Electric Bikes - Scanning interest.

Originally Posted by tigersaw

Batteries are heavy and expensive. I've got some old 80A or 100A traction batteries in the garage somewhere, but they are REALLY heavy. Lithium Ion are light but mega bucks

You can get Lithium Ion batteries direct from China at vastly reduced cost (compared to buying them over here). I think that they even do 48v packs for EVs.

Could you use supercapacitors for regenerative braking?

If you're going green, then perhaps this isn't the best route.. Seeing as how the production of the materials you require produces more pollution than what your 125 (diesel if you must) will produce in its lifespan...
However, if you are going to do some innovative engine designs, why not go the H way?
And I don't mean hydrogen fuel cells, which are IMHO a dead end (expensive, hard to produce etc), or liquid hydrogen which is also very hard to contain & use safely
I mean producing the hydrogen on the way. I saw a design dating back from the '80 which some guy sent to BMW so that they could reproduce what he built and help him develop it. It was basically producing hydrogen from the electrolysis of water & aluminum, which produced enough h to power the electrolysis & charge a capacitor which would power an electric engine. The byproduct was some oxidized aluminum (which can be used to extract aluminum back by the use of energy) which is solid and gets deposited at the bottom of the electrolysis vessel. To extract the aluminum back you use power from the grid back home.

Soooo, if you reuse the aluminum and only consume water (with the only byproduct being safely deposited at the bottom of the electrolysis vessel), you get a pretty green vehicle which doesn't require batteries or the likes..
Btw, for general information, the guy died before he could continue, and BMW did reproduce his work and asked him if he could design the system so that the byproduct could be easily extracted after there is none left.. He died before he could..

I'm not entirely sure of the details, of all of this, but I will search for a linky..

Right, found it.. Seems simple enough (though a bit dangerous..)

http://anon99.tripod.com/water_engine/index2.html

The guy had a patent on it too..

Worked out to a car weighing in at 900kg would drive 600km on 20L of water and 1kg aluminum

Originally Posted by andreis

Right, found it.. Seems simple enough (though a bit dangerous..)

http://anon99.tripod.com/water_engine/index2.html

The guy had a patent on it too..

Worked out to a car weighing in at 900kg would drive 600km on 20L of water and 1kg aluminum

http://www.technologyreview.com/energy/19338

You need a vast amount of energy to create the aluminium. Then you have to dispose of, or recycle aluminium oxide. You also have to prevent the aluminium from oxidising before use.

Ok, I must say I didn't actually research what is required to recycle aluminum. Apparently it does produce CO2 and requires huge amounts of energy.
Putting the energy requirement aside (say that you could produce it using some green source - solar, wind, let's hope fusion soon..), the co2 produced is bad.. very bad..

just gotta keep looking, I guess.. I'm quite sure someone is close to finding alternative ways (if they haven't already and are keeping it to themselves... bit of a conspiracy enthusiast here..). And when they do, o joy of joys!

Make petrol using sun power, im sure I saw something about the yanks being close.

i have a bit of experience with this, but gave up on my project electric...

if you are serious about it, look at the RC cars/planes. they have it all figured out, and the competition ones have motors easily capable of propelling a bicycle, likely even a stripped down 125.... .
if you want to make a good one, it will be expensive - lipo battery for my RC helicopter is ~$1200 (US), and you'll need at least 4, maybe 6... (20mins of flihgt /charge)... and they last some 4-500 cycles only... most expensive will probably be the speed controller (~$2000), and a good motor ... the rest is easy...

you can use regular acid batteries, i saw an electric made of an old cb650 run on 3 car batteries... they are soooo heavy though... i think there are few youtube videos on it...

unless it's about the "journey, not the destination", you're better of getting a ready-made electric scooter - there is quite a few of them out there..., or a gas 125, as already suggested.

[embee]

Whenever considering anything of this sort, first go back to thermodynamic basics and decide what the system is and what efficiency it can achieve.

I used to be on a company committee assessing inventions/patents relating to powertrain stuff, and so often (invariably?) they ended up being either quasi perpetual motion machines (i.e. they just couldn't work due to basic thermo laws) or they were simply different mechanisms wrapped round the same old thermo cycle.

The starting point must always be doing an energy/power demand assessment so you know for definite what it is you are trying to provide, then sort out the potential efficiencies of the processes you're going to use, then decide whether the current technology of that method will allow you to achieve the result within size/weight/cost/legal limitations.

Finally decide whether it's all worth the effort, or just walk to the shops once in a while.

If you want to have a play, on the other hand, go right ahead.

Just build it! I can't see it's worth the candle, even CG125's do 120mpg, and their engines are beyond basic. I'm sure much could be done to improve efficiency of small-capacity bike engines.

There are also a fair few diesel bikes. Pic is a diesel-electric, but most are CVT transmission. Link to the site below.

http://www.dieselbike.net/privatecon...ersionsI-R.htm

None of these are valid reasons for not building it. Do it for the experience.