Electric assist - thoughts

[alexanderfoti]

Hi all

Am thinking about whether an hybridised electrification is a good idea?

Take one of these motors:



A 3000watt planetary gear equipped motor. 100nm max torque!

There is enough space on my secondary shaft that another gear could run next to the main sprocket that runs the rear wheel chain.

Link it to the secondary shaft of my CVT and a lithium ion 72v battery pack of yet to be determined capacity, probably 40ah.

With the engine off, the front cvt pulleys are completely disengaged and so there is no drag on the cvt belts, and the electric motor can be used to drive the bike, depending on gearing, probably up to 30mph quite easily.

Range would not be far, maybe 5 miles or so, due to the weight of the whole thing. Could be used when in slow moving traffic/city situations.

Further engineering could be made to use the engine to drive a large(er) alternator and charge the battery back, but not sure on the utility of that.

MPG calculations would be off as well, you could use the commonly referred to Empg rating which is made up really.

[alexanderfoti]

Forgot to mention pricing!

Motor is about £300 with controller and all wiring required. Brackets etc will have to be made as required.

Batteries vary from £300-600 depending on capacity etc.

[boutje]

You could use the same the electric motor also as a generator to charge the battery.

[alexanderfoti]

You could use the same the electric motor also as a generator to charge the battery.

I could! but the battery wouldn't charge at idle, or when the bike isnt moving.

Actually, I could get rid of the 12v battery altogether and run it from a 72-12v buck/boost converter.

[Eddy Wane]

Hi Alex.
I thought that all new (2117) push bikes with electric assist had to have pedals to start off the motor as there is no longer a twist grip on the bike. My mates bike is the earlier kind that would start from rest on the motor or he could pedal it away first then use the twist grip as normal.
If that is the case is there a conversion kit to alter the motor or does the pushbike ruling not apply?
Eddy.

[coachgeo]

put it on the front wheel..... assist when needed with a thumb throttle?

[Diesel Dave]

It’s a nice idea, if you’re serious I have 200 Samsung 18650 30A cells that can be available (I was going to build an electric scooter), 72v controller too.

I was going to build a hybrid scooter as I bought a 3kw hub motored 12” wheel and was looking for a suitable donor (perhaps a 250 Honda Foresight) and use a small diesel generator setup; possibly in a trailer.