Thanks flecc I suppose at least you still have a potential front hub motor if you replace the Torq's & lack those skills... maybe not ideal but useful nonetheless?

Just been doing a bit of surfing, and it seems that there are indeed a number of bespoke frame builders that will build it whatever way you want for reasonable prices too.

 

John

 

Yes, I knew of those sort of makers John, but the standards are too high, mainly for sporting types. You said reasonable prices, but starting at about £600, but which would be higher at probably £800 upwards for a battery frame variant they weren't experienced with, would make the finished bike very expensive indeed. Think motor/control side at £300, battery at least £250, decent wheels/tubes/tyres and wheel building at £180, derailleur parts, chainwheel and chain, crankset at the very least £90, then brakes and all the little bits, probably £100 or more, that's £1720 at least, and for mainly low priced components, so it could go well over £2000 for a higher standard.

 

I had in mind someone knocking out a batch to sell from stock at around £300 which would keep the price down.

.

Edited June 17, 200718 yr by flecc

Thanks flecc I suppose at least you still have a potential front hub motor if you replace the Torq's & lack those skills... maybe not ideal but useful nonetheless?

 

Yes indeed, it's a great motor for 20" to 24" wheels, and has some use in 26" for speed but not to good hill climbing, but the 28" wheel of the torq went too far for anything other than fairly flat country, or elsewhere in a lightened and boosted version for use by a fairly light rider, like my T bike.

.

Thanks flecc.

 

I had in mind someone knocking out a batch to sell from stock at around £300 which would keep the price down.

Maybe, if there was sufficient demand, we could get hold of a batch of the sort of frames (if they're of good quality) that are used to make many of the lookalike electric bikes we see for sale all over Europe, and maybe even more widely?

 

Still rather radical though . Hey, that has a kind of ring to it for a name?

 

pedelecs radical?!

 

EDIT: On second thoughts, maybe not the wisest choice of terminology...

 

Stuart.

Edited June 17, 200718 yr by coops

 

Maybe, if there was sufficient demand, we could get hold of a batch of the sort of frames (if they're of good quality) that are used to make many of the lookalike electric bikes we see for sale all over Europe, and maybe even more widely?

 

Stuart.

 

The Chinese wouldn't entertain any order for less than £10,000 probably, so not really an option, though it seems an attractive idea. The only way it might work is if a supplier of existing bikes got in a batch of frames as spares for the bikes he handled, but he'd have to be nuts to do that, conceivably doing himself out of sales.

 

There'd still be the forks problem as well, no choice of width and sprung/rigid.

 

Second hand e-bikes will become an increasingly attractive source of suitable frames as their electrics fail and they are left useless, so we have that to look forward to.

 

Maybe a Grandad cartoon of vulture like e-bike types following others around waiting for them to fail?

.

Second hand e-bikes will become an increasingly attractive source of suitable frames as their electrics fail and they are left useless, so we have that to look forward to.

 

Maybe a Grandad cartoon of vulture like e-bike types following others around waiting for them to fail?

 

Well, waste not, want not . The pedelecs "recycle" then?

 

The pedelecs "recycle" then?

 

Yes, or the Recyclagain, or the Againicle, or "I thought I'd thrown that away!"

.

Or, if you salvage it from the tip, "freewheels"! (working parts, batteries etc. not included )

Just been reviewing the battery discussion earlier... (can't think on two things at once ). To whet your appetite a bit more John, see what you think...

 

Just thinking hypothetically at the mo. Each of those D cells weighs 166gms, so 20 would be 3.3Kg, 30 is 4.9Kg, 40 would be 6.6Kg, and 60 is a wopping 9.8Kg!!! (for ref, I carry the charger everywhere with me on my Twist, and I dont want to do that).

 

If I had a 36V motor like the puma (if theres a 250W version or one that can be adapted to 250W), then I would need at least 30 cells in series (or 60 in parrallel) and I would get power and range (esp from the 60).

 

So NiMH gives: (battery weights only)

 

20 x 11Ah (1 x 24V) is ~ 264Wh ~ 3.3kg+

40 x 11Ah (2 x 24V) is ~ 528Wh ~ 6.6kg+

 

30 x 11Ah (1 x 36V) is ~ 396Wh ~ 5kg

60 x 11Ah (2 x 36V) is ~ 792Wh !!! (but weighs ~ 10kg as you say!!!)

 

Current eZee batteries: 36V 9Ah ~324Wh NimH; 37V 10Ah ~370Wh Li

 

Since newer Li batteries are about 2/3 weight of NiMH for same capacity, roughly 3/2 (i.e. 1.5) times the capacity gives the same weight.

 

So how about "expanding" a battery case (like the T-bike case) as far as is practical to take as many Li batteries as possible, hopefully giving around 1.5 times the current NiMH capacity for the same weight i.e. around 500Wh for ~4.5 - 5kg.

 

That should give around 1.5 times the current range, and be less reduced by hills due to good motor gearing, so conservative possible ranges, even in mixed terrain, could be ~20-22.5 miles at 20mph (if delimited for off-road) ~ 25-30 miles at 17-18mph and around 40-45 miles at 15mph (3 hours trip), close to 50 miles at 11-13mph if you want a really long, slow "potter" for 4 hours :-).

 

Might be worth carrying the charger though, if they can be recharged in ~15-30 mins . This would cost a bit, mind, and I think I'd keep using my NiMH till I'm confident that these new Lithiums pass muster :-) but its a possibility - I'm seriously considering a severe stress test, as I've said before, of a small capacity, portable lithium, say only a few Ah & 36V, to assess their performance. Hopefully by then we'll have a better idea of their rate of degradation over time, so it'll be more a question of performance.

 

Tempted? enough range for you? Are all the ideas converging? :-)

 

One more thing - the tyres could be swapped for M+ similar to the T-bike's 2nd biggest performance enhancement, for better efficiency, which would just leave the biggest performance improver...

 

...think how well it'll perform for an optimum weight rider .

 

I think that's a contender, what do you think?

 

Stuart.

Edited June 18, 200718 yr by coops

Wouldn't the ideal E-bike frame be made (aside from low center of gravity, with a space to run different configurations of batteries), strong in necessary areas, like the motor to wheels, but still light in other areas? Or maybe that's a minimal change from what's already available?

To Stuart:

 

You can't add Lithium cells like that Stuart. In the groups of 7 or 10 cells in a battery, each cell has it's own management circuit, and those are all tied to a master circuit controlling the charge and discharge of the group, the latter feeding the current to the bike. Adding cells would mean a total redesign of the electronics. Too dangerous to run them in parallel either, so those add on options aren't on. See here.

 

If they had been, I would have definitely gone that route for the Radical battery, but threw out that idea right at the beginning.

 

You could pack two batteries into a case, but it would probably be too tall and need a manual switch, so they're probably best in two locations anyway to distribute the weight.

 

To prState:

 

I think some of the better e-bike frames are like that already, as I think you suspected. That's certainly true of the eZee Torq frame for example, extra strong downtube and fork flexure allowed to take the powerful motor pull, with the rear frame very lightweight.

.

Edited June 18, 200718 yr by flecc

You can't add Lithium cells like that Stuart. In the groups of 7 or 10 cells in a battery' date=' each cell has it's own management circuit, and those are all tied to a master circuit controlling the charge and discharge of the group, the latter feeding the current to the bike. Adding cells would mean a total redesign of the electronics.[/quote']

 

I can see that adding lithium cells to an existing Li battery is ruled out, but I was thinking more along the lines of (maybe, eventually) somehow celling an empty case with Li e.g. the nanophosphate, Fe3PO4 type: designing & building the whole battery into the existing case?

 

Is that a possibility do you think? Or would that be too dangerous or ruled out for other reasons e.g. insufficient space, or too complex to build? (apart from fact they're a bit costly & may be unsuitable for ebike use )...

 

whatamistakatomaka! .

 

Stuart.

Edited June 18, 200718 yr by coops

Building a newer complete design into the existing case would be fine Stuart, a bit like the reverse that Ian and I do in building NiMh into Li cases. But it wouldn't be possible to build from components without electronics designed for it, and no-one is going to do that for a one off.

 

I'm not at all happy about using the nanophosphate, Fe3PO4 type cells or other newer types independently as someone has posted with model use. The high loadings and long periods of use on electric bikes are a very different case from using a very high current and high discharge/charge rates for cells used for a few minutes on a model helicopter.

 

The latter is reproducing the same sort of tests that battery development labs use, afterwards publishing the results with the extravagant claims that have let us down time after time in the past and currently with lithium types.

.

Thanks flecc

 

What do you think about a small-scale "test" of some of the newer Li batteries, like trying a small, low capacity one just to see? That would also serve the purpose of a stress test to see if even a small no. cells can meet the demand for current required by the bikes?

 

I'd be a bit nervous about building my own, and probably give up if it was too difficult... but I'd make it a DIY job if necessary .

 

On the subject, I've seen this site which appears to be advocating li nanophosphate for ebike use, and I hear that Mark at Team Hybrid may be stocking some nanophosphate too?

 

EDIT: Mind you, given the "quality" issue with some of the Li-polymer...

 

I know, it would be great if they match their "hype" with good, real performance, but nothing conclusively shown yet, but is there any harm in a little test?! actually, I recall you saying some ebike manufacturers were trialling batteries like these: any news of those? Would that render our own trials unnecessary? (remember what happened on your Q bike with the Lithium ezees...!).

 

P.S. This is all still in the interest of efficiency John, weight saving & range extending etc. :-)

 

Stuart.

Edited June 18, 200718 yr by coops

I think I'd struggle to mod an existing bike, John. is your idea to really design & build an ebike from start to finish? do you really think that's do-able?! (I'm open to persuasion, & no harm brainstorming )

 

Which type of motor do you think would be best/easiest/most economical i.e. best "bang for buck"? (hopefully no bangs though... )? I guess hub motors are simplest?

 

Stuart.

 

Stuart - I am not so sure. I think from what I have seen, that some existing touring bikes do have the right shape to become ebikes, a number of them have 2 -3 inches gap between the back wheel and the downtube, which might be enough for a velcro 'bat-pack' perhaps. Additionally I do not know which would be the better, a rear hub (Puma style ) or a Curry style kit.

 

Flecc - Yes those prices can be a little high although Wilsons advertise bespoke frames from £250. But I guess that it could easily go to £500+ for a 1-off design (but they do give a 3yr warranty I believe). However, if you were ordering more, perhaps the price would go down some. At the moment though I am still putting ideas together but my basis for budget is 'replacement vehicle for commuting, as apposed to a car', so still a bit of room in the budget even if I had the perfect e-bike at £2000 with its Q-bike capabilities and 36V 50Ah battery at 2.5Kg (but I am hoping it wont go that far - but I think that if the views on this forum had expressed that the swissbee was the best bar none, I would probably be riding one now).

 

 

RE the battery

I am not saying that the battery fixing should be frame mounted. I am thinking of a pack either by the panniers, that could be lifted off using a shoulder strap, or a circular velcro pack that would attach around the downtube. Some fundementals though are the gearing must be full range, the motor needs to power the chain or the rear, and it should be made for the efficient use of rider power.

 

If I am miles off on this, please let me know, Its all a good learning experience.

 

John

I was in two minds again about where to post this one, but decided not to overclutter this thread :-). Its relevant though.

 

Its all good stuff John, and food for thought. I think hub motors seem more available, affordable and aesthetically quite good: I don't think I could fit my own transmission drive, even if it is more efficient: if one optimises efficiencies elsewhere, then the tradeoff looks better on all fronts: cost, efficiency & ease of build :-). I really don't think a useful commute bike needs to nor should cost the "earth" - its still a bit of a lottery, and could still be unreliable in so many ways, unless you have the technical skill, experience & understanding to make it durable, and maintain it well too!

 

I've thought long & hard about battery fixture for ebikes, I even thought about velcro-type battery packs myself John :-): to me, only light, low-capacity batteries could really be attached to the frame, especially downtube which takes a lot of stress anyway? What do you think flecc? Panniers would make it very back heavy, especially with a rear-mounted currie or hub motor, which could itself weigh up to 3.5kg/8lbs (curries are a fair bit lighter i think, but tend to be noisier), but I don't see much alternative... unless you already have a battery compartment built into the frame like on purpose-built electric bikes .

 

Yes, its all a learning experience for me too John, definitely! :-).

 

36V 50Ah battery at 2.5Kg

 

I wish!...

 

Stuart.

As far as amp hours, put 18 kg of batteries in a bike trailer. Give the trailer its own little motor. Zero weight gain. I don't know about the legality or stability of it all. Of course, all that weight, you wouldn't want to find out by surprise you need better brakes on a steep downhill

 

It might be easier to buld a motorized trailer to carry lots of batteries, than build a bike from scratch though.

prState, with a motorized, battery equipped trailer like that, you wouldn't need to build an electric bike; just let it push you along .

 

I don't know the legality or stability either, could be a bit hairy if you lose control of the trailer though a Grandad cartoon moment?! .

 

Stuart.

To Stuart:

 

eZee were trialling Fe3PO4 many months ago but still it seems nothing has come of it, and they said the Li-polymer was "terribly disappointing" for their bikes. The fact is that lithium batteries aren't willing to issue demands for high currents, hence the cutting out seen on eZee and now Wisper's powerful models when hill climbing.

 

Lab tests and promises are based on using very small cells, the sort kraeuterbutter uses in models, and that's very easy to do, since small cells haven't very far to pass current to get it out of the cell. It's when we translate to large cells that the high internal density to contain a large charge impedes the outward flow of current.

 

Of course we could use banks of small cells in parallel as well as series, but when it came to charging they all have to be dealt with in series rows only, so the switching requirements would be complex, heavy and potentially troublesome. In addition, to keep charge time down to the usual, you'd have to have a charger for each series bank needing charging, so costs would multiply.

 

I'll look separately at your last posting Stuart.

 

 

To John and Stuart:

 

A simple solution to frames is to buy a strong 700c frame (28" wheel) and build the bike around 24" wheels. Then there'd be as much as a 5" gap ahead of the rear wheel for a battery. You wouldn't have a "poke through" facility like the eZee bikes, it would be like the Twist's space, but would be entirely practical. You'd need to choose a frame/bike that had good crank to ground clearance, and perhaps use shorter cranks. I use 160 mm instead of 175 mm on my Q bike for example. The front wheel could remain larger which would help with ground clearance if necessary.

 

To prState:

 

The snag with trailers is they are very inefficient regarding rolling resistance. Two extra wheels, usually of small diameter, and a large drag is added. I ride with a large goods trailer a lot, but whenever I can get a load onto the bike only, I always prefer that option, so I think that's always preferable for batteries.

.

Edited June 18, 200718 yr by flecc

prState, with a motorized, battery equipped trailer like that, you wouldn't need to build an electric bike; just let it push you along .

 

I don't know the legality or stability either, could be a bit hairy if you lose control of the trailer though a Grandad cartoon moment?! .

 

Stuart.

 

There's one pushing trailer for bikes, trikes and recumbents already on the market. It has the motor and battery in the lower half, goods space in the upper half. From the Dutch Cab Bike company:

 

http://users.tinyworld.co.uk/flecc/images/powerbox.jpg

 

No problem with legality. UK laws with only one exception refer to "bicycles, tricycles, and bicycles with four or more wheels.

.

To Stuart:

 

Re: your last post I referred to. On the link you asked if there was any reason why such a high geared motor was used for the Torq. That's one I've explained many times. It's the Quando motor, designed for 20" wheels, so when put in 28" it's geared up 40%. Not design, just using an existing component. If the gearing was changed to normal it would only run to legal speeds so there'd be no point, just duplicating what existed already in the bikes with the Sprint motors.

 

I've already given an answer and possible solution to the frame in the posting above to John and yourself.

.

Edited June 18, 200718 yr by flecc

Thanks flecc

 

I'd better reply here to that, now .

 

from here:

28" just seems a bit... big! might there be extra strain on or losses through the spokes at that diameter? I just can't help but think there's something intuitively amiss about hubs in 28" wheels? Though I suppose the Torq works quite well' date=' is there maybe a reason why it was made with a highgeared motor...?[/quote']

 

I didn't put it very clearly, I meant, in the context, was there possibly some reason why a relatively "low torque" motor - given its high-gearing in the 28" wheel - was used i.e. not just to use an existing component to make a fast bike, but to avoid using a higher torque motor within 28" wheels, though point taken that if so it would have been a 28" "sporty" looking sprint instead!

 

EDIT: I just re-read your last post:

When you said "Not design, just using an existing component" is that the answer, that 28" need not be precluded from "normal" geared hub motors for legal speed & low-speed torque on grounds of torque affecting the large wheel size adversely? It seems a difficult question to frame, sorry still don't think I've put it right...

 

Stuart.

Edited June 18, 200718 yr by coops

In theory any wheel size is fine, but as you mentioned previously, spokes play a part. There comes a point in applying power when heavier components are needed, like using a moped type wheel. At that point it's self defeating for a pedal bike, so I think 28" wheels using cycle components with a powerful and high torque motor is probably undesirable. Best stick to 26" or smaller. After all, that's what the bike-like mopeds from Honda and others do, use smaller wheels.

 

As for using a higher power motor for the torq, it wouldn't have been conceived as a model. It came into being solely because eZee had seen the power of their existing Quando motor and thought it a good way to further exploit it. My comment in the Q bike introduction on the difference in philosophy applies here, my exploiting the motor in a better way by keeping it's gearing correct and adding to it's capabilities with multiple cycle gears and high bike efficiency.

.

Thanks flecc, thats what I suspected. Does that rather put the "kibosh" on the Puma, geared for 28" wheel, then? Unless sufficiently strong spokes etc. are used...? Back to the drawing board?

 

To be honest I find 26" wheels a more manageable size and prefer them to 28", and the efficiency decrease from 28"-26" in rolling resistance is marginal (with better tyres on 26" wheels, friction may be less than some 28" tyres?). Just need a suitable 26" electric frame to use... then a good motor geared for the wheelsize... could still use the puma for that, just needs a frame can take batteries... .

 

Stuart.

As far as amp hours, put 18 kg of batteries in a bike trailer. Give the trailer its own little motor. Zero weight gain. I don't know about the legality or stability of it all. Of course, all that weight, you wouldn't want to find out by surprise you need better brakes on a steep downhill

 

It might be easier to buld a motorized trailer to carry lots of batteries, than build a bike from scratch though.

http://grandads.googlepages.com/TrailerReverse.jpg/TrailerReverse-full.jpg