charging electric bike by it own?

hi all, this is my first time on instructable and i think i can built an electirc bike with self-charging feature when pedalling or not using motor or downhill of freewheeling but i doesn't have any electric background i'm just a car mechanic from pakistan. i think if i put a 36v mid drive blcd motor kit in my bike as a drive motor and also put two 72v hub motors in both wheels then will it can be able to charge the battery or not? i know that hub motor produces AC volts and i neet to use 3-phase bridge rectifier, i just want to know is it possible or not? if possible then what are the pros and cons will i have with this system?

sorry if mistaken in english.

millions of thanks,

ali shamsi.

Picture of charging electric bike by it own?
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iceng1 year ago

I live next to lake Tahoe where you have to drive over a 8911 ft mountain from the Reno valley 4411 ft airport that is a 4500 ft elevation change and then down to 6225 ft of the lake Tahoe level which is a 2686 ft elevation change..

Simply when you pass top parking area there are a great many rocks above the tree line which you can load into your E_vehicle or fill a water bladder from streams and then recharge / regenerate using the added potential mass energy descending in either direction to recharge the batteries with way more energy then it took to drive up.

At the bottom remove the rocks or drain the bladder and drive on free energy.. Make sure you save enough battery juice to drive back up to the 8911 ft parking area to load additional mass for a full recharge going down hill.

This procedure will run your E_vehicle using free Energy year in year out, and flatten the hill very slightly compared to plate tectonic push up.

Put another way the potential energy mass of the rock that you bring down from mountain will be converted to battery energy in the valley where you take the rock out of your E_vehicle in a garden or quarry that needs rocks.

alis231 (author)  iceng1 year ago

this is exactly what i want to know, thanks alot bro, but in my city there isn't any up-steep or downhill situation in my route, most of area is just flat except bridges or underpasses, so i think i can recover most of the energy by pedal force or freewheeling, that's why i'm trying to design some hydraulic set which boost my pedal force to generator so i can produce maximum 600 to 700 watts, then i'll change my bike's design, i'll use pedall for just producing power and wheels are totally connected with motor, i mean pedall will not drive the bike, it just drive generator which produce energy for motor that will driving wheel, i think its the right idea,
with this drive train i can use my all force (with hydraulic pressure) for producing electricity my force is not going to wheels so i can produce more power for the battery, and the electricity produced with my pedall force will use to drive the wheel from motor.

seandogue1 year ago

Yes, recovery energy is possible, with the caveat that it will act as a frictional force when doing so. Trains have been using it for decades. Again, with the caveat that friction will be generated as a direct result of generator operation, and in proportion to the amount of energy being drawn from momentum (or peddling)

alis231 (author)  seandogue1 year ago

what is caveat??? i think if i can design some hydraulic pedalling then i'll be easier to get sufficient power by pedal force..

A caveat is a modifying condition, a caution if you like.

AC/DC makes no difference your still not going to generate enough power to charge the battery faster than your using the energy. Assuming you can drive the generator hard enough at all.

A few experiments should prove what I saw to you.

alis231 (author)  rickharris1 year ago

what if i design a hydraulic powered pedal to drive generator? will it produces enough power to charge the battery fast with human power?

No chance. 376 watts input = something less than 376 watts out put in a different form of energy. There is no way to gain power.

Gearing transforms torque into speed, so higher speed lower torque.

Hydraulics transform input movement in to higher force but less movement.

an electrical transformer changes voltage in proportion to the current, more volts less current.

You can't get something energy wise for nothing.

You only have 376 watts to play with. Your best bet is to build a bike that is as light as possible, with low rolling resistance so you waste as little of the power you have as possible.

Beyond that your very limited by the small power output of the human body.

alis231 (author)  rickharris1 year ago

ok sir, now i understand that i can only produce around 350 to 370 watts of power for any lenth of time, on normal pedalling so i can just improve my range to 150 miles on lightweigh bike with some pedalling and some juice of battery,

thanks alot for guiding me right,

may GOD bless you all.

Correct - Good luck.

Yonatan241 year ago

The charging device will slow you down, and make it harder to pedal and bike.

alis231 (author)  Yonatan241 year ago

thanks for sharing this information but i saw a video on youtube a guy makes 15v 3A by using 48v 500 watt hub motor by driving by hand force so if i put 2 hub motors of 72v 1500 watt in both wheels and connect parallel then will it produce much power to charge the battery when normal pedalling?

https://www.youtube.com/watch?v=OD1gSx92DuM

That will work, but it will slow you down. There's no such a thing as "Free Energy" (as of today)

alis231 (author)  Yonatan241 year ago

if i only use generator when i don't want speed and riding on pedall and not using generator when using motor then will it improve my range?? force needed to generate electricity is not problem for me it'll be a good excercise for me.

Okay, yes. Makes sense.

alis231 (author)  Yonatan241 year ago

thanks alot,

And something i want to know about direct drive hub motors that are
they have any preload (force needed to turn) when not connected to
battery?? i think it only take preload to turn with mechanical force
when it connected to battery and controller when regulator (throttle) is
not twisted to give power?

and i think it produce voltages when
connected to battery but not moving by electricity (no throttle), and it
is free to move when power is not connected and will not produce
voltages when turn by mechanical force? if is it true then i'll design
my bike according to this when i use mid-drive motor to run i switch off
the power from hub generators so bike moves freely and when i use
pedall when i use to charge battery then i switch on the power to the
hub but not give throttle so it not consumes electricity but charge the
battery it think?

I'm not sure. Not sure how to do that... :)

alis231 (author) 1 year ago

what about if i design this whole system with AC motor (mid-drive) and AC generator
(alternator) with AC-DC charger and inverter for using battery

alis231 (author) 1 year ago

millions of thanks to all of you genius persons. GOD bless you all with health, wealth, peace, and more knowledge.

rickharris1 year ago

YES and NO.

In principle it is quite possible to drive a generator with human power and charge a battery.

HOWEVER: The average human can output about 1/2 hp or 373 watts for any length of time. This isn't going to be enough to charge your battery faster then your using the electricity.

You can recover energy when going down hill but again on average this will be a lot less than you used getting uphill.

No problem building an electric bike, you just need to accept it needs charging from a power source daily.

Good luck.

alis231 (author)  rickharris1 year ago

thanks alot for your kind information, i accept it needs to charge by external power source but i just want to recover anergy as much as i can for reducing the charging time by external source, in my city there is no uphill position in my route and of course as you say that human produced energy is not enough to charge the battery fast but i think if i put both of hub generators of 1000 watts and connect parallel to charge the battery with driving motor of 500 watt with some pedaling then will it improve my range on smaller battery which i can detach when i park the bike somewhere outside? secondly i thought if i put another type of motor as generator which i fit with some gearing for high rpm then will it make enough power to charge the battery fast?

i'm planing all of this because electricity and fuel charges are too high in my state and my routes are too long and karachi is also a most poluted city in the world, so i though may be this idea can help to reduce polution in my city. and make our environment clean and green.

No, sorry. 1. 15 volts x 3 amps is 45 watts - Possible.

BUT your not going to charge your battery in any significant amount on 45 watts of energy in a short time.

2. Your efforts will ONLY produce 373 watts of energy total, some of that will be used to make the bike moves along at (x) speed how much depends on how fast you want to go.

On average a normal cyclist travels at around 6 MPH or perhaps 10 MPH over a short journey. That's is NOT a keen fit cyclist on a light weight bike with narrow low resistance tires. However they are not on average going to go a lot faster.

The size of the motors your using to generate isn't relevant as you have to drive them with a very limited amount of available power.

By all means try this but I can tell you now it isn't going to work. the Maths is against you.

As far as going further for a given amount of effort your better off trying to build a bike as light as possible and forget the electric power totally UNLESS you happy to go with the recharge from a static source every 150 miles or so. beyond that just peddle it is far more energy efficient then any other form of transport. Light weight!

alis231 (author)  rickharris1 year ago

thats what i want to know, thanks alot SIR for guiding me right, i know i need to charge electric bike with utility power but i just want to increase the range on battery with the help of generator and some pedalling, if i need to charge after 120 to 150 miles or above then its OK for me :)

i'm fit enough to pedall a bike, and about long distance travel i can use motor and pedall both(for example: when i use battery power i don't use pedall and when i'm not using battery power i use pedall to drive the wheel or both of generators) so if i used battery power 10% on a specific distance and stop using motor and pedall the bike for same distance which i travelled on motor then i think i can recover half of the power which i used to drive a motor?

And something i want to know about direct drive hub motors that are they have any preload (force needed to turn) when not connected to battery?? i think it only take preload to turn with mechanical force when it connected to battery and controller when regulator (throttle) is not twisted to give power?

and i think it produce voltages when connected to battery but not moving by electricity (no throttle), and it is free to move when power is not connected and will not produce voltages when turn by mechanical force? if is it true then i'll design my bike according to this when i use mid-drive motor to run i switch off the power from hub generators so bike moves freely and when i use pedall when i use to charge battery then i switch on the power to the hub but not give throttle so it not consumes electricity but charge the battery it think?

rickharris1 year ago

373 watts input is all you can ever get out, some of that is pushing the bike along lets say 1/2 so your going to go slower + your pushing along the extra weight of a biggish battery and 2 motors. less power available for charging.

My electric car

https://www.instructables.com/id/Building-an-electr...

has a 24volt motor run at 500 watts to get 30 MPH for about 2 hours of running so 60 miles. (on the flat with no other input)

That's drawing 17 amps - So lets take your 36 volt motor and say it is 250 watts, that requires 8 amps minimum from the battery to drive it.

Your providing possibly 150 watts of energy no matter how big the generator is 150 watts in = something less than 150 watts out that's less than half what your taking from the battery.

Assuming you can provide that energy your going to have to power the bike engine off for more then twice the distance you used it engine on to recharge the battery.

This is impracticable - if it could work then people would already do it because the world is hungry for an electric vehicle that has infinite range but even the car makers haven't been able to make something like this work without using a big internal combustion engine to supply the power to recharge the battery pack. No where near as effecient as using mains power.

I am sorry but NO this idea will not work.

BUT don't let me stop you trying.

iceng1 year ago

I know someone who built an electric vehicle and put generators on the wheels to charge the battery.

The device traveled further without the generators.

! proves the point.