Powering a device with an exercise bike?

[r896neo]

So, my keep fit mad wife has taken the notion that she would like to utilise some of her pedalling on her exercise bike and power something with it.

I have told her it's very inefficient and at best it might give her enough to run a radio or something.

So my thoughts so far are belt driven off bikes fly wheel connected to a DC motor on to a 12v motorcycle battery then into a 12v radio or maybe if i could get a cheap invertor run something off that.

but the specifics of this i need some help with. First, can any dc motor be used as a generator if so what wattage/ type of motor would be best? would i need a diode in there? how about a regulator?

Any advice most welcome, especailly advice consisting of things i can find in scrapyards because i'm not going to be spending much dough on her hair-brained scheme!

Cheers y'all

 

[^woody^]

Is she a member of the Viet-Cong?

 

[HERTS P&D]

Could you not fix it to the cooker, that way she can keep fit and look good for you, while cooking your dinner. Happy Days.

Andy

 

[r896neo]

Am i missing something with the VC remark? i don't get it?

Maybe its the 6 inches of snow here dulling my senses....

Any practical/ on topic replies also appreciated.

 

[Burnerman]

You'd be better looking out for a scrapper alternator as they come complete with voltage regulator and rectifier. All you need is a 12v battery and your lass will be the governments answer to future power generation if you can get the bike wheel to spin it somehow
John

 

[r896neo]

will an alternator off an old car for exapmle complete with the regulator etc work?

 

[Burnerman]

An alternator is a complete self contained power station. Connected to a 12v battery, it will happily charge it up so long as you can spin it!
Depending on the type, its worth looking at a wiring diagram as the unit needs 12v going in as an exciter current to produce 12v (at much higher current) going out.
Much more efficient than a dynamo too, which needs a separate voltage regulator. Back to the Joe Lucas days...Prince of Darkness!
John

 

[TicklyT]

The biggest problem with any setup would be the mechanical losses associated with gearing up the drive speed to, say, 1000 RPM or more to get any output from an alternator. Washing machines and tumble driers often use belt drives with about those sort of reduction ratios, so may be a useful source of drive train parts.

 

[r896neo]

yea the rpm required was why i hadn't gone down that route.

I have an old windscreen wiper motor from a truck that is a simple 12v dc armature motor. would that work in reverse as a generator?

 

[wreckedit]

Maybe its the 6 inches of snow here dulling my senses....

.

What about a snow shovel, then you would have to think about making any thing.