/diy/ trying to build my own generator >I want to build a

>>1108119

>>https://www.google.bg/search?q=old+bike+dynamo&num=100&newwindow=1&safe=off&client=ubuntu&espv=2&source=lnms&tbm=isch&sa=X&ved=0ahUKEwjRr-fcq6TRAhXE2SwKHfwEDS0Q_AUICCgB&biw=1366&bih=681

here take a look at that design, much better, safer and reliable.

Just take a motor, put 3d printed (if you are a faggot and can't do it otherwise) head on top of it strap it somehow to the front wheel and done.

Add a diode and a capacitor on the other side, now hook a charging unit and 2 AA charging batteries, now hook them to LED or even better leave a usb port so you can use it as powerbank charged by your bike.

>>1108119
>I want to use an electromagnet instead of a real magnet
Apparently you don't understand even basic physics or you'd know that not only won't work, it'll do the opposite of what you want (i.e. CONSUME power instead of GENERATING power). Go look up 'laws of thermodynamics' and get back to us, k?

>>1108315
Hey kid before you go on a huge rant you should know that is how pretty much every alternator works

>>1108315
mechanical power + power consumed by the controlled static field = controllable output power & loading

>>1108316
You're still wasting power that could be put into the battery.
Wasting because magnets do it for free.

>>1108119
>without the converting into lower watts
What the actual fuck is this guy trying to say?

>>1108328
Natural magnetic generators are much weaker then electromagnetic because the fields are weaker. There's a reason cars use them and can get anywhere from 60 amps in a 6^3" package to 200 amps in a 9^3" package.

>>1108119
What the fuck are you talking about op?

You can't just magic your way into higher wattage

Bicycles have a solid cap to their output known as human output.

A human can only output about 1 kilowatt hour per day.


Think about it this way.

You eat around 2000 calories Per day, technically these are kilocalories so really 2,000,000 calories per day.

The base metabolic rate of someone around 180 pounds at 5'10 is around 1,500 kilocalories per day, that is the base amount necessary to survive without losing weight just laying in bed 24/7.

This means that person expends just 500 kcal going through his day. This includes about 10,000 steps (3 miles of walking)

This means you only output in actual usable energy 581 watt hours per day. But here's the kicker. Those 581 watt hours can't be salvaged, those are the bare minimum to get you from point a to point b. If you want to salvage any of that power for energy production, you'll have to produce more energy from your body, which means even greater input, and humans are VERY inefficient at outputting power vs input power.

Now the real question: why do you think you want to harvest bicycle energy? Do you think you'll be saving the world?

I hate to break it to you but humans output a lot more wasteful energy feeding ourselves than coal plants powering our little gadgets

Think of it this way, that kale tofu burger you ate today used hundreds to thousands of gallons of water to grow, water that needed to be transported using giant pumps hooked up to coal power plants that shoved a shit ton of co2 into the atmosphere. Just so you could have the extra calories needed to push your stationary bike long enough to power your phone for a couple hours longer. Vs just plugging your phone into a coal power plant to charge it.


Trying to save the world by reducing greenhouse gases is a noble task that needs to be done, but don't get fooled into thinking YOU are more efficient than a coal power plant.

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>>1108449
When you think of human energy usage also think about it this way. A 1kg loaf of bread would supply you almost all of your calories for the day. Do you think you could bike 1600 litres of water (remember 1 litre is 1 kg) between a farm and a river in a single day, with less than 500 calories burned? (I'll give you a hint, is literally impossible)

>>1108449
>>1108454
Holy shit

This is like the definition of the insult "getting schooled"

>>1108316
>>1108319
You dumb asses.. I know how a goddamned alternator works, but you need a BATTERY to initially energize the field coil located on the rotor, and you have and ENGINE to spin the thing, not some DYEL kid pedaling his bike. DO THE MATH.

>>1108449
Let me give you a different take on what you're saying, from the perspective of a cyclst who trains and road races:

The average UNTRAINED (meaning you don't train to race, you 'just ride') cyclist averages 150 watts or less for any appreciable distance; a really good non-racer can average 200 watts. A TRAINED cyclist can average up to, say, 400 watts for an hour. I personally have been able to average about 300 watts for 90 minutes ('Tempo' ride). In the grand scheme of things, none of that is much at all.

Now, let's use 100 watts as an example, since that's your average, recreational, untrained cyclist. Even siphoning off 10 or 20 watts of that is a big deal, and won't power much of anything.

Now, let's talk about practicalities for electric power generated on a bike. Let's use a figure of 14 watt-hours for a smartphone battery. That means you'd have to feed it at least 14 watts of steady power for an hour to charge it. For someone averaging 100 watts, you'll feel that, it'll slow you down 14%. Now consider this: with conversion inefficiencies, power dissipated as heat, etc, it'll take much MORE than 14 watt-hours of power to charge that battery, maybe as much as 20 watt-hours. Now you REALLY feel it, as 20% of your power is being siphoned off; on the flat, you'll feel like you're constantly climbing a shallow grade. If you slow down too much, or stop, you stop generating power, the battery doesn't get charged; now it takes MUCH LONGER to charge it, and you're constantly feeling like you're climbing a hill. Now you actually CLIMB a hill; you're DYING, and slowing WAY down, and your battery isn't charging much at all.

Oh, and by the way: This doesn't EVEN begin to cover what your smartphone itself is drawing, power-wise, WHILE it's charging the battery. Let's say that's 25 watts total.

This is just ONE LITTLE SMARTPHONE we're talking about, and it's sucking away ONE QUARTER of your effort.

Do you begin to see the problem?

>>1108337
He don't want to only have a few milliwatts in the output, but the full gigawatts version, like a regular nuclear power plant.

Apparently he plans on charging a tesla in a few minutes, not just lighting the road ahead of him like regular cyclists.

>>1111217
A. a are you gonna be OK?

You really should take your meds and have a nice nap.

>>1111217
>>1108449

great posts, it seems like it doesn't make sense to generate the power with your legs.

for a city cyclist like me, there is a lot of stop and go with traffic lights. what are your thoughts on a regenerative breaking set up of a bicycle? so when i press the brake it siphons off power electromagnetically

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>>1111217
>>1111238

Your just lying theres no such thing please we need the power companies stop being a racist and take your drugs.

>>1111211
>>1108315

You don't need a battery, see the dynamo self-excitation phenomenon:
https://en.wikipedia.org/wiki/Excitation_(magnetic)

>>1108119
Why don't you want to use permanent magnets OP? Permanent magnets are pretty fucking cheap these days and have better performance than electromagnets.

>>1111243
>what are your thoughts on a regenerative breaking set up of a bicycle?

Not even worth the extra weight.

The overall conversion of momentum>geartrain>generator>electronics>storage>electronics>motor>momentum just has too many steps in it. You get hardly anything back.

That being said, I have mused over the viability of using a flywheel rather than electrical storage. The downside with that some form of CVT is required, and they're not usually that efficient even one way, much less both. The ones that are efficient tend to be pretty pricey. Plus they're even heavier than an equivalent electronics setup, and much more mechanically complex and prone to failure.

Tl;dr: not werf. More practical to just build an ebike with a small, low-geared motor and battery pack and only use it to get going from a standstill.

>>1111296
>Not even worth the extra weight.
This. You start adding all that extra hardware, suddenly your 18 pound bike is a 50 pound bike. Have fun riding that up steep hills.

Just ride your bikes, and charge your electronics at home. Seriously, the bulb(s) lighting your bedroom costs more to operate than charging your electronics does.

>>1111269
>dynamo self-excitation
Or you can just not bother with any of it, charge your electronics at home, and have a nice, lightweight bike to ride that you won't kill yourself getting up hills. Also, less things on your bike to attract theives, or kids that just like to wreck things for the sake of wrecking things.

>>1108446
I'm pretty sure that's wrong, though. A permanent magnet motor from a 700-size heli can handle as much as 3 kW despite being far smaller and lighter than any car alternator.

>>1111217
>Smartphone is draining 5 watt-hours
You what?

>>1108119
>similar to this but without the converting into lower watts

Watts are a measure of power, ability to do work.

Amperage x Voltage

You can fuck around with how many volts you want to put out at corresponding amps, and the other way around, but you can't just "increase the wattage"

The watts are your legs, and they are fucking noodly. Look at that youtube video of a cyclist toasting some bread and decide whether or not you think it is still worth your time to make a human powered generator when there are so many other better ways to make power.

Literally case definition of work smarter, not harder.

>>1111333
5 watts is a common charger. I have a 12 watt apple one, but it only draws about half that or 6 for my iPhone 6S Plus.

>>1111639
Yes, charger. Unless you've got the phone running at 100% while its plugged in it's consuming less than that.

>>1111725
My kill-a-watt disagrees.

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>>1111788
The phone consumes less than it takes in via charging or else it couldn't charge.

Also there is a small transformer inside your charger so it will consume the same amount from the wall no matter whether it's charging or not

Pic related
My phone is a note 5, it's battery is 3000mah at a 3.7V nominal voltage, this translates to 11.1 watt hours. It takes 24 hours to deplete a full charge, meaning my actual usage is only .4625 watts over the course of 24 hours


My charger however runs at 9V at 1.67A or 15 watts

>>1111855
Its* Fucking autocorrect