Portable Charger for EUC batteries with a Turbine or Pedal

[Kudays]

Hi Guys,

Do you know if there are any portable chargers for EUC batteries with a Turbine or Pedal ? There are already portable chargers for mobile phones. I think it would be a great solution in emergency cases. 

Here is one example for mobile phones: 

 

[Chriull]

29 minutes ago, Kudays said:

Hi Guys,

Do you know if there are any portable chargers for EUC batteries with a Turbine or Pedal ? There are already portable chargers for mobile phones. I think it would be a great solution in emergency cases. 

Here is one example for mobile phones: 

 

For mobile phones one just need energy in the range of 3wh (to fully charge them). For a unicycle this is about nothing...

Just for a rough idea of the requirements: the motor in the euc is  (like every e motor) also a generator. To get energy from it to drive again, one has to put (a bit more) mechanical energy "into" it than one want to use afterwards.

Also one could make a generator more efficient (gearbox, rpm) and smaller (euc does not need to be fully recharged), but still would be not really portable.

So better to plan a stop for longer tours and recharge with the normal charger.

 

[Keith]

 

3 hours ago, Kudays said:

Do you know if there are any portable chargers for EUC batteries with a Turbine or Pedal ?

I did have to giggle at this question, if you want to wind a handle to charge up the battery why not cut out the middle man - and all the associated efficiency losses and just use a bicycle, if you run out of energy on one of them you just need a snickers or mars bar to top up again! 

3 hours ago, Chriull said:

Just for a rough idea of the requirements: the motor in the euc is  (like every e motor) also a generator.

To put this into perspective, a very good cyclist can probably sustain about 250W http://mapawatt.com/2009/07/19/bicycle-power-how-many-watts-can-you-produce . Turning that into electrical power is likely to be (say)80% efficient so generating around 200W. Hence to recharge a 400Wh battery is going to take at least two hours of VERY strenuous peddling. Not to mention the weight of the equipment you would have to carry to do it. As @Chriull says, the EUC motor is a generator so you could possibly add gears and peddles to that motor and spin it up to charge but I doubt very much that regenerative braking would have anything close to 80% efficiency or even half that figure.

pretty much a non-starter really.

 

[Kudays]

19 hours ago, Keith said:

 

I did have to giggle at this question, if you want to wind a handle to charge up the battery why not cut out the middle man - and all the associated efficiency losses and just use a bicycle, if you run out of energy on one of them you just need a snickers or mars bar to top up again! 

To put this into perspective, a very good cyclist can probably sustain about 250W http://mapawatt.com/2009/07/19/bicycle-power-how-many-watts-can-you-produce . Turning that into electrical power is likely to be (say)80% efficient so generating around 200W. Hence to recharge a 400Wh battery is going to take at least two hours of VERY strenuous peddling. Not to mention the weight of the equipment you would have to carry to do it. As @Chriull says, the EUC motor is a generator so you could possibly add gears and peddles to that motor and spin it up to charge but I doubt very much that regenerative braking would have anything close to 80% efficiency or even half that figure.

pretty much a non-starter really.

 

 

I cannot just use a bicycle, because it is not portable. Imagine that you realised that your EUC ran out of charge, just in the middle of an off-road tour. Thinking that you can go about 30 - 40 km far away from the starting point, it is not a distance to walk back carrying your EUC in your hand. 

250 W power is quite enough to use in emergency situations. Not only for EUC! Imagine that you are using an electrical engine for your boat and ran out of charge in the middle of ocean. You must have a powerful mechanical recharger system to use in emergency situations. I thought it is already needed and produced by some companies.    

     

[US69]

20 minutes ago, Kudays said:

250 W power is quite enough to use in emergency situations. Not only for EUC! Imagine that you are using an electrical engine for your boat and ran out of charge in the middle of ocean. You must have a powerful mechanical recharger system to use in emergency situations. I thought it is already needed and produced by some companies.    

This charger in your Video is able to Charge about a 3-4000mah cell....Our Ewheels hold about from 15 - 130 of this cells. Lets say in middle 60cells.

So just think about "turning" 60 of this diy charges at the same time 

[IPS Malta]

Well, as many above mentioned motor also acts as a generator. It only takes to find some long slope, walk it up and ride it down (probably several times), or at worst on your way help the EUC uphill by kick riding (slowly) while braking and brake downhill to regenerate energy in the battery. It should help for the last solution without battery and make sure you charge it normally ASAP

[Keith]

6 hours ago, Kudays said:

I cannot just use a bicycle, because it is not portable. 

250 W power is quite enough to use in emergency situations.

Ah, you didn’t get it did you?

In order to generate 200W (not 250 that is input power not output power) of electricity would take a highly efficient generator being powered by a bicycle like rig, at the very least something like an exercise bike. Only a very fit pair of legs could produce that sort of power for an extended period of time - it is, after all 1/3 of a horse power. So a 200W generator would be every bit as unportable as a bike. Any sort of hand generator would, as @KingSong69 and @Chriull have pointed out above produce just about enough power to keep the headlight lit and not much more.

[esaj]

I join the choir here, and say it's not practical, similarly to the ideas of using solar panels (unless you can carry a very big and heavy panel with you). The power needed to charge a unicycle in any "sensible" time is about hundred-fold compared to a mobile device, which are designed to work on as little power as possible. A cellphone battery holds less than 10Wh, "decent" EUCs have batteries ranging from 680 to 2400Wh. You're spending about 10-20Wh per kilometer, that's about one to three cell phone charges from zero to full, depending on the phone battery size. 

I took a quick look to find some values for the device, but didn't really... just picked these up from some review:

"Eton says that 1 minute of cranking will give you 4 minutes of talk time. You need to rotate it about one or two revolutions per second to generate enough energy to charge the battery."

Not bad, but how much talk time does a full phone have, something like a couple of hours at least (>100 minutes)? It would be more useful if they'd give some other unit than "talk time minutes", but still, that's not much charge. That still sounds like at least half an hour of cranking to get the phone battery full, which would get you about 1km on wheel, if you weight 60kg (130lb) or less and the wheel is low powered.

Also, I suspect that pumping the voltage up high enough will flush the efficiency further down the toilet, at least most phones seem to use single cell (4.2V maximum voltage when fully charger), most EUCs have 16 or 20 cells in series (67.2-84V max), which means even more cranking.

"Though the BoostTurbine has four LEDs that lit up to show the battery's level when I turned the crank, it was hard to tell exactly how much power I was creating. For instance, if the battery is at 50 percent, two LEDs will light up solid and a third will blink, indicating that you're charging the battery. I never got the next light to come on, as my hands got tired after a few minutes of continuous cranking."

Hands tired after a few minutes? To get a few kilometers/miles home, you're looking at least an hour or more of continuous cranking...

 

Edit: just want to point out that I'm not saying it's "stupid" or anyone's stupid for suggesting this, just a general problem that human body is not very good at producing such an amount of energy (especially with all the inefficiencies of the entire chain from mechanical motion to electrical/chemical energy in the battery) that's needed to charge the wheels. Usually the problem is either the low power produced, if using a person to produce the power, or with renewable energy sources (such as wind turbines or solar panels), the size and weight of the equipment for enough power (As an example, about 1 square meter / 10 square feet solar-panel would weigh about 10-20kg, that's 22-44lbs, and would produce something like about 200-250W in direct sunlight, minus all the losses that come in the voltage boosting for the final power output) . BUT, if someone manages to make a foldable, relatively light-weight solar panel and circuitry that can boost the voltage up high enough without significant losses, even with a couple of hundred watts of actual power output and fitting into a backpack, that you can then just take out and spread out during a break of an hour or so, it would start to make sense.

 

[dmethvin]

If recharging via pedaling is desired, it seems like the best way to go would be to get an electric bicycle with regenerative ability. As others have noted, a setup with an EUC will require a bunch of extra external equipment that isn't portable. With an electric bike you get all the equipment in an integrated package that's easy to take with you.

[Hunka Hunka Burning Love]

K-Tor pedal generator.

 

[Keith]

13 hours ago, Hunka Hunka Burning Love said:

K-Tor pedal generator.

Interesting, great find @Hunka Hunka Burning Love and well worth further investigation - but not THAT much investigation. I quickly found this YouTube video 

 

That states that this is an “amazing, portable 20 WATT generator for only $200”.

This quickly allows us to put some, very convenient, EUC numbers onto this device. It is generally considered that most EUC’s carrying an average load will consume around 20Wh per mile.

Let us be REALLY generous and  assume absolutely 100% efficiency in your charge circuit and that this device plus some sort of charging  converter generates a high enough voltage to actually charge your EUC. Then after peddling the device for one whole hour (just like the wife in @Hunka Hunka Burning Love‘ video) you will get exactly 1 mile of range out of your EUC.

If not actually completely impractical it certainly would border on the masochistic, I very much suspect walking the EUC with its handle would burn less energy and get you home quicker.

 

[Hunka Hunka Burning Love]

Maybe get a couple of the hand generators and two of the pedal ones to put them all in parallel to pump out some serious wattage!    I can just imagine the looks as people see you and your riding friend hand cranking and pedaling to charge up your rides over 5 hours of cranking!

[Kudays]

15 hours ago, Hunka Hunka Burning Love said:

Maybe get a couple of the hand generators and two of the pedal ones to put them all in parallel to pump out some serious wattage!    I can just imagine the looks as people see you and your riding friend hand cranking and pedaling to charge up your rides over 5 hours of cranking!

 

On 3 December 2017 at 4:13 PM, Keith said:

Let us be REALLY generous and  assume absolutely 100% efficiency in your charge circuit and that this device plus some sort of charging  converter generates a high enough voltage to actually charge your EUC. Then after peddling the device for one whole hour (just like the wife in @Hunka Hunka Burning Love‘ video) you will get exactly 1 mile of range out of your EUC.

Thanks, i got my answer to the question. I guess portable pedal power generator is a very new prototype. I expect they will make a more powerful product. So that we can charge our EUCs in a very near future.

 

[dbfrese]

2 hours ago, Kudays said:

I expect they will make a more powerful product.

Probably not. The efficiency of a generator is not something that will get better any time soon, and it isn't even the efficiency of it that is the limiting factor. The power limitation is on the input side, in other words the human element. Watch the video below and see how much effort it takes to toast bread. The amount of energy needed to power the motor in an electric unicycle is not trivial, and is even greater than the needs of a toaster. 

Even if you hired this Olympian to follow you around on your EUC carrying the bicycle hooked up to a generator, it would take him several hours of all out effort to charge your wheel back up to 100%

 

 

[Chriull]

9 hours ago, Kudays said:

 

Thanks, i got my answer to the question. I guess portable pedal power generator is a very new prototype. I expect they will make a more powerful product. So that we can charge our EUCs in a very near future.

 

No. Generators are an old, well developed and understood technology. Future efficiency increases by new materials/developments will be marginal.

And even increasing efficiency to 100% would not help, as

6 hours ago, dbfrese said:

Even if you hired this Olympian to follow you around on your EUC carrying the bicycle hooked up to a generator, it would take him several hours of all out effort to charge your wheel back up to 100%

 

 

this man produced ~700W for 1 to 2 minutes generating in total 21Wh, leaving him totally exhausted!

The above linked amazing, portable 20W generator would need 1h for the same amount of energy, 10 hours for 200Wh. And now regarding 100% efficiency not beeing possible, its easy to see that this never ever is going to be a feasable solution.

Until portable fusion reactors or similar new technologies are available spare battery packs, recharging stops at restaurants,etc or trollying/carrying the euc are about our only possibilities!

Ps.: @kudays, your "wrong" thought is to hope for "a more powerful product", but a generator is just transforming power. So one would need more powerfull human beeings...

Pps.: ...which would lead to much more powerfull eucs needed to be interesting and by this make portable generators no solution again...

[Hunka Hunka Burning Love]

I wonder if that cycle generator that he was riding had a gearing system like on a 10 or 21 speed bike whether that would have made it easier for him to produce power for a longer amount of time.  Maybe add on a heavy fly wheel too?  Sort of like climbing a really steep hill if you have it in the wrong gear it will be a bear to climb, but gear it down a bit, and it's manageable with lighter forces on the pedals.

With all these Tesla Supercharger stations popping up, it would be cool if someone could create an adapter to connect to the Supercharger port and convert it to allow us to charge our EUCs.

[Chriull]

5 minutes ago, Hunka Hunka Burning Love said:

I wonder if that cycle generator that he was riding had a gearing system like on a 10 or 21 speed bike whether that would have made it easier for him to produce power for a longer amount of time. 

Looking at https://en.m.wikipedia.org/wiki/Human_power it seems that he was already at some quite efficient gear ratio.

5 minutes ago, Hunka Hunka Burning Love said:

Maybe add on a heavy fly wheel too? 

A fly wheel should just average peaks, or be "feed" over hours with energy to release it in short time - anyhow it won't help as it does not produce energy - it just can "store" it.

5 minutes ago, Hunka Hunka Burning Love said:

With all these Tesla Supercharger stations popping up, it would be cool if someone could create an adapter to connect to the Supercharger port and convert it to allow us to charge our EUCs.

Yeah! Charge the euc to 100% in a second ?

[Kudays]

15 hours ago, Chriull said:

Ps.: @kudays, your "wrong" thought is to hope for "a more powerful product", but a generator is just transforming power. So one would need more powerfull human beeings..

No i am not wrong. In the video you have sent, Robert forced the finish the task in minutes! That's the problem. So that's why he has to use his full energy = 700 Watt. So the calculation: 700 W x 2 minute = 700 W x 0,033 h = 23,3 Wh energy. One can easily pedal for 1 hour if driving parts have frictionless just as in the video below

  

This man can produce 300 Wh energy in 1 hour pedalling that i think enough to charge a EUC battery. But i need something portable so i will buy a  K-tor powerbox (20 W pedal generator) and pray to find more people around to help me pedalling in an emergency. 

[US69]

purposeless....

[Chriull]

40 minutes ago, Kudays said:

No i am not wrong. In the video you have sent, Robert forced the finish the task in minutes! That's the problem. So that's why he has to use his full energy = 700 Watt. So the calculation: 700 W x 2 minute = 700 W x 0,033 h = 23,3 Wh energy. One can easily pedal for 1 hour if driving parts have frictionless just as in the video below

  

This man can produce 300 Wh energy in 1 hour pedalling that i think enough to charge a EUC battery. 

He _stated_ that he _could_ produce 300Wh if he _would_ ride for one hour!

According to the link https://en.m.wikipedia.org/wiki/Human_power of my previous post he would by this almost perform like a well trained cyclist during a one hour race! But he stated while riding he feels comfortable. Like riding up a moderate hill!

"During a bicycle race, a well trained cyclist can produce / sustain close to 400 watts of mechanical power over an hour and in very short bursts over double that: 1000 to 1100 watts (modern racing cycles have greater than 95% mechanical efficiency). An adult of good fitness is more likely to average between 50 and 150 watts for an hour of vigorous exercise."

So between 50 to 150 Wh are possible for an adult of good fitness!

There is _no_ way to get more than this 50 to 150Wh per hour into the battery as an adult of good fitness. No matter how frictionless, powerfull or whatever the generator is!

Ok one way is possible - take a break and invest another hour, and than another hour... or train like a professional cyclist and one can deliver about 400Wh...

One could use this 50 to 150Wh better and more efficient to walk/carry/trolly his euc for an hour...

... Or take a 3-400Wh spare battery pack, a dc to constant current converter and recharge the wheel for an hour taking a break...

Quote

i need something portable so i will buy a  K-tor powerbox  or) and pray to find more people around to help me pedalling in an emergency. 

So it takes an hour to produce 20Wh...

Since driving this generator did not seem exhausting (and 20W also should not) you'd need no more people but very very much time...

[dbfrese]

[Mono]

To quickly recap: let's say you need to travel 10km. For this you need to charge the EUC at the very least 100Wh, which requires at the very least 1 hour of pedaling (given that suitable equipment is available). Plus 1/2 hour for driving 10km (probably longer though, because fast driving requires more Wh). That means even in the most optimistic scenario you can only save 25% of travel time compared to walking 10km in 2h.

[RooEUC]

I have a portable pedal generator. It’s called a Power Box by KTor. It maxes out at 20w at 120v DC.  It folds to fit in a backpack and it’s great for charging multiple phones on camping trips but it would be useless for charging an EUC.  

I also converted an electric mountain bike into a pedal generator.  I could sustain an output of 80 watts but it was hard work.  To charge my EUC I need 125 watts for a couple of hours. Imagine pedalling as hard as you can, breaking a huge sweat, exhausting your body for 30 minutes to put 30 minutes of ride time back into your EUC.  And carrying the large, heavy, bulky generator in a huge backpack.  It would make more sense just to walk.  A small folding kick scooter would be less bulky and heavy than an EUC and powerful pedal generator.  And it would be less work.  It is just not possible for a human to charge an EUC by pedal power in a way that makes it useful.  

There is no new pedal generator about to hit the market that will let a human produce say 200 watts comfortably for long enough to charge an EUC.  We are limited by the amount of kinetic energy we can produce with our limbs.  The laws of physics are not on your side with this. 

Why not just carry a portable power pack?  I ride with enough extra power in my backpack to triple my range.  And it takes up no more space than a small laptop.

[KalSeth]

Not to hijack the thread but slightly related.  I wonder if an old unicycle could be repurposed to be a turbine for a micro hydro installation

[Chriull]

3 hours ago, KalSeth said:

Not to hijack the thread but slightly related.  I wonder if an old unicycle could be repurposed to be a turbine for a micro hydro installation

Yes. Should work out. Just nothing is waterproof!

And maybe one has to look to reach some range of rotational speed to get some efficiency.

Also care should be taken that the LiIon's are not overcharged (too high current by too high speeds of the "turbine") and overvoltage protection is by BMS shutoff at some voltage a bit above 4,2V, so not optimal for battery lifetime. Cell balancing of the BMS could be insufficient, too.