Alternative power...Exercise Bike

[Jamie]

OK....I have been kicking this idea around for a bit, but haven't found exactly what I'm looking for on the interweb. I'd like to take an exercise bike we have, add an automotive alternator or two to it, and charge a deep cycle battery or two for use at our cabin in Vermont. What I need is a list of additional components and a proper "how-to" wiring diagram to pull this off successfully. Any help would be greatly appreciated.

What I have at the moment:

1 old exercise bike with rubber covered front wheel

2 mid 80s GM alternators (i believe these to have the internal voltage regulators)

Plenty of scrap metal, hardware to mount the alternators to the bike, and quite a bit of wire also, various gauges.

1 deep cycle marine battery...I'm planning on purchasing another.


The end goal is to be able to attach an inverter to run small household items for short intervals, and also to power some 12 volt DC lighting that I'm looking at.

 

[Climbnsink]

The professor would be proud.

 

[Jamie]

There's a secondary reason for the bike idea. Between my girlfriend and I we have 5 kids, all below the age of 12. When it's raining or snowing we usually stick to the cabin. This may prevent them from running around in circles, screaming, with their underwear on their heads and instead create a usable resource that kind of fun for them too.

 

[Fixxah]

Why not set up some gerbil wheels? Barney breeds them.

Are you sure you wouldn't rather use solar to charge the batteries? Those old exercise bikes weren't very comfortable from what I remember. Kudos for the ingenuity though.

 

[Jamie]

I'm trying to be cheap, plus the panels can be damaged while we're not there. I have no desire to take a tumble off the steep metal roof either. I also don't want to buy all the associated gear to properly run the solar set-up right now.

This bike has a nice wide padded seat for my fat ass. Super comfy.

 

[Brian5582]

Sounds like a good plan... well except for the wild kids pedaling the bike part lol. I predict the fun of that would wear off very quickly for them but I may be wrong.

 

[Coyote33]

http://training.fitness.com/home/generate-electricity-bicycle-29830.html

http://training.fitness.com/home/generate-electricity-bicycle-29830.html

http://www.moonbattery.com/archives/2009/04/welcome_to_gill.html

http://www.reliableplant.com/Read/10732/what-can-us-plant-leaders-learn-from-'gilligan's-isl'
http://ecomodder.com/forum/showthread.php/using-stationary-bike-make-electricity-4155.html

I always imagined an entire gym full of bikes, rowers, treadmills, all hooked up like a turn of the century mill with big belts to one big dynamo, so they could all contribute to the power.

 

[Coyote33]

http://www.sfgate.com/cgi-bin/article.cgi?f=/c/a/2008/08/22/HOKO11469A.DTL

http://www.freerepublic.com/focus/f-news/1871516/posts

http://training.fitness.com/home/generate-electricity-bicycle-29830.html

http://training.fitness.com/home/generate-electricity-bicycle-29830.html

http://www.moonbattery.com/archives/2009/04/welcome_to_gill.html

http://www.reliableplant.com/Read/10732/what-can-us-plant-leaders-learn-from-'gilligan's-isl'
http://ecomodder.com/forum/showthread.php/using-stationary-bike-make-electricity-4155.html

I always imagined an entire gym full of bikes, rowers, treadmills, all hooked up like a turn of the century mill with big belts to one big dynamo, so they could all contribute to the power.


Two new links:
http://www.los-gatos.ca.us/davidbu/pedgen/genesee_genny.html
http://www.sfgate.com/cgi-bin/article.cgi?f=/c/a/2008/08/22/HOKO11469A.DTL

bonus:
http://arvadahoundz.com/sparkys_southwestern_colorado_trip.htm

 

[Climbnsink]

I always imagined an entire gym full of bikes, rowers, treadmills, all hooked up like a turn of the century mill with big belts to one big dynamo, so they could all contribute to the power.

You just described O's energy and health plans.

 

[BenDover]

Cheaper than dirt has a mil surp radio generator in the last catalog for about 100 bucks or so.

 

[BruceW]

I had a similar idea, and Ive been looking into it for a little wile (2-3 weeks now)
Ive read a few articles stating that Auto Alternators dont work very well. Something about needing the Very high RPMs to produce power the power you would expect from them..
I'm still looking into it, and learning, so dont hold me to that.

 

[BenDover]

Here's the thing I saw:

http://www.cheaperthandirt.com/MIL2132-1.html

Looks like it folds into a backpack. 6.3V @ 2 amps = 12.6 watts

 

[n1zfg]

From what you described, mechanically, one of two things come to mind:
Direct connection: Attach another rubber covered wheel to the alternator shaft and build a hinged mount that allows you to push (or pull) the two wheels together with the aid of a spring.
Belt connection: Find a belt that won't likely fall off the bike wheel (if it looks like a tire, a flat belt is probably a good bet). Otherwise you get to machine the outside of the bike wheel to accommodate the belt. Mount the alternator in the same way as in the direct connection, and get a compatible pulley for the alternator.

Electrically, things could get complicated. The trick is that most battery chargers like to charge systems with as many watts as possible until you are up fully charged. In general, this kind of project could probably get you published in something like Make Magazine

About a dozen years ago, I had the privilege of working on a project involving a club grade exercise bike and got to take apart one that used an alternator and 250W resistor to provide the user resistance. Unfortunately, I don't remember who's bike it was. It did require the user to "start pedaling" for so many seconds before the display would come to life, which is a good clue that the bike is ripe for modification into a human powered generator set.

 

[radioman]

It will work all right but just remember that the average adult human produces about 1/4 horse power! Ouch!! So, your whole family is good for about 1 horse power. Those of you with generators know what a 1 hp generator will do. All but nothing. You can power a bulb or two or after pedaling for a wile charging your battery and continuing while the TV is on you could power a small LCD TV to watch a movie. Yes it will work but don't expect a whole lot.

 

[BenDover]

I bet a regular pedal bike on a trainer would make a good mechanical starting point. Something like this:

The driven shaft is moving very fast due to the large ratio of bike tire to driven wheel diameter....i bet you could directly drive an alternator (might be too fast).

 

[Titan]

Don't forget that there's no free lunch.

Exercise aimed at creating electricity rather than other productive pursuits, also burns calories and increases your requirements for nutrition.

A solar panel setup, although initially pricey, will be effort-free electricity when you need it most (assuming the sun isn't obliterated by a nuclear cloud).

 

[cockpitbob]

To elaborate on what Radioman said, with your legs you can't put out more than about 200W for any period of time. A 60A car generator is good for 800W, so you only need one. Personally I would get a small motorcycle generator, or better yet, that Cheaper Than Dirt unit looks great. It's only 60W, but that will top off a car battery (in a few hours of cranking).

 

[ACfarmer]

If you go with the belt drive system, include a belt tensioner in the system. I like the previous poster's recommendation on the flat belt so you could use a tensioner from a car's serpentine drive. You might also want to look at the wheel:alternator ratio and determine the rpm at the alternator so see the expected output. If you're in the market for another battery, you might want to look at the gel cell batteries (similar cost to the deep marine type) as they tend to last a bit longer with the repeated draining/charging cycles.

 

[Nuke8401]

I made a "camp charger" from a GM alternator and a 5 hp B&S engine. The wiring is simple if using a GM "one wire" alternator. Easy to identify as they have only one electrical connection meaning they have an internal regulator. Just connect a 10 ga wire from the alternator terminal to the + battery post and a wire from the alternator case to the negative post. You could get fancy and add a volt meter and or an amp meter. One word of warning, the alternator must be connected to a battery with some usable voltage BEFORE spinning the alternator or the regulator will toasted in short order. Don't ask me how I know this. I would guess that you would need a pulley on the bike that would be close to the size of the pulley of the alternator, if the bike pulley were the size of the tire it would be way hard to pedal the bike me thinks.

 

[Nuke8401]

Better yet check this link out. http://www.theepicenter.com/tow02077.html

 

[guywithglasses]

Here's an alternator that doesn't require high RPM to produce power:
http://www.windbluepower.com/Permanent_Magnet_Alternator_Wind_Blue_Low_Wind_p/dc-540.htm

 

[cstockwell]

Here are some posts on the same info on another site and I have posted my exercise bike experiment on that site as well with a couple of photos.

http://www.survivalistboards.com/showthread.php?t=60422

 

[green_metalflake]

Why use an alternator vs. a DC motor?

 

[cstockwell]

Why use an alternator vs. a DC motor?

I personally would not use an alternator as it requires much higher rpm and is only putting out a regulated 14 volts. A small dc motor can use lower rpm and higher volts. I think many think a used (free) alternator is a good choice and easily replaced with other free ones that can be salvaged just about anywhere. If you are looking at an exercise bike that will take a great deal of manpower to produce a STEADY charging then you want a lower rpm motor. On my setup I can keep a moderate steady pedaling that you would do during a normal bike ride and still produce 14-16 volts. In order to reach the full 24v you need to pedal your @ss off and that can not be sustained. Your motor choice is also important depending on your type of setup. Windmills are better served having a brushless motor or even home made generators made from lawnmower engines. So I guess a good reason for the alternator is cheap and designed for constant high rpm use.

 

[green_metalflake]

I personally would not use an alternator as it requires much higher rpm and is only putting out a regulated 14 volts. A small dc motor can use lower rpm and higher volts.

I seem to have the best luck at coming up with DC motors either from treadmills or Razor scooters. The tech can be either high or low. Amazing what can actually work. That's an early 60's VW generator, not alternator, at the bottom right of the pic -

 

[green_metalflake]

Last year I looked at many different exercise bikes and finally found a good one free on craigslist. There are several varieties but the one that seems to be the easiest to get going has a solid iron flywheel. Resistance is via a band that tightens up to increase the load. Amazingly, these are called friction-band bikes. That could narrow down your search. It took me awhile to get to that point.

The FB types all look more or less like the one below and weigh 60-70 lbs. The flywheel is grooved also which is convenient. Linked belts sold on woodworking sites (Grizzly) seem to fit the groove close enough to work without other mods. The tab on each link is the ~same width as the groove and lays flat along the outside of the flywheel.