Gas/Generator/Battery hybrid drive?

[Dreddydave]

Has anyone tried creating an ebike that also has a really small gas engine (maybe 15cc?) that charges the batteries or runs the electric motor once the batteries have expired? I'd be thinking it could be a good way to get a higher range for those longer trips, rather than purchasing more and more lipo (alternating monthly for work between 2 different offices, one is only 5km away while the other is ~40km).

A midnight perusal just came across this and got me wondering:
http://www.hobbyking.com/hobbyking/..._CD_Ignition_2_1HP_1_54kw_AUS_Warehouse_.html

 

[TylerDurden]

Another option is a gas-powered pusher trailer. Only hook it up for the long hauls.

 

[Whiplash]

I mentioned doing something like this before, everyone shot it down. I still think it would ne awesome if it could work, just have it on a seat post rack and clamp it on for long/endless range! Remember most bikes will cruise at 25-30 mph on 500 watts so if you had say, 15AH@44v like me, then you had a small generator like that just putting out 500 watts, you could do 25ish MPH indefinitely if you had fuel... This is still a dream I would like to try..

 

[rolf_w]

something like this:

http://www.torcman.de/faszination/praxis/jochen/honda-gx35_430-30.htm
using http://engines.honda.com/models/model-detail/gx25
r

 

[mr.electric]

I actually did something along these lines in October 2006. It was heavy and complicated. The hybrid works as follows:
Electric motor and gas motor both drive the rear wheel. Electric is geared to go like 10 mph, gas geared to go more like 20 mph. At speed the electric has a light regen since it is at WOT and spinning quite a bit faster than the no load speed. The gas motor has no power off the line since it is a small 4 stroke geared too high. The electric gets the vehicle moving the gas maintains speed for long flat drives on open road. I used a bmx style 2 to 1 brake cable to pull both throttles simultaneously. Little barrels on the cabes allow some fine tuning. Since building this hybrid I have a better appreciation of the basic set up, A few R/C packs, sensorless hub motor and a throttle.

 

[REdiculous]

I was thinking about trying it w/ a slightly cheaper glow engine and rc motor. *shrug*

The engine I was looking at the other night was less than $75 shipped (/no discount(s)!) and the motor was on clearance for less than $50 (didn't check shipping).

 

[mr.electric]

I ended up pulling off the gas motor, mounting a plastic body and this scooter became the Giant's Mascot scooter for 2 or 3 seasons

 

[Dreddydave]

I actually did something along these lines in October 2006. It was heavy and complicated.

Thanks Mr. Electric; I'm expecting those are SLA batteries? Looks like you did a good job on that one.

I was thinking about trying it w/ a slightly cheaper glow engine and rc motor. *shrug*

Yeah the gas engine seems overkill; that 15cc motor puts out 1.54kw which is more than my 1kw hub motor (and more than would be used at cruising speed)!

My ideal would be something similar to the way the Chevy Volt works. So the batteries would be charged at home, you'd travel until they're about 50% DOD, then start the gas engine to both charge and keep the power going to the electric motor (so the gas engine isn't mechanically connected to the drive wheel).

Not sure how that could work with LiPo batteries though? If the LiPo charger was always connected to the cells on the bike (even while using them to run the electric motor), could the gas engine/generator power the 12v battery charger and then start charging the batteries while they're getting used? I'd obviously need a bigger charger than the 50w one I've got now; probably one powerful enough to cover the cruising wattage. I know LiPos shouldn't be "trickle charged" but that's more because they can't handle overcharging (?) but a LiPo charger would stop the charge cycle if it reached 4.2/cell. Any comments?

 

[spinningmagnets]

The smallest 4-stroke Honda GX generator I know of is this one: http://advancedmower.com/honda/generators/quiet/eu1000.htm

it is 29-LBS, 1000W, 120V AC, 50cc, advertised as unusually quiet when running. Can be found on EBAY for around $650

This pic is a 1200W Chinese copy that is 1/3 the price. It is the same size, just for comparison to the other options you may consider.

 

[Whiplash]

Yeah, that bonds is only 1.8hp and 50cc so I BET a RC airplane motor would work hooked to a small lower KV brushed motor/generator. It could be made very small! It would just need a circuit to keep from over charging the batts if you were say going downhill..

 

[Hillhater]

I BET a RC airplane motor would work ..

.. do you know how much fuel a RC ICE motor consumes ?
... and how long you can expect one to run at full power ( with no prop air blast !) ?
.. and how noisy ?

 

[Whiplash]

Nope, but I do know engines, and a four stroke that size if tuned correctly will consume VERY little dns you only need an hour or so run time to make a big difference, and its an engine so just filler up when it uses the whole quart or so of fuel! As for longevity, I am sure they last a while or people would complain that they can't fly their planes for more than a few flights a year or their motor will die. Just be patient, this is a challenging I AM going to tackle sooner than later, I just need to get through the more pressing things I have going on. As for noise, any engine can be muffled, it just has to be done to not hurt power. If I can quiet down a 1000hp big block Chevy to be daily driven, I am confident I can muffle an engine the size of my palm of my hand to near inaudible.

 

[Hillhater]

If you want quiet, relialable , economical, then you best stick with those Honda GX 25/35 motors that rolf posted.
..and steer well clear of RC gas engines. !

 

[altugunal]

Hi Everyone

So could you come up to anything on this topic dreddydave
I was looking exactly for the same thing
I think 200w is far too good for me but size and weight does matter here

 

[panurge]

I know that FXs light motorcycles has researched and experimented a bit on this field for their 50+ Kg light motorcycle that usually is powered by gas engines....

from their website:

Hybrid-Electric and Fully-Electric Models

- Battery-electric and extended-range series-hybrid (gasoline-electric) models in development (diesel-electric has excessive size/weight but lightweight alternatives in research)
- Same size, weight, main components as gasoline models
- Up to 1 hour silent running on full-electric (approx. 30 miles at 30mph; 50km at 50km/h)
- Up to 4 hours continuous running on hybrid-electric (approx. 120 miles at 30mph; 200km at 50km/h)
- Hybrid has indefinite recharging using on-board micro-generator

*Gasoline contravenes the single fuel concept but the lightest commercial diesel engines weigh more than this entire motorcycle; we’re researching diesel micro-generators for long-range hybrid-electric models and have gasoline-hybrid and full-electric in pipeline

Don't know what kind of develop this project has reached, though, they was looking for small diesel engines.....if something would exist this would be good.

I Agree with Tyler Durden, the Trailer field should be perfect.
Figure out a battery cargo Heavy Duty trailer that carries a gas generator, a PV cover, and a couple of regen brakes for the 2 wheels....(friction or....)

 

[Grey beard]

http://m.youtube.com/watch?v=bNLTLRx8sTI&feature=youtu.be

 

[gogo]

A moped bob trailer made from a lightweight shaft-drive Yamahopper? You would have a lot of room to make a whisper quiet muffler. You could tune the gas motor to run well at high speed and use a modern synthetic oil at 100:1 for nearly smokeless operation. You could graft a small outrunner to the crankshaft of the Yamaha, or use a friction coupling for the electric motor on the bob tire.

Such a thing might be a nightmare to make consumer-friendly, but a one-of tailored to your needs would be possible.

 

[n3glv]

I ride a currie electro-drive chain drive DC system bike.
My current shunt said it pulls 35A on hills and 9-10A on flat under ideal condtitons.
(no wind, good tire pressure etc).
My plan some day is to rig a trailer with Harbor Freight '900w' genny, this is 20cc
I think and 2 stroke. With umbilical to the bikes electrical system. The trick is
that I need 120v AC to 24v @ say 15A or so DC (ideal would be 20-30A) that would
not be HEAVY. Some of these generators use multiple windings in series to get
the higher voltage, if I were an expert I would get inside and see if I could rewire
it to give me say 36V@30A, then I could regulate that down to the 29v I need.
I think this is doable and expect the weight to be around 50lbs.
Trailer is rated at 100# so that leaves 50 for cargo...
No telling what the strain going up hills will do to the bike motor though.