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help setting up electric system for bike

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jpoopdog

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Hi,

I recently decided im too fat so i bought a bike to excersize, but then i got to thinking, why not build a bunch of stuff for it as well!
Im presently unemployed and bored out of my mind so i need something to do that serves a function.

Now, heres what i eventually want the bike to have,
An generator which can also serve as an electrical assist (if i need it for whatever reason), though its easy enough done with the right gearbox.
regulated 12v 5v and 3v rails which can be used all over the bike, the 5v and 3v being stepped down instead of just trimmed and regulated so as to conserve power and allow for higher current flow, a bunch of flashing lights for night use, a high powered light set, (i have a 10v 1A led and several 1W ones that run only on 3v), Numerous USB ports all over the bike to charge my phone, ipod and other random devices i may have a, a solar charger to charge the battery in the event the generator breaks, appropriately a regulator for the generator and lastly, a huge Asterics Li-Ion Battery like 10-20A, or otherwise a 12v SLA as big as i can fit on the bike. Being for excersize purposes, heavier is better so the battery will just be the highest capacity battery i can find that will fit on the bike and cost under $150.

For most of this im pretty much set, but there are a few things i need help and advice on, the first and foremost are the usb power rails and the the generators regulator.
With the generators regulator i want to get roughly 12-13v out at all times to power a battery charger, i can ensure that the motor rpm is always high enough that it a good deal of voltage out of it will be high enough to use directly, but how should i be handling this power so its fit for the charger circuit? i want to get maximum efficiency out of it and waste as little as possible.

Also, with the usb ports i bought a 15W stepdown converter that converts the 12v down pretty efficiently, what should i do to this 5v (max 3A), should i just hook it up to 3 parallel usb ports just like that or is there any circuitry that needs to be added like individual regulators and such.

any help with those or other parts of the bikes electrics would be greatly appreciated.
 
You do realize that the maximum average sustained human output power on a bike is only a couple hundred watts. You will need a very efficient mechanical connection from the bike to the generator to recover even half of that at the generator output. Is that sufficient power for your needs?
 
You do realize that the maximum average sustained human output power on a bike is only a couple hundred watts.

Maybe for a fit and in shape pro cyclist they can sustain that for a hour or so but for the rest of us it's more like 100 watts for a person in average shape.

https://hypertextbook.com/facts/2003/WeiLiangMok.shtml

Overweight and underfit might make half of that at best.:p
 
.....and most of those Watts will be needed just to move bike + cyclist. So very few Watts available to power the generator etc :(
 
.....and most of those Watts will be needed just to move bike + cyclist. So very few Watts available to power the generator etc

I used to be avid cyclist! Until I turned 14 and we got a three wheeler. :p

I say save the time effort and money of buying a new bike and refitting all the toys to it and go out and buy a good used motorcycle or scooter.

You may not get fit as fast but you will be much happier along the way!
 
I used to be avid cyclist! Until I turned 14 and we got a three wheeler. :p

I say save the time effort and money of buying a new bike and refitting all the toys to it and go out and buy a good used motorcycle or scooter.

You may not get fit as fast but you will be much happier along the way!
it defeats the purpose of riding the bike to get fit.

Also, im aware im not going to get amazingly high amounts of power out of a generator, but anything is better than nothing, for general intents and purposes i just want to keep my phone charged. and again, ill have a huge battery there also which i just need to keep topped up, when i ride i go out for hours, and at night, ill be using some strong headlights plus all the generic flashers, unless the moon is out in which case headlights arent neccesary, at least here anyway. The point being is ill be charging that battery the day before i go out just in case. But it makes sense to put a generator on the bike to charge the battery, for those extra long distance rides.

The generator is a definite MUST, the question is how to i manage its power, im happy even with only a few Watts of power in, so long as it maintains the batteries charge and maybe even then some.
I have a 3D printer and too much spare time on my hands, i have nearly everything accounted for except for a way to efficiently manage power and i would appreciate your help on this
 
Here is a thought:

Use a 12 volt motor/generator and one of these little guys. You could set the voltage at the float voltage of a 12 volt lead acid battery then adjust the current to the level that gives you the desired workout.. Oh man. Makes me tired just thinking about it. :(

**broken link removed**
 
I'm doing something remotely similar right now, except mine is not going to be electric assist, I'm too fat too, giving up booze hasnt really worked either, but I feel way better.
Its not practical to use a motor big enough to power the bike as a gen, unless its one of these hub motors - £££, if you want to do it cheap then maybe a seperate motor and dynamo.
I have an effecient 6v3w hub dynamo, its modded to produce 12v10w and I can tell the difference when its on full load, a 100w generator would feel like your riding with the brakes on, 200w would probably stop you.
To provide 5v for usb and any other step down efficiently use a switching reg like a lm2575 - 5 (5v), or for a custom voltage or to drive a power led at constant current a lm2575 - adj (adjustable).
If you really want a motor/gen at high power look into modding a car alternator, if you replace the rotor winding with microwave magnets you get a reasoable gen and if you generate 3 phases with a micro and some fets you also get a powerfull motor.
 
It seems that the overloaded electric bikes creeping along the roads (dangerous) are ridden by fat heavy people. The same with electric wheelchairs.
Runners are the slimmest people especially the women runners who have no bouncing t**s.

There was a thread where a bicycle rider wanted to use a computer fan as a generator to charge a battery for lighting lights at night. The lights lit for only a few seconds. The rider did not know that it takes a lot of physical power to charge a battery, like riding and towing a huge open umbrella behind him.
 
I have been thinking about designing an electric assist system for exercise bikes.:p

That way you can put on your 2 - 5 miles a day on one without ever having to pedal while doing it. ;)

Bet I would be rich within a year! :D
 
Only problem is tcm you'd still get exercise even if the bike pushed your legs round, you'd still lose weight.
I'm thinking of building something instead of generating electric from pedalling, it generates beer.
I could give the bikes away and make a living from selling spares.
 
Only problem is tcm you'd still get exercise even if the bike pushed your legs round, you'd still lose weight.

That's why I would add a set of foot pegs so a person can just rest their feet on those while the electric drive spins the pedals for them. ;)
 
What kind of member name is jpoopdog? Are you some old dog that's always pooped out from being obese? Or are you some sort of gansta rapper now unemployed?


Just buy a moped- they already use a fuel source that yields the highest BTU of most fuels: gasoline! If you feel guilty for using the gas engine, leave it off and pedal the bike... burning more calories from the extra weight of that type of bike. If you feel ambitious in losing weight and want to involve a high output bike, get youself a Harley Davidson ElectraGlide Fat Boy and push it up an 10% grade road. Make sure !the tire pressure is on the low side
 
I have weighed the same for 51 years (all my adult life) because I eat normal food, not much "fat" food. I do not eat too much. I frequently run around the block and in the park. S** with my wife nearly every night is also good exercise.

After they repaired my heart attack with two stents a few years ago I did a "stress test" to see how much damage was caused. No damage was caused and my performance was like a fit teenager. Before the test they said to go as hard and as long as I can. During the test they said I am fine, slow down then stop.

I do not know why so many people get obese and do not exercise.
 
An unemployed gansta rappa, I like it.
Maybe the reccession is biting them too.
 
thankyou.
Im only considering doing an electric assist if the motor speed at the ideal ratio happens to permit it, unless i can put together a proper manual gearbox, in which case again, should it actually be viable enough to move me or be even worth using then i will. but remember this isnt a huge electric motor, though its big, its not really anything more powerful that youde see in those electric scooters (the kids ones which are basically the same as normal un motorized scooters).

Why the hell would i buy a moped with pedals to lose weight when i have a perfectly good bike here? if i wanted to put more strain on myself, i could just move up the gears, i can go so fast that wind resistance actually has a detectable impact, easy done, otherwise i can also just put actual weights on the bike to make it harder to move, but given the large amount hills here and strong winds, they make it hard enough.

Now that 600W dc boost converter looks perfect for what im after, thanks ronv. its also fairly inexpensive too, im surprised i havent come across this before. I might also try using it first for another project i have in mind that needs about 30v output
 
remember this isnt a huge electric motor, though its big, its not really anything more powerful that youde see in those electric scooters (the kids ones which are basically the same as normal un motorized scooters).

My niece has one and those motors are nearly worthless for anyone over 100 pounds. I am 6'3" 250 # and that poor little scooter has a tough time moving me around on anything but concrete. :p

Her skinny little 65# butt however flies like a rocket on it! ;)
 
not neccesarily when you have a gearbox. with that is just a matter of slowly accelerating while applying enough power to overcome the resistances in play.
in any case its just for fun i dont intend to actually use it for travel, it will just be a happy side feature
 
On the contrary. Power has everything to do with it.

What you are implying is that gearing will make up for limited power which in ot true. No matter how you gear it a lawn mower engine will not move a car down the road at highway speeds and a kids scooter motor wont move a fat man on a bike at a normal riding speed into the wind up while going up a hill either. :p
 
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