Exercise bike conversion with $9.99 2.25 HP treadmill motor

[PHinker]

I order one of the 9.99 2.25 HP 260vdc motors from surplus.com.  This was posted by 'The Professor' in this post:

http://www.fieldlines.com/story/2005/3/1/1960/91893

I had been looking for something like this for a while since I had an old recumbent exercise bike which was just gathering dust in the corner.  Pulling the skins off the bike I found the following:

You can see that the crank drives an aluminum flywheel.  You can just see the row of ceramic magnets which can be moved closer to the flywheel to adjust the 'magnetic resistance'.  I stopped using this bike originally because there wasn't enough resistance and the high RPMs was hard on my knees.  You can also see that the belt is one of those mini-v belts and the $9.99 motor has a similar pulley head so this made the project easy.

Here I've taken off the flywheel and mounted the PM motor in its place.

I have a set of Ryobi 18v cordless tools.  One of the pieces in the package was a flashlight which never worked very well.  I cut off the flashlight head so I had a handy battery holder.

Hooking up my multi-meter and turning the cranks by hand I see 20+VDC open voltage.  Shorting the leads makes it hard but not impossible to turn.  The large pulley is just under 11" in diameter and the motor pulley is just under 1.5" so the gearing ratio is just over 7:1.

The charger for these 18v batteries must have some circuitry which prevents them from working on weak batteries.  I had one battery pack which had dropped to under 11v and the charger wouldn't charge it.  I hooked it up to this unit and cranked it by hand for about 10 minutes.  The battery read 14.8 vdc so I put it in the charger and the charger recognized and started charging it.  The battery may well be dead but I have a small hope that it will recover.

[ghurd]

Looks good!

I can't find a belt to mesh with the existing motor pulley.

If yours fits right, what brand is it?

Is it the same as a 6 groove compressor belt?

(I can't find one local to see, but there was one in a catalog "6 Groove Compressor Belt".  Thats all it said except lengths.)

G-

[PHinker]

There's a label on the belt that says : CONTITECH 430 J6

It is a 6 ridge/5 groove belt that seems to fit the pulley on the motor perfectly.

[hiker]

a lot of those old nicad batts can be brouht back to life by --just zapping them with

high volts for a few secounds--use a auto batt or batt, charger...it breaks up the crud that builds up inside of them--or the memory barrier...

[Chagrin]

Just remember that these rechargables can explode. Take care as to how much power you put into them.

[Norm]

  Yeah I found that out after I threw one away

my youngest son tells me that little trick!

   .....he walked into a store...there is a bin

where you can deposit these old batteries for

cordless drills...he asked if he could have some

they were puzzled why he would want them...but

they said 'Sure...I guess....' he got a few...

and they came back to life with this little trick

....I don't think the bin is there anymore....

but it was good while it lasted!

  I still use the other battery that came with this drill.

   In the meantime I got another drill with 2 batteries same size same type recepticle same 14.4 volts not a smart charger those batteries run down...put them in the Smart charger and the light is green ...I have to charge these batteries on the dumb charger that came with them and overnight??? go figure!

            Puzzled  ( :>)Norm!      

[ghurd]

Found their site. But no product number.

(Their site leaves much to be desired)

The parts store guys can find it now I'm sure.

Thanks.

G-

[Norm]

   Wish I'd have thought about it the belt you

were talking about was hanging right over the workbench right in front of your eyes and like

PH says ...its a 6ridge/5groove belt that fits

it perfectly it's almost new just stretched too

much to work on the snow thrower.  I tried it on

that the generator pulley and the 6-1/4 inch diameter pulley and stretched tight ...9.5 inches center to center.

   New one cost about $13 give me your mailing address if you want it and you can have it for the price of envelope and postage.

                  ( :>) Norm.

[PHinker]

I played with this setup a little today and have some rough numbers.  Cranking the pedals by hand and charging an 18 volt battery I see around 3 amps into the battery and the voltage of the battery right at 19 volts.  Estimated RPMs (by counting them for a minute) were around 100 which makes the generator turning at about 710-720 RPM.  A little higher gear ratio would be nice because the cranks turn too easily even when turning by hand.  Would be much too easy pedaling with legs and the turnover would be too high.

I might tear this down and set it up to drive off the rear wheel of my mountain bike.  Might also be interesting to make a set of 6' blades for it and put it into the wind to see how it does.

Paul

[Norm]

  On second thought that might not be long enough to clear the pedals...and according to

PH it's not a high enough ratio anyway.

                     ( :>) Norm.

[ghurd]

It fits the treadmill motor I left with the big old flywheel.

So you will need it there!

And I got 12v no load easy by hand and slow.

And I think I need about 48~60" for my current plan.

But it may get wind blades instead. (no belt)

Norm,

the mini conversion numbers I had are bad.

I think there was a bad connection.

With a blade in the wind today I got 'much' better numbers!

G-

[ghurd]

See Paul's post a couple down.

It was turning 'too' easy.

G-

[ghurd]

Why not put the bike back like it was,

and drive the lower mounted genny from the flywheel?

G-

[Norm]

Why not put the bike back like it was,

and drive the lower mounted genny from the flywheel?

  I've got an old serpentine belt from the Astrovan

Think I'll use it and make a larger crank-pulley

from particle board about 18 inches diameter?

...ought to be a pretty good ratio?

Or larger/smaller?

of course with a mountain bike he could go like

Dr.Butcher....

http://users.erols.com/mshaver/bikegen.htm

and he has a lot of useful information and where

I got the particle board idea

here

http://www.los-gatos.ca.us/davidbu/pedgen.html

...but I don't think I'd need that big of a front pulley...

('tho it might work out pretty good on one of my

heater blower motors)

              Fun!

               ( :>) Norm.

 

[cdg378]

I have some 8 year old ryobi 18 volt batteries that are like that, when I put them in the charger they won't charge.

What I have found is this, plug the charger in, you will see both yellow and green lights come on which means the batteries are no good. Unplug the charger and very quickly replug just when the yellow light goes out...you may have to repeat this 5 10 or 20 times to get it right but pulsing it like that makes the charger start and the red light will turn on and start charging...works everytime.

Basically you are glitching the charger, just hold the plug up to the wall socket but don't plug it all the way in, this will allow you to be faster between glitches, takes some practice but it works on those ryobi chargers.

[PHinker]

Thanks, cdg378, putting the bad battery on my bike driven charger straightened the battery out enough for the charger to get a bite on it.  I'll remember your trick for the future, though.

Paul

[Norm]

 The way I'm going to have it set up will be about 20:1 ratio...like this





I think it might work like this, the crank would be direct drive, like a tricycle wheel.

The tire is actually driving the belt, the lawnmower wheel just keeps the belt tight around

the generator pulley.

              Fun!

            ( :>) Norm.

[PHinker]

That should get you some reasonable power, Norm.  You might need an idler though since I'm seeing a fair amount of slippage in that mini-v belt once you get up to 80-100 watts.

Paul

[Norm]

  No problem with tightening the belt....as

you can probably see in this pic...

http://www.fieldlines.com/story/2005/3/23/225230/317

  ...the arm that is attached to the wheel bolt

swings down and you can adjust the tension

...but since that picture...just a temporary

set up...now I have a new wheel with ball bearings

and some square tubing and it'll look

about like your exersize bike frame except the

wheel will be in place of your crank pulley.

   I've got some real exciting future plans

involving this little motor...wish I had about a

dozen of them!

              Havin' so much fun I can hardly stand it!

                     ( :>) Norm.

 

[PHinker]

Great looking setup, Norm!

These are nice little motors all right.  If I ever get the remodeling of my house done it would be great to use this motor on a human-electric hybrid trike idea I've been kicking around in my head for a couple years.

Paul

[Norm]

  That was the wood one...wait till I get the new

improved model. I had some pieces of square tubing and decided to relearn how to weld again,

at one time I had a 220v ...200 amp welder, my

youngest son traded me the use of his 110v mig

welder ...then he borrowed it temporarily to use

at his work.

   Well that left me with my 110v 50amp. welder

using 3/64 rod Gad!...that sure is hard getting

an arc struck but once started ...I don't have

to worry about deep penetration...(HOLES that is}

   See that's my problem I used to be in maintainence and I'm used to welding with DC and

like 1/2 steel!

   Well any;how I finally got the hang of welding

with the little welder and the project is looking

pretty good.

   would be great to use this motor on a human-electric hybrid trike idea

    Yeah me too...like charge up the battery

run out to the store with the wife...about 4

miles out....charge up the battery while waiting

for wife to get all her shopping done.

    ...and best of all you wouldn't have to stop on the way back for $2.09 per gallon gas!

                Have Fun!

             ( :>) Norm.

1    

[coldspot]

Yes, Ni-Cads can explode, (I've seen a car hood blow up, from down/allmost closed to fully open, from a 7.2VDC pack overcharged off 12 VDC car battery).

 I've been using a RC Race Car battery charger "Tekin" since the late 80's to charge all kinds of Ni-Cads from cordless phones to Video Camera packs. This unit will peak charge them then trickle them to full. All off a 12 VDC source.