2 wheel drive ebike with self charging

[fabieville]

I have a ebike with a 24v-72v 3000watt mid drive cyclone motor currently running off a 24v lithium battery pack.
I am planning to install a 48v or 60v front hub motor on the front wheel for the sole purpose of recharging the battery. So basically whenever the bike is in motion at a certain rpm I suspect that the front hub motor would produce a voltage higher than the 24v battery and with the aid of a blocking diode it would send the current to the battery.
The front hub motor will weight around 8-10 lbs, and it has little to no drag.
Do you think this method is feasible? Will the charging performance makes sense even with the added weight on the bike?
So in essence if I use to get a 15mph commute on my bike on a flat terrain at full throttle, with the charging method addon I will get more mph even with the added 8 or 10lbs at full throttle?

 

[john61ct]

No, same reason a perpetual motion machine or those "unlimited energy" schemes are impossible.

Like mounting a wind generator driven by the side-effect airflow on a fossil-fueled truck

Regen certainly works, **when you are coasting** down a long hill or have to stop every few blocks.

But it is in reality at most 10-15% of the energy taken from the battery in most circumstances.

Using the power expended from one motor as the input for the other "generating" power, is **always** going to be a huge net loss from all the inefficiencies involved.

 

[MadRhino]

So far, the only self charging means are solar (slow), and wind (rare). So you have choice of crawling under your large solar panels, or flying occasionally where your sail wants to.

Freedom is a powerful, fast charging battery.

 

[john61ct]

Yes, ideally with an onboard charger plugs into EVSEs as well as a variety of regular outlets.

Not practical for most (yet)

 

[amberwolf]

I have a ebike with a 24v-72v 3000watt mid drive cyclone motor currently running off a 24v lithium battery pack.
I am planning to install a 48v or 60v front hub motor on the front wheel for the sole purpose of recharging the battery. So basically whenever the bike is in motion at a certain rpm I suspect that the front hub motor would produce a voltage higher than the 24v battery and with the aid of a blocking diode it would send the current to the battery.
The front hub motor will weight around 8-10 lbs, and it has little to no drag.
Do you think this method is feasible? Will the charging performance makes sense even with the added weight on the bike?
So in essence if I use to get a 15mph commute on my bike on a flat terrain at full throttle, with the charging method addon I will get more mph even with the added 8 or 10lbs at full throttle?

If it were possible for this to work, then it would be perpetual motion / overunity / free energy....

If you want to know why this won't do what you want, I recommend reading the existing threads on the topic, which explain the problem in many ways.

Like this, which is a long concatenation of threads on this topic:
https://endless-sphere.com/forums/viewtopic.php?f=14&t=78660
and this
https://www.diyelectriccar.com/forums/showthread.php/alternators-free-energy-perpetual-motion-over-13449.html
And these
https://endless-sphere.com/forums/viewtopic.php?f=3&t=95921
https://endless-sphere.com/forums/viewtopic.php?f=41&t=45365
https://endless-sphere.com/forums/viewtopic.php?f=3&t=95921
and lots of others.

 

[donn]

I have to wonder if there may be some misapprehension over the expectations. It isn't clear to me that it isn't just intended as an auxiliary that adds a regen function in a setup that didn't have it already.

Not that I'm saying it would work, anyway. It sounds ("certain rpm ... voltage higher than the 24v battery") like there's to be no controller for this hub, it's just wired straight to the battery (via that diode.) I see nothing about any control device like an e-brake that would limit the switchover to downhills, and the diode apparently cuts the mid drive out, so we would hope that threshold is higher than a speed the mid motor can reach. As the grade gets steeper, the hub voltage will keep going up, which seems like it would be an interesting challenge for the BMS if there is one.

 

[amberwolf]

Well, given the underlined part (see quote of OP at end of this post) specifying just a motor and diode to go to the battery, it can't be just for regen braking--that would require a controller. Using just a diode (assuming a BLDC would need a three-phase bridge rectifier) will simply do what he says, above a certain speed the motor will generate enough voltage to be higher than the battery and so begin dragging the bike's speed down, converting it to energy to charge the battery instead.


Then, in bold, he is expecting to go *faster* while the above is happening, which wont' work (as noted it will *slow* the bike).

Additionally this whole process is just going to drain his battery faster than if he didn't waste power by converting it into forward motion that is then converted into braking that is then converted into battery power, with the losses at each stage eating up the battery faster.


The links I posted explain these problems, and why this kind of system does not (cannot) do what those that propose it want it to do.

I have a ebike with a 24v-72v 3000watt mid drive cyclone motor currently running off a 24v lithium battery pack.
I am planning to install a 48v or 60v front hub motor on the front wheel for the sole purpose of recharging the battery. So basically whenever the bike is in motion at a certain rpm I suspect that the front hub motor would produce a voltage higher than the 24v battery and with the aid of a blocking diode it would send the current to the battery.[
The front hub motor will weight around 8-10 lbs, and it has little to no drag.
Do you think this method is feasible? Will the charging performance makes sense even with the added weight on the bike?
So in essence if I use to get a 15mph commute on my bike on a flat terrain at full throttle, with the charging method addon I will get more mph even with the added 8 or 10lbs at full throttle?

 

[dogman dan]

The really impossible thing he asked for, is the motor has little or no drag. Sure, if its not in regen, and going slow enough, drag is low. But at faster rpm, and regen engaged, its going to feel like he's towing a few anvils.

That drag, that's the catch 22 that makes it a perpetual motion idea. if you could do it without the drag, we'd all have our houses powered by a perpetual motion machine. Fan blowing on a windmill, etc.

 

[MadRhino]

Some people want to believe in magic. But, there is none, and we have only logic to deal with.

 

[john61ct]

Oh no, magic is real, just that your negativity will ruin it!

We really need more positive thinking around here, then anything is possible. . .

 

[MadRhino]

Oh no, magic is real, just that your negativity will ruin it!

We really need more positive thinking around here, then anything is possible. . .

Carpets are cheap. Buy one, sit on it and think positive until it does replace your bike. Tell us when you are ready, so we can all think positive together with you, to help it fly higher and faster. If the experience is positive, then all of us will save a lot of money, and give a boost to carpet industry.

If it doesn’t work, you could paint pigeons in flashy colors, and sell them for parrots to positive thinking people. Then you can buy a better bike and a bigger battery.

 

[dogman dan]

Re reading his original post, he could use a voltage converter to bump his voltage up, increasing his potential speed.

The thing would make heat though, reducing his total usable watt hours, and then of course his wind drag at higher speed would cost him even more range.

I'm not generally a negative thinker, like some here can be. But I positively believe in some basic science being correct.

If what we wish for was possible, Tesla would have been the guy who figured it out.

 

[momus3]

OK, it was a hassle, but I got the pigeons painted. Trouble is, they still don't look much like parrots (maybe I should have used acrylics?), and they absolutely refuse to talk no matter how much I try to bribe them with McDonald's french fries.

 

[MadRhino]

You are half way there. Tell them to shut up. If they start talking, everyone will know they are not parrots. And, positive thinking persons are not expecting cheap parrots to talk from the start. They want to teach them. Then you need to improve your painting technique in the nature, not in rave parties or psychedelic experiences.