E-bike battery charging while riding

[Kingfish]

The only way this arrangement will ever produce more power than what is consumed is by starting at the top of a steep hill and ending up at the bottom, or perhaps if you have Lance Armstrong's legs that can keep up with the load.

Wishful, KF

 

[GrayKard]

this has given me a idea when i build my bike to use a small, light , geared motor on the front wheel and batteries and controller on the triple clamps, not a lot of batteries as i will only us when a steep gradient off road happens, the added weight may even stabilize front end a little. it will free-wheel when not in use and help on braking this beast down-hill, still up in the air about using hub-motor on rear or mid-drive for my build, the regen may not be worth it but for a billy-goat climber for brief periods may be the answer than overloading and overheating a single motor, may be better for longer range as the gearing would not be so low to handle hills because of the helper front motor, could use a ratio for longer distance and slightly higher speed

A geared hub on front won't be able to help with the braking unless you get rid of the clutch/freewheel.

Regen really helps slow brake pad wear but doesn't return much unless you have a long ride. I use it on my rear direct drive hub and hardly have to change pads now.

Gary

 

[amberwolf]

it will free-wheel when not in use and help on braking this beast down-hill,

No, it won't. Can't have both.

 

[Ykick]

One potential valid reason for this would be if you have a gas engine bicycle and wanted to make it hybrid or tribrid. For people who simply have too far to travel on electric only you could use a gas engine on the rear plus a DD front hub motor with small battery pack. Use only electric when you require stealth in populated areas and/or need extra acceleration from stops or climbing hills. Cruise long distances under gas power while using regen to recharge the battery pack.

Of course there would be losses and all of that but for some situations this could be useful? Hasn't somebody done this around here before?

 

[Jethro56]

For some reason the most typical question I get from people when I tell them that I have an electric bike is "Can you charge the battery while you're riding?" I say "Yes, but why would I want to?" I take a spin class at the Y and working my ass off for an hour I can average just under 200 watts. The cost of electricity in my area is 13 cents/kwh. So even if the system was 100% efficient I could generate .2 X 13 or 2.6 cents of electricity and that's if I was sitting still.

P.S. These people also drive their SUV's 2 miles to the Y so they can walk on the treadmill.

 

[dogman dan]

Shows how far the EV hype has penetrated. They don't say regen will recliam all of your energy when stopping giving a free ride. But they don't go out of their way, when selling a prius, to mention how piss poor the return of regen really is.

I'm not knocking regen here. 10% or whatever back is fantastic. But the way they write the copy makes it sound like so much better.

Next thing you know, the general population thinks you pedal the bike a block, and get 500wh of charge for it.

If you ask me, I think all that EV sales hype just does the cause a big disservice. People just start out expecting all this stuff they aren't going to get due to the misleading sales spiel. Typicaly it's the range at speed lies, and then they are dissapointed after having been sort of told, to expect more.

 

[corkscrew]

They used to make 6v bicycle light generators that friction drove on the tire. Perhaps one of those would be best for that small recharge purpose. Lighter than motor hubs. Pedaling with on of those on the bike was a real big resistance. Really amazing how much pedaling it took to keep that little bulb bright.

Those old friction drive dynamo's suffered from a lot of the same things early adopters of friction drives saw. Mainly slippage.

Anymore if your looking at bicycle stuff from an unpowered perspective, people will go with a hub dynamo, and there are device charging options available.

http://www.peterwhitecycles.com/schmidt.asp
http://www.peterwhitecycles.com/pedalpowerplus.asp

Although now that I'm on the powered side of things - it would almost be cheaper to just buy a new hub motor than one of Peter White's hub dynamos.

 

[vintagerider]

very cool headlight system thanks http://www.peterwhitecycles.com/schmidt.asp but correct me if i am wrong isnt this just a brushless hub generator? (Dynamo?) on a smaller scale? so the hub making power is already been done and is quite expensive for this teeny little hub generator , but it looks very cool and i love the red anodized ones. looks like it can power two headlamps while riding with very little resistance, thank you corkscrew this almost justifies looking further into modifyind and old used hub to see how much the rolling resistace can be reduced by removing some windings and possibly magnets so it produces some power with little resistance will be looking on e-bay for some old stuff to play with

 

[amberwolf]

The thing is, you are still wasting much more power than you could possibly get back from the generator. it would make much more sense to just carry that much weight in more battery.

If you already have a motor on the bike then you already have a generator by using regen mode. Only way you don't is if you have a freewheel between motor and wheel. So don't use a freewheel, and you have your generator and your motor in one smaller lighter package than having a second generator. Use the saved weigth for more battery.

Really...it's that simple.

Your choice, though.

 

[fmadwid]

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

 

[chvidgov.bc.ca]

The Second Law of Thermodynamics?

 

[NeilP]

You could, but you would be using more power to make the bike go, because the drag they create needs to be overcome, so that power will need to come from somewhere..so if you are nto pedalling then that power will be coming from the bike battery, via the controller, motor and wheel. If you could engage it only on the downhill sections, or engage them somehow only when you want to slow down and use them like that then you can create power, but otherwise it is nto worth it..you will only end up with less power hence :

The Second Law of Thermodynamics?

if you did make it work though and ended up with more power than you started with..then you have created perpetual motion and have suddenly become a multi billionaire over night..or more likely you will be assassinated by the oil companies

 

[dogman dan]

It would work going down hills. It would work if you pedaled the bike while stationary, with the wheel off the ground, and the generators were on the back wheel.

But it's not efficeint, while just turning down the throttle and pedaling is.

 

[itchynackers]

To answer the question, no there isn't any reason you couldn't do it. It depends on what your are trying to do though. If you are pedaling (no assist), then you could charge the battery. You could also power a light. But if you are trying to charge the battery while your battery is driving the motor, then you are wasting energy.

 

[HAROX]

This is the thread I've been hoping for. Every couple months someone asks this again, and each time the answer gets closer. You don't get something for nothing, and you could get something for going downhill :lol:
I think a separate generator and battery bank could allow one to capture and store on the downhill run. Yeah, it's a drag, it's a drag that can power some profound electric gadgets.
That's all I'm going to say.

 

[Dauntless]

This is the thread I've been hoping for. Every couple months someone asks this again, and each time the answer gets closer.

Closer to WHAT?

You don't get something for nothing, and you could get something for going downhill :lol:

So what you're saying is, you're going to lug around the weight of these generators with them doing nothing for you until that moment when you head downhill, then for that one mad instant:

POOF!

They charge the battery. A penny's worth? two? What did you spend on all that? How much did the weight waste until then? My feeling is that damned "Degenerative Braking" slows such things as my Voy Electra when I go downhill so I lose momentum without getting anything in return. Same thing when I try to coast a bit on flat ground, the DEGENERATIVE braking wastes electricity.

To you, even more than those usually asking that question, I have an analogy. It's been said that if you were stranded with no food or water except celery, you would die sooner if you ate the celery. For the effort of getting a stalk of it and chewing/disgesting it, not only are you using more energy than you can get from celery (This is why it's considered diet food) but the SALT would dehydrate you faster. Now, can you convince yourself, starving as you are, to NOT EAT THE CELERY????

 

[HAROX]

POOF!

They charge the battery. A penny's worth?

To you, even more than those usually asking that question, I have an analogy. It's been said that if you were stranded with no food or water except celery, you would die sooner if you ate the celery. For the effort of getting a stalk of it and chewing/disgesting it, not only are you using more energy than you can get from celery (This is why it's considered diet food) but the SALT would dehydrate you faster. Now, can you convince yourself, starving as you are, to NOT EAT THE CELERY????

I got it, just like last time, Dauntless. It's a diminishing return, still. Charging any battery requires a super amount of power, and that shit don't grow on trees, or in a celery patch.
Oh that I wish it did, or that my brains were algae and I could make gas out of two places at once...

 

[itchynackers]

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

 

[Dauntless]

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). The assumption that it doesn't cost anything energywise to carry the little generators around when they're not in use, that you are simply losing all that energy of descending the hill, that's not really true. The recovery doesn't match the losses. And that is before you pay for these parts. It's not what we're assuming, it's what we're seeing.

Someone even carried the celery story over to another thread that has the same "Free energy that isn't really free energy" concept being discussed. The discussion would be fun if only the people making the mistake didn't get so irate. All these relatives that swear they can build a self charging electric motorcycle by hanging generators off it, a 3.5hp engine can power a dyno to run the whole house if just help it to speed first, etc., they sure get annoyed when I try to shed a little light on the process.

(Wait 'til you hear my NEXT analogy. And maybe the one after THAT.)

Some things you just can't avoid, no matter what you argue. Such as:

 

[NeilP]

I have my regen on my bike wired in two ways, via the brake switch and also a on/off switch on handlebars. I often go down some particularly steep hills in traffic where you are braking all the way. So regen is on all the time.

As soon as someone asks about recharging the battery while pedalling, I flick the switch, and tell them to go for a pedal and figure it out for themselves. They soon get the idea that it would make a good exercise bike, creating more effort to cycle, but as an idea for an electric assist bike to make your life easier it does not work. With my regen on, you even have to pedal hard going down hill

 

[HAROX]

Someone even carried the celery story over to another thread that has the same "Free energy that isn't really free energy" concept being discussed. The discussion would be fun if only the people making the mistake didn't get so irate. - they sure get annoyed when I try to shed a little light on the process.
(Wait 'til you hear my NEXT analogy. And maybe the one after THAT.)

Dauntless, let me crawl out of my cave-man and say, I was the one who exported your analogy to the other thread, since it was directed to me. I'm not irate, so according to you this discussion could be fun once again. As for being annoyed, maybe you could be annoyed with me, in which case, I'd go crawl back in my cave-man.

As for your analogies, they are less anal and more logical :lol: Getting tired of making the point is no excuse for not trying to "shed a little light". Even me, a dumbass, reconizes what you're saying is valid. BTW that's what they call a "valid argument".

 

[dogman dan]

Well, he never asked if it would be efficient. Just could you do it. Sure you can.

We just chimed in with how inefficient it would be. It can make sense in a few situations, like keeping a battery for something (usually music) charged in a place with no power, but lots of young energetic people.

If the bike has a direct drive motor, then you already have a generator, and need only to enable it to regen down hills and during braking. The big return is mostly less brakes wear though.

 

[arkmundi]

By far the best use I've seen is the guys hooking up a bike generator to a blender for smoothies at the local fairs. They bike with a trailer to haul the gear and fresh fruit, setup and sit back in the sun to pedal their way into everyone's hearts.

 

[HAROX]

Damn! THIS is why endless sphere is an asset to all critical thinkers, and all novices to the art form! See, the men in blue lead the throngs to some real insight. All critical thinking requires this sort of interplay, and it's something severely missing in all our daily lives. Kudos to everyone. Hang in there.

 

[Jeremy Harris]

A good illustration of the potential of regen (which is essentially what using a generator to charge when going down hill or braking is), is to look at the practical figures achieved by vehicles that use it. The Prius, for example, has a pretty optimised regen system, with the ability to dump well over 100A back into the battery pack when braking. The Prius uses regen instead of the brakes all the time, and only uses the brakes for emergency stops and for bringing the car to a final halt when stopping. Despite all this optimisation, regen only gives between 5 and 8% improvement in mpg. Those who've measured the effect have concluded that the efficiency of regen as a means of recovering energy when braking or going downhill depends on vehicle weight. The heavier the vehicle, the more likelihood of making a worthwhile gain.

On an ebike it's not likely that the gain would be worth more than a few percent of extra range at best, probably not worth the hassle of doing it. If you have a direct drive hub and live in a hilly area then it might be worth doing by using a regen capable controller, but I doubt if carrying the extra weight of additional generators around would make much sense.