Bicycle generated power

[Skvez]

[Hrusai]

[Lightspeed]

I've been toying with the idea of bicycle generated power for some time, but have done absolutely nothing about it.... typical :-)

My thoughts are going in the direction of setting up something a little like the cycle trainer pin in H's post, but using it to support the back wheel rim which caould then be used to drive a pulley belt to a 12v car alternator. Gears on the bike will help you find viable load for your legs, and the idea of belt drive is because tyres will eventually perish/ be unavailable wheras a pulley belt could be fashioned from cloth ot even animal hide.

Why an alternator? Because dynamos are hared to find nowdays, also Alternators kick out greater power on average. the snag is taht an alternator requires 12v input, so will be ueselss if you have zero batery power. ( Dynamos generate without any input power)

[Hrusai]

[Lightspeed]

[Skvez]

Lightspeed

I had been under the impression that a car alternator powered by a bike wasn't very practical because the car alternator needed such a high rpm. However doing a bit of maths suggests it's reasonable:

Typical bike wheel diameter 0.63 m
Typical bike wheel circumference 1.98 m
Reasonable power 'bike speed' 20 mph (miles per hour)
= Reasonable power 'bike speed' 533 mpm (meters per minute)
= wheel rotation of 270 rpm

Given that a car charging alt really needs 2500 to 3000 rpm to get good generation means we need a 10:1 ratio from the bike wheel rpm to the alternator rpm.
If we have a belt on the 0.63m diameter bike wheel we need a 6.3cm diameter pulley wheel on the car alternator.

This seems quite reasonable.

[Hrusai]

hmm this thread is giving rise to all manner of ideas.

ok so the dynohub is quite similar to the idea i was having, accept doing it in a different way and providing lower amount of power than i ideally wanted, but i just need to think about it all and do more research on the matter, see how viable the dynohub is and amounts it can comfortably generate, as well how possible it is to edit its design and such like.

as for the wind idea, thats bloody great!! whilst using the bike as a vehicle or to generate power via pedalling i'd keep it all together, but the idea of using the bike to generate extra power even while im not using it is bloody brilliant! after all i aint gonna spend all my time at my BOL just pedalling xD...the other thing you could do from that idea, is not just to simply overturn the bike, but actually remove the wheels and bearings, attach the card, then mount the wheels in a little holder up in a tree or some such, to catch more wind, so you can still use the bike after a few minutes reassembling it, and it acts as a make shift wind turbine!!....which would also suit the idea a dynohub/whatever the hell i call my idea nicely too

heh i was having similar reservations about the whole alternator idea, but after seeing those numbers, how can you argue with cold hard maths xD...and it translates into some very workable numbers!

[Lightspeed]

Lightspeed

I had been under the impression that a car alternator powered by a bike wasn't very practical because the car alternator needed such a high rpm. However doing a bit of maths suggests it's reasonable:

Typical bike wheel diameter 0.63 m
Typical bike wheel circumference 1.98 m
Reasonable power 'bike speed' 20 mph (miles per hour)
= Reasonable power 'bike speed' 533 mpm (meters per minute)
= wheel rotation of 270 rpm

Given that a car charging alt really needs 2500 to 3000 rpm to get good generation means we need a 10:1 ratio from the bike wheel rpm to the alternator rpm.
If we have a belt on the 0.63m diameter bike wheel we need a 6.3cm diameter pulley wheel on the car alternator.

This seems quite reasonable.

Thanks for doing he math Skvez

As I said it was just a fanciful idea. The pulley method will give the mechanical advantage necessary, as alternators tend to come with drive pulleyse that are in the 6cm dia range. Thanks for evaluating that.

Next question will be power generated. I fear that pulling a big alternator of a deisel Merc for example would be an error. It's designed to generate too much power, and my likkle legs probably would not be up to the task. I'm guessing a puny alternator off a citroen 2cv or off a small moped would be better suited to the task?

I dunno... just some thoughts.

LS

[Hrusai]

i guess its mostly down to what do we need it for? some people wont need any electricity

i guess the main things you'd want in the long term would be, lighting, radio, charging batteries, kindles, possibly laptops.

most of the stuff you'd need power for would be for entertainment unless in the long term you take to scavaging and start to set things up like electric pumps for drinking water from springs, or irrigation for land, or even power storage....yep thats right eletric pumps for power storage!...so batteries have a finite lifespan right in my mind i'd set up a reservoir high up and then any excess power generated after a battery is full, will pump water up into that resevoir, then when you need the power from it, you slowly release it through a pipe with a generator inside, then the water would push it and makes you some nice electricity ...to be honest you could probably achieve a similar sort of thing by having some piping aimed at a wind turbine, the jet of water would push it round making more poworz :~P

i guess its hard to have cohesive ideas on seperate things without considering the whole picture, i think that most of us probably do that...you gotta know enough about each thing to know whats viable and then also know what your working towards and how you'd do it, then highlight issues and come up with solutions like this to fix them

maybe we should start some threads discussing the bigger picture, realistic setups for your new wilderness home because its all very well and good having the knowledge to survive short term, but i think the point of prepping is not to simply survive scavenging and hunting and moving aruond for the rest of your days, alot is to get where you need to be to build yourself a home, not just a place to live.

[Skvez]

eletric pumps for power storage!... batteries have a finite lifespan [so] i'd set up a reservoir high up and then any excess power generated after a battery is full, will pump water up into that resevoir, then when you need the power from it, you slowly release it through a pipe with a generator inside

This is called "pumped storage" if you want to do a web search about it. Unfortunately typical efficiency of power out vs power in is only around 10%.