# Onboard generator on bicycle?



## Theremin (Nov 9, 2014)

Hi everyone! I have been thinking about building an electric bike with an onboard gas-powered generator. I would be happy to get some feedback from you regarding this idea. 

For the generator part I plan on using a lawn mower engine coupled with a car alternator or similar. The power would then be fed to a LiPo charger (preferably one with about 1000w output power) to charge the batteries on the fly. Since I am new to this I have a lot of questions.

How does a typical LiPo charger react when charging a battery that is under load?

Will the generator part be able to supply enough power to keep a 500-1000 w electric motor running under normal conditions?

And finally, what are your thoughts about the efficiency of this setup compared to a conventional moped under various conditions (straight roads, stop and go traffic etc.).

Any input will be appreciated!


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## RIPPERTON (Jan 26, 2010)

The smaller the vehicle the less it needs to be a hybrid.
A bicycle will be better off simply charged from the mains.
You will find it will be too much of a contraption to be ridden comfortably, ie it will be too heavy and cumbersome and dangerous with all that shit hanging off it.
It will be borderline too heavy even with just a Lipo pack and electric motor.
A Hybrid GenSet is a valid concept but not with a automotive alternator.
You would simply belt drive a "lawnmower engine straight to the brushless motor and run it on regen in neutral if you had the pack crash while you were out driving.


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## Woodsmith (Jun 5, 2008)

If it is to increase range then you'd probably be better off without all the extra weight of the lawnmower engine, the alternator, the charger, the batteries and the drive motor, and just using the pedals!

With a lightweight vehicle like a bicycle adding all that extra stuff just makes it too heavy and complex to be useful and also adds huge inefficiencies at each stage.

You'd be better just connecting the lawnmower engine to directly drive the bike wheel and losing all the electrical stuff.

Then you'd have far more efficiency, and a more ridable machine, if you just bought an off the shelf moped.

I would say either just ride a pedal powered bicycle, or build/buy an electric assist bicycle in a more conventional arrangement of lightweight motor, controller and pack leaving the charger at home.


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## agniusm (Apr 30, 2012)

http://translate.google.co.uk/trans...patobulinimas-tolimoms-kelionems/&prev=search


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## dcb (Dec 5, 2009)

$140 shipped.
If you pedal, you have a human/gas hybrid. Throw it on a $20 garage sale bike and use it for longer trips? Maybe shop around for a 4 stroke?

Using a generator as a series hybrid is going to be woefully inefficient and cumbersome on a bike.


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