7500 MPG bike project?

mew905 · Jul 31, 2013

I'm probably off in calculations, but I was always fascinated by range-extender type hybrid cars. That is, pure electric drivetrain, with a small engine, perhaps 2-cylinder, that simply drives a charging system. VW is building a prototype car that so far has an estimated milage of 485 MPG. Pretty damn good considering it's a full-out car.

So my calculations are as follows:
a 50cc motor is rated at 150mpg (and some forum members here have achieved very close to that). I figure that's around 32km/h (about 20mph), or 8.88 m/s.
44T sprocket to a 10T drive sprocket means a ratio of 4.4:1 and internal gearing of 4.1:1.
26" bicycle tire measures 183cm around, or 1.83m, spinning 4.857 times per second, or ~291.5 RPM to equate to 32km/hr
using that gearing, thats 5258 RPM, mid-range for the 50cc.
Take the throttle off, and use the idle screw to maintain a constant-ish 1300 RPM. ASSUMING a carb gives the same amount of gas per-stroke (not utilizing an expansion chamber), this should mean 1/4th the fuel consumption.
Run it a little lean, it'll be run with nearly no-load (alternators are easy to spin with the hand so a motor shouldnt have a problem)
150MPG at 20mph equates to 7.5 hours of runtime on a gallon. assuming the above about fuel consumption, I get 30 hours of runtime at idle speeds before the gas runs out. we'll assume this number even if we run lean.

The motor does not drive the wheel, but rather drives a 320A 12v alternator, by my calculations, the 50cc motor should be able to drive said alternator with ease at 1300RPM, utilizing a belt-drive system replacing the small bevel gear.
convert the voltage to 24v for 160A (minus losses)
Utilize a 24v 20AH battery setup of some kind that can take rapid charging.
run a 500w 24v electric hub motor. That's just a little bit over 20A on 24v for 500w, and should be able to push us over 50km/h (my friend's 500w scooter weighs 420lbs with me on it and hits 45 with relative ease)

So all that said, we can get into the milage conversions. the batteries will drive the motor for an hour for a respectable 50km range. Kick in the engine to charge the batteries, 20A goes to power the motor while the batteries charge, 140A charges the batteries in ~8.6 minutes (ASSUMING they can take that kind of amperage). you have 30 hours of runtime, totalling 209 full-charges for a one-gallon tank.

1 charge = 1 hour of run time
8.6 minutes of charging per charge
so 8.6 mins x 209 = 30 hours + 209 hours (1 hour per charge) + initial charge = 240 hours. 10 days. 240 hours x 50 km/hr = 12,000 KM... or just shy of 7500 miles per gallon. To put that into perspective... Toronto, Ontario to Austin, TX is a mere 2600km. can you imagine going 3 round trips on $5 gas? it'd take forever, sure, but the cost would be... nothing.

EDIT: Sit and rotate, EPA

Mike B · Jul 31, 2013

Your numbers are all wrong.

20A @ 24 volt is 500 watts. 160A at 24 volts is 4000 watts.

So you think the little 50cc engine is going to provide 4.5 KW (9.5 HP) at 1300 rpm?

mew905 · Aug 1, 2013

Mike B said:
Your numbers are all wrong.

20A @ 24 volt is 500 watts. 160A at 24 volts is 4000 watts.

So you think the little 50cc engine is going to provide 4.5 KW (9.5 HP) at 1300 rpm?

4.5 kw is 6hp, btw, but I dont think it would take 9.5hp to spin an alternator, it doesn't take 3hp to spin an 80A alternator, you can do it with your hand effortlessly, it's easy enough you could probably use your tongue to do it if you dont mind the taste of metal/oil/rubber. however perhaps it would take significantly more to run the alternator at full power (I cant find resistance ratings or rated RPMs anywhere, that is how much force it takes to spin the alternator at x RPM where the full 320A is produced). Even so, I would imagine an alternator that produces 4000 watts @ say 5000 RPM should be able to crank out 2000 watts at 1800 RPM (around there?).

And the numbers you listed that you say are wrong are exactly the same as the ones I listed. It's actually a bit more than 20A on 24v (because 20x24 = 480, so it'd be something like 20.9A). Even if the alternator can only crank out 80A @ 12v, upconverted to 24v is 40A, 20A runs the motor, 20A charges the battery, the engine runs for an hour to fully charge the batteries, then the electric motor runs on the batteries for an hour, and repeat, giving you 30 full charges. 1 charge = 1 hour, + batteries last 1 hour per charge = 2 x 30 = 60 hours runtime + initial charge. 61 x 50 km/hr = 3050 km, or ~1900 MPG, which is still ridiculously good.

60A alternator = 30A @ 24v = 20A to motors, 10A to batteries, 0.5 charges per hour, 30 hours runtime = 15 charges. 15 x 1h + 30h = 45h @ 50kph = 1400 MPG

Remember this is also assuming WOT constantly. An electric motor conserves alot of energy if you run it at half the speed (minus efficiencies). So if you ran at say 1/2 the speed, you may see 3x the range from a single charge. the above is basically worst case scenario.

Why do these numbers seem so much higher than normal? like 1400MPG even with a slow charging system is still 10x as much as normal milage, compared to hybrid cars that seem to only net 1.5-3x the milage of their competitors. Because range extender hybrids are freaking amazing. there are (to my knowledge) only 3 cars so far that use this technology. One is a supercar, another is the VW prototype, and the last one... is the Hammerhead Eagle iThrust from Top Gear's own crew.

Mike B · Aug 1, 2013

Yes, you can spin an *unloaded* alternator effortlessly, but I can assure you that will not be the case for one outputting sixty amps.

mew905 · Aug 1, 2013

Mike B said:
Yes, you can spin an *unloaded* alternator effortlessly, but I can assure you that will not be the case for one outputting sixty amps.

Yeah, I just looked it up, its roughly 1hp for every 30A at 4:1 ratio (which means around 4000 RPM). Of course there's no solid numbers because of inefficiencies and mechanical statistics and such. But let's recalculate that then.

4000 RPM = 4/5 of 5000 RPM = , a 60A alternator will output 30A @ 24v minus losses. so ~9 hours runtime at 4000 RPM pumping out 30A

electric motors suck up 20A, leaving 10A to charge batteries, batteries charge in 2 hours, meaning 4.5 full charges.
4.5 hours runtime from full charges plus 2 hours per charge running on engine power while charging = 9 hours + 4.5 = 13.5 hours total runtime @ 50kph = 675 km = 419mpg.

Aaaaaaaaand there goes my dreams of ridiculous milage laff

Of course this is assuming an out-of-the-box engine, being aimed for a very specific RPM and not a range, you can port and tune for that RPM and increase power, but the question is: will that extra power end up costing you fuel efficiency as a whole?

mew905 · Aug 28, 2013

Alright, so for an 100 amp alternator, it should output roughly 50 amps at 24v. I calculate it should take about 2hp to crank it at full load. Utilizing a 50cc motor geared at 1:1 you should be able to run the alternator at 4k RPM (a low cruising speed with respect to actually using the motor to turn the wheel). This should net you close to 80% of the alternators max output (about 40A @ 12v). I'm not sure what the milage would be at that RPM, but lets say 100mpg.

you have a 1/2 gallon tank
4k RPM = 17.2mph on a 44T
17.2 mph @ 100mpg = 5.8 hours runtime per gallon, or 2.9 hours per tank
500 watt motor @ 24v = ~21 A
Alternator output is 40A
20AH battery = 1 hour charge time + 1 hour of alternator powering E hub
2.9 full charges (lets round to 3 full charges for sake of simplicity) + 1 hour of runtime on full battery. 500w motor hauls up to 32mph
initial charge = 1 hour = 32 miles
charging = 3 hours = 96 miles
discharging = 3 hours = 96 miles

Total miles = 224 miles per tank, x2 for full gallon = 448 miles per gallon.

If anyone knows the power band and milage of the 50cc morini, I'd love to know, I know they put out way more power but I hear their milage is poor for a motor their size. a 9.4hp morini or KTM clone would be perfect. Milage at a consistent 4k RPM would be best, as well as power output (probably not as likely to get this info).

BarelyAWake · Aug 28, 2013

As is the case with any theory, there's a bit of wiggle room in the numbers. There's always factors overlooked & when combined with guesstimates can lead to disappointment or a pleasant surprise depending which way things were rounded off... please don't take me wrong, I love experimentation - but it pays to be an optimist only during the conceptual phase, thereupon pessimism should rule, like when estimating preformance & gains.

For a few examples & just food for thought;

"bout 2hp to crank it at full load... close to 80% of the alternators max output (about 40A @ 12v)" 40a @ 12v = 480w/0.64hp or a net loss of 1.36hp

"100 amp alternator... output roughly 50 amps at 24v" 50a @ 24v = 1200w & 1200w = 1.6hp, a net loss of .4hp

"500w motor hauls up to 32mph" 500w = 0.67hp, 1000w/1.34hp motors w/twice the hp generally reach no more than 27/30mph even in a standalone application.

Hybrids are a very tricky business, there's parasitic losses to be considered everywhere such as the additional weight & drag of multiple motors & drive systems, which are difficult at best to estimate. The gains often fractional very much depends on the application, the usage of the hybrid system, and that's also dependent on what type of hybrid you're considering.

In this instance you're describing a serial hybrid (one motor exists to supply power to another) vs a parallel hybrid (both motors power the vehicle directly).

Generally speaking an electric drive serial hybrid has a ICE with less max HP output then the electric, relying on a battery bank to supply the necessary additional amperage under heavier load, such as start offs, hills & hard acceleration. The ICE maintains a steady RPM & recharge rate, making up for the losses during cruise & idle. As there are no sudden & severe loads on the ICE, it's fuel efficiency is usually improved over a standalone ICE vehicle, but power may be lacking in comparison to a standalone.

A parallel hybrid (both the ICE & electric driving the vehicle directly) usually has an ICE of slightly greater HP then the electric, the electric being utilized automatically or manually to assist under load applications (start offs, hills & acceleration) or even alone during slow cruise. As the sudden & severe loads on the ICE are reduced, fuel efficiency is usually improved or you've greater preformance then that particular ICE alone would have, allowing for a smaller more efficient engine to be used.

The there's also standalone & plug in hybrids - if the onboard ICE can generate enough by itself to fully power the electric plus recharge vs one that needs or can be plugged in to an external power source. Obviously the latter will appear to outperform the former in fuel efficiency, except the fact it's simply reallocating some of it's consumption - factoring actual "fuel efficiency" can be nearly impossible with a plug in hybrid, unless you're generating that external power source yourself.

In all the above variations maximizing efficiency is of paramount importance as any/all gains will be a culmination of many small factors adding up - I would not suggest a two stroke for any type of hybrid as while they often have an impressive power to weight ratio, their fuel efficiency even as a standalone is often abysmal in comparison to a four stroke of equivalent HP... and no hybrid will have improved efficiency/overall fuel consumption of any significance over it's ICE alone equivalent if subject to constant heavy load - if the power required is the same to reach that preformance level, the consumption will be the same regardless of where the fuel is or what it comes from.

Again though - I am not trying to discourage you or "naysay" in any way, I'm simply attempting to illustrate the complexities of hybrid systems as you've presented, that estimated math is subject to a massive & exponential margin of error, that once you're familiar with the generalities - there comes a time in which only real-world experimentation has any value & I wouldn't suggest that experimentation be expected to come even close to having the results anticipated...

...then again, who knows? Give it a shot I figure, the knowledge gained while having fun trying is often worth so much more than whatever was built

miked826 · Aug 29, 2013

BarelyAWake said:
As is the case with any theory, there's a bit of wiggle room in the numbers. There's always factors overlooked & when combined with guesstimates can lead to disappointment or a pleasant surprise depending which way things were rounded off... please don't take me wrong, I love experimentation - but it pays to be an optimist only during the conceptual phase, thereupon pessimism should rule, like when estimating preformance & gains.

For a few examples & just food for thought;

"bout 2hp to crank it at full load... close to 80% of the alternators max output (about 40A @ 12v)" 40a @ 12v = 480w/0.64hp or a net loss of 1.36hp

"100 amp alternator... output roughly 50 amps at 24v" 50a @ 24v = 1200w & 1200w = 1.6hp, a net loss of .4hp

"500w motor hauls up to 32mph" 500w = 0.67hp, 1000w/1.34hp motors w/twice the hp generally reach no more than 27/30mph even in a standalone application.

Hybrids are a very tricky business, there's parasitic losses to be considered everywhere such as the additional weight & drag of multiple motors & drive systems, which are difficult at best to estimate. The gains often fractional very much depends on the application, the usage of the hybrid system, and that's also dependent on what type of hybrid you're considering.

In this instance you're describing a serial hybrid (one motor exists to supply power to another) vs a parallel hybrid (both motors power the vehicle directly).

Generally speaking an electric drive serial hybrid has a ICE with less max HP output then the electric, relying on a battery bank to supply the necessary additional amperage under heavier load, such as start offs, hills & hard acceleration. The ICE maintains a steady RPM & recharge rate, making up for the losses during cruise & idle. As there are no sudden & severe loads on the ICE, it's fuel efficiency is usually improved over a standalone ICE vehicle, but power may be lacking in comparison to a standalone.

A parallel hybrid (both the ICE & electric driving the vehicle directly) usually has an ICE of slightly greater HP then the electric, the electric being utilized automatically or manually to assist under load applications (start offs, hills & acceleration) or even alone during slow cruise. As the sudden & severe loads on the ICE are reduced, fuel efficiency is usually improved or you've greater preformance then that particular ICE alone would have, allowing for a smaller more efficient engine to be used.

The there's also standalone & plug in hybrids - if the onboard ICE can generate enough by itself to fully power the electric plus recharge vs one that needs or can be plugged in to an external power source. Obviously the latter will appear to outperform the former in fuel efficiency, except the fact it's simply reallocating some of it's consumption - factoring actual "fuel efficiency" can be nearly impossible with a plug in hybrid, unless you're generating that external power source yourself.

In all the above variations maximizing efficiency is of paramount importance as any/all gains will be a culmination of many small factors adding up - I would not suggest a two stroke for any type of hybrid as while they often have an impressive power to weight ratio, their fuel efficiency even as a standalone is often abysmal in comparison to a four stroke of equivalent HP... and no hybrid will have improved efficiency/overall fuel consumption of any significance over it's ICE alone equivalent if subject to constant heavy load - if the power required is the same to reach that preformance level, the consumption will be the same regardless of where the fuel is or what it comes from.

Again though - I am not trying to discourage you or "naysay" in any way, I'm simply attempting to illustrate the complexities of hybrid systems as you've presented, that estimated math is subject to a massive & exponential margin of error, that once you're familiar with the generalities - there comes a time in which only real-world experimentation has any value & I wouldn't suggest that experimentation be expected to come even close to having the results anticipated...

...then again, who knows? Give it a shy r so much more than whatever was built

I say, Go for it! LOL

My ICE needs to be a lot bigger. My Parallel Hybrid with Brake Regen and my ICE running, extends my battery range by 300% and I'm sure my MPG went up as well. Not sure how much though.

BarelyAWake · Aug 29, 2013

miked826 said:
I say, Go for it! LOL

My ICE needs to be a lot bigger. My Parallel Hybrid with Brake Regen and my ICE running, extends my battery range by 300% and I'm sure my MPG went up as well. Not sure how much though.

Agreed on all counts except displacement heh (I'm set w/the 49cc four smoker), it is a real pain trying to figure out an actual fuel consumption rate w/these lil hybrids - for a coupla reasons.

First & foremost, what are the riding habits? Not just style of riding (aggressive or passive) or environment (hills, stop'n go etc) but what are primary motive systems used? If it's the pedal/electric than the "gas mileage" is essentially infinite... which isn't really fair when discussing actual fuel consumption ofc.

I have managed to ballpark my "worst case" fuel mileage w/the tribrid tadpole, I spent an entire three day weekend either screaming it out at redline and/or hauling a overloaded trailer (roughly 100lbs+) in mostly hilly, mixed terrain and I had no external power sources, as I was on a rally weekend camping trip so the taddy was on it's own, even helping to power my campsite (lighting, tunes etc).

To my somewhat skeptical delight I got around 250mpg, "skeptical" because I still didn't manage a full gallon so there's a margin of error and because I've not finished tuning the ICE properly, while it runs great there's still a lot of room for improvement.

This ofc means if I wanted my absolute "best case" fuel mileage - running out a minimum of a measured gallon, I'd need a highway trip of not less than 3-400 miles, which would be from here to Boston, back again & then some lol

Even my average normal usage is difficult to ascertain as it's not my commuter, so there's no "normal" usage - sometimes it's all stop'n go & doughnuts in the parking lot, sometimes it's an idle all day cruise to who knows where...

...I guess I can't complain, given I just can't seem to use enough fuel to establish it's actual average consumption rate lol - but now that I've run the kinks out, it's time for a major cross country trip anyway right?

miked826 · Aug 29, 2013

BarelyAWake said:
Agreed on all counts except displacement heh (I'm set w/the 49cc four smoker), it is a real pain trying to figure out an actual fuel consumption rate w/these lil hybrids - for a coupla reasons.

First & foremost, what are the riding habits? Not just style of riding (aggressive or passive) or environment (hills, stop'n go etc) but what are primary motive systems used? If it's the pedal/electric than the "gas mileage" is essentially infinite... which isn't really fair when discussing actual fuel consumption ofc.

I have managed to ballpark my "worst case" fuel mileage w/the tribrid tadpole, I spent an entire three day weekend either screaming it out at redline and/or hauling a overloaded trailer (roughly 100lbs+) in mostly hilly, mixed terrain and I had no external power sources, as I was on a rally weekend camping trip so the taddy was on it's own, even helping to power my campsite (lighting, tunes etc).

To my somewhat skeptical delight I got around 250mpg, "skeptical" because I still didn't manage a full gallon so there's a margin of error and because I've not finished tuning the ICE properly, while it runs great there's still a lot of room for improvement.

This ofc means if I wanted my absolute "best case" fuel mileage - running out a minimum of a measured gallon, I'd need a highway trip of not less than 3-400 miles, which would be from here to Boston, back again & then some lol

Even my average normal usage is difficult to ascertain as it's not my commuter, so there's no "normal" usage - sometimes it's all stop'n go & doughnuts in the parking lot, sometimes it's an idle all day cruise to who knows where...

...I guess I can't complain, given I just can't seem to use enough fuel to establish it's actual average consumption rate lol - but now that I've run the kinks out, it's time for a major cross country trip anyway right?

I got 2250 watts plus 49cc both going to the rear wheel and both can be used simultaneously or independently. Gas is basically free for me with that setup. Never actually measured the MPG but I know it gets pretty darn good gas mileage per mile traveled now that I have Brake Regen engaged and working.

mew905 · Sep 23, 2013

Alright, so going to a generator system instead of a wildly inefficient alternator setup (I'll figure out the regulation and rectification later), we'll be looking for a 48v generator. Typing that in to Ebay comes up with tons of wind power generators. I'm looking into 1500w generators.

48v @ 500 watts is about 10 amps, simple enough. Get a 48v 20AH battery, and you're looking at a good 2 hours runtime per charge. so 2.5hp is about 1.8kw, which should run the generator easily enough (wind generators are pretty efficient, in the 95% range), geared at 2:1 our original 1300 RPM will turn the generator at 2600 RPM, tune the motor for maximum power at this speed (which uhh... will be a challenge no doubt, 4 stroke potential here)

So, 1500w @ 48v = 31A, we'll say 30A for back of the envelope math. to charge a 20AH battery pack you're looking at 40 minutes without running the electric motor, or 1 hour with the electric running at full speed. Slap a 1 gallon gas tank on that sucker, and run for your 30 hours. 1 hour to charge, gives you 30 full charges. Each charge gives you 2 hours runtime for a total of 60 hours, plus your original 2 hours AND the 30 hours it took to recharge the battery 30 times gives you 92 hours runtime. 24.5 hours @ 31mph = 2852 miles per gallon.

Without seeing all the math, running the engine at 5300 RPM nets you about 750mpg, which is still ridiculously good. AND, this actually seems doable now. Why am I confident this will work? Because even though I'm using my original numbers from the OP, the 1/4 fuel consumption of 1300 RPM vs 5250 RPM didn't take into account the fact that the throttle will be mostly closed, sucking up less gas than the 1/4 assumed. I also rounded any restrictive numbers up, and any beneficial numbers down to give a margin of error of probably close to 98%. This also doesnt factor in any brake regeneration, but also doesn't factor in losses from rectification or wire resistance.

DBB · Sep 24, 2013

The alternator or generator will resist turning in proportion to the current draw. Maybe enough to stall the engine.

mew905 · Sep 26, 2013

shouldn't be, 1.5KW is only 2hp, but we'll have to see. the question is will the generator dump as much amperage as it possibly can into the batteries? or is there some kind of limiting number I need to be looking for, such as a maximum charge rate, listed on most LiION batteries (though I'll be using LiFePO most likely because of it's density and prefabbed bicycle applications). I know charging LiION too quickly can have devastating consequences, so if I can find a battery (or battery bank) to take the charge quickly enough, as long as it beats out 10A/hr, I should be in the clear. Problem is I dont know of many electric vehicles that have been able to charge at a higher rate than they use electricity, notably if you get 2 hrs runtime out of an electric, it could take 6-8 hours to recharge. Not very fun (of course these numbers are purely dependent on the size, power consumption and charge rate of the battery and vehicle, I wouldnt expect a tiny toy helicopter with 30 minutes of flight time to take much longer than 15 minutes to charge.).

I also included the alternate calculations for running the engine at 5300 RPM to demonstrate that great milage can still be had, 5x more than normal, 3/4 of 1000 mpg is still ridiculously good, and is well within the boundaries of reality (as these motors with few modifications should be able to produce around 3hp at 5300 RPM with ease). The first half I'm not entirely sure about, being that actual engine runtime is unknown, battery charge rate is unknown (though that generator on ebay states 25-30 amps [depending which one you look at] into a battery bank), actual engine power at such a low RPM is definitely unknown...

mew905 · Sep 29, 2013

Alternately you can run two 24v 8A scooter chargers in series with no battery system (or a battery filtering/cache, ~400w = 0.5hp) and direct drive the engine for 30h.... which would net you 930mpg.

Tang · Jan 13, 2014

Good stuff here Mew. Been thinking of building an electric for awhile , even bought a book on them. The cost is high, but wouldn't mind a go at a hybrid bike to make it cheaper and probly funner at that. So keep up the stuff here.

.shft.

Tang
The trail life for me.

mew905 · Jan 13, 2014

when i get time off at the oil rigs ill be goin for this, probably with a morini, however, i dont know, but ill have more than enough resources to test all sorts of combinations: ht, morini, etc.

16v4nrbrgr · Jan 13, 2014

Mew905, consider that every time you convert energy that there are losses. I think if you want a high mpg series hybrid, the best bet for good mileage is to get the tiniest two stroke generator you can find under 400W and running it to a basic electric bicycle kit, if you want enough assist to be meaningful at that wattage I'd consider a mid-drive setup with some batteries in line to take the surge energy usage that usually is about 1.5 times the rated wattage. At cruise the generator could recharge the batteries, and you could use a couple cheap AGM batteries for a 24V system and they would last a long time since you wouldn't be deep cycling them.

mew905 · Jan 13, 2014

yeah the best efficiency would be gained at lower power... But then you think, if theres not enough power, you'll never move, or move very slowly. So there's got to be a curve, just like with gas milage, however the curve peaks early with electric setups. one would need approximately 1.66hp per 1KW, without losses. A generator is assumed to be ~95% efficient (as opposed to an alternator assumed to be around ~40% efficient), means that I will lose minimum power, though it needs to be regulated to a specific voltage. Not difficult, setting the idle will run the generator at a specific speed (aside from startup) and run at a constant voltage, then all I'd need is a transformer and a rectifier.

I'm thinking a 500w motor with an 800w+ generator setup would be perfect for use with the HT motors and a small generator. Let the motor spin up, then engage the generator to charge the batteries. Perhaps even a 250w motor and a 500w generator, though I'm unsure of the 250w motors capabilities, as the 500w motor seems to struggle to get up to speed, but also that was a 200lb scooter with me (240lbs) on it.

mew905 · Jan 13, 2014

150MPG at 20mph equates to 7.5 hours of runtime on a gallon. 500w 24v generator = 20A. get a 24v 20AH battery, it'll charge at 0.5C (2 hour charge), and have a runtime of 2 hours.
250w motor runs at saayy... 25mph, a little slow but it's ok.
we get 3.75 charges out of the motor, which equates to 7.5 hours with the motor running, and 7.5 hours on battery so... 15 hours runtime @ a maximum 25mph, or about 375mpg... a little more than double, but we sacrificed a bit of speed for better milage. But again, 2-strokes arent exactly known for efficiency, I imagine I could get more out of a 2hp 4-stroker, but not knowing the milage counts on them makes it difficult.

Again, though, all this will be trial and error, I just like calculating optimist outcomes for fun. I'd quite enjoy it if I could beat VW's new hybrid, though, being that theirs is more than likely much faster than 25mph (I'd say a 99.999999% chance of it) Sure I could just go out and buy one, or get ridiculously meticulous and technical and innovative, but I also like thinking about what I can do for cheap, and if a super hybrid can be had for as little as $1000 (excluding the bicycle itself), then we could all benefit greatly, especially being that electric bikes are accepted pretty much everywhere, we could all be legal everywhere, and because the engine doesn't drive the wheel, the laws regarding gas powered bicycles would be rendered ineffective to us (though that doesnt mean you wont be stopped and the bicycle possibly temporarily impounded under the assumption it's gas powered, though quickly pointing out the engine is not connected to the wheel at all may save you), and yet get the excellent range we want... even though the range and joy of having a powered bicycle is a big thrill already. I cant wait to get this project underway.

16v4nrbrgr · Jan 13, 2014

If you had a 800w generator and a 500W mid-drive on a bicycle you wouldn't need a HT to go with it, which will kill any fuel efficiency goals you're shooting for. I'm sure you could get 300mpg with a series hybrid bicycle.

7500 MPG bike project?

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