quandry-motor size

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tortuga0303
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quandry-motor size

Okay, Im building a commuter cycle, preferable hybrid human style, and have run in to the ol "wow wish I had that". I was looking at the LEM 130 motor... http://www.lemcoltd.com/lem_130.htm and am pretty much drueling. Problem is that I think this maybe larger than I need. I love the effieciency aspects, and hear that they are unparalleled. Basically in terms of performance I am looking at 35ish in the mph range, and hopefully 20 miles or so on a charge (thinking either NiMh or lithium polymer, depending on several factors).

Is this overkill? is there another comperable motor,

in smaller size that could give me this performance?

echuckj5
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Re: quandry-motor size

tortuga,

I like the motor. Except for the 150 rpm a volt. The common battery packs that seem to be the best are in the 36 to 48 volt range. Gear reduction issues at 5400 rpm at 36 volts is expensive and difficult. I am using a 2 stage reduction at 3000 rpm. What is the wheel size?

chuck

[b]AGM BATTERIES[/b]

chas_stevenson
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Re: quandry-motor size

tortuga,

I am looking at 35ish in the mph range, and hopefully 20 miles or so on a charge... Is this overkill?

35ish is very fast for a bicycle when most are designed to go about 25 MPH with a top speed of about 30 MPH. The brakes, tires, rims, and frame are not designed to handle that kind of speed especially when you add the extra weight of the motor and batteries.

As for the motor, well if you can get it to run for 20 miles on a charge you will be carrying so many batteries the frame will be overloaded. This motor sucks lots of AMPS!!!!! The gearing issue aside bikes aren't made for the kind of power this motor can produce. It would be one awesome bike but I wouldn't trust it to hold up long. I don't know if you have ever seen some one riding a bike when the frame decides to come apart but it's not a pretty site.

"Is this overkill?" I think so. "35ish?" Not with todays bikes.

BTW there is another motor which is better but hard to come by, the Etek.

MHO,
Chas S.
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tortuga0303
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Re: quandry-motor size

I understand what you are getting at especially with the battery power needed. I dont think I will have to much problem with frame stability, as I chose a older style shwin sloaping frame that is built like a tank. I am using Bomber downhill shocks for the front fork, and downhill racing wheels with disk brakes (in the front at least, havent figured out the back). The Etek seems a little large as well specs say up to 8 horsepower, which is huge (some 5.9 kw) again more than I think I need. Of course I can run it on lower power, however I understand that this lessens teh efficiency of the motor. Is there something more on the order of 2 - 3 horsepower out there with similar efficiency?

Wont catch me ridin dirty

chas_stevenson
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Re: quandry-motor size

tortuga,

I wish there were a 2 - 3 horsepower with similar efficiency but I don't know of one. I have had my best results using a 24-volt 400-watt motor running on 36-volts. You can get about 900-watts out of it. My current ride can do about 23 MPH for about 22 miles using 3 12-volt 12AH lead bricks. I am in the process of converting to the DeWalt 36-volt battery packs. I plan to be able to run 2 to 6 packs on my bike. I just bought 4 packs and 4 charges. I plan to build 2 racks which can hold 3 packs each and place them on either side of my bike rack. With all 6 packs I will have 36-volts @ 13.2AH. The lead weighed 30Lbs. and the DeWalt will weigh 15 Lbs. The DeWalt packs will remain in their stock cases and simply slide onto a special built slot with a connector. I also plan to build another bike using a 500 or 600 watt 24-volt motor and run it at 36 volts as well. Gearing becomes an even bigger problem because of increased RPM, but it can and has been done.

Chas S.
My Bicycle Pages

amp_head
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Re: quandry-motor size

Another option would be to use a powerpack motor http://powerpackmotors.com/ and a Currie drive system with the upgraded bearing from http://evdeals.com/. This is the option I leaning towards.
Another option is the Crystalite, X5 rear hub motor and matching controller.

Matt

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Re: quandry-motor size

Hi Tortuga,

Perhaps some research into motors used for Electrathons could help. A lot of these builders have done extensive research (with the data to back it up) on motors with peak efficiency for specific (similar) applications. I know there is quite a lot of information published about these races.

Just a thought.

Dave

MB-1-E
Electric - Bridgestone MB-1 Mountain Bike
Icon Photo of lighning striking Eiffel Tower Jun 3, 1902, taken by MG Loppe'

Dave B

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<a href="http://visforvoltage.org/book-page/996-mountain-bike-conversion-24v-3-4h... - Bridgestone MB-1 Mountain Bike</a>

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