Sensible Improvements

[aroncox]

What kind of sensible (by 'sensible' I mean possible right now, i.e. not rocket powered bikes) improvements would you like to see on your electric bike:

I have an eZee Torq and I'd like to see the following:

1. Switch on the handlebars to enable/disable speed limiter
2. Easily disconnectable power from the front wheel so it can be removed
3. A lighter frame, I'm assuming there are more exotic materials out there
4. Better waterproofing, I had troubles after going through a large puddle
5. A more accurate indication of the amount of power left in the battery

Of course, a longer lasting battery would be useful, but battery technology is complex.

 

[rsscott]

With regards to the battery, 50Cycles have added a page to their site:

http://www.50cycles.com/info_lith.shtml

On there they talk about offering Lithium Phosphate batteries soon although how soon I don't know yet. I'm intrigued to know what difference this kind of battery would make - would it primarily be increased range?

 

[Tony Youens]

Those would be wonderful improvements and entirely feasible. One small improvement I'd like is wider (and better) handlebar grips. I don't have particularly large hands but I still find the Torq's grips too small.

Tony

 

[flecc]

My thoughts on those suggestions

1. Switch on the handlebars to enable/disable speed limiter.
Yes, definitely a good thing.

2. Easily disconnectable power from the front wheel so it can be removed.
Can be done but there's a risk of more troubles due to poor Hall wire connections. The resulting collisions between rotor and armature can be damaging. It's easier to do this on the bikes you have to pedal up to a couple of mph like the Giant Suede, since the multi Hall wire setup doesn't exist.

3. A lighter frame, I'm assuming there are more exotic materials out there.
Carbon fibre, Kevlar or titanium would be needed, but the price would rocket and the weight reduction would be small. I doubt if it would really make a difference to riding performance.

4. Better waterproofing, I had troubles after going through a large puddle.
Dead right, this is eZeebike's biggest area of failure. Connecting exposed wires and connectors with heatshrink sleeving and clamping the ends with tiewraps is a bodge, and standard rubber entry grommets in the control box and meter are just not good enough for outdoor use. It's caused in part by insufficient scale of manufacture though, since specifying custom designed sealed components costs a lot if it's not spread over a very large number of products. Of course it's just as much Crystallite who's to blame here, Wai Won Ching of eZeebike told me that constantly chasing product quality and fitness for purpose is his biggest workload, necessitating many trips to China.

5. A more accurate indication of the amount of power left in the battery.
Every engineer and designer would love this, but it's technically not possible, especially when running. Here's not the place to go into really lengthy explanation, but in essence, it's the fact that the readout from any gauge is dependent on the amount left in the battery, the amount actually being drawn by the motor, and the amount being demanded by the throttle, so the readout swings about as it's pulled three ways. To make matters worse, some technologies like Lithium reduce the available charge when chemically stressed by high demand, then recover afterwards, so that alone makes accuracy impossible. A gauge built into the battery stands a better chance, but still only when the bike's switched off, but those in turn can be unreliable since they lose synch. To keep the gauge in synch, the battery has to be fully discharged every few charges, but full discharging shortens lithium battery life, a classic catch 22 situation.

 

[flecc]

Reply to the Lithium Phosphate query

I don't know if it will gain much in range, that would only be a small gain though. The main gain would be in the ability to deliver sustained power, a weakness with Lithium technology accounting for all these chemical changes as the boffins struggle to overcome that limitation bit by bit.

 

[Jaytee]

All good stuff. What about a small meter measuring the power thats actually been used since the last charge? I know this doesn't say what's left in the battery, but it would give an indication as we could define the total power availability by laboratory measurment.

This is after all, exactly what we all have in our electricity meters at home. A small meter, digital readout or even percentage readout would not be too costly.

 

[Jaytee]

As front wheel removal is so tedious, (back wheel as well!), fitting puncture proof tyres would be a real advantage. I know Schwalbe Marathon plus tyres are more expensive, but if these were factory fitted, the oncost would not be much.

 

[Jaytee]

Sorry about all these posts. I should have collected my thoughts more sensibly!!

A much improved front brake would be a real improvement, particularly as the weight and speed is much greater that intended for the primitive brake used.

Some front fork shock-damping would also be welcome.

 

[rsscott]

Looks like we're designing a new bike here

All very useful comments. My previous electric bike was a MTB style with front and rear suspension. While not as powerful as the Torq, it was certainly a lot more comfortable on the road soaking up the bumps.

A front disc brake would be good, but it would probably need to be hydraulic rather than the cheaper cable variants.

 

[flecc]

That metering of usage via a dedicated computing chip is possible Jaytee, but only if it was refined, only if the meter was in the battery, and only if it was checked without anything running. With a more sophisticated charger checking the back emf, the gradual rise in cell internal resistance could be checked and the information fed back to the chip in the battery as a recalibration signal at every charge. That would then give a quite precise readout of remaining content when static. The only remaining problem would be to find bike customers prepared to pay for all that.

Without that sophistication, metering usage wouldn't be acceptable due to the substantial loss of capacity over a battery's life. Our bikes are all quite new, and the shocks are still to come in this respect. Over it's three year life a Lithium battery can have it's capacity halved, so the meter would say half full then when the battery was just about empty. That capacity loss is so variable it's impossible to predict. The user like me who charges often after about four miles or less could lose 10% a year, but the user who fully discharges every day could lose half the capacity in a year.

 

[flecc]

Disc Brakes and Marathon Plus

Car and motorbike disc brakes are great, but I'm not a fan of bike ones since the disc is so flimsy and easily buckled. One small accidental knock or a vandal's kick and it's had it, also making it impossible to ride home without complete caliper removal.

On the tyres, the point the administrator makes is very relevant. The Torq's ride quality without suspension is only just about acceptable on our bumpier roads. Unfortunately the largest Marathon Plus tyres are considerably smaller section than the fitted Kendos, so there's going to be some further loss of comfort and more battering for the motor components.

I'm into Edit to add this. I seem to be the wet blanket in this thread, raising all the objections, but it's best to be realistic, there's more than enough unrealism on the electric bike scene vis-a-vis range etc, without us adding to it.

 

[rsscott]

Something minor which I find annoying with the Torq, is removing the battery with the seat-post lever in the way. I've scraped a few knuckles doing that !

 

[flecc]

Different Wheels

I've done the things like twistgrip improvement and waterproofing, but the change I'd like is for the Torq to have 26" wheels. Gear theory says this would lose 2 mph, but in practice the average loss would only be 1 mph, since the lower gearing would improve the performance when conditions were in any way adverse, headwind, slopes etc. Since the motor would be spinning faster in any given condition, the consumption would be lower than the overgeared standard bike so the range would probably improve as well. The present Torq is terrific in flat terrain, but in even moderately hilly country, the overgearing puts it at a disadvantage.

Not only would the 26" version gain 10% hillclimbing ability from the motor, the Sora's bottom gear would reduce by 5.5", from 58" to below 53", so there'd be a 10% gain in rider's hill climbing contribution too, a total of around 20%. This would mean virtually all main road hills could be tackled, something definitely not possible at present as I have two A roads hills near here beyond the present Torq's capability even with the fittest of riders. Carrying shopping, towing trailers, all would be improved, making it a far more capable all rounder than at present, and all for the loss of just 1 mph. The lower gearing's reduced peak battery drain would mean less chemical exhaustion of the Li-ion batteries too. I'm so convinced of the benefits that I've been seriously considering the possibility of having the forks shortened and doing the mod. The rear frame wouldn't need changing since both wheels lowered would keep the head angle nearly the same as at present, the mudguard could be mounted with short spacers and the carrier dropped a notch.

I wouldn't change the present Torq for Dutch or East Anglian conditions where it's terrific, but for much if not most of the UK, I definitely would.

 

[Jaytee]

Interesting topic! I've always wondered why 28" wheels were available as, in my youth, 26" was the norm. It would be interesting to see a comparison road test with a Torq in standard trim compared with a Cadence model from 50cycles.The Cadence appears from the specification to be very comparable to a Torq, but with 26" wheels.

Perhaps this could be arranged with 50cycles help. Afterall it would be a product promotion and the result significant to all interested in elctric bikes!!

 

[flecc]

I've seen the Cadence and it's very different in the flesh. It's the heaviest and slowest of the full size eZee bikes at around 30% more weight, and the motor is a lower powered direct drive, unlike the geared Torq motor. I'm afraid the Torq would run away with any test comparison, the Cadence being just meant for comfort and a leisurely ride.

When I went into the trade as a kid in 1950, 28" wheel bikes were still around in numbers since they were common in Britain during the 1920s and 1930s, and they were the true 28" size, not the slightly smaller 700c that's on the Torq. The second world war meant no new bikes were available again for years so all the old ones had to go on for ever. In Holland and Germany where there are plenty of tall people, the 28" wheel is still very popular on new bikes. There's also the advantage that the larger wheel is more comfortable over bumpy surfaces, needs bigger potholes to drop into!

 

[urstuart16v@talktalk.net]

Stuart

hi i have a sprint7 speed and a lithium torq on the question of a reliable battery meter i have fitted to the torq something called a watts up meter ,fitted to your bike it reads amp hours peak voltage voltage peak watts and watt hrs it comes from America and its website gives you a wiring diagram for an electric bike over here it is available from model helicopter sites it sells for about £40.great bit of kit.can someone tell me if they have found the lithium battery to have more duration ,i have not does the cut off inside the battery to stop damage leave a lot of unused capacity -regards stuart

 

[flecc]

I also don't find more duration from Li-ion than with NiMh in a hilly area Stuart, and that's with either the Torq or the Quando. It's the way the Li-ion suffers chemical exhaustion that make it suffer when it's doing hard work. In a flat or fairly flat area with a rider who gives genuine help, the Li-ion should then give a lot more range since it won't suffer the same high current drains.

I take it that meter you mention measures the ampere hours consumption rate? If it claims to accurately measure the capacity left in the battery, I disagree with the manufacturer.

 

[urstuart16v@talktalk.net]

battery meter

hi flecc you are quite right it does not measure the capacity left in the battery what it does do is after each run give you a reading in amp hrs which i believe is not too accurate as the amp hr reading is affected by the discharge rate but also gives you a watt hrs reading which is ampsxvoltsxtime which i am told is pretty accurate so before my last run i had a reading of 792 watt hrs so to be on the safe side i need to head for home around 350 watt hrs on the meter so far i have found it to work well. What i found with the metal hydride battery in my sprint that the supplied bike meter was quite easy to read and that after about 20 miles it would start to flicker amber so i would know it was time to head home,not so with the lithium battery in the torque the meter supplied with the bike which i assume is some sort of volt meter stays green until a minute or so before it cuts out then flickers amber and then you know your in trouble ,on a different subject have people had trouble with the clearance between the rear mudguard and the tyre on the torq i could not adjust mine enough and had to resort to grinding off an eighth of an inch off the rear support bracket cheers Stuart.

 

[flecc]

Yes, these LED meters are all volt meters Stuart. They're driven by an IC (chip) that's called a ladder IC. It works by measuring very small voltage changes, with each small change, the chip steps the signal up or down to the next LED. These chips are made in a variety of types up to 10 step (hence the ladder term), and they can be cascaded to make an infinite number of steps and LEDs.

The water analogy that's often used to explain electricity is useful for explaining the problem of determining what power is left in the battery. We can put a gauge on a tap to check the water pressure (voltage). We can put a flow meter on the tap to measure quantity passing (current). But there's no way that we can measure at the tap how much water there is in the water company's mains network. Likewise, there's no way we can measure at the battery's terminals what's in the battery, because the battery terminals are just an outlet, like the tap. All we can do is measure the small decline in voltage as the battery discharges and estimate what's left from that. Because that voltage decline is not linear, our estimate can never be accurate.

 

[rsscott]

Something got me thinking this morning while shaving! What has this got to do with electric bikes you say? Well, my shaver has a battery guage and as it drains the little bars on the display drop off until it reaches a point where it tells me I have 20 mins shaving time left. It then updates the display every minute until 1 minute is left and then sure enough, it starts to die. It amazes me how accurate it is. Is there a correlation between an electric bike battery and a shaver battery and if so, why is a shaver manufacturer able to guage battery status so accurately?