Over 400 Watt Pedal Generator !

[CmeBREW]

Hello Friends,

   I just got 400 watts with my latest changes to my big pedal generator.(No Joking)

  I could do way more but the back tire starts to slip. I am VERY happy with my progression  so far-- so I thought I would share these ideas with those who like to get some excersize and make some decent usuable power for a smaller system.

This 400 watts is MAX temporary achieving power for about 10 seconds though. But it gives an idea of what it can do, especially with an easier 200-300 Watts sustained for,perhaps, 2-5 minutes, depending on a persons choice (and time factor)  of 'Workout'. (Not to mention level of strength and/or fitness)

Since this is in my Diary, this is just the first part of the development of my big flywheel Ped gen.  I am making some big changes to it in the days ahead and will do a second part that will have a Video of me pedaling to prove the power I am getting.(with 'live' Ammeter AND Voltmeter)

I hope to achieve over 500 Watts (Brief MAX) into a 24 volt battery system. (48v system would be even much more)

Don't laugh, this is only a first prototype made from a lot of wood to support things.

After I get the maximum design, I will make more supports from steel.

 

This is one of my brothers pedaling. I am about the same typical size. Please keep in mind I am Not an athlete-- but I am beginning to get in better shape.

(Sorry about the big photo but I can not figure out what I am doing wrong with posting JPG pictures here recently. I reduced it down to around 40K , but when I post it here, the software apparenly Blows it up to a giant,low-resolution picture??!  What am I doing wrong??)

I got MUCH more power for the same effort by switching from a 12v batt system, to a 24v batt system. Half the resistance.  However, I just made some more changes and DOUBLED the power achieved.  I was using a 40' long 16ga. extension cord for a line. (3 wires for the big 3-phase servo motor)

I cut the run wire in half and then doubled up the wire to make it twice as big as 16ga wire.  Boy did that make a difference!

Resistance is a big killer of power with ped gens.

I believe I know some of the Secret(s) now to getting the most efficient power transfer from a human to batteries. (even though I am still experimenting and no expert)

The WORST mistake is a small, high resistance (low amp/hp rating)motor. I am certain of that. (Or, Any high resistance motor)

I believe the Bigger the motor and the rated AMPS the better. (within the ped gen high rpm range)

Inotherwords, the bigger the neo-super magnets inside allowing for the bigger gauge wire inside, the less the resistance will be, which means much more power transfer esp for higher rpm ped gens.

So a BIG home made Axial flux alternator like that of a 10' Hawt, would be MOST excellent as long as it was wired with Big Ga. wire for high rpm. (perhaps 700-1000rpm max with a 24 or 48volt batt system)

It means you can achieve more power at a reletively high rpm with a higher voltage battery bank.  Speed is good in order to keep lowing resistance even lower and thus even more power for the same effort.

I also think a big flywheel is excellent also. The faster the better!(within safety margins though) I will talk about that factor next time along with body fatique.

There are a lot of factors to consider though. There will be much more in my next diary soon when I hopefully can do over 500 watts.

I also wanted to share about this really cool high resolution 10.2" TV/dvd to watch more than my big power hungry 27 inch Tv and dvd player which totals 170watts.  The little TV/dvd is only 20 Watts hooked directly to 12v battery system. (or,25 watts if you use the 120v adapter thru your power inverter)  I got it from Wallymart.com on-line along with an extra year extended warranty.  The picture up close is better than my Sharp 27" TV. (standard Tv is 740X480/ But this little screen is higher like 840X520)

With headphones the Doulby Stereo is really good also. The small speakers are OK.

So I can fairly easily get hours of lighting and (small)Tv/dvd pedaling on my big electric pedal generator especially on gloomy days when my solar panels are doing El' Zippo nothing, and my 6' windmill is motionless with no wind.  

Of course, it is still only 50-100 watt hours in a Half and hour (total) workout.

Or twice that if you want to work out for a whole hour. (which I don't)

But I am happy to get it, and more importantly good exercise for me to keep in shape.

Any questions I will try my best to answer.                          -Thanks.

 

[hiker]

kinda fun to see how much power you can create.......

nice ped gen...

i use exersize bikes to make my pedgens-real easy build.

hardly any loss due to friction..

heres a few radom shots of my  pedgens...my 110v pedgen uses no batts just straight 110v ac to the tv-stereo-floresent lights or whatever.................. :}

    http://www.otherpower.com/images/scimages/1236/stereo_test_motormill.MOV

[Flux]

This is like wind, you are gradually learning that matching the load is critical.

Alternator efficiency is everything here, not like the wind case where some resistance is beneficial.

Big motors are more efficient than small ones and this applies almost to the extreme where bearing and friction losses become significant so it probably sets the limit at about 10hp for best results.

Winding resistance needs to be very low and connecting cables should be so low as to be negligible. Iron loss and cogging will affect you to some extent but not as badly as for wind.

Yes the axial machines would be better if you choose a large and costly one with very high efficiency at 500W. I think a radial design with overlapped coils could get you there with less initial cost but the construction is not as easy.

Except for rectifier loss the system voltage doesn't matter, it's just that your motor is not efficient at 12v.

I personally don't see any virtue in the flywheel and a decent sized axial suitably chain geared would have more than enough inertia without adding flywheels. I would keep a chain drive rather than use a very large direct coupled axial as the speed will get you a far more efficient alternator at much reduced cost. The chain losses will be small as you are not aiming for a low output condition ( your low wind condition will occur at full load if you excuse the joke).

Try force commutated mosfet rectifiers for power factor correction and minimum volt drop if you want the ultimate at 12v, even a smallish alternator could get you in the 90% region for efficiency.

Flux

[Junkie]

Nice work there. Have you considered getting SPD pedals to improve YOUR efficiency ? I use them all the time when riding/racing they do improve your speed a bit, plus everyone gets to laugh when you forget to unclip and fall off ;-)

[Reno]

I think you just solved the child obesity problem. Connnect iPod, video games etc to your gadgets. If the kids want to play they have to pay.

[CmeBREW]

Thanks Hiker!

 Yes, for well over a year, your ped-gen experiements contributed the most to my interest. Very good work. I also appreciate everyone else's ped gen projects. Thanks for posting your videos or I probably would have not believed in those high numbers .  It was much more than everyone else on Youtube or anywhere. But seeing is believing! Thanks for experimenting with the higher voltages.(Less resistance and more speed and inertia)

I especially like the last one with the nice Axial alternator. It would be interesting to see the max and sustained 'Workout' watts into a 48v batt bank with that one. The batts 'clamp' the volts down so it might be a little less power than directly into lights or heating elements which allow the volts to be totally free.

It certainly makes me wonder about the big 120 volt battery bank system.

[CmeBREW]

Ha! Thats what I have always thought too. If I had kids I would teach (brain-wash) them that they have to EARN their lights, TV, and video games, etc.!

Of course, heating and air-conditioning is going TOO far!

[CmeBREW]

Thanks Junkie,

    That is certainly an entire different area to consider. Body fatique, the different muscles involved, and the cycle rotation, etc.

Your idea of the pedal straps might help utilize more leg muscles, but then again, I sorta like having those 'Mini-vactions'  of rest for some of my leg muscles during different parts of the cycle rotation. It is difficult to know which would be better.

I am not a Cyclist, so I really know little and can only speculate on things. This whole body fatique and 'workout' factor is interesting to me also.

I actually was thinking about making a whole body workout ped gen machine that works not only the legs but both arms cranking at the same time also. I can actually get a fairly easy 50 watts from each arm. (100 easy watts from both arms/ or probably 200 watts for a quick one-minute workout)

Right now I am getting a fairly easy 100 watts from the legs, so plus the 100 from the arms-- might just make an Awesome 200 watts average 20-30 min workout.

I mean actually including both arm cranks on the same pedaling machine and combine all the power in the big flywheel mechanically.

But I suspect it would actually detract quite a bit from the Max power from main leg pedaling cycle.  But for as a 'Workout machine' having the Legs and arms working out together would be very interesting I believe.

It would also probably be better to be sitting down in a chair pedaling for more comfort and leverage instead of sitting on the bicicle.  I am still working on the design.

Of course, the main purpose of a Ped-gen (in the developed contries) has to be more for excersize than for actual power production since 100-200 watt hours a day is only signifacant for a small system like I have. Its only a drop in the bucket for more serious RE-systems.  But I like doing both myself!

[CmeBREW]

Thanks for all the comments Flux,

Yes, I am very glad I am still learning in the RIGHT direction-- even if it is in a Zig-Zag pattern. Ha.

The big Servo I am using is rated at 5.5 Hp (22amps).  I was also thinking that something around 8-10 Hp might (possibly) be about the maximum giant size motor/generator for a human Ped-generator due to the (seemingly) signifacant friction loss in the BIG bearings.  But I would try a giant 7' diameter flywheel with a monster motor like that!

But I would STILL only try it for the higher voltage batt systems like 48-120vdc myself for the awesome inertia of spinning something that big 500-800rpm. (If possible)  

"I personally don't see any virtue in the flywheel and a decent sized axial suitably chain geared would have more than enough inertia without adding flywheels. I would keep a chain drive rather than use a very large direct coupled axial as the speed will get you a far more efficient alternator at much reduced cost."

This is interesting you would say that. I never got to go to 'Mechanical school' (Wish I could've!) , but it just seems to me that the big flywheel could make it more 'Mechanically efficient' and possible get 10-20 percent more power over-all.

The TRAIN example comes to my mind.  They say a Train like a hundred times (or whatever?) more Efficient at transporting things than a bunch of trucks.

Why? Yes there is far less air resistance and wheel resistance, but the massive weight in motion seems to play a big part also I would think.  Who knows?

In any case, it is interesting to try and I will give it a shot.  Some of the big changes I am doing now to it is, like you said, switching to a normal bicicle direct chain drive. I am also, moving up to a Bigger 4' diameter flywheel. (two screwed together equals about 55lbs/// Even thoug, I tend to think the diam size might mean more than just the weight)  The flywheel on it now is only 30". (25lbs not including the mount or spinning motor rotor)

Like you say, it will mean less drag and friction loss, which I think I am getting some from the big treaded (studed) tire in the back , since the tire studs go out at 45 degree angles.  I don't have a smooth tire bicycle to try.

Also , it would be reducing down from a Double stage gearing to only a single gearing, which might mean alittle more power too.

Anyway, I will keep trying and experimenting and post the results in my next Diary soon.

-Thanks for the extra help and ideas.

[CmeBREW]

Thought I better show this here in this posting - since I am now changing it to direct chain drive.

The picture here is the simple tire method which is still good, but was beginning to rub the tire down a little in only a week:

Someone might get an idea from it.  It simply is made from wood 2x4's and plywood supports for the bicycle. There are two short pieces of angle steel to hold the bicycle on, and the angle steel hits the bolt that hold the back wheel on in order to keep it firmly against the flywheel. I let some air out of the tire to screw it together, and then pumped up the tire with a footpump to make it 'locked-in' tight.

Today I did briefly hit 500 Watts with this simple set-up by pumping up the tire more.  I had to pedal much too fast though and the tire was slipping agian at 500watt. Of course, the tire may not last too long with this method.

I thought I better show it before I change it to the chain method.

(change note: there was another 10lb 30" plywood flywheel screwed to the Particle board flywheel. It is not shown in the photo)

 

[thirteen]

you might try and put a tire on the flywheel to get rubber to rubber. I work with several conveyors that are tire to tire. Just a idea.

[boB]

FWIW, we found that wind MPPT methods work well for excersize bicycles to help

with the varying speeds.

boB

[s4w2099]

Another thing that might help you is to use a street tire in the back instead of mountain bike tires.

[hiker]

fun stuff.......

that 12" dual rotor alt--blew up when i was trying to lite up a 28? volt 400w aircraft lite--mags went flyin..came close to getting there just before it

went ballestic...:{ [ceramic powered-big coils-8&6 setup-#14wire -wired in star}...

it later took a flyin leap off the back of my motorhome-when i was tryin to put it on the post. wind caught the tail and blew it off of the roof..it never did get a

chance to fly..:{

[CmeBREW]

Well, it's been a month of testing and changing gear ratios and batt system voltages, and Flux was right again. (Dagnabit!)

I can see now I was simply trading SPEED for TORQUE.  And the 12-speed bicycle actually had very good Speed AND Torque when pedaling all out real fast (WAY too fast)-- but this is actually worthless anyway since you can't keep it up for long.  The big flywheel only helps a little bit to even out the pedal rotation some.  (My 'Train in motion' theory proved to be BS! --I took it way up to around 700rpm/100v)

I switched to an Exercise bike like Hiker said And finally chose a nice, easy 75Watt, slow pedal which I can do very easily while watching my small 20Watt TV/dvd player for an hour or two. I also found that laying back in a chair is much more comfortable and easy for slowly pedaling 20-40min.  It is not even a workout at all.

I can also do around 100watts or so, but it is more of a workout after 5-15 min.(Heart actually starts beating faster)

Here I am doing initial testing on the new set-up.  It is about 10ft long.

Even though the final results were somewhat discouraging, since I had thought I had solved the world's energy crisis,,,(hoped for an easy 200watts-BigHa) , I am still quite happy with the results.

I have to finish the mounting, but I will post a follow-up diary and show a video as soon as my Bro's wife gets back from a Florida vacation with his Digital camera. (which does little movies)

-Thanks.

[Norm]

Right now I am getting a fairly easy 100 watts from the legs, so plus the 100 from the arms-- might just make an Awesome 200 watts average 20-30 min workout.
Your quote CmeBREW....
Yeah I've got that with the full body workout (levers connected to the pedals) that I got from
K-Mart a couple of years ago.....had it working for foot pedaling by putting a stool behind it ....
only then I can't reach the hand part .
Kept thinking about how I could hook it up when I first got it (flywheel in place of a bike wheel)
at an 1:8 ratio so ....I put a matching pedal sprocket on the left hand side that drives a small bike
wheel (direct ....no coaster brake ) under the seat then friction wheel drive to the EMC .
BTW finally managed to get back on otherpower this morning.....been a couple years or more....
eversince they changed over.....Hooray.....or maybe not ?  LOL.
Norm.

[bob golding]

don't do too much cycling any more. too dangerous on these narrow roads around here. however i have friends who are keep cyclists and they all swear by recliners. i see you are half way there already. think i saw something somewhere where you had a recliner and also used your arms operating levers that you pull and push at the same time. bit like a rowing machine but vertical if you see what i mean.