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Thread: Hub motors

              
   
   
  1. #1
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    Hub motors

    In my research i haven't come across much about hub motors or many people using them, I was even warned against using them when I first started researching this but I was recently told that they would be a better choice and thought that I should at the very least give them a proper look. So I would like to know how they compare and which ones I should be looking at. I will be doing more research alongside this but any thoughts from more experienced people and those who have looked into this already would be very helpful.

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    Electric Warrior CaptainKlapton's Avatar
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    In my opinion, Hub motors can be a very good choice, especially if frame space is limited. The only real drawback I see for a street bike is that the top speed is set by the voltage because there is no gear ratio and that could make it difficult to adjust if your initial voltage doesn't fit your needs.
    The Enertrac is the best choice I know of for a motorcycle.
    "Never let schooling interfere with your education."
    -Mark Twain

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    Seņor Member podolefsky's Avatar
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    They add unsprung weight, but that's a minor tradeoff for the space savings. They're also nearly silent, no chain noise.

    Enertrac is the one to look at. They need at least 96V, as far as I know.
    - Noah Podolefsky -
    The GSX-E

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    Senior Member EV_Scoot's Avatar
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    They can use lower voltage than that, but I'm planning on using 96 to give me a decent speed. Not sure whether to get the double 602, cause if I get the single and its not enough, it's a lot of money wasted.

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    Senior Member __Tango's Avatar
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    Hub motors like the Enertrac definitely make it easier to fit more batteries in the frame and also make it easier to mount the motor (those are the reasons I picked a hub motor). If you get an Enertrac, get the water cooled version and listen to Mark when he tells you about how to setup your cooling system. I setup a system where there's not enough water volume used for cooling and the radiator is too small, so it doesn't cool that well (like i said, my fault...not enertrac's).

    The drawbacks that I've found are that the bike i built plus the weight of the rider (me) are a bit heavy for the single-wide MH602 (bike is about 465lbs, I'm about 210lbs, total 675lbs). This means my acceleration isn't great and I used to have a lot of issues with heat when I had an air-cooled version of the motor (but that's been helped somewhat by the aforementioned water cooling system). I believe the Enertrac site says 65mph for 96V with a 325lb bike and 170 rider (495lb total).

    Also, I run a 120V nominal thundersky pack that sags to about 110V when doing highway speeds. At that voltage, I was getting about 72mph (via GPS) max with a Kelly controller.

    The Kelly controller I was using (a brushless KBL12401IC) 120V/400A had a horrible (to me) cogging problem. At low speed, the motor would "cog" as it rotated past the poles. This was pretty noticeable until about 20-25mph. Once I was going faster than that, the cogging went away and it was like riding on air. I've since changed over to a Sevcon controller, and the cogging is gone so it's a smooth ride from 0mph.

    I was seriously considering upgrading to the double wide. However, I'd need new controllers (that would go back to the Kellys since there isn't a "size 6" version of the high voltage controller). I'd also need new batteries, so it'd almost be an entirely new build.

    If you are looking for top speed, get batteries and a controller for as high a voltage as you can. Likely this is 144V. Other suggestions for using an Enertrac are: get the double wide and/or build as light a bike as you can.
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    They're fine as long as your application is relatively low speed and the surfaces you'll be riding on at top speed are reasonably smooth.
    The unsprung weight podolofsky mentions is my main concern about them - it becomes a very significant issue if decent handling is a goal.

    They're fine for moped type applications (relatively low speed city use) but I'd advise against them for anything intented for motorway or "sports" use.

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    Seņor Member podolefsky's Avatar
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    Mark's motors are fine at highway speed. Handling might take a small hit, but it worked well enough for Catavolt to become 2012 75 class champs.

    http://www.catavolt.com.au
    - Noah Podolefsky -
    The GSX-E

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  10. #8
    Senior Member __Tango's Avatar
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    Quote Originally Posted by Spoonman View Post
    They're fine as long as your application is relatively low speed and the surfaces you'll be riding on at top speed are reasonably smooth.
    The unsprung weight podolofsky mentions is my main concern about them - it becomes a very significant issue if decent handling is a goal.

    They're fine for moped type applications (relatively low speed city use) but I'd advise against them for anything intented for motorway or "sports" use.
    Similar to podolefsky, I respectfully disagree.

    The handling of the bike is more due to how you distribute the weight overall. The hub motor means that you have 50 or 100 lbs very low, and can give you a bit more freedom for how you layout the weight of the batteries. My bike handles fine at all speeds including motorway/freeway speeds and I've had a bunch of others validate this claim.

    I've also taken mine on the track at Laguna Seca and it handled under those conditions as well. Granted, I was a fair bit slower at the top speed due to the voltage as I mentioned in my earlier post, but it handled just as well as the others in the corners.

    As podoloefsky mentioned, Catavolt won the australian TTXGP race series a couple of years back on an Enertrac dual-wide at 144V. In fact, there's a video that covered the aussie series out there on the interwebs and in one small section, they talk about how they were able to turn the unsprung weight into a bit of an advantage. In particular, with l00lbs of unsprung weight, the rear wheel is glued to the ground and will never lose contact. The rider was able to change his riding style a bit where he could be more aggressive heading into turns as he was able to enter a turn much faster and was able to brake much later and with more force since he had way more traction in the rear.

    That's not to say hub motors with their unsprung weight are superior to a more traditional setup, but they're also not completely inferior either. They're different and if you're like me (mainly commuting) it's fine and the unsprung weight has basically no bearing on how I feel the ride is. If you're racing or being more aggressive with the bike, you may find there are different ways to use the unsprung weight to your advantage in some scenarios.
    EVs: 2007 Zapino Scooter, Honda VF500 Conversion (electriceptor.wordpress.com), Red Nissan LEAF SL (Arrived!)

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    The unsprung weight isn't a problem for 99% of the riders ! Maybe if your plan is to use it at very high speed on circuit, even then... Catavolt is a good example.
    As tango said Mark's Enertrac motor is a very good motor if want to facilitate the motor mounting and keep space for battery. As he said, don't hesitate to choose the liquid cooled version to prevent from heat problem, particularly at low speed (especially if you plan to use it in city with a lot of stop and starts), because of direct drive, phase current are huge at low speed and the motor could heat rapidly.
    If you want to avoid from high cogging sound between 0 and 30kph, choose a real sine controller (HV Gen4 Sevcon size4 or 6?). I use the KHB 120v/600A Kelly controller, but I'm thinking to change for a Sevcon controller...
    Then, according to your needs, the MH-602 is great ; if you want more power, consider the double hub motor...
    I drove ~5500km with my 602 hub motor and I'm fully satisfied with it. If you want to get an idea of the motor in action, have a look here : http://youtu.be/d-OecTGMuNs
    Don't hesitate if you need more informations.

  12. #10
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    It's good to hear that the unsprung weight is a surmountable issue - it's still not a setup that I'd opt for but my handling expectations may be higher than average, or perhaps it's due to the nature of our roads over here where routes are far more often bendy than straight, and rarely all that smooth, so handling and suspension come to the forefront.

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