Can we build a wind turbine bike battery?

[Gaston]

I don't know anything about electricity at all (but I understand and learn quickly!)
If we have a battery that will be used to power a 24V 250W motor, is it possible to recharge this battery with a wind turbine that produces 5V?

Technically, yes.
But whatever the solution used, the wind turbine will brake the bike in proportion to the electric power it will provide (just like a dynamo rubbing on the tire)

The pragmatic question is: How long will it take me to charge the battery?

This is THE right question.
If we take as an example the mini wind turbine that you proposed above (whose power is comparable to a bicycle dynamo), it takes about 63 hours of operation to use 1 hour of assistance.

With a larger and more powerful wind turbine, it will take less time, but it will slow down much more the advancement (without counting the additional weight).

[Iubito]

5V is a bit low, but you can recharge from any voltage below that of your battery, thanks to an MPPT converter (Maximum Power Point Tracker) especially ideal for solar.
What matters is how much watt you take in. a 24V for a 250W motor does not give me the size of the tank, I have the power, the voltage ... but what capacity (in Ah or Wh)?
On my old one I had a capacity of 8Ah, for a nominal 24V, therefore 28.8V max (NiMH), which gives for a operating voltage around 26V, 208Wh. If I pulled 250W continuously, I would have less than 1 hour of autonomy.
On my kit I am in 48V (58.8V max), and I have about 20Ah.

In fact if you put a ball in the pedals, you will no longer use the assistance, I fear that everything will be ineffective. If you put a ball in weight (panel), you still keep the power in the pedaling for the ribs and raises.

Brushless motors have a no-load speed (in rev / min per Volt), above the no-load speed, it becomes a generator, naturally, but with a forced command on the brake lever, you can start the regeneration at any time. Same principle on the tgv, the prius perhaps?

Then there's the battery techno that can charge / collect more or less current. For example 1m² of panel on a small 12V lead battery, quickly burnt out ... then regen ...!
The lightest is LiPo I think, but dangerous in case of overload (fire), LiFePo4 is the most stable.

[neuzy182]

Wow, thank you for responding so quickly and correctly!

In order (I'll try)

@Gaston:

My goal is not to move the bike by myself, just to charge a battery that will assist the bike (www.mottrix.com)
So I am amazed at your calculation, how did you know how much energy I would need to be assisted for an hour?

@iubito:
As for the batteries, basic it would allow "coupled with a 'standard' bike a range without pedaling of about 20km with its pair of lead batteries"
Not very explicit, but the batteries are changeable easily so if you have better in stock fart

I did not understand the history of the ball ...

[Iubito]

For the ball ...
the crankset makes few turns in a minute 80 to 120 ... which provides little energy compared to a dynamo on the sidewall of the tire or a hub dynamo (dynamo SON for example) or a hub motor becoming generator on demand .
The ball would have to pedal harder to generate current in addition to pulling the chain.
When the generator (solar panel) is a "weight" ball, it brakes when starting, on a hill, but not on a flat once started or when going down.

With a hub motor, you can, thanks to the downhill regen, extend the range by 30% by managing well.

Lead batteries, forget it! weight ++ does not support strong recharges (solar, regen !!)

my kit comes from there: www.declic-eco.fr
it's based on nine continent, but improved
Before I had a BionX ... well screwed up electronically, but dead ends on stuff well damage ... and system lock with electronics in engine + battery + console = big mess.
There it is nickel, the motor on one side which does nothing but turn, the battery which does nothing but supply / recover current, the controller which makes the 'nipples don’t electrify, and the Cycle Analyst to clamp, monitor consumption, speed ...

So to know the recharge time, you need:
- battery capacity (in Wh or Ah, in this case we do Ah * V to have Wh)
- generator power (100W peak panel, 75W good conditions, dynamo?)
and there if we consider that the energy input is regular, 75W in 1h = 75Wh
we divide capa battery by quantity of energy entered in 1 hour ... = recharge time.
For my 1000Wh battery, I need about 13h.
A driving day in the summer sun = 500 to 600Wh
In winter much much less! (lower angle, shorter days): 50Wh in one day?

In assistance, there are some who have tested a sail ... but you need the right angle, wind strength, not too much traffic (we make deviations), straight road. When there are the right conditions it works, but 95% of the time we transport the gear for nothing (experienced by 2 tourdumondistes)

[neuzy182]

Excellent! Thank you!

Brushless motor, hub motor ... BionX (apparently not important)
Not easy to follow without knowing!

So let's forget about sailing the Mottrix system is nice for its ease of adaptation to any type of cycle, but I try to make it feel free from the "renewability" of the electrons that make it turn.

I understood the history of the ball, and that's why I'm looking for a wind or solar system, to avoid the horrible friction of a dynamo.
Are the pv cells on your panel really better than those that can be placed on backpacks or other? (big difference in weight !!)

I did not follow well if you answered for the recovery of braking energy, I know it exists, but I have no idea how it works, but I understand that it exists for models electric bike ...

I am well aware that having a system that works on its own probably does not exist, but I'm talking here about helping the pedaling action, so the main energy is human action on the pedals ...

A wind turbine on a model of a scarf in the wind, which moves alone without losing ergodynamics, it does not exist, but is it stupid or not?

[Iubito]

brushless = gearless motor, friction ... with magnets and current flowing through it. Nine Continent, BionX ... are brushless motors. They are in the rear wheel hub for a trike, front wheel for a 2nd wheel (= 2 drive wheels)
there are reduced motors (but I don't have any details) and pedal / chain motors.
Crank / chain motors (like the "cyclone") cannot recover energy.
The hub motors can naturally (physical property of this system) recover energy (regen) beyond a certain speed which depends on the characteristics (winding) of the motor.

On some bikes, and this is the case on my kit, we can force the regeneration, and therefore recover energy by having a secure engine brake, on demand. In a steep slope, the peak of energy recovered can be monstrous: a lead battery would not support, a NiMH cash, a LiFePo4 laughs.

Unfortunately many commercial electric bikes do not have this function, which is a shame !!
On flat ground, not very useful.
In town / commuting, we recover little (the goal is to get to work on time and get home as quickly as possible in the evening): we recover little energy and / or we ask for more assistance with the restarts at stop / lights.
When hiking, and on hilly terrain there is potential for recovery in the descents, and when you are loaded an engine brake is really reassuring.

[dirk pitt]

brushless = gearless motor,

having or not having a gear reducer has NOTHING to do with motor technology: brush or brushless.
a brushless motor as its name suggests has no brushes. (or coals)

[Gaston]

So I am amazed at your calculation, how did you know how much energy I would need to be assisted for an hour?

I obviously assumed that the assistance operated at maximum power (250W) for one hour.
Just as I assumed that the mini-wind turbine constantly provides its maximum power.

In the absence of other information, this gives a first order of magnitude.

A wind turbine on a model of a scarf in the wind, which moves alone without losing ergodynamics, it does not exist, but is it stupid or not?

A device that recovers energy from the wind necessarily causes the wind to slow down. If this device is attached to a moving object, it causes a braking force on that object (just like the "horrible friction" of the dynamo.)

[Iubito]

aerodynamics, I don't know much about it, but those who do speed put on a streamlined helmet (point to the rear), and on a recumbent bike there are rear spikes instead of the luggage rack.
on the velomobile there is the complete fairing, pointed at the rear.
it avoids leaving a disturbance of air behind and therefore "sucking" the bike backwards (thus slowing it down)