Some costs

In my probably pointless pursuit of an electric powered replacement for my ancient Voyager, I've established some cost estimates for an electric powertrain roughly equivelent to BMW's C-Evo (long range version) - comfortably enough to produce Voyager-levels of performance, if not range. These are from local E-bicycle* enthusiasts and battery specialists.

There seem to be two routes to a custom battery pack, flat, rectangular "Apple-style" batteries that may be best for packaging but are known for exploding or catching fire if abused and smaller cylindrical, "Tesla-style/laptop" items, usually packed into 'cells', these are apparently more rocust and unlikely to combust. I'm currently focussing on these latter items. To replicate C-Evo output I'll need 2,500 of these packed into 150 cells that will wiegh 75Kgs, less than the Reliant/Guzzi powertrain. This number of batteries will cost, new, 5,400 Euro's (and probably £s by next year). I'll work up a package size optimised to fit in an FF keel area.

To this cost and wieght must be added a power management controller at £700, wieght unspecified but not huge. This is a programmable unit that can provide regen, traction control and torque limits and so on. Also a battery management system that seems to be regarded as simple and cheap. And a water-cooled motor, capable of 35Kw peak, 17 Kw continuous, at £2000.

So subject to some CAD work to establish battery packaging it's possible to buy a powertrain that will serve most prectical purposes for an FF. It'll cost about £8500, assuming a bit for the battery assembly and management, cabling, intumentation and so on (and £/Euro equivelence). The "Vehicle" end of an FF costs about £5,000 (ignoring the free labour of the enthusiast building it) which adds up to £13500, surprisingly similar to the cost of a C-Evo and an interesting insight into how much BMW must be paying for parts and labour. Not much of this can be found in scrapyards, although a frontalled C-Evo might supply a cheaper motor/rear end unit. (anyone?)

I'll publish a drawing, like previous ones, of the battery packaging in due course. This is not mysterious. The cells I've seen measure 102mm x 82mm x 70m. but need 10mm adding to the last figure to allow cooling airflow. Package 150 of these and you;ve cracked it. Meanwhile I'll have to get a ferry contract, or something, from Bozo to raise the dosh...

*In this world the term "bicycle" is used estremely flexibly, officer.

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Mental arithmatic

Instead of trying to do mental arithmatic while listening carefully to a battery specialist, himself trying to translate electronic speak into hammer action, I've gone home and used a pocket calculator. So you only need 125 cells to get 2,500 li-ion units, not 150. Doesn't make any difference to the price but highly relevent if you're trying to package the battery. Good job nobody takes any notice of this stuff...

Anybody listening?

Morning, Royce. Well, I'm paying attention. I have to admit, I didn't check your calculations. Just took them as read. I'd very much like to go the FF route, as we've recently bought an electric car, and I'm sold on the principle. However, range must still be an issue, if like me, you live in the country, and have miles and miles of tempting roads on your doorstep. My experience of our car is that you shouldn't charge it to 100% unless you're going to use it immediately, so 80% is the target for everyday. Also, the charge rate drops dramatically, once you reach 80% of battery capacity. So increased charging time also becomes a constraint. Then at the bottom end of the scale, you don't want to let the battery drop below around 10% charge, unless you're close to a KNOWN working charger. And that is forgetting that the 50Kw battery is restrained to only allow 45 or so usable units. So going back to our car, from a quoted range of 211 miles, you immediately lose 30% in day to day driving, although if planning a long journey, that would only go down to 10%, then in winter you lose another 10 - 15 % due to lower temperatures. So even if you manage to get a theoretical range of 150 miles from an eFF which would be class leading at the moment, you'd still only have a usable range of around 100 miles. More than enough for city riding / commuting, but not enough for touring / leisure. Of course battery technology appears to be progressing rapidly, so maybe in a couple of years, 150 miles of usable range will be available. At that point, I would be 100% converted.

Further work

Range is going to be the limitation for a while I think. The battery people here say that charging above 80% reduces battery life so you're on the money with your range remarks. Thay say the UK is good for EV's because it doesn't get hot enough to seriously need cooling, although some battery heating will help in mid-winter. I've done some work on the battery packaging issue, using the cells I mentioned. I'm supposed to get 125 in and so far I'm up to 102, inside the chassis I put up here recently. I'm going to do some more work on that but I doubt if I'll get to 125. 110 may be the limit and that will restrict passenger space. (2,200 individual units). I need to define motor dimensions and mess with the chassis a bit more. I'm thinking using a water cooled motor, then using the heat exchanger outlet air to heat the batteries on cold days (and me) but I can see a diesel heater being the answer there.

I guess that Aero's are the area where range can be extended, over a C-Evo etc. but that only works if you're going fast enough for it to matter. Tooling around Bristol in the 20 limit it could be brick (Bricks are of course quite good..) for aero purposes. The annoying thing is that it'll take three years to build, assuming I live that long, and the next-gen batteries will arrive around then, rendering most of this obsolete.

It's an interesting excercise though. I can understand why the E-Motorised bicycle people are focussing on recreational vehicles (Moto-cross, trials etc.) and lightweight urban scooters, it's really difficult to get enough batteries into anything longer range. The C-Evo is basically a battery box on wheels. The seat can't go any lower because of the batteries.

I think that, at the moment, instead of trying to replace something like a Voyager, it's down to acepting a limited range and designing a vehicle for a use where that isn't an issue - like Trials, commuting and so on. But with limited speed and range some FF advantages, aero efficiency, comfort, become less relevent.

eFF Analysis.

Royce, I'm sure you're correct about the type of eFF for the moment. Shorter range commuters, and lower speeds. But that experience will benefit the eventual eFF tourer, if I live that long. I'm currently wrestling with waterproofing the engine electrics on the Pete Lawrence Delta, after being left at the side of the road in torrential rain on Monday. No such problems on an eFF, I would imagine.

Cargo Scooter

The application that leaps off the page is an E-cargo scooter. Could be limited to 60 mph without loss of usability. It's also easier to package without a passenger option and would be easy to upgrade to E-Voayger spec. when better batteries arrive - due to neccessarily robust chassis and supsension details. I think I'll proceed, design-wise, on that basis.

Only snag is that it's clearly an industrial project not something Royce is going to use as retirement activity! Cue the whole sorry business of finding an industrial partner. One of the most significant things anyones said about my FF projects was "I think you're living in the wrong country" I'm not moving now, not that anyone would let me in. So I'm not going to build a prototype E-cargo scooter! But don't let that stop anyone else, younger, more naive and so on. (much richer would be a good starting point) but anyone can steal the design, but then the problem is that although they'll know what I've done, they won't know why. Could make development tricky. although for Honad it'll be 'almost simple', they'd just have to get over the corporate cowadice problem.

You should be relieved your 'water in the electrics problem' in only on the Delta, if it had been an E-FF you'd be keeping your head down in a ditch waiting for the molten battery parts to stop flying about...

Cell orientation

Make sure you stack the cells vertically. Horizontal stacking leads to more failures apparently, as the insides of the battery develop micro cracks due to bending loads.

Good tip

Thanks for that. It's very encouraging to see the accumalation of EV info. I'm relieved to note that the best packaging I've managed so far does align the individual battery units vertically.

I'd spend more time on this but right now I'm engaged in working out how to fit an earth return wire to the (Lucas)rearlight of a 1956 Norton 99 Dominator. The worst of it is that I know exactly what I did to deserve this...

E-FF range & battery costs. Some grounds for optimism?

Just a few points, 'off the cuff', so to speak, but based on real-life experience, both mine and others. One solution to the high cost of batteries is to buy second hand from crashed electric cars. I know two people who have bought a pallet-full of Nissan Leaf batteries for much, much less than £5,000. More like a quarter of that. One Leaf-full should be more than enough for the biggest FF, with several years' of use still available. I've also read about several people who've converted old Vectrix e-maxiscooters from their original NiCad to 2nd hand lithium batteries. (And new Vectrixes are now available with lithium batteries as standard; ironically, they are quite possibly the most aerodynamic, FF-ish ePTWs currently on sale, apart from the Peraves Monoracer).
And when it comes to range, remember what was achieved a whole decade ago in the RTW ZeroRace of 2010-2011. The modified ZeroRace Vectrix was capable of well over 200 miles on a charge (350kms). The winning DesignWerk ZeroTracer was capable of the same, going a lot faster (as was the X-prize-winning Peraves E-Tracer).
And Cedric Lynch told me two years ago that he thought it would be possible to cover the 870 miles from Land's End to John O'Groats on a single charge in a modern version of his streamliner.
And Terry Hershner managed to cover more than 1,000 miles in under 23 hours on a Vetterised 2012 Zero back in 2014.
And the latest 2020 Energicas have a 20kWh battery pack. I haven't got my calculator out yet, but all of the above achievements and specifications make me think that it should be possible for a Voyager-sized FF with a Cevo amount of power and weight to cover 250 miles on a single charge at a steady 70mph. Just musing. PNB

Go for it!

I bow to your knowledge of all things EV. I'm just a mech tech, with FF design experience, relying on local EV specialists and a rather good supply of used Li-ion batteries. My ancient CAD software shows that, using current battery tech, it's very difficult to fit enough batteries into a Voyager-sized FF*, for 150 mile plus range, without intruding on the (Two) passenger space or ergonomics. However, even in Bristol, several people are fitting second-hand batteries to some highly unlikely once-ICE vehicles. The bigger the vehicle the easier this is.

In a C-Evo (And similar vehicles) the rider sits on top of the battery box. In an FF the rider must sit almost among the battery box, reducing the space available. E-FF design at the lower end of the size range is just another packaging job. I have chosen to design an FF that is small, practical and cheap enough to attract enough users to actually make a difference to road vehicle efficiency (The "Ford Option"). Despite it's good looks and high specification the Mono racer is not in that category. I believe it is also the only current production E-FF.

There are no 'magic solutions' in EVs. Only battery tech is currently showing any signs of major advance. (See Tesla news release on it's new batteries a few weeks ago.) The vehicle industry seems confident that this ("Dry cell") tech will be in production in less than five years and is spending hugely to achieve that.

But this is just what I have learned so far. I salute anyone who can produce a production-standard E-FF in any part of the size range, including Arnold of course. Please feel free to do better - Someone, somewhere, should be able to do this. Why not you?

*I apologise for using the term "Voyager-size" It's obviously due updating. I'm referring to the minimum sized FF that can carry two people without compromising the standards of comfort, handling, safety and efficiency that desgin established. I very much regret that more modern examples do not exist (so I could buy one)

Seating options

Why would seating 2 people be a priority for an eFF? I know some people imagine they'd carry passengers most of the time, but even 5 seat cars do most of their miles with only the driver aboard. The cargo version seems the best option for utility for the most users. For passengers, a car seems to provide the answer.

When Royce asks "why not do it yourself?", I have the capability but right now don't have the enthusiasm to devote enough time and money to it. The main constraint is getting a road version insured in my country. Registration may also be an issue but I expect something could be done to make that happen.


I don't think utilisation rates are very relevent in the market place. I have use of a five-seat car which also usually carries one or two people. But it was chosen because it could carry five people and quite a lot of freight when that was needed. Which it has been on many occasions. I also have use of a 2.5 tonne Transit, that rarely carries 2.5 tonnes,. but is extremely usefull when it does. And so it is with PTWs. FJ rarely carries two people, but can carry 80Kgs of freight instead, quite valuable in Bristol, about to initiate Clean Air Zones penalising all deisels but not PTWs. People buy utility. Buying a single seat PTW is a commitment to never carrying a passenger - unlikely to be a selling point, especially with young people.

The Cargo option, although a potentially large market, is a speed and range limited vehicle, not the full spectrum FF of the type represented by FJ. This may be possible - I haven't finished packaging yet - and certainly will be when dry cells arrive. Such a vehicle fully exploits the FF advantages and maximises attraction to the market. I do not intend to be a delivery rider but I do wish to replace FJ with a modern version. That is my design criteria.

You make a good point about the difficulty of registering a single vehicle under EU single vehicle approval proceedures, although it is possible. It's a lot easier in England where the state is disinterested and, post-brexit, is allowing a reversion to the 1986 Construction and Use Regulations - as far as I can make out...

It's good that you have the capability to make an E-FF and not surprising that you lack the enthusiasm. You share the company of Honad, Ford and Piaggio in that respect (among many others).

FabrizioCross's picture

Electric FF thoughts.

Hi Royce, I've been working on a recumbent e-bike design for some time (, and while the power limits are different, I do have a few thoughts to share.Trulli

1. Batteries- It is true that charging to 85% of rated capacity will double the lifespan of you pack. This is because in the early days of Lithium batteries the manufactures agreed on 4.2 volts per cell as fully charged, even though it was not ideal for the cell. The capacities were lower then and they needed to get as much power per cell as they could. Now that capacities are so much better we don't need to do this to our battery cells. I run a programmable charger that lets me charge to 85% most of the time but if I have a longer trip coming up I charge to 100%.

2. More on Batteries. the two dominant cell formats right now are 18650's and 2170's which are respectively 18mm X 65mm and 21mm X 70mm. The 18650 was the dominant size but the 2170 is slightly larger and has much greater capacity. The downside of the 2170 is that with the larger size it does not shed heat as well. Heat is the real killer on any battery pack. I don't build packs, I simply order pre-made packs with BMS (battery management system) boards built in. My bike is running on a 72 volt 40 amp-hour pack. This gives it a top speed of 65 kph. For Motorbike speeds I would suggest that a 110 volt pack would be the minimum.

3 Motor. Direct Drive Hub motors make a lot of sense for a street machine. They support regenerative braking, are mechanically simple, require no complicated chain-line, and leave all the space on the chassis for batteries and controller. Most Direct Drive Hub motors are run by 3 phase AC controllers that are commonly available.

Enertrack make one of the more popular conversion motors.

QS motor is also popular with the conversion crowd.

One of the cool things about hub motors is that they make an dual-wheel-drive system easy. I think Dual-wheel drive would be especially advantageous on an FF bike.

A good place to check out what the Electric Moto crowd is up to is at

Good stuff

Good the hear from Vehicle E-specialists. I've learned so much about E-power recently I understand at least half of this! I;m pretty sure I'm looking at using the 18650 batteries, put together locally into packa of 20. These are used, tested, batteries initially recovered from laptops but now apparanetly joined by ex-vehicle batteries. Being enthusiastically used by E-bicycle er... maniacs. I see 'dry cell' tech coming over the horizon, that may solve the basic packaging problem, but not the cost, at least intially.

Hub motors are very interesting for the reasons you mention, better space utilisation and two wheel drive. However, unsprung weight is an issue and also power output, although twinning helps with that. As a vehicle engineer I'm also a bit worried about power management, there needs to be a power split that's managed and also measures to prevent harmonic variation in power delivery. This is a serious issue that can cause loss of control and killed John Cooper when he lost control of a double engined Mini many years ago. All solvable, except perhaps weight. There are some nice hub motors being shown (e.g. I've also been pointed at as the 'conventional' motor I need, although I'd prefer the water cooled version so I can use that for cockpit heating (An Essential feature!)

It's interesting that the AC/DC debate continues. A lecture on this would be informative for simple vehicle engineers like me...

FabrizioCross's picture

AC vs DC

I think the AC vs DC debate is pretty much done. Now that AC motor control is affordable there are not many good reasons to go with DC. I can say from personal experience, having used both, that AC is far superior. It is easier to integrate, offers smaller components, and has higher efficiency. Here's a simple article.

"My ancient CAD software

"My ancient CAD software shows that, using current battery tech, it's very difficult to fit enough batteries into a Voyager-sized FF*, for 150 mile plus range, without intruding on the (Two) passenger space or ergonomics."

I sold off my new motor and controller (comparable to a several year-old Zero) and gave up on my e-FF project because 1) with only designing for a solo rider but for the 150-200 mile highway range I ended up with batteries below, in front and behind the rider (and a fairly heavy vehicle), and 2) the batteries that could be had that might work for the range and form factor desired were not even close to being in what I thought of as a reasonable budget.

Batteries seem to come in big rectangular blocks that don't fit well into a low FF vehicle that leans into the corners and so has ground clearance as an issue, or they come in small cylinders (which are actually just the pouch cells rolled and stuffed in a can) that open up pack shapes but will need thousands spot-welded together into a pack. I can make a wiring harness, but I know my limits and I wasn't going to deal with trying to DIY a 100V and 20+ kWh pack, and buying in a custom pack makes instead buying a couple of donor ICE bikes for projects look pretty appealing.

I like the idea of e-power, and if I was interested in making an e-FF with a 50 mile range it could have been a doable project. But I do have range anxiety, even if most of my rides are under 100 miles, and it looks like batteries from a decade or two in the future are what were needed.

Batteries and PTW packaging

I think Michael Moore and I are on the same page, as old-school vehicle techs, somewhat appalled at the voltages and amperages needed and discouraged by the size of appropriate battery packs. But E-power is the future (for now) and we have to accept sticking with some ancient heat-engined vehicle, or try and get a handle on this emerging tech. Two trends seem to be emerging. On one hand there are the bicycle maniacs putting together DIY systems of relatively low power and voltages in mainly, I think, DC systems. This seems quite do-able but isn't up to FF power specs. On the other hand there are car-scale projects, using AC systems and more or less stock car motors and battery packs, running at hundreds of volts and amps. For FFs the power outputs are way higher than needed for an FF and the motors far too big.

I think Michael is right that a motorcycle power train is best in terms of size and rating, although that gets us back to the problem of packaging a relayively large battery pack and the alarming task of assembling and wiring up a box that can not only kill but do a decent roast in the process. Motorcycle manufacturers also fall into the gap between bicycles and cars, hence the plethora of lightwwight, short range motorcycles (as seen on EMN) and the rarity of full-size E-motorcycles that could be FF Donors. The C-Evo is a perfect example of the difficulty with a battery box that cannot be fitted to an FF, tightly integrated into a motor/controller system. The rarity means that suitable donors are scarce and any that turn up in scrapyards are instantly bought. The Kart race motor linked to above is an interesting alternative.

All these difficulties can, as usual, be solved by the simple application of money. Anyone with lots of that can stop reading this thread and get on with spending some. As a proponent of the Frank Williams approach (No money? do it any way) I can only continue to examine the packaging of second-hand batteries, while studying the motor market - in case something turns up...

Following the mention of Nissan Leaf batteries I have been sent this link with a comment that the battery tech used has a shorter life than current tech.

FabrizioCross's picture

more thoughts

Hi Royce, the bike maniacs are using AC systems as well. All batteries are DC of course, but the majority of bicycle hub motors and mid-drive systems are using AC motor control.

Here's what I think would be an ideal hub motor for an FF Motorbike.

Rated power:10KW or 12KW

Wheel size: 6.0×17

Matching tire:180/70-17 to 220/70-17

Max. Speed: 140kmph

Required rear fork width: 230mm
QSMOTOR 12000W 17inch In-Wheel Hub Motor with 6.0×17 Rim

heilige scheisse!

That's a bit of a game changer then... At the site I see a plethora of hub motors and it's interesting that the key data, weight, isn't mentioned. So I've asked. Then there's cost. But 12Kw is almost enough power, and if two of these could be coupled, with one built into a suitable width front wheel, they'd be more than enough, maybe allowing something smaller, lighter and cheaper. If the weight is low enough. I can compare it directly with a Mk11 HCS unit, which is lighter than a Guzzi rear wheel and drive unit. Neither are as light as I'd like, but they work. 12Kw hub motors at similar weight would crack it, the battery box could be 25% longer.

("Unsprung weight" - mainly wheel weight - is about the ratio to the sprung weight, the heavier the vehicle the more wheel weight can be tolerated. 'Course, integrating a hub motor into a HCS unit would be a challenge, but not impossible. 2WD also implies 2W regenerative braking, further increasing range and offering 2W ABS integration. In production a single, simple, rolling chassis could fill a wide range of roles simply by changing the wheels, battery pack and software. Suddenly Honad hove into view, saying "Told you so, the vehicle Is almost simple"!

I've done the Norton*, might have to get back on the CAD before aomeone else does it in vapourware. Thanks for clearing up the AC/DC issue, last time I asked some experts they were still argueing about it.

*Previous owner/restorer had carefully used a battery retaining post, in the battery box, as the combined earthing point. Then just as carefully isolated, by rubber mounting, the entire battery box. Took a while to put my finger on that...

Christus auf einem Fahrrad

Speed on an electric motor is dependent on voltage unless I'm very much mistaken, while it's current that determines torque. So how can a motor be said to give a certain speed (140kmh) if the voltage is unknown?

Revs (Not Reverends)

It's the motor rev limit. Single speed EVs (i.e. most of them) are caught between high current load when accelerating hard from low motor revs and the maximum revs the motor is safe to. 9,000 rpm seems to be a common limit and many are lower. I think this may be the main reason why 100 mph seems to be a common (limited) top speed. So a 140mph terminal ability is unusual and probably needs some explanation, Of course getting to 140mph with only 12KW might be aerodynamically challenging, although Monoliner's .21CDa might make it possible. for reference Voyagers get to almost 120mph* with 40BHP (and similar torque) at the rear wheel. I don't have any way of converting BHP to KW - anyone? Voyagers run about .29/.3CDa. I think you'd need to know frontal area to make much sense from this but assuming 1 square metre wouldn't be too far out. Usual caveat, anyone who actually knows how to do these sums should feel free to pile on!

Obviously one could fit a (two speed?) gearbox but that's cost, complexity, weight and power loss. Best not...

*Voyager certified at 118 mph in 1989.

Metric not Imperial

Just to confirm, before we get too excited, the top speed quoted is 140 KMph not Mph, which less than 90 mph, but no matter, the speed is surely only limited by the controller or the motor exploding due to 'centrifugal' forces, obviously assuming the vehicle can overcome aerodynamic drag.

For kw to hp says the nerd, simply add one third. So 12 kw = 16 hp.

I know this is bikeweb, but....

The problem with battery storage an electric ff two wheeler is that it has to lean to turn, which effectively means that the batteries cannot be stored low in the chassis if high g force cornering is to be achieved.

Two 'bikes' running in parallel though could carry the rider and batteries between them on a horizontal remaining platform, being the bottom of a parallelogram. Keep the wheels close enough together and it would still qualify as a bike.

More cost and mechanical drag admittedly, but much easier to store the batteries.

EDIT Looks like someone almost beat me to it

Just needs to be a bit narrower!

More info

Thanks to Martin for producing those more believable performance figures. I also have a reply from the QS motor manufacturer. It weighs 35Kg. I think that's outside the envelope of feasibllity... So, back to battery packaging. I think there's probably a direct relationship between power output and weight with electric motors, unless permanent magnets can be excluded. I'm increasingly confident that someone here will be able to tell us. Is it essential that permanent magents be involved? or even 'ferrous' materials, isn't it the elecricity that makes the magnetism, not the metal? (shut up Royce, you're out of area)

Sorry to object to the idea that leaning conflicts with battery packaging. In reality the need for the rider to put their legs down at a standstill is the limitation on battery box width (front mounted box). Obviously it's much easier with a bigger vehicle - see 'Peraves'. Last time I looked I could get 102 cells into an FJ-scale FF, not hugely short of target. I think that's a more promising avenue than turning it into a tilter (Or 'narrow car') - but feel free to prove me wrong!

In terms of cornering force generally I expect that a leaned wheel can generate as much grip as a non-learning wheel (about 1.2G), the great limitation for PTWs is the lack of any aerodynamic downforce (But see my Supoerbike article 'Movable Aerodynamic Device' - MAD) which can get cornering G up to 4.5 or so. With motorcycles it's rider control that sets cornering force limits.

Mechanical g force

According to Bill Milliken's limited (but possibly unique) experiments on high profile crossply? tyres back in the 60's, grip on a negatively cambered wheel increases with applied load, while that of a non cambered wheel decreases with load. So a bike tyre will stay consistent, but a car tyre will drop off.

The experiments were eventually discontinued as aerodynamic downforce devices came into play.

Hub Motors

I've had the chance to talk to the bicycle maniacs again about hub motors. There is a direct relationship between power output and wieght in electric motors and permanent magnets are used in all motors in the vehicle power range. Wieght has been reduced by using rare earth magnets, but basically hub motors in full size two wheelers are just too heavy to be usable. If you're looking at a lightweight four wheeler it's a different story, mulitple motors in a relatively heavy vehicle can achieve a usable sprung/unsprung wieght ratio with good total power.

Also my current battery packaging total (2,040 units) will apparantly give good power perfromance, just less range than target ("Better than a C-Evo") And plywood is a good material for a supported battery box. (Fire retardent, non-conductive, easy to fabricate, not too heavy, stong, cheap. All good things) It's a composite after all. Batteries need to be protected from shock loading.

More on hub motors

One of the issues with hub motors in a four wheeled vehicle is that those designed for PTW use are not designed to resist the side loadings found in conventional four wheeled vehicles.I am not aware of any hub motors that are suitable for a not tilting cabin scooter type vehicle.


Can you be a bit more specific? It's jargon of course but "Tilter" implies a multi-track narrow vehicle that avoids falling over in turns by tilting into the turns - like a single-track vehicle, usally a Powered Two Wheeler (PTW). On the other hand "Scooter" refers to a PTW with small wheels and there are several "Cabin Scooters", even Lighning Motorcycles prototype E-FF could be called a Cabin Scooter. Also ther;s Benilli's Adiva and BMW's C.1. Perhaps you mean a "Narrow car" like a Tango that simply massively ballasts it's floor to stay upright. That obviously puts lateral loads on it's wheels.

In any case I have to note that 1. PTWs Do laterally load their wheels and much else and their stiffness in resisting such loads defines their steering and control precision - although I accept that such loads tend to be transitory and lower than the 1G plus loads that multi-tracks routinely impose. and 2. there are a number of small multi track, non-tilting, four wheelers ("micro cars"), that use four hub motors. The bicycle maniacs recently showed me a Chinese micro-car with exactly that layout, on sale in China for less than 1K eu.

While Hub motors, light and powerful enough for just one to power a full-scale FF may be impossible due to unsprung weight problems, pretty much every other option, including 2WD hubs motors for PTWs, seems to be under active consideration or production in the electric vehicle world, although due to WestDems preoccupation with 'seething pile of escalating paper' rather than manufacture, most of this is happening eslewhere. In reality all that's needed to make a perfectly reasonable E-FF (or anything else with wheels) is enough money and the will to spend it. Nothing's really changed in the last forty years except the addition of the letter 'E'

Cabin Scooter

I'm using the term cabin scooter to refer to a single or tandem seater vehicle that has more than 2 points of contact with the ground, is enclosed and can reach the national speed limit in the UK i.e. 70 mph.

So what I was saying is that I don't see any hub motors available that are suitable for a non tilting version of such a vehicle.

An example

on there's a good picture of a current E-motorised bicycle that well illustates the difficulty in fitting a decent battery pack into an FF. Literally, the bigger the vehicle, the easier it is.

Packaging, watching

After a bit of re-aranging I've got up to 114 packs of 20 cells each into a Voyager spec. FF, using an ME1507 motor. That includes some rear-mounted batteries that intrude on passenger/cargo space, 102 packs meets full spec. for cargo and passenger, 15750 wheelbase, 400mm rider seatbase. In a reprise of the original Voyager design, the 'powertrain' is so big that it dominates the entire structure, which must be dedicated to this particular set of motor and batteries. The chassis is extremely simple, the easiest part of the task. Eveything else is pretty much cut'n paste and the cost isn't wildly out of line with an ICE build (using second-hand batteries). Mostly it's cockpit, fittings and bodywork.

However BMW's 'concept scooter', discussed in another thread, (along with Peraves and Lighning) show how electric PTW production powertrains could appear that are immediately suitable for the FF layout, as the Tmax is for an ICE powertrain. Rather than cut metal on a powertrain package that might suddenly become obsolete, I think it's time to watch what all the other damm fools are doing...

Battery packaging and assembly

Continueing study of this issue has produced some interesting products and techniques that answer some questions about packaging and actually assembling a battery pack. A lot of this stuff in American and involves larger vehicles where battery packaging is not so difficult, but there's enough here to let me do some more work on packaging a 'voyager-scale' pack;- Battery packaging kit, for close packaging of 18650 (lap top) cells. There seem to be several options for this sort of component, allowing non-rectangular packs to be built up. Here's a guy actually building up a battery pack, using what is described as the Tesla approach of putting individual fuses on each cell, connected through copper bus bars. I'm being assured that forced draft air cooling is enough for 20Kw systems using these battery packs with a 10mm air gap between layers of packs. If I come up with anything uiseful, in terms of a battery box that will, effectively, replace the voyager power train I'll put up a sketch.

Hi Royce If you don't want

Hi Royce
If you don't want the hassle, or don't have the time, you can hopefully use individual modules of the Tesla car. Warning different packs are different sizes, but say on average comprise 444 cells, 25.2v 232ah 5.3kw 27" x 12 x 3.25" thick x 25kg and sell on ebay circa £850 each. Ive been looking to buy a complete but written off example to cannibalise, buy unable to get below £20k, but if anybody is interested happy to go halves, and would either be happy for just half a 100 kw pack, or take on board the rest of the vehicle. I am no expert but looking through earlier posts on this, i find it a bit inappropriate to just write off DC power for our projects, yes i agree on all counts, (except cost) and that i have found has always been the limiting factor to a lot of my projects. You can get a complete 100hp plus DC drivetrain for below £1000 and with little expertise, wire it up yourself, and then download free software, and armed with an old laptop, program in all parameters required very quickly, and off you go. The other end of the spectrum, i have just acquired 7 off Yasa P400 motors to get the price right, from someone elses abandoned project, these are over £9000 a pop, and the controllers are over £6500 each, and the software to suit is a snip at £2500 and looks intimidating, and i imagine a very time consuming tomb, to fully absorb. These are very serious motors, at 160kw output from a 50lb lump which is exceptional, but this is at 700v, so all the downstream system is also ultra expensive and bespoke to suit, which is why i am coupling 2 together at circa 400v and drag stuff off from any breakers shelves for a fraction of the cost. For our needs, If you insist on AC go for something like a nissan leaf motor or mitsubishi phev drive motor, their are some very smart people currently working on reworking the existing drives on these motors, and this may be a viable option for some, at a similar price to a 25kw ( for 2 mins ) in wheel motor, so don't write of DC just yet. yours Dave


Some impressive costs there! Can you put up some links to some of this stuff? I'm currently going down the low-cost, minimal acceptable power ratings rabbit hole. After aome investigation I've concluded that in-wheel motors are too heavy in anything like the poawer ratings needed to meet the E-Voyager spec. I'm working to (30-35Kw.) so I'm looking at chassic mounted motors and a French Kart racing motor seems to be leading the charge at present (about £2K) for batteries I'm going with 18650 ex-laptop cells that I have a local angle on and I've just invented a batttery packaging system that may get enough batteries into the space formerely occupied by ICE products from Reliant and Moto Guzzi. My local E-vehicle contacts/consultants are all AC believers so I'm going that way at present. I'm hoping to make up any power performance deficiencies with ever-more cunning aerodynamics and minimal motor vehicle. for this reason I need want to avoid anything too big, powerful or heavy.

Also, for me, being broke etc. this is just a design excercise. I'm working on the assumption that everything will get smaller, cheaper and better during this process so that when I'm ready to actualy start cutting metal (and wood, and plastic) everything will fit even better and the premium bond I've had since 1965 may have a chance to come up..

I guess it would be useful to have a forum better aligned to the subject of E-FF design, compentry and systems, but I've no idea how it would be done. Something like Car builder solutions - "Electric FF builder solutions"?

Other forums

The Endless Sphere forums are dedicated to all types of EVs from bicycles to planes. I found a few discussions of FF design on there, including posts by Julian linking back to this site.
Due to having such a wide range of posts it can take some digging to find it, but there's an enormous amount of infomration there about all aspects of EV design & construction so I'd advise anyone interested in EVs to take a look through it.

I'd also like to clarify that the ex-laptop cells we have are going into lower power packs for electric bicyles & static storage. The cells we recommended for the e-FF are the same format but new ones rated to provide the required power density & current supply for the application.

laptop battery

From what i have seen it is perfectly ok to harvest used laptop cells, even after several years of use, and sometimes a perfectly good laptop battery can be scrapped off for 1 low cell. But as clarified in the above, new cells are better, and last year i made a big investment to purchase approx 55KW of new laptop battery packs for my own project, direct from a public auction, straight off the warehouse shelves, all still in their original packing. Once i got them home, i did start to strip a few, but i have been so busy with other work, this part has just been on hold, and as i have subsequently realized my own fully enclosed electric FF with its much larger footprint, can easily accommodate Tesla pack modules, and that is now the way i intend to go. Although in itself, its not a difficult job to construct your own pack, doing so properly, will take up a lot of time, and so i have now decided to sell them on. At just £3000 plus vat for the lot, this works out at less than buying second hand, and also if you wish, a small business sideline, as their are many different types, and these are currently selling on ebay circa £10+ each. If nobody wants the lot in one go, i will probably sell to the wife, and she can then split them up, and spend the time faffing about, something i can't afford to do, but if anybody has any other ev stuff they have to part exchange i would be very interested, from motors controllers to the front wheel off a BMW 1200 Hossack front end, ive already bought the forks, but would consider a complete front end. Anybody interested, i can forward photos, will try to upload 1 here, but you can get me on for more info. yours Dave

Laptop batteries

I've had about a 2/3 success rate with cells from dead laptop packs which are acquired for free from a PC repair shop when they replace batteries for customers, and currently have almost 1600 usable cells waiting to be built into packs. Of the usable ones it's about a 50/50 split between good cells and mediocre but still usable ones. I've never seen the type of cell in a laptop pack that I'd use in a high-density pack like the one needed for Royce's project.
The ~200 best cells will be used in my current ebike project and the rest will probably go to static storage packs. New packs from a warehouse should give a higher rate of good cells, but you can't beat free when it comes to pricing.

No space

I've now got some dead 18650 cells to play with but despite working out a mounting system that can be assembled into a number of shapes I can't get near to enough of these cells fitting in a Voyager-sized FF. I haven't given up yet, I'm going to start again with the vehicle to see if I can make more space, but I'm reminded of Michael Moores comments above where he mentiuoned having batteries in front, behind and below him. I think everyone is having a similar problem, PTW's are caught in a corner where there isn't a huge amount more space than there is in a bicycle but performance needs to be similar to cars. FF aero advantage gives an edge over motorcycles and limiting speed and range would be OK in a delivery scooter but current battery tech just isn't energy-dense enough. Looking at EMN it's clear that most attention is focussed on lightweight, urban and recreational markets. FF's, with the rider sitting in, rather than on, the vehicle just makes this packaging problem worse. Frankly, I'd rather be developing better aero shapes than trying to squeeze 186560s another mil closer together!

Packaging falls short

Re-surfacing after yet another session trying to package 18650 cells I've got to 1880 cells, well short of the target 2400 cells needed to match or beat a C-Evo. That's with a mounting battery system that I could make, individually fused and meeting space and cooling requirements. That's for a Voyager-type specification, two people, some luggage, goes through a doorway, sll the traditional stuff.

This is a core problem for E-powered FFs at this scale. It's absolutely clear that if the rider/s were sitting on top of this thing, rather than in it, there would be room for the rest of the battery pack. I'm sure there are people who could get some more cells on board. I could get more cells on board by sacrificing the passenger space. But that space is also cargo space, which I use quite often on FJ, more often than I carry a passenger.

So I'm stuck with a basic design problem, no suitable powertrain. To which I have to add the fact that I'm not really interested in building battery packs. For me Aerodynamics, including cockpit environment and, by extention, other ways of doing open-cockpit, is pretty much the only 'unfinished business'. So, unless someone else does a powertrain with enough power/storage, or batteries get 30% better I don't see a route to an E-FF. FJ will just have to keep working until one of us is banned or dies of old age. It's been intersting...

Re-running the numbers

I think the cells used to calculate the requirement of 2400 cells must have been lower quality ones than the Samsung 35E cells I'd recommend using to build the pack.
The C-Evo battery pack options are 8KWh (estimated 60 mile range) and 12.5KWh (estimated 100 mile range)
1 Samsung 35E cell has about 11Wh of usable capacity at a 5A discharge rate, so 1880 of them would give over 20KWh capacity. Using the C-Evo's stated consumption of 8.5-9KWh/100KM, that's almost 150 miles range.

less is more

Hi Gutyex Royce Yes if you compare the module size of a Tesla pack, which i posted previously, and with the number of cells in a 5KW module the numbers are similar to your calcs, or as you say, you can get (more from less), with the correct cells, in a smaller package. Although i have now more than enough bits to produce something, i still keep looking out, and the Mitsubishi i MIEV motors kick out a min of 47KW and are available for approx £500 and a bit more from a Nissan Leaf motor, and lets not forget the Prius motor, cheap and readily available, plus several people are now able to communicate with the standard inverters, and charging systems, via a small interface board, making it a viable alternative, and i would hope, these boards will soon be available for those of us with a less able skillset in electronics, (including me) for a reasonable price. An absolute mountain of wealth information is available by just going onto Diy electric car forums, and if you haven't tried the site, its well worth a look, and can give a better insight of what's needed for your own project. yours Dave

Here's a question

I think I'm convinced that battery tech is on the verge of adequate power density, 150 miles range is my minimum range limit. And it'll get better and so on. So, that leaves the motors. The C-Evo powertrain looks fine to me, the whole shooting match unbolts and is in the right power range. One day someone will front end one.

Can a C-Evo back end be hacked into the sort of custom controller/battery packs described above? BMW don't make this stuff easy, but it's just a motor isn't it? Be nice to use BMW's power management system, but that may not have been hacked yet...

Isn't it likely that some electric mtorocycle powertrain or other, from Zero, Lightning, BMW, whoever, taken as a whole unit, is going to serve the FF specs better than anything patched together from various sources? Just asking for a friend...