600w, 900w, 24v, 36v motor. Not sure which is best

Discussion in 'Electric Bicycles' started by Will Snow, Dec 26, 2009.

  1. Will Snow

    Will Snow Member

    I am putting together a electric recumbent trike that will have gear selection to the drive wheel.

    I will be using SLA batteries for now so weight is something I need to think about.

    Here is what I am interested in doing: top speed of 20-25 mph and pretty good range for around town, maybe 20 miles with very limited peddling and mostly level terrain. I thought for longer trips I could add a trailer carring batteries connected to the main system and may installing a switch easy to reach to activate these trailer batteries.

    So far my thoughts have been a 600w or 900w 24v motor or moving up to 36v. I have been looking at motors that may fit between peddle cranks which I need for this application.

    Somewhere along the line I think I was warned that a higher powered motor is not good at slower speeds, say, 7-10 mph. So that is something I don't know about. I don't want the bike to be a wimp, but also don't want to go into "overkill".

    I have been leaning toward the 600w 24v approach, thinking the gearing will be a big help for performance and I could carry more batterie for more range than with 36v. As you can tell, I am not sure about the best way to do this.

    I already got some good help on this forum from Professor and Johnrobholmes regarding another part of this project. So, thought I would try again with these questions.

  2. SimpleSimon

    SimpleSimon Active Member

    Well, from my reading I have concluded that probably the best match of power and performance is in a 36v system, for bicycle uses. Since you are looking at SLA batteries and a tadpole recumbent, I'd suggest you consider a main rail motor mounting point under the seat, with a chain loop forward to an inside secondary crank sprocket so as to feed the power directly through the pedal power system and utilize the gearing. Depending on what recumbent you are using, there may be room under/behind the seat to place 3 series connected high amp hour motorcycle batteries. The battery trailer idea has merit.

    My recollection is that CA limits e-bikes to one shaft horsepower, which is (approx) 750 watts, so a 600 watt motor will be legal. However, are there CA restrictions on "transmissions" for e-bikes? Any multiple gearing shifter system is a transmission.
  3. Will Snow

    Will Snow Member


    The trike is a Terra. I know California has some restrictions: 20 mph speed limit for electric, peddles, etc. and I believe I read 1000w is the limit. Think you are probably right about the transmission. So far, in the 29 years I have been tinkering with and riding motorized bicycles an officer has never questioned me about it, except one time at a police station and that was more out of interest in it. But there could always be s first.

    36v, Well, behind the seat there maybe room. 900w 36v, wonder how that would do? I'll recheck California law, pretty sure it is 1000 watts.

    The last bike I put together was a Tour Easy recumbent with the motor under the seat and running a chain to the main sprocket as you suggested, which turned out very well. This time I want to have a shorter chain from motor to sprocket if I can mount it neatly.
  4. Will Snow

    Will Snow Member

    California law

    Just reviewed the California DMV handbook under motorized bicycles,section 406A & 406B. 406B is for electric bicycles.

    Up tp 1000 watts is legal, but no more than 20 mph

    No mention is made of a tranmission so it looks like I am ok using gears.
  5. SimpleSimon

    SimpleSimon Active Member

    Sounds good. It gets a bit pricey, but with the forward boom design the Terra Trike uses, it would work to use a motor from high end RC technology, such as an outrunner, and a custom fabbed gear reduction system. Look up the work log and posts by recompence, here - he did a truly outstanding piece of design and fab work for his recumbent. Another consideration might be to go with a pair of 500W wheelmotors as your front power and simply forego gearing - leaving the rear wheel powered by the pedal system.

    I am actually working on a design for a tadpole velomobile using just that - two powered front wheels and a pedal driven rear. Louisiana law says a powered trike must have a roll cage, so if I have to go that route I might as well make it a velomobile.
  6. Will Snow

    Will Snow Member

    Wheel motors, is that hub motors?

    RC motors, I saw his video and you are right, that trike really goes. I remember the RC motor application but not sure what they are.

    The trike is still being shipped, after it gets here I'll be able to take a closer look being this is my first trike. still working it out. Motor under the seat, motor up front, wheel motors ???, will have to learn more and think about it for awhile.

    Velomobile, now that's interesting. What kind of body are you making? Hope we can see some pictures of it later.
  7. SimpleSimon

    SimpleSimon Active Member

    On the velomobile design, I am looking at resinated stretch fabric as being the lightest skin I could make. A basic bullet body with the front wheels outboard of the cabin, and a lucite type windscreen, open top. As I work the design up I may post some sketches, if I get to build it there will be pics.
  8. Will Snow

    Will Snow Member


    A covering that I know of that I thought would work good is stits ( I may have spelled that wrong) It's a covering we used on older fabric aircraft. It's good to work with, strong and will last for years if painted to proctect from UV. One plane had never been hangered and still checked in the green after 20 years. A special glue is used to attach it to the frame. When dry any wrinkle can easly be ironed out. It comes in standard and light weight material.
  9. Bobocop

    Bobocop Member

    Not sure a trailer with more SLA's will do you any good for distance. (depends how many batteries your going to put on the trailer)
    You will have more amps, but look at the extra weight you have to pull (trailer and batteries)
    A 12 Volt 12 Amp weighs about 10lbs, a 12v 18ah weighs 14lbs

    Motorcycle batteries wouldn't last more then a few runs (if your lucky)
    they are not meant to be fully discharged, they are made to start a motor only, (just as car batteries, they are not deep cycle)
    You need to use deep cycle batteries.

    Even thou a motorcycle battery or a UPS system battery raated 12v 12ah they are not the same as a 12v 12ah scooter battery.

    Oh, I would also go with the 36v (as SimpleSimon suggested) over the 24v anytime.
    Last edited: Dec 29, 2009
  10. Will Snow

    Will Snow Member


    I understand about the deepcycle and the 36v battery. I have been on a forum that is all electric and 36v and up is what they suggest. Several recommend 48v, I really don't want to go with that many volts. Some suggest higher power motors and other tell me they will drain too much power to get a good range. With what I am learning my thoughts so far are 36v as suggested and 600w motor. Many feel the hub motor is a good way to go and it probably is. I am still leaning toward using the chain drive as described by Simple Simon so I have some selection over gearing. In my area that is mostly flat, gearing is probably not that important and the hub motor may be a better choice. I am still going to give it some thought, just not sure yet.
  11. rearengine

    rearengine New Member

    Will ... Hub 36v 500 or 600 w motor... with free wheel ... peddle if you want to.. Less to go wrong... MHO Bill
  12. Will Snow

    Will Snow Member

    Hi Bill

    I have received a lot of information regarding this subject from a all electric forum called "Endless-sphere. Most have the same recommendation for reliable basic transportation as you suggested.

    I also am begining to think 500-600w will be what I end up with and maybe a hub motor. I am still thinking of using gearing like I did on the gas powered Tour Easy recumbent that I posted on this forum. While I agree it is not as simple to install and maybe not as quiet as a hub motor, it is a good feature to select a desired rpm at most (within reason) speeds. Should a hill come along, it is a must for me. For someone very good condition, it may not be a big issue, but for that reason alone, the chain gearing has the leading edge in my case.

    Still a little on the fence, need to think on it more. I do want to thank you for your input, simple, reliable is hard to beat and also draws me to your type of application.


  13. veloman

    veloman Member

    Go with the 36v motor. Charge time for your batteries will be faster than 24v. And battery capacity is not an issue since you can select a number of different ah designs. my 36v 12ah SLA weigh less than the 24v 17ah one I did last year. I'm getting better range on this 36v design too.

    36v will also draw less amps for the same power, improving efficiency and torque with the higher voltage. 24v is only really good for super cheap systems that require little power.
    Last edited: Mar 29, 2010
  14. Will Snow

    Will Snow Member

    You are probably right about the 36v system. I have my trike with a velo body kit on it finished. I have a 1000w motor and a controler that will handle 24,35,48v. I have everything together to mount as a center gear drive. I think it will be pretty neat, but because I am green at this I also have mounted a 35cc Subaru motor just in case my electrical drive fails while out on the road.

    I have been side tracked because of other responsibilites, so it maybe awhile before I install the electric drive.

  15. Tanaka40

    Tanaka40 Member

    Will, check out this website for motors, http://www.cyclone-tw.com/order-M.htm . They have systems for bents and other bikes. The DMV website is not clear, however California is one of the exceptions to the FEd 20 MPH rule. We are blessed with a generous 30 MPH and 1000 watts limit. http://www.dmv.ca.gov/pubs/vctop/d01/vc406.htm . I see the confusion and I approached a CHP on his interpretation. 30MPH is OK and if you have a gas engine too, you will fall into that nice gray area that exists in the law. Heck I have GEBE with the Tanaka PF-4000 that puts out 1.8 to 2.4 HP depending on which website you refer to.(and yes I live in Fresno county and the local PD doesn't bother me at all, as a matter of fact they wanted a ride !! ) PM if you want to talk about it.
  16. Will Snow

    Will Snow Member

    Tanaka 40

    That is good to hear about the california law and am glad you checked it out. I have been ridiing around the neighborhood using the gas motor and it is a real kick to ride. The red body draws a lot of attention and gives me somthing to talk about. I posted a picture of it on the powered trike section which you may like to see. I have the electric mid drive kit here in a box ready to install, just don't know when I'll get to it. I have seen the Cyclone system you refered me to. They look real neat but I already have this other one that I will use.

    I can not take much credit for this set up, I just put things on that other people made and like the way it turned out.

    What part of fresno county do you live in?