I can tell, the Cute made for 48V is slightly larger and heavier than the suggested Q100 - it's a Q128. But checking back on here, it seems that this larger, heavier version may not be worthwhile.

Checking one final time before I make the decision here - if I'm going to be running at 53.5V (which is what my theoretical 48V battery pack gets fully charged to) and 5-7A (continuously for about an hour), do any of you with experience believe the Q100H will perform reliably day in and day out, or is there anything to worry about with exceeding the 36V voltage spec? My controller is made for 48V, and I already have two chargers and a battery pack for the same voltage. I definitely want a 48V system. The Q128 looks suitable to me on paper, but if the lighter Q100H will perform reliably, I'll go with it.

What I'm leaning towards: https://bmsbattery.com/ebike-kit/630-q100h-36v350w-front-driving-ebike-hub-motor-ebike-kit.html#/327-rpm-260

Again, thank you.

 

[motomech]

Before I hooked up my PAS, i used the cruise like you do, set it @ a speed a little less than I want to go and pedal to add a little. But I'm retired and don't commute and around town I found that I was constantly having to cut the cruise and reset to a different speed, annoying.
Ok, a quick explanation of the two types of budget PAS;
1)The very simple 3-speed type. Set the speed and when the PAS disc makes one or two rotations the motor engages, a slight delay of one or two seconds. Stop pedaling and there is a one or two second "over-run" til the motor stops. This works fine w/ a low-powered system like my Q100C rear(maybe 500 Watts). The problems arise as the system power(and speed) goes up. Since the 3 settings are speed limits, more powerful system tend to "lunge" up to the speed caps. And the 3 "pie slices" that divided the 20 mph top speed Ebike(14 mph, 17 mph and top speed) are divided on a 25 mph top speed machine, holes are left. Lastly, the over-run of a 1000 Watt system can be scary and an E-brake cut is needed, where I can easily stop my Cute w/ the hand brake if need be.
2)The "Torque imitation" feature of the sine wave controllers. The genius here is the 5-range PAS is limited by current, it steps up in force and there is no "lunging". Also the 5-ranges add versatility in dividing the operating speed range into smaller segments. This is a giant step up from the crude 3-speed system and offers the best pedal experience short of the very expensive "strain gauge" systems.

 

[motomech]

Well, I've just spent quite a bit of time looking at Cutes (Q100). As far as I can tell, the Cute made for 48V is slightly larger and heavier than the suggested Q100 - it's a Q128. But checking back on here, it seems that this larger, heavier version may not be worthwhile.

Checking one final time before I make the decision here - if I'm going to be running at 53.5V (which is what my theoretical 48V battery pack gets fully charged to) and 5-7A (continuously for about an hour), do any of you with experience believe the Q100H will perform reliably day in and day out, or is there anything to worry about with exceeding the 36V voltage spec? My controller is made for 48V, and I already have two chargers and a battery pack for the same voltage. I definitely want a 48V system. The Q128 looks suitable to me on paper, but if the lighter Q100H will perform reliably, I'll go with it.

What I'm leaning towards: https://bmsbattery.com/ebike-kit/630-q100h-36v350w-front-driving-ebike-hub-motor-ebike-kit.html#/327-rpm-260

Again, thank you.

The Q128 is a completely different motor and is very worthwhile to those in the know. It is smaller in diameter than the Ezee, but it's much wider, weighs about the same and will handle more power than the original Ezee(or at least the same). You don't want that.

Yes, the Q100 is reliable, in fact, it's the most reliable $85 motor you will ever buy
if you are going to ask questions about your controller, it would be nice if you told us what it is. But I can guess, It would be the 20 Amp Grin/Infineon that they offered back around 2007 to 2008. The precursor to the 20 and 25 A 6-FETS they sell now. I had one once and they have 63 V caps and are safe to use @ 48V.
You will also need a 9-pin connector pair to mate the Cute with your current controller. BMS B. sells them.

 

[Kevin Crawford]

Thank you once again. My controller is the eZee one that came with the kit - purchased in 2013. I believe it is 20A.

I know the controller is 48V-capable. My concern was/is whether the Q100H will work reliably at that voltage and 5-7A continuous.

As for the PAS, I get what you're saying. I use my auto-cruise without even having a speedomoter installed. In this case, the CA will just lock into the throttle setting instead. I initially used it with a speedometer, but didn't like how it would start and stop the motor drive to maintain the speed. So now, I'm basically running at max throttle most of the time. When I'm coming to a stop, coasting down a hill, or riding somewhere where I should be going slower (like a MUP), I just cut off the throttle. This has worked well for me, but my only concern is that I wonder if I'm using more current than I would be otherwise (this is one reason I use lower current limits). I'm hoping to get more life out of my next battery pack (or new cells). I limped to the 2-year mark the first time - 2.5-3 years would be nice for the next one.