Propping up the backwheel and regen by pedaling

[swbluto]

So, you're about 70 miles away from home and you ran out of energy and you didn't bring your charger with you.

Sucks, doesn't it? I was just there.

I just wanted enough energy for the hills as pedaling on the flats is pretty easy, but I barely had enough energy for that. (Thankfully, I had *just* enough since I went slow enough and furiously pedaled in the granny gear, but not a watthour more)

What if you could somehow prop up your backwheel and start pedaling to regenerate electricity? With an easy 90watts of human effort for 30 minutes, one could hypothetically regenerate 45wh which would be enough energy to at least conquer hills without the "Omg, it's impossible" factor climbing up them on your pedal power when you're packing an extra 50 pounds of gear ontop of your 20 pounds of batteries.

So, how would one go about this? Seems like it should be easy to figure out a "stand" of some sort out there, somewhere when you're 70+ miles away from home, but I'm fresh out of ideas I'm afraid.

 

[swbluto]

Would taking a rope and throwing it over a treelimb and suspending the back tire by lifting the back of the bicycle into the air work?

 

[swbluto]

Is the premise of this question too ridiculous to seriously entertain?

I have to laugh when imagining it, but I seriously would've considered it with the amount of torturous pedaling I had to do. I think I pulled a ligament in my back from the over-exertion or did something to my vertebra. I started seeing stars throughout the day as I'm sure my vertebra was at least slightly displaced and pressing against the spinal cord, affecting vision.

 

[Drunkskunk]

One experiment is worth a thousand replies. Try it.

I think what you'll find is you get less than half of your effort back from the bike.

 

[swbluto]

Will do. But, I realized I don't usually bring a rope with me, so if I'm diligent enough to think of bringing a rope, I'm pretty sure I would've brought a charger.

I think I'll just make sure to bring along a backup charger next time. Or maybe a small solar panel should I not be able to find an outlet near the bike. (Wouldn't want to leave the bike if it has valuable unsecured cargo tied to it, although I think I'm going to fix that problem by adding a securable luggage carrier next time.)

 

[wesnewell]

Some place, and I don't remember where, I saw a kickstand that attached to both sides of the axle and then folded down to raise the rear wheel off the ground. Looked like it would be strong enough. Folded to behind the rear wheel while riding.

 

[dogman dan]

That would be the kind of stand you would want. Alternatively, a normal center stand would get one wheel off the ground, so you'd have to come up with some way to tie down the light end, or lift the heavy end. Rope and tree could be the thing.

You'd be a wise man to start carrying at least a cheapo 2 amps charger on that long a trip.

You'd get some charge, but my gut feeling is that unless you were facing a steep hill, you'd get more bang for the buck by just pedaling the bike to a plug. The sooner you started that the better, ideally you stopped using more than 50w of power on the motor before you got below 100wh left. That would get you two hours of travel with no cogging on a dd motor.

 

[shenzhen_ex]

Some place, and I don't remember where, I saw a kickstand that attached to both sides of the axle and then folded down to raise the rear wheel off the ground. Looked like it would be strong enough. Folded to behind the rear wheel while riding.

That type of stand is very popular here in China. I would not want to put too much weight on one of those.

 

[speedmd]

Why not just get off and walk up the hills if too difficult to ride them. :? Better than standing in one place to get maybe half of your effort back and than loose 20- 30% of that to motor up the hills. Reminds me of the folks standing at the side of the road with their thumbs in the air hoping to get a ride instead of simply walking the few miles they are going. Some times doing things the hard way is easiest.

 

[HAROX]

Pedaling on all grades...downhill, will regen. Generation requires absolute location, in this case, in the wheel, on the downhill run, unfortunately, generation only happens part of the time.
:lol:
Equipment to generate and store super power isn't as portable (as the ebike is), which consumes super power, even the 100 Watters are using a super version of power. It takes super power to produce the same, and super power is what your ebike uses.
Household current is superpower.
Remember the correctional institution (somewhere in the world) using inmates' power on bikes (plural) to charge batteries for the prison houses' lights? They pedal several hours each day and receive time off sentences.

 

[swbluto]

Why not just get off and walk up the hills if too difficult to ride them. :? Better than standing in one place to get maybe half of your effort back and than loose 20- 30% of that to motor up the hills. Reminds me of the folks standing at the side of the road with their thumbs in the air hoping to get a ride instead of simply walking the few miles they are going. Some times doing things the hard way is easiest.

40lb bike + 20lb battery + 20lb motor + 50lb of gear = 130 lbs. I would love to see you push that up a 20% grade. :wink:

(I weigh 180 lbs and the bike was pretty top heavy, so I only had so much ability to prevent the bike from falling over to begin with once I got off.)

 

[swbluto]

That would be the kind of stand you would want. Alternatively, a normal center stand would get one wheel off the ground, so you'd have to come up with some way to tie down the light end, or lift the heavy end. Rope and tree could be the thing.

You'd be a wise man to start carrying at least a cheapo 2 amps charger on that long a trip.

You'd get some charge, but my gut feeling is that unless you were facing a steep hill, you'd get more bang for the buck by just pedaling the bike to a plug. The sooner you started that the better, ideally you stopped using more than 50w of power on the motor before you got below 100wh left. That would get you two hours of travel with no cogging on a dd motor.

Well, there was a lot of unforeseen elements on the trip, for sure. I didn't anticipate my energy usage would be nearly double with the 50lb cargo at 17mph and I had to maintain at least 17mph to get to the destination before 7 (It closed) so energy conservation wasn't in the picture. I also didn't expect that my 700wh battery pack would actually only be 400wh, which I only discovered once I was far far away from home. (It's the battery pack's second cycle, so I assume its capacity is still growing? Still, that does seems like it's too small.)

Lastly, I didn't realize that the "trail" that google showed connecting up with the nice, gentle flat trail I knew and love never actually connected with it and instead was a road that connected to a nearby road, and this road went up a BIGGG mountain, so I tried using a shortcut which was definitely a one way shortcut after I came out the steep dropoff at the end, and I had to climb up this mountain to get back to the road. That was a pretty view, btw, with the golden crescent moon shimmering across the lake, but I still had to climb the mountain, in the dark which expended what little energy I had saved up for the return trip.

Luckily, I thought to bring my other batteries at the last moment, so I wasn't as bad off as I could've been.

 

[speedmd]

40lb bike + 20lb battery + 20lb motor + 50lb of gear = 130 lbs. I would love to see you push that up a 20% grade. :wink:

I hear you. I have pushed my fair share of motor bikes a good ways home that were much much heavier than that. Many times after tremendous efforts of extracting them from deep soggy mud or deep snow. Been there more times than I like to admit.

 

[melodious]

Go around the obstacles (big graded hills) when you have no power. Spending 30 minutes to power up a battery for a small climb vs. spending 15 minutes just going around it

I have ran out of "juice" with a 20" folding bike full of cargo and even with the geared hub it was a haul to keep moving forward. But it does move, just not at electric speeds. Ride judiciously and save the energy for the uphill climbs. :wink:

 

[e-beach]

Get a suitable fold-able motorcycle rear wheel jack stand for about $40.00 USA, jack up the bike, secure the front brake and start peddling.

Or if you want a multi-purpose stand, use one of your carrying cases as a base with a top that will support the chain stays of your bike. You may have to take the stuff out of the case to fit the tire in a "slot" in the case, but built right you should be able to get it to work.

 

[nechaus]

Rope + man in car that could tow you for a couple of km with regen on full.

 

[shenzhen_ex]

Rope + man in car that could tow you for a couple of km with regen on full.

pick-up truck + bike in back that could carry you for a couple of km with radio on full.

 

[voicecoils]

If you can only provide a limited amount of human energy before exhaustion, your best bet is to set your bike up with suitable pedal gearing to allow you to crawl along slowly if you are loaded up, climbing hills or both. Nothing will be as efficient as using you legs to power the bike directly.

If the thought of pedalling your ebike without power makes you feel ill and you're not able to ration your battery power to last the full trip (for whatever reason) then a much better alternative to regen is simply to carry an 'emergency pack' perhaps 150-200Wh and at a lower voltage then you normally use. That will encourage you to use the available power at a lower speed where it will be the least wasteful and last the longest to get you home.

 

[Sokol]

Looking at this another way, you could convince your wife to use your ebike as an exercise bike and get bonus battery charge! Variable regen can simulate hills?!

 

[melodious]

Rope + man in car that could tow you for a couple of km with regen on full.

pick-up truck + bike in back that could carry you for a couple of km with radio on full.

pick-up truck + migrant farm workers + bike in back that could carry you for a couple of km with radio on full & fruits and veggies to snack on.