Hill Climber Challenge...photos?

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jawnn

New Member
Jan 26, 2010
9
0
0
port townsend wa
I need to see an electric bike that can climb an 18% grade with 350lbs and only 500 watts. More power requires more batteries.

It should have a 30-mile range minimum with hills. I think that a ‘cyclone’ motor with it’s planetary gears, and a 24” wheel rim on a 26” wheel connected by a timing belt will be the only chance.

But I want to make sure that it will work before I start building, I’m not sure that the motor will be geared down low enough to produce enough torque with out over heating.

I need some photos and info. like gear reduction ratios. Can it be done?
 
PaulFlorida

PaulFlorida

New Member
Dec 4, 2009
52
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central florida
With enough gear reduction, a baby could move a train. It can be done. You just wont go very fast. We had an old Suzuki KingQuad 280cc 15hp, and in low range 1st gear, we pulled 10"Diameter stumps out of the ground. It topped out at a fast walk/ jog in that gear.
 
professor

professor

New Member
Oct 14, 2009
500
1
0
Buffalo ny area
Jawnn, welcome to motorbicycling! When you find that 1/2 hp 30 mile range, 18 percent grade climber motor, be sure to post it here.
And when I find some Unobtainium bar stock I will also post it here!
 
J

jawnn

New Member
Jan 26, 2010
9
0
0
port townsend wa
RESULTS to investigation

well I found that it's not possible to use only 24 volts because of the Peukert exponent. and I got other tech info but I can't leave a link to it here. So your just going to have to google my blog:
"commutercycling" at the blogspot.....maybe some one else can drop a link ... or maybe tell me that it is OK.

professor said:
When you find that 1/2 hp 30 mile range, 18 percent grade climber motor, be sure to post it here.
Click to expand...
 
M

mabman

New Member
Oct 4, 2008
258
1
0
In the wind
Take in to account that a 500w motor will still burst to say 750w or even more when under the type of load you are talking about. The only way to satisfy your needs would be to run a higher voltage battery pack probably 72v or even more. Also as you surmise you will need to run the motor through a gear system of some sort or have one gear that is so low that you will not be able to reach your 30 mile range due to the lack of speed overland. Unfortunately having a shifting type system on a motor assist bicycle is not legal, not saying it isn't being done.

The battery is the key ingredient though. In order to get 30 miles of range if you pull that type of load/grade consistently you will need probably 40ah at least. And a 72v 40ah Li-Po type battery will set you back some serious coin and weigh alot, like close to 30 lbs. Electric motors tend to get pretty hot also when they are asked to do more than they are supposed to. You could get an Etek type motor though that has more hp that would be more reliable within your parameters but they are way over your 500w goal.

I think that the best bet for you would be to use a hybrid type of system? A 49cc 4 cycle gas motor, again skirting the legal issue by running through a gear system that provides for gear inches in the teens, and a geared hub motor with an 8ah battery for use around town and also some extra assistance as needed for the larger loads/steeper grades. Keep in mind that this will not go real fast up an 18% grade either with that type of load. But the weight of a gas engine will be less than the aforementioned battery pack and extend your range to as far as you have gas for.

Gas is not the devil. It is the oil companies that control it that are. Electric has issues along those lines also if you plug in to the grid.
 
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