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gas to 300 watt electric motor
By hiker, Section Homebrewed Electricity Posted on Tue Sep 28th, 2004 at 04:42:26 AM MST
moped

picked up a moped 49cc 1980 year---102sp pugougt--have a 300 watt electric motor to
replaces---the gas motor--would 300 watts --get me at least 15 mhp--on the flat.
would overhaul the motor but some one screwed the points-bent out of shape !!
it's not a pm motor??

gas to 300 watt electric motor | 7 comments (7 topical, 0 editorial)

Re: gas to 300 watt electric motor (3.00 / 0) (#1)
by finnsawyer on Tue Sep 28th, 2004 at 08:23:01 AM MST
(User Info)

300 watts is .4 horsepower or 221 lb-ft/sec. 15 mph is 22 ft/sec so you could in theory maintain a maximum force of 10 pounds on the bike. Is this enough to overcome wind and friction losses at 15 mph? It might be.
GeoM

Re: gas to 300 watt electric motor (3.00 / 0) (#2)
by troy on Tue Sep 28th, 2004 at 09:29:50 AM MST
(User Info)

The original motor probably produced a few horsepower. Your electric is a fraction of a horsepower. Better have some big batteries if you want much range, and some pedals to allow some human input as well to get any speed. I think it would be slow slow slow. What voltage is your motor?

Best regards,

troy

Re: gas to 300 watt electric motor (3.00 / 0) (#3)
by hydrosun on Tue Sep 28th, 2004 at 10:59:36 AM MST
(User Info)

I've been looking into the idea of human powered transportation with assist for awhile. I go everywhere by bicycle and wanted to extend my range and have more energy for working when I got somewhere. I tried a recumbent bike but found it harder to get up steep hills because you can't stand on the pedals. I added a small electric assist but my battery pack was heavy to carry on the flats but did make it easier to get up hills, unless it was so steep that the front wheel came off the ground. Maybe I could have redesigned the weight distribution. Instead I went back to the drawing board to see if I could reduce the amount of energy needed to move. At 20 mph over 80% of the energy is needed to overcome air resistance. So I googled and found out about aerodynamic fairings for bikes. I put one on the recumbent but because it was too far forward the air went around it and still hit my body. It helped some. So then I put a fairing on my lightweight 20 year old road bike. By crouching behind this small 20 by 20 bubble I could increase my speed by one or two gears. And use it like a sail when going with the wind. And only adding 1 1/2 pounds to carry up hills. So it definately is worthwile. I just ordered a larger fairing from Zzipper.com that can be used with a full body stocking to really cut down on aerodynamic drag, but still be very light weight. I looked at one web site that said the key to making electric bike practical ( higher speeds and longer range) was to reduce the amount of energy needed so that the human component can make a bigger percentage of the contribution to propulsion. With an lightweigt aerodynamic bike that could hold 60 pounds of lead acid batteries they claimed a 25mph 50 mile range. And adding more batteries could extend the range to 100miles. Alightly larger motor could push the speed to 30-35 mph, but at a cost in the range. Most electric bikes seem to be limited to 20 mph for 20 miles before the batteries become to heavy to be practical.
I also looked into having a motor, electrical or gas powered. on an attached trailer for when I needed to carry a heavy load or increased speed and range.
So far I 've used my wifes currie electric bike to pull and old not aerodynamic trailer to haul recyclables 10 miles and back. I added a partial teardrop fairing to the bike and put in a better nimh battery pack. It made it a breeze to pull the heavy load up hills and ride into the wind on the way home. I think if the trailer was more aerodynamic I could really extent the range, befor I'd have to add more batteries.
So I think alternative transportion is like alterntive energy energy in the home. It's very important to first reduce the amount of energy neededto do something. In the home it's compact flouresent lights and efficient appliances. On the road it's reducing weight and aerodynamic drag. Or on both reducing the need for light by windows or on the road by being independent and stayiing home. In both cases being efficient really makes it practical and more affordable to use alternatives.
Chris

Re: gas to 300 watt electric motor (3.00 / 0) (#4)
by ghurd on Tue Sep 28th, 2004 at 12:22:19 PM MST
(User Info)

Know a kid with a "500w" scooter. 36v 9ah battery bank. Guessing 10~12 mph on level ground.
Brand new.
He gets 1.5 miles at good speed, about another mile before it is dead.
The owners manual claims many more miles.

G-

Re: gas to 300 watt electric motor (3.00 / 0) (#6)
by ghurd on Tue Sep 28th, 2004 at 05:08:56 PM MST
(User Info)

The kid is here now. I have to take him and his scooter home. Dead batteries. Daughter's boy friend...

[ Parent ]

Re: gas to 300 watt electric motor (3.00 / 0) (#5)
by fuzz on Tue Sep 28th, 2004 at 12:45:50 PM MST
(User Info)

300 real Watts must bring your bicycle up to 30Km/h or 18.7 Mph, however the efficiency of most electric motors are terrible to give you a example:
Last year I equipped my old bicycle with a 36V 500 W electric motor, the maximum speed I achieved
was 31 Km/h , which bring the total efficiency to 60 %.

Some useful links about this subject:
http://www.users.globalnet.co.uk/~pattle/nacc/arc0186.htm
http://www.bicycle-power.com/electric.html

or take a look here: http://www.xs4all.nl/~janfreak/fiets.html

It's in Dutch but with the formula's you can calculate your speed or needed power.

fuzz

Re: gas to 300 watt electric motor (3.00 / 0) (#7)
by Tommy L on Tue Sep 28th, 2004 at 11:55:12 PM MST
(User Info)

Hi !

Take i look at this http://www.austinev.org/evalbum/ maybe you can get any idea from it.

/ Tommy L / Sweden

[ Parent ]

gas to 300 watt electric motor | 7 comments (7 topical, 0 editorial)

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