E-bike battery charging while riding

[HAROX]

men in blue lead the throngs to some real insight.

I go a whole step further here. Without a doubt, every moderator, administrator and guru all share in delivering this critical thinking, and without this thinking from them, there would be no progress.
And the progression goes further than discriminating, as if we were somehow disconnected from them. We're not. They need us to fuel the fire, a lot of us! I guess the analogy would be the production of electricity. It takes some real physical power to do it, a lot of coaxing, calculating, etc., and the trickle of juice is as rewarding as the massive flow. Both require the same, thinking, and assent.
While it may be exasperating for these thinkers to answer the same old questions repeatedly, all one needs to realize are the sheer numbers of "more better thinkers" which are produced in this forum.
Whether you BUILD it or BUY it, and regardless of the power of it, these critical tenets are necessary to success, one would think... even with algae on the brain.

 

[amberwolf]

Is there any reason why a couple of 12V 6w tire generators couldn't be hooked up to the batteries to generate some juice?

Various threads discussing the same kind of thing in different ways:

http://www.endless-sphere.com/forums/viewtopic.php?f=41&t=32624
http://www.endless-sphere.com/forums/viewtopic.php?f=41&t=45365
http://www.endless-sphere.com/forums/viewtopic.php?f=41&t=29997

Short answer: Yes, you can do it, but you will *lose* power from it, not gain any back.

FWIW, it's the most common suggestion I get from people that talk to me about my bike(s); and explaining it to them takes too long, so I almsot always just give the short answer above.

 

[SamTexas]

Is there any reason why a couple of 12V 6w tire generators couldn't be hooked up to the batteries to generate some juice?

Short answer: Yes, you can do it, but you will *lose* power from it, not gain any back.

Here's one way for you to actually GAIN energy from your "tire electricity generators": Connect the generators to the brake levers so that the generators are engaged when you squeeze the brake levers and only when you squeeze the brake levers.

 

[itchynackers]

I still don't see where the OP is asking for free energy. Others seem to be assuming that.

Okay, what you're not seeing is that he's talking about USING the energy going downhill AND having it back. His cake and eat it two(2).

quote]

Where did the OP say that?

 

[Dauntless]

It's fine you posted in another thread, I was trying to make the point almost exactly the same discussion was going with more or less the same points, almost interchangeable. I'm not sure at what point not getting it begins after the just wanting to yank chains ends, but there are real people who wig out when you tell them NO.

I wish I could find this one video from maybe 8 years ago, online. This guy I guess had magnets all around a 26" bicycle wheel, erected with the derailleur and a battery powered drill turning the crank. As he shifted the gears he's showing the voltage going up from the wheel, as well as the voltage dropping for the drill battery. When there's more voltage coming from the wheel he starts screaming that he's done it. He'd said before this was his first test and he was recording it in case it was a success. What he was saying was that he was creating more power than he was using because the volt meter for the wheel was reading more than the volt meter for the batteries running the drill. You heard it here first.

I cannot begin to describe what came after. He stopped the drill and bent over to get his face in front of the camera, boy did he look semi human. Had trouble breathing too. The crazed eyes. He's going on about his invention and he's putting this out there so they don't get him the way they got this and that inventor of free power in the past and more. Yeah, now that we knew he'd done it they couldn't make him disappear in the night. Only thing missing was his address so they knew where to send his Nobel Prize.

I wonder if he has ever figured out what he was doing wrong. Damn I wish I could find that video again. THAT kind of stuff can really make these discussions fun. To think all it took was a derailleur to make the armature turn faster, so we get free energy.

 

[amberwolf]

Here's one way for you to actually GAIN energy from your "tire electricity generators": Connect the generators to the brake levers so that the generators are engaged when you squeeze the brake levers and only when you squeeze the brake levers.

5that's true, and I *almost* went back to add that in right after I posted, but I didn't, because it seemed obvious to me. (I guess it isn't, necessarily, for anyone new enough at this to want to add the generator in the first place).

 

[lbz5mc12]

I found an interesting disk brake mountable gear on amazon made by origin 8. http://www.amazon.com/dp/B008ZTLYOE/ref=wl_it_dp_o_pC_S_img?_encoding=UTF8&colid=2SRYXRN13FLKU&coliid=I15OPEUCC05UGY. I was thinking what if you were to bolt this on to a brushless hub motor and run a chain from it to a small Currie style motor? You use the regen while using the Currie motor to turn the hub motor along with pedaling. This would significantly lessen the resistant feeling of pedaling a bike with the regen engaged. Not only that you could use both motors at the same time like you would on a dual motor bike for climbing hills and greater acceleration. Just a though, I'm still working out the other details in my head. I have almost everything I need to try it. I just need a 24V battery pack, the gear and a way to mount the Currie motor over my front wheel. My Currie motor has a freewheel gear so I wouldn't have any resistance from just using the hub motor to drive the bike.

 

[dogman dan]

Pedaling with regen enabled should not increase the drag of a dd motor. Engaged, you'd just be braking of course.

This idea would work for getting dual motors and regen, on a hub motor with internal clutch, a gearmotor.

 

[amberwolf]

I found an interesting disk brake mountable gear on amazon made by origin 8. http://www.amazon.com/dp/B008ZTLYOE/ref=wl_it_dp_o_pC_S_img?_encoding=UTF8&colid=2SRYXRN13FLKU&coliid=I15OPEUCC05UGY. I was thinking what if you were to bolt this on to a brushless hub motor and run a chain from it to a small Currie style motor? You use the regen while using the Currie motor to turn the hub motor along with pedaling. This would significantly lessen the resistant feeling of pedaling a bike with the regen engaged. Not only that you could use both motors at the same time like you would on a dual motor bike for climbing hills and greater acceleration. Just a though, I'm still working out the other details in my head. I have almost everything I need to try it. I just need a 24V battery pack, the gear and a way to mount the Currie motor over my front wheel. My Currie motor has a freewheel gear so I wouldn't have any resistance from just using the hub motor to drive the bike.

I'm afraid I don't understand exactly what you're wanting to do.

I *think* you are talking about using one motor simply as a brake, and only using the other motor as the drive motor?

That'd be kind of a waste, especially since you are adding weight and complexity, having each motor plus it's own controller and wiring and whatnot, perhaps it's own battery pack, but only using one as a motor and one as a brake, when you could easily use just one of them as a brake.

There will actually be a little more drag on the system even on the flats because of hte extra motor, even with the freewheel there is sitll some resistance though it's small enough you problaby won't feel it. That, plus the extra mass of the additional system, will actually make your bike less efficient, and harder to accelrate and to go up hills because it weighs more.

If you want ot use the currie as a drive motor thru the side of the hubmotor, then you have ot set it up so it doesn't freewheel in the drive direciton, but only freewheels in the braking direciton (and thus can't be used as a brake). And ot use it as a brake, the freewheel will prevent using it to drive.


If you are talking about using the hub motor in regen mode *all the tiem* while using hte currie to drive the bike, well, you have just invented a power-wasting device. You can read all the other threads about that sort of thing scattered around the forum over the years, where people want ot use one motor to regen/capture energy at the same time the other motor drives.


If you want ot use them both for motors, then it makes some sense to add the currie to make 2WD, if you need the extra power for accleration or hill climbing, but since you are also adding the weight of motor/battery/contorller you are also using some of tha tpower just to acclerate/lift that added weight (that's the disadvantage of any 2WD system, plus it's one more thing to fail...though it also gives you redundancy in case the main systme fails).

 

[lbz5mc12]

No the hub motor would still be used as the primary motor. It's just when the battery for the hub kit gets discharged about 60% then start using the regen more constantly on the flats while having the Currie motor engaged. This way you still have a motor for assistance with pedaling and you're also getting the benefit of regen. Also with the Currie motor linked up to the hub motor, you could set the regen on the hub motor to the highest resistance level to maximize the affect. Another benefit would be to experiment with different gear ratios to see which works most efficiently. Originally the amazon seller had 3 sizes of gears, 16, 18, and 20 tooth count. I'll have to wait until the seller gets more in to order some which is fine cause I still need the money for them. Then of course there is still the benefit of it being a dual motor setup for acceleration and hill climbing.

While using the regen I would constantly pedal so I wouldn't be wasting energy.

 

[biohazardman]

With a motor running and you pedaling the energy you put out will be far greater than the energy you capture using regen. Motors are halfway efficient these days often 80-90% in the correct rpm and load range. Regen and generators not so much. They must be fed much more energy than they are capable of making. As amberwolf says you're reinventing an "energy wasting device" that has been invented so many times with the same end result. Find the specs on efficiency for the motor and then the efficiency of your regen device so you can see how huge the difference really is. Pedaling alone with regen on will charge the battery albeit barely with alot of effort. Pedaling with a motor going at the same time will discharge the battery. There is no free ride here. Maybe you can make a smallish inexpensive motor/generator and battery model with a hand crank to demonstrate your idea. This may save some $ for you and others.

 

[dogman dan]

If you want to regen while you pedal along to charge the battery, it will only take about a hundred miles of pedaling to fill up a 500wh battery.

This can be fine if you just need 100w of power to run a DJ and the bike is not moving.

But to fill a large bike battery takes epic pedaling. It's just horribly inefficient. That's why those wind turbines are so huge. That's why a coal fired plant wastes so much of the energy burned there. That's why it's not a great solution to tow a generator behind your leaf. Pedaling up much power is similar, only a tiny bit of the wattage you will sweat will get into the battery. Ever try to fill the battery on one of those wind up flashlights? Takes forever.

My experience with regen descending a mountain hill 4 miles long is that it slows you down, leaves you coasting less distance at the bottom, and barely put anything at all back into the battery.

And, I get to stop and check if my axle nuts got loose. I need a better torque plate to actually use my regen.

 

[amberwolf]

No the hub motor would still be used as the primary motor. It's just when the battery for the hub kit gets discharged about 60% then start using the regen more constantly on the flats while having the Currie motor engaged.

And thus you are "inventing" an energy-wasting machine, because it takes more power than you can possibly get out of it.

Pardon my bluntness, but this kind of thing has been discussed to death, but everyone that thinks of it themselves always thinks they have found a new way that will work where no one else's has. Many people (including myself) think of it when they first get into electric motors, magnets, and the like...but it simply can't work.

I'm not going to re-state the same things said hundreds of times before, so I highly recommend you go read all the other threads about people trying to use regen to recover energy while *not* slowing down. That's what you're all talking about doing, however y'all word it.

If you're really stubborn, go try it. Hook up calibrated wattmeters so you cna measure the energy usage of the motors, and the energy recovery of the motors, and you'll see you can't get back even what you put into it.

An even better proof is just to try braking with one motor while you power with the other, and see how quickly you come to a stop. (no pedalling is allowed, because then you are not testing the setup, as you are inputting separate energy).

Then of course there is still the benefit of it being a dual motor setup for acceleration and hill climbing.

Tha'ts the only benefit you get out of it. The ohter stuff is not a benefit becaues it doesn't work.

While using the regen I would constantly pedal so I wouldn't be wasting energy.[/quote]
Yes, you are--you're simply adding in your own body's energy, and you'll probalby find it's too hard to pedal against, once you have lost enough battery power in the system to run yoru batteries flat.



it'd be nice if it could work...but it doesn't.

 

[Drunkskunk]

No the hub motor would still be used as the primary motor. It's just when the battery for the hub kit gets discharged about 60% then start using the regen more constantly on the flats while having the Currie motor engaged. This way you still have a motor for assistance with pedaling and you're also getting the benefit of regen. Also with the Currie motor linked up to the hub motor, you could set the regen on the hub motor to the highest resistance level to maximize the affect. Another benefit would be to experiment with different gear ratios to see which works most efficiently. Originally the amazon seller had 3 sizes of gears, 16, 18, and 20 tooth count. I'll have to wait until the seller gets more in to order some which is fine cause I still need the money for them. Then of course there is still the benefit of it being a dual motor setup for acceleration and hill climbing.

While using the regen I would constantly pedal so I wouldn't be wasting energy.

I think the point you are missing is that regen is only recovering energy supplied in some other way..
For example, If the hub motor produces 80 watts while in regen mode, it does so by a 100 watt input. If that geared motor trying to drive it produces the 100 watts needed to make the effect neutral on your riding, it's consuming 120 watts. So you are putting 120 watts in, getting 80 watts out, and have wasted 40 watts you could have saved by not even trying. Those are example numbers, the real values would likely be much worse.

 

[UKTab]

My background is in ideas rather than technical knowledge so please go easy!
Is it possible to charge an e-bike battery while you're riding? I have a couple of blueprints that can 'feed' a battery while a bike is travelling, and just wondered if charging on the go is feasible.
Thanks,
UKTab

 

[Jon NCal]

When going down hills there is a method called regenerative braking that can recharge the battery. Also, solar charging is possible, well if sun is out.

 

[titusmc]

It has been done with solar panels, but it isn't practical to have much more than 100-200W and even that requires a trike or a trailer for mounting, along with a DC-DC converter/charge controller. Generally this amount of power wouldn't be enough to power the bike alone (need at least 250w for any reasonable performance), so you'd be drawing from both the battery and the panel while moving. Of course, when you stop the panel(s) can recharge the battery, although it will take several hours of good sun for a typical battery capacity (say 5 hours of perfect sun for a 500 Wh battery and 100W panel).

As for charging by other means, such as pedaling in regen mode, it has been covered many times on ES and is simply not sensible.

I imagine you could have a hydrogen fuel cell powered ebike, but it would be pretty damn expensive and complex.

 

[UKTab]

Thanks Jon, I meant how would I physically get power into the battery.
I know the battery goes through a controller which distributes the power, and I have a couple of ways to extract power from cycling that could charge up the battery. I suppose I was after a technical answer.

 

[UKTab]

Hi titusmc,
I don't need to power the bike or fully recharge the battery. It's more about getting some extra miles from the battery.

 

[Lurkin]

Yes, been done for years. Google bicycle Dynamo hub.

Regen is essentially the same thing, only rather than having a hub motor dedicated to charging batteries, it can be reversed to allow the motor to use power one way (going forward) and regen (brake).

Yes, you could cycle against it. No, its not a feasible way to charge your battery on its own really. You can expect to reclaim a max of 5% ordinarily. Better off with a larger battery or a faster charging small battery as the amount of power you are likely to use is going to be a rate far higher than your regen will generate (usually).

Yes, solar power is an alternative for charging on the go, others have already identified why this can work but usually isnt ideal.

 

[titusmc]

Hi titusmc,
I don't need to power the bike or fully recharge the battery. It's more about getting some extra miles from the battery.

In that case, regen braking with a direct-drive hub motor is your best bet. I have read that regen typically increases range by 6-14% - best I have seen on my bike so far is 7.2%. It really works best when you are descending a long hill that is steep enough that you would want to limit your speed anyway.

 

[amberwolf]

Regen braking will not increase your range, unless you already do a lot of hard braking anyway, or you have to brake on long downhills anyway.

If you do not brake a lot, regen isn't going to increase anything. If you just use regen while trying to move forward, you are wasting power and losing range.


I have about a dozen complete stops and starts on a 2.5 mile one-way commute, and I get at most about 2-2.5% regen on my CrazyBike2. On longer trips with less stops-per-mile, there is a lot lower percentage.

I have a couple of ways to extract power from cycling that could charge up the battery. I suppose I was after a technical answer.

The technical answer is that by taking ANY of your forward motion away to convert into any other form of energy, while using the motor at all, all you would be doing is discharging your battery faster, and getting LESS range from your battery.

If you are thinking that you will pedal with the motor off to generate power to charge it, you would be far better off to just pedal; you'll go farther doing that.

There is another recent thread
https://endless-sphere.com/forums/viewtopic.php?f=1&t=76337
on someone else that wants to do this, with many explanations that that member ignored, and there are dozens or hundreds of other threads on this too.

Read that whole thread first, it explains all this in many ways. If that's not enough, you can look for and read other threads about it.



IF you still want to experiment with it after that, simply turn on regen braking and try pedalling with that; it will add power back to the battery, but you probably won't be going forward very far before you turn it off.

 

[UKTab]

Thanks Etrike and Amberwolf.
I'll take a look through the thread.

 

[dogman dan]

Some form of external power supply, be it solar, or you just carry a generator, is easy. You just run the power through the charger port into the battery. Solar through a charge controller, or if running a gas generator you simply plug your charger into the generator.

To clarify about regen, regen works great when there is some weight involved. Stopping a lot of weight can generate some noticeable power. Like open pit mine trucks. Stopping a bike, assuming it's under 300 pounds generates hardly noticeable power. The inertia is low, and so is the energy available to harvest back.

But regen has it's uses, its good for reducing brake wear. I found as long as you had no stop light at the bottom of a hill, I could coast farther on the inertia than regen generated power could take me. Running regen all the way down a 3 mile hill made enough power to run about 1/4 mile. But it slowed me so much, I lost all my coast at the bottom. The coast could take me a full mile.

To me, the bottom line was clear, harvesting the inertia back through coasting, when possible, is more efficient.

But like I said, regen has it's uses. If a hill is too long and too steep to coast down safely, regen is a great way to slow down for many miles of downhill, without wearing out brakes. Regen works fine no matter how wet it is. Having regen is a good thing. It's just not going to put a ton of energy back into your battery because your bike is so light.

Pedaling while stationary, using regen to charge is fine. It just takes about 10 miles of pedaling to put in 1 ah, which then takes you about a mile. Seems to me easier to just pedal the one mile. But it still can be usefull, charge phones, run some light, in a remote place.

 

[agniusm]

I think 5-10% regen figure is for cars. Bikes must be more pessimistic.