Electric Motorbikes

[Mr. Dazzle]

A little battery doesn't take you far, it's as simple as that.

Universal swappable batteries need to be roughly cube shaped....some common simple shape anyway. They also need to be not-that-structural, bigger batteries tend to be structural simply 'cause they're so big and you may as well get them to pull double-duty. You could make a swappable battery structural, but then you're into a whole world of "what if?" when you have to consider how it might get installed wrong.

So if you want a feasibly swappable battery it has to be a semi sensible size and shape, which limits it power and capacity which in turn limits the bike range and performance.

You could put in more than one at a time I suppose, but it just adds weight and complexity. Especially when you consider most vaguley high performance batteries require forced cooling of some nature.

FWIW swappable batteries are an area of active interest in E-VOTL aircraft, but it's much much easier to put user restrictions on aircraft.

[The Spin Doctor]

It's more like standardising petrol really.

Standardising batteries should make them cheaper, not leave you locked in to batteries supplied by the bike manufacturer etc.

The holy grail would be 'hot' swap batteries. Pull into a service station, ride out with a fresh, fully charged battery (as you can in some places with electric bicycles). No hanging around chargers, no worries about broken ones/incompatible ones, no more range anxiety than with a (small) petrol tank. Needs standard batteries of course.

No, I really did mean standardising engines.

Look how people are getting used to the 'platform' concept, where one engine is shared across a range of differently styled bike, and even different model ranges - Honda engines were used by Hero, and the 790 KTM is now in a Chinese bike for instance.

There's actually little need to go down the line of designing different electric power trains for most purposes - it really won't matter to someone who buys a commuter scooter that the battery / motor / controller are identical under the bodywork of their choice. Heck, it probably won't matter to all but the most fanatical fans of a particular marque.

The whole point of the Honda / Yamaha / KTM / Piaggio deal is to create swappable batteries using a common design.

[The Spin Doctor]

A little battery doesn't take you far, it's as simple as that.

Universal swappable batteries need to be roughly cube shaped....some common simple shape anyway. They also need to be not-that-structural, bigger batteries tend to be structural simply 'cause they're so big and you may as well get them to pull double-duty. You could make a swappable battery structural, but then you're into a whole world of "what if?" when you have to consider how it might get installed wrong.

So if you want a feasibly swappable battery it has to be a semi sensible size and shape, which limits it power and capacity which in turn limits the bike range and performance.

You could put in more than one at a time I suppose, but it just adds weight and complexity. Especially when you consider most vaguley high performance batteries require forced cooling of some nature.

FWIW swappable batteries are an area of active interest in E-VOTL aircraft, but it's much much easier to put user restrictions on aircraft.

You have a roughly cube-shaped hole beneath the rider and between the wheels.

There's at least one scooter with twinned batteries that can be swapped independently. There's also one that has the pull-out battery pack pop out a pair of wheels and a handle so you can move it like luggage. Lots of clever thinking, the need is to standardise... there's no future in a hundred different battery pack designs if you're going to go the route of exchange centres.

[Count Steer]

The other thing we tend to forget in the UK is that bikes are very niche. Young people don't ride them much and many (most?) are, basically, expensive toys and sell in low volumes. When you consider that Honda made and sold 100m Honda 50s it's not too hard to see why we (and the bikes we buy) may not be the target market for the high volume manufacturers and their electric bike efforts yet.

So the disruptors and the £11k+ scooters etc will have their day, and may continue to if things continue as they are. Younger people may be drawn in via e-bicycles and the small, cheap scooters but if they aren't I can only see bike sales going in one direction here. Meanwhile Asia will be getting competition in the small electric bike, scooter and tuk tuk market and then larger bikes may become aspirational and that sector will get going properly.

Basically, we probably won't see a great range of the sort of things we want, at prices we want, from the big manufacturers for a while because we're not driving the volume market.

Kerching! Another 2d.

[MingtheMerciless]

Battery tech is marching on, the need for swappable batteries will only be a transitory thing. It seems a bit pointless wasting all that R&D for something that’ll be necessary for 10 years or so.

[Whysub]

I had a Lifan electric scooter (50cc petrol equivalent). Range was about 30ish miles, top speed was about 45 mph (tweaked controller). The rear hub motor was a Bosch, battery was a normal car sized lithium and was easy to remove from under the seat.

It was good around town on the flat, as the constant stop/start regeneneration kept the range to roughly what Lifan said it could be. I moved to a fairly remote area of Spain halfway up a montain, which the Lifan would not cope with (incidentally, nor would the Citroen Ami I tried driving from the town to my house). Otherwise the Lifan was fine. Even colour matched my RC8.

I had the loan of a Zero SR which I used on my commute. Brilliant bike, the instant full power was really good BUT my 60 mile each way commute was all dual carriageway/motorway, and it barely got me from home to work on a full charge. Same on the way home too. And this was in summer, the range would have been much less at 5am on a December morning.

The best electric bike build I have seen is on the "The Inja" on YouTube as they show how to build a battery pack from scratch. The CB750 they built is quite ugly, due to the restrictions placed by the way the battery has to be constructed. They are building a new bike using a Ducati Monster chassis an a rear hub motor this time, so maybe the shape of the battery pack will be more pleasing to the eye.

[The Spin Doctor]

Battery tech is marching on, the need for swappable batteries will only be a transitory thing. It seems a bit pointless wasting all that R&D for something that’ll be necessary for 10 years or so.

Inexpensive bikes will be using less-than-cutting edge tech for many years yet.

How many ICE bikes are still air-cooled, with tubed tyres and halogen lights?

[Mr. Dazzle]

There's at least one scooter

Exactly. Scooters.

Scooters need small batteries because people don't expect them to go very fast, very far, or handle especially well. Therefore for them, swappable batteries are more feasible.

If you want a 200bhp battery (and remember a 200bhp motor needs a 200bhp battery) then it's going the be physically larger. The bike it's in will need to be stronger and stiffer too, making it much harder to meet the conflicting needs of a stiff compact chassis and the ability to remove a large chunk of it on demand.

200bhp is obviously a lot, but even a 50bhp battery is roughly 5 times larger than the 10bhp one in a scooter.

[The Spin Doctor]

I moved to a fairly remote area of Spain halfway up a montain, which the Lifan would not cope with (incidentally, nor would the Citroen Ami I tried driving from the town to my house).

Should have done the journey the other way round and charged it up going downhill first

[I know, not 100% efficient ]

But I'm a little surprised - I got most of the way up a fair climb in the foothills of the Sierra Nevada in the Audi hybrid I drove in California before I ran out of 'leccie and had to let the ICE kick in, then recovered about 60% of the energy expended going uphill doing the same road descending. That's pretty impressive and far better than just wasting that energy as heat from the brakes.

I had the loan of a Zero SR which I used on my commute. Brilliant bike, the instant full power was really good BUT my 60 mile each way commute was all dual carriageway/motorway, and it barely got me from home to work on a full charge. Same on the way home too. And this was in summer, the range would have been much less at 5am on a December morning.

I liked the Zero very much. I reckoned that in mixed riding, I'd have got about 90 miles out of it. I need around 150 to be guaranteed to get to a training course, run the session and get back again. So some way short... but for an average afternoon's ride in the country for a cuppa and sarnie, it would do.

I still think there's a market for a hybrid bike with a small - 300cc or so motor - which would be quite capable of cruising at 75-80, and a 'top up' electric motor for urban LEZ riding and an acceleration boost when needed. Best of both worlds.

The best electric bike build I have seen is on the "The Inja" on YouTube as they show how to build a battery pack from scratch. The CB750 they built is quite ugly, due to the restrictions placed by the way the battery has to be constructed. They are building a new bike using a Ducati Monster chassis an a rear hub motor this time, so maybe the shape of the battery pack will be more pleasing to the eye.

I will take a look.

[The Spin Doctor]

There's at least one scooter

Exactly. Scooters.

Scooters need small batteries because people don't expect them to go very fast, very far, or handle especially well. Therefore for them, swappable batteries are more feasible.

If you want a 200bhp battery (and remember a 200bhp motor needs a 200bhp battery) then it's going the be physically larger. The bike it's in will need to be stronger and stiffer too, making it much to meet the conflicting needs of a stiff compact chassis and the ability to remove a large chunk of it on demand.

But you don't actually NEED a 200 hp motor on a motorcycle because you physically can't use all that power. You can't exploit it for acceleration because the bike would loop, and you'd only need it for overcoming wind resistance at 200+ mph.

As I'm sure you know.

[Mr. Dazzle]

Yeah you can say that, but the number of 200bhp bikes you can buy would suggest your argument is falling on deaf ears.

[The Spin Doctor]

Yeah you can say that, but the number of 200bhp bikes you can buy would suggest your argument is falling on deaf ears.

Which is why people need to stop looking at hp figures and start thinking about thrust. Electric motors change the game completely with their ability to deliver torque at zero revs.

[Mr. Dazzle]

That's true, but you're still talking significantly more power than a suitcase sized battery is presently capable of delivering.

[Skub]

But you don't actually NEED a 200 hp motor on a motorcycle because you physically can't use all that power.

Need and want are two separate and very different things. You don't need to dig too deep into the human psyche before you discover the desire for power and speed.

For some there is a visceral pleasure in riding a motorcycle that has too much of everything. That feeling of being on the edge of one's abilities,of not entirely being in control is a massive rush. It's why humans love speed and rollercoasters and being frightened.

[MingtheMerciless]

Hot swappables throw up another problem of contact wear and alignment. After a few hundred plug ins and extractions out of bikes, into chargers and back into bikes; contacts, battery cases and receptors will be wearing, especially if it's being "thrown" in by someone in a hurry. It will be interesting seeing how they get around that issue at a sensible cost.

In my industry (rail electric traction) we have some interesting and sometimes rather thermal failures due to contact misalignment and wear, add in a battery that won't stop combusting until its burnt its self to death, then who's responsible for the damage?

[The Spin Doctor]

Need and want are two separate and very different things. You don't need to dig too deep into the human psyche before you discover the desire for power and speed.

For some there is a visceral pleasure in riding a motorcycle that has too much of everything. That feeling of being on the edge of one's abilities,of not entirely being in control is a massive rush. It's why humans love speed and rollercoasters and being frightened.

OK how about 'want' and 'useable'?

As I've said, 200hp is unusable. The bike won't even let you try to use it.

And I can be on the edge of my ability trying to maintain speed on a 125! It's hard to get round a 60 mph corner any faster, no matter how much power you have.

Electric motors redefine how engines respond to a twist of the throttle. As I said, we need to forget hp and start thinking thrust.

[The Spin Doctor]

Hot swappables throw up another problem of contact wear and alignment. After a few hundred plug ins and extractions out of bikes, into chargers and back into bikes; contacts, battery cases and receptors will be wearing, especially if it's being "thrown" in by someone in a hurry. It will be interesting seeing how they get around that issue at a sensible cost.

In my industry (rail electric traction) we have some interesting and sometimes rather thermal failures due to contact misalignment and wear, add in a battery that won't stop combusting until its burnt its self to death, then who's responsible for the damage?

By coincidence, my LinkedIn page had a pic from one of my fire service contacts of a burned out hallway from an e-scooter that caught light being recharged.

Nevertheless, there are plenty of rechargeable items that don't go up in flames regularly, and many have swappable batteries. There must be billions of power drills and the like with swappable battery packs.

So yes, it's a problem to be aware of. Can it be overcome? I think so.

[The Spin Doctor]

That's true, but you're still talking significantly more power than a suitcase sized battery is presently capable of delivering.

Still yes and no

Depends how fast you drain the power!

You can ride a Zero down a motorway at the limit and you'll be lucky to get 50 miles. Ride it round town and it'll hit 100.

[Cousin Jack]

Nevertheless, there are plenty of rechargeable items that don't go up in flames regularly, and many have swappable batteries. There must be billions of power drills and the like with swappable battery packs.

So yes, it's a problem to be aware of. Can it be overcome? I think so.

The difference is probably in the maximum power the charger will deliver. A drill battery being overcharged will get hot, will probably start to deform, and perhaps melt some of the plastic, but the charger is probably not capable of delivering enough energy to start a fire in less than a few hours, and the smell of cooking plastic will be obvious long before then.

Car-type chargers capable of delivering 22kW will get stuff very hot very quickly indeed.

[Mr. Dazzle]

Depends how fast you drain the power!

Not really, no. That's what I've been saying.

Batteries aren't like fuel tanks. They're limited on capacity and power (sometimes called capability). If you want a 100bhp motor you need a battery that is also capable of supplying at least the equivalent 100bhp of electricity.

Small batteries can't do that. Its like having petrol tanks where the size of the pipe out is inextricably linked to the volume of the tank.

A 5bhp battery is never going to make a bike fast. Its true that electric motors make max torque at low rpm, but you still need to spin them up to make the vehicle move....which requires power.