Please consider and discuss, hybrid motorised bikes, its not as silly as it sounds

1/ legal issues affect many of us re petrol bikes. Laws are often largely honored in the breach, but why push your luck?

2/ low torque petrol power is a pain to start and for stop go work (as are chain drives)

3/ electric range issues ~go away with a regen capable motor and controller

4/ adding a front hub motor is simple and cheapish (NB, i really think the premium for a 2 speed one is worth it)

SO:

A front motor with regen and fast charge storage could charge the bike when under petrol power or braking. A; big, heavy, expensive battery is not mandatory. Just a; light, fast charge/discharge, ~5ah 36v one should do (36o watts of power for half an hour or 720watts for 15 minutes, even 1000 watts on a 3c max discharge battery like mainstream lifepo4 chemistry units).

Getting rolling on electric and dropping the clutch = electric start convenience

Use electric when cops are a risk, motor on back roads and hill climbs where the extra power is really appreciated. Once altitude is gained, a puny electric alone is fine. A QUIET petrol motor seems a must for similar reasons. Why push your luck.

Much of life is factoring risk. Get this one wrong, and once the local cop has warned you once, your petrol bike may as well be scrapped. They dont like their rulings, no matter how silly, being ignored.

Technically, it's only illegal if the petrol motor is powering it on a public road, maybe even if the motor is warm? "I only use that motor on private land officer" should work sort of.

A simple example is a farm kid rides to the edge of town on petrol, and switches to electric around town. If he is sensible, the town cop may well turn a blind eye, even if he spots him on rural roads.

Aside from the above, electric when it suffices, is so much more pleasant.

Much as I love my mid drive ebike, the chain and cogs have been the most troublesome bit of an otherwise very maintenance free, joyous workhorse.

For many, the extra traction of an AWD bike may have big appeal - mud/snow etc.

I have to say, its kind of cool that such cutting edge prius like automotive technology, is so readily accessible to DIY folk in the bike world. I predict that for EV autos to work, they have to be lighter and simpler. The minimalist Nissan Leaf, is 1600 kilos for gods sake. Its just too big an ask for batteries to propel such mass very far for a long time to come. 150 kilos should be easily doable for a four passenger tuk tuk/mini moke type vehicle made from bike framing and bits.

 

[p4cm4n]

I don't know if I ever posted about this a long time ago or not but I did do this - for exactly the reasons you said.

Never tried regen tho. I just used it as a project that I drove to walmart and such.

Was planning on a mini road trip/solo camping trip. Never did it.

It was heavy tho

 

[libranskeptic]

Much as i like them, A mid drive wont give you regen. A pity. Regen would often mean a smallish battery would suffice.

 

[libranskeptic]

I like the idea. I've considered it myself.

Two different throttles could be a bit of a problem. Someone a few posts up alluded to this.

One other thing, too. I'm no expert. But I've gotten the impression that re-charging from rolling is a neat idea in theory, but difficult in practice. My understanding is that the the circuitry becomes a great deal more complex and expensive, with little actual gain. No personal experience with this. It's just what I've heard. But it sounds believable.

I wonder, though. Imagine two twelve volt bottle generators be mounted on the bike. Could their output be wired in series? Put a cheap automotive voltage regulator on each, then wire their outputs in series, giving 24 Volts.

If that's feasible, then that would seem like a good way to charge the electrical part of the bike. A 24 Volt system, anyway.

No comment on the electrics, but I suspect 2 throttles, one twist and other thumb, could effectively control both with one hand.

In short, the main issue with regen is that its mostly? unregulated. Heavy regen braking could overload electric components.

An easily avoided? issue, is that its not good to use regen if the battery is already fully charged, obviously.

 

[libranskeptic]

I would humbly suggest its a deeper issue than it seems.

I dont think either users or makers have really grasped the the new balance which must be struck in the new paradigm that EVs are.

The old paradigm was, historically, almost free, compact ~petrol energy. Massively heavy cars was a no-brainer, reliable solution.

Now, We have the plug in ~Leaf or the hybrid ~Prius. Both absurdly heavy and arguably a poor balance of EVs upsides and downsides.

Clearly the plug in concept works for some (and much loved by those lucky few), but range anxiety is surely a deal breaker for many.

So what about a Leaf say, with an onboard ~petrol charger?

Lets look at some rough numbers for the Leaf purely to illustrate?

Off the top of my head, 680lbs of batteries. 16-20 kwh, claimed 100 mile range.

generously assume 20kwh battery, that means each mile consumes an average 200w. Even if you double that to 400w per mile (ie-a range of 50 miles), its not much.

Yet even a 110cc honda dream step thru scooter motor is 7000w maxed out, or 35x average 200w per mile usage. Even a superlight 25cc brush cutter motor should yield 1kw, or 5x average power use. So only exceptional power use need drain the battery at all, and if the motor isnt needed for range, it only weighs a few kilos. If it is used, perhaps half the heavy and dear batteries could be economised on. During an average mile, up to 6800 watts is available for battery charging. The above 20kwh should be able to absorb up to 10kw when below 80% charged, so to all intents, the battery can restore usable charge very fast.

i.e., its a plug in, but by the time the batteries are flat, even w/o charging points, you are too tired to drive anyway.

It covers all bases except continuous freeway speeds and no recharge points, yet is much lighter than either of these cars by over 300lbs (~150kg), which yields further weight savings in construction, as well as lower power use and better power to weight.

The customer can opt for a configuration that just does his normal commute on batteries with ~no motor, but he has range anxiety relief if needed.

NB, the prius oth, has similar powered engines to an equivalent ICE car like a corolla - 75kw~?, and it also has to have a gearbox/transmission to drive the wheels directly from the ICE, which is complex and heavy also.

A gearbox isnt needed on newer electric only cars, they simply vary voltage i think, for torque vs rpm variation.

Engine efficiency is a bit academic, if the engine is correctly, intended to ~never be used. Similarly moot, is electric motor power. You can have as much as you want, easily. The problem is feeding the motor.

 

[rexamillion59]

Yeah I know and love mine. Cruise the electric all around town and hit the gas on backroads

 

[BikeBuilder43]

I like the idea. I've considered it myself.

Two different throttles could be a bit of a problem. Someone a few posts up alluded to this.

One other thing, too. I'm no expert. But I've gotten the impression that re-charging from rolling is a neat idea in theory, but difficult in practice. My understanding is that the the circuitry becomes a great deal more complex and expensive, with little actual gain. No personal experience with this. It's just what I've heard. But it sounds believable.

I wonder, though. Imagine two twelve volt bottle generators be mounted on the bike. Could their output be wired in series? Put a cheap automotive voltage regulator on each, then wire their outputs in series, giving 24 Volts.

If that's feasible, then that would seem like a good way to charge the electrical part of the bike. A 24 Volt system, anyway.

Why not use a dual brake lever for both throttles?

 

[Frankenstein]

Why is there a second Steve Best here?

 

[gary55]

Same Steve. He just had to change the pic. when he saw this one as a bolo on forensic files.

 

[Frankenstein]

That picture looks like that one serial killer, I'm not worried though he's in Canada.

 

[Steve Best]

That picture looks like that one serial killer, I'm not worried though he's in Canada.

This is my serial killer pose.

Obviously The Queen taught me to be dangerous!
Don't worry, I'm over it...
Not even a killer mustache anymore.

It used to be "Search and Destroy". These days it's "Search and Rescue":

Back on to the main topic, I am still having hybrid dreams.
Forget regen on a bicycle. Not enough inertia. Not worthwhile.
Forget solar panels. Not enough horizontal surfaces and not worth the weight/sail area to carry.
A 2 stroke may make sense for weight saving, perhaps even 30cc. Just enough for 30mph/50kph.
A small battery would make sense too. Just enough for 5-10 miles because we can go to fuel.
250w motor would be enough for 20mph/30kph max around town.
Big hills? We can power on both.

Hopefully both motors and battery would be under 20kg/44 lbs.

I do like the idea of a front hub motor 250w electric and Li batteries.
A rear drive single speed 48cc China Girl is a pragmatic start.
Fuel efficient and capable of 30mph.
I gotta build it...