# Electric/Petrol hybrid bike



## daealc (18 Jul 2015)

Good day all,

I am aware that direct drive petrol engine bikes require basically a moped license and legislation etc... but I do wonder what would happen in the case I specced up a basic electric bike with only a small charge battery, and ran a small petrol engine onto an alternator to charge the battery constantly or prefferable have enough grunt from the alternator to drive the motor without no reserve charge.

Would this be legal?

-- cheers paul


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## daealc (18 Jul 2015)

my main reason for this is of course small hobyist engines can kick out 1HP at a cost of around 300gram for the engine block, from which a small alternator could be easily run, so makingm y solution alot lighter than large battery storage. If it was legal may look for the smallest diesel engine I can find and run it on rape seed oil 8)


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## Pale Rider (19 Jul 2015)

Legal ebikes come under Electrically Assisted Pedal Cycle (EAPC) regulations.

I expect your idea would fall outside those, so couldn't be classed as a bicycle, although you could build it and register it as a moped.

The EAPC regs are complicated - the EU is involved - and open to interpretation, so don't take my word for it.

I don't envy you the task of trawling through the regs, but that's the only way to be sure.


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## byegad (19 Jul 2015)

Yes. I agree with Pale Rider, trawling through the regs will be a big job, getting past Construction and Use approval a huge one if it falls in the moped class, and building it the easy bit if it doesn't. However I suspect it will be classed as a moped.


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## cyberknight (19 Jul 2015)

I think anything over 15 mph comes under moped .


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## daealc (19 Jul 2015)

Pale Rider said:


> Legal ebikes come under Electrically Assisted Pedal Cycle (EAPC) regulations.
> 
> I expect your idea would fall outside those, so couldn't be classed as a bicycle, although you could build it and register it as a moped.
> 
> ...



Having a cursory glance at https://www.gov.uk/electric-bike-rules my bike would meet that criteria, all I am doing really is removing the need for lots of batteries and replacing them for one capacitor and a dynamo+small engine, the engine its self cannot drive the motors.


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## daealc (19 Jul 2015)

Well apart from the manufacturers plate .... that I would just have to make my self


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## stuee147 (2 Nov 2015)

Would it not be easier to just run the dynamo/generator off the bike it's self to keep batteries charged up ?


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## voyager (8 Nov 2015)

Legal as LONG AS THE MOTOR IS NOT RUN WHIST THE VEHICLE IS MOVING 
it has been thrashed out long ago on the AZ site and the parallax argument is the same as a cement mixer on the move which I believe is now the only exception 

Solar power I beleive would met the EAPC law
charging a second battery not connected to the bike is also a grey area 

regards emma


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## mickle (8 Nov 2015)

This red tape is stifling small vehicle development


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## TheDoctor (8 Nov 2015)

Aren't you essentially building a diesel-electric motorbike?


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## voyager (8 Nov 2015)

Our earlier conversation about a year ago included several cyclists one whose friend was a high court judge , There were a few gray areas but unless you have a few grand to waste on solicitors etc or enough knowledge on the subject to tie the learned people up in knots - take the advice - leave well alone 
secondary battery charging on the move is the nearest as previously stated is the closest you could get but that would need to be in a sealed compartment etc to prove that it could not be used to power the vehicle on the move 

EU 
silly rules , 
silly laws 

regards emma


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## steveindenmark (9 Nov 2015)

When you can get Electric bikes to travel 120 km on one charge, I am wondering why you would want to consider a petrol engine.


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## sidevalve (9 Nov 2015)

You don't get anything for nothing - add the weight of an alternator + the battery it's charging + the engine + it's fuel + mechanical losses and the weight would cut the range of the small battery you intend to use. Further a diesel moped [yes they did exist back in the 50s even] could achieve over 200mpg without the added complications of charging batteries so what exactly is the point. An interesting exercise in engineering maybe but not really practical. It's either electric or engine.


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## markg0vbr (26 Dec 2015)

The answer I got when I looked in to the same thing.

There is a mobility scooter that has a petrol generator and a very small battery it is aimed at people who want descent range butt not the massive batteries it has a top speed of 8mph on the road and like all mobility scooters a pavement mode of 4mph maximum.







You can do this as long as the petrol motor is not driving the wheels directly, you are in assist mod ie you must be peddling and the assist must stop at 15mph if you go above 8mph on the road without peddling it must be registered as a moped, the contraption must be limited to 8 mph on road and 4mph in a pedestrian zone.

All this was thrashed out ove several years for the electric vans and street sweepers in town also we thought about the traffic wardens whizzing about to give out extra fines.


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