12V DC Motor Harbor Freight

ZnsaneRyder

New Member
Nov 21, 2008
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FLORIDA
I wanted to let you electric guys know of a 12V motor to use for some electric bicycles!

http://www.harborfreightusa.com/usa...oryName=SHOP EQUIPMENT&SubCategoryName=Motors

It's only available in the store, not online BTW.

It's a 5/8" keyed shaft, so it would be compatible with many sprockets.

The motor is under-rated for sure. It's industrial-grade, and meant for continuous duty, so it should not overheat if used for long periods at high power.

It's HUGE, and it's rated at 250W, but the math of 12V x 28A = 336W. Most 12V stuff can take 14-15V, so this motor has real potential for some power. I plan on using this motor, but want to try 24V max, and make a controller, so that over 1000W will be possible in short bursts, and would be great for a hybrid setup.

Just thought I'd bring this to light in the electric bicycle forum section!

Crazy Riding,
ZnsaneRyder
 

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eDJ

Member
Jul 8, 2008
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Wayne National Forest
Did you say hybrid ?

I've got one on the drawing board and mentioned it in another thread here (laws Ohio)
just today.

I've looked at that motor at my closest HF every time I've been in there. Are you thinking
of friction driving the front wheel like Deacon's set up or setting up a chain drive ?

I'm in Ohio where our laws and BMV clerks make it nearly impossible to get one of these
bikes leagal & licensed to use on the road.

I'm wanting to mate a auto alternator with internal voltage regulator to a small motor to
use as an onboard generator to charge the batteries. I'd like to be able to run it while
running on the electric motor all while under way. Possibly use a small string trimmer motor
to turn the alternator to start with. But I may be faced with having to park the bike while
the generator recharges the battery.

You may be with more understanding of electrical matters than I. But, what do you think
of such a set up ?
 

ZnsaneRyder

New Member
Nov 21, 2008
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Did you say hybrid ?
Sure did! The ultimate goal is both gas & electric motors for driving the wheels.

I would NOT use a friction drive, as it wastes power, is unbalanced, and with electric, waste is bad. I mentioned the 5/8" shaft because it's compatible with chain sprockets and also some trike freewheels that are made for 5/8" shaft.

For your idea with the car 12V alternator.........it would work with a strong enough gas engine, but you would also need an onboard charger to plug into an 120VAC outlet so you don't have to run the engine when parked. I plan that with my hybrid. I know there's free power outlets in the city if you look around.

I believe the HF 12V DC motor has Permanent Magnets, so there's even a possibility of using the motor as a generator, or even for regenerative braking.

The main issue I see is carrying the batteries. They would most likely outweigh a gas motor, unless going with expensive LiPo or Li-Ion batteries. I originally planned on Lead-Acid until $$$ allows for better batteries. I want to mount the batteries ON the bike, and NOT use a trailer, as trailers get WAY too much attention, because the average dummy can't comprehend the thought of a bicycle pulling a trailer, and would rather avoid the hassle.

The advantage of the big 12V motor, is not needing 36V or 48V worth of batteries to make it work.
 

eDJ

Member
Jul 8, 2008
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Wayne National Forest
I was wondering if the alternator with a built in voltage regulator could be set up to
recharge while under way. The motor that powers the alternator may have to run thru
a sprocket chain set up to step up the speed of the alternator to get the constant
output. A flywheel may even be needed to keep up the inertia.

Deacon's electric DIY bike project went thru a revision where he had a chain drive front
sprocket.

I've looked at some plans for hybrid electric cars, such as plans offered by Mother Earth
News magazine. The controller box and a chopper were the components that put me off
for inertial brake/recharging etc. I don't have quite that much electrical know how.

Below is a platform I like the concept of. I'd remove the motor as you see it and install
the battery there and the generator above in the front of the wooden freight bed. The HF
electric motor could be set up over the front wheel and run thru a chain driven
sprocket where it would provide a 20 mph speed. (legal limit in Ohio)
 

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svc

New Member
Jan 10, 2009
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sydney australia
heres an old link i found laying around. He uses a starter motor from a car and a very simple but clever circuit to switch between off/12v/24v for recharging. It is explained there better than i can. It should be simple enough to add a few more voltage settings (If you have more batteries). Didn't you skip a few generations of batteries in your considerations? I see NiCad and Ni MH as the 'value bet' for price to power/weight. (if you semi scavenge (surplus store's box lots on Ebay))


Browser Warning

for anyone who doesn't wanna click strange links heres the guts of it. I do recommend it though, the guy knows his stuff.

'' Two batteries are used with a double pole, double throw (DPDT) switch wired to configure the batteries in either series or parallel. (A further switch acts as an on/off control.) Let’s assume that they’re 12V batteries. When the batteries are configured in series, 24V is available at the motor. When the batteries are switched to parallel, 12V is available at the motor.

The natural speed of the bike in 24V mode might be 20 km/h, but in 12V mode it’s more likely to be just a quick walking pace. So when you switch to 12V mode when rolling down a hill, the motor tries to pull you back to that slow speed. As a result, regen braking is very effective – in fact, in this example, the regen will work at all speeds down to a walking pace... at which point the 12V batteries then start driving the bike forward.''

John
 

jasonh

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Jun 23, 2008
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Longmont, CO
How much does that motor cost?

I'd love to build an e-bike, but I'm afraid the wife would veto that idea since I have a decent amount of money put into my gas bike already...
 

ZnsaneRyder

New Member
Nov 21, 2008
163
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FLORIDA
I still am considering this motor sure for sure. However, there's a bigger issue, and that's batteries.

Any of you electric bicycle pioneers know where to get some good batteries?