Research and development on the new battery technology

[Footie]

I find the posts about the problems relating to the new battery technology disturbing.
I may be wrong about this, but it seems to me that the manufactures have skipped the research and development and gone straight to production. Turning the customers who have bought their expensive products into unpaid testers. Sadly, when one reads the post on the many battery issues it becomes very evident (at least to me).
This bad press is doing nothing to encourage electric bike use and I feel the manufactures should do more to ensure their products do what there supposed to do
I went for lead acid batteries myself, because of all the problems and issues, so I have a detached view on this.
Am I totally wrong? What do other forum members think?
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[flecc]

NiMh are also fine and well proven.

Smaller Lithium batteries were also well proven in many low to medium current applications, and were also ok in larger sizes when used in well controlled current environments. They still are.

These batteries used cobalt cathodes which carried with them a theoretical fire risk, but for more than a decade they proved safe, until Sony made a disastrous mistake in releasing huge numbers of defective laptop batteries which caught fire in various ways. The same relaxation in manufacturing standards brought with it a few cheap E-bike batteries which similarly failed.

These cobalt cathode batteries were quite good at delivering high current rates, but the fear those fires caused meant that manufacturers were panicked into changing the designs, adopting much safer manganese cathodes. Unfortunately manganese is lower down the elemental scale of suitability for this purpose and current delivery suffered.

And Sodds Law being what it is, this change coincided with manufacturers of more powerful bikes like the eZee models finally making the leap to Li-ion after cautiously hanging back for a long time.

Worse still, with the last frontiers of the switch to lithium being seemingly conquered and the possibility of dropping the potentially toxic Nickel from use arriving at last, NiMh production was phased down and all further research and investment in that stopped.

A triple whammee as the Conservatives like to say, and the rest we know.

You can see that it's not really so much a fault with the behaviour of the bike suppliers so much as one of the unfortunate sequences of events that beset technological progress from time to time catching them out.

Now they're between a rock and a hard place, with the battery manufacturers on the one hand knowing that many bikes perform perfectly on lithium and therefore unprepared to step backwards, while faced on the other hand with customers up in arms. They should switch to making beer, since after consuming that, customers are no longer able to coherently complain, apart from "Come outside and say that" or "I love you".

Making decisions more difficult is the fact that the use of Iron cathodes is at last starting to show promise, Iron 56 being theoretically the best element of all as a lithium battery cathode with four times the length of life. We need the larger sizes of those to hurry up and arrive, but there's always the fear that they too might not measure up when upscaled.

It's a hard life in the powerful e-bike manufacturing world.
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[Jeremy]

the possibility of dropping the potentially toxic Nickel from use arriving at last

? Nickel has a fairly low toxicity as far as metals go; you have to directly ingest very large quantities of Nickel in the form of a soluble compound to get close to being poisoned by it. Most of our coinage has a very high percentage of Nickel, yet our children have been accidentally swallowing it for decades without being poisoned by it.

Jeremy

(who started life as a chemist many years ago)

 

[Critical Mass]

Jeremy

(who started life as a chemist many years ago)

Crikey Jeremy! Are you an android, like Data in Star Treck?
When I started life I was a slavering idiot! I didn't know the first thing about chemistry. In fact I couldn't tie my own shoe laces. Actually I didn't even know I had feet...

 

[Ian]

As Jeremy has correctly said nickel is virtually non-toxic, much of our food being prepared using stainless steel utensils which contain a high percentage of nickel, not to mention surgeons using stainless steel instruments and occasionally leaving them inside a patient.

NiMh batteries are generally regarded as being the "greenest" being the only re-chargables that can be legally disposed of in landfill, another point in their favour ignored by manufacturers who insist lithium is best.

My own belief is that the rapid push towards lithium is based largely on financial principals, the rapidly escalating nickel prices having reduced the margins on NiMh to the point where lithium is much more profitable, especially with the added value of being marketed as "new technology".

NiMh batteries still have mass-market applications, they are the only really suitable re-chargable substitutes for single use cells in toys, torches etc, and capacities continue to increase indicating some development is taking place.

 

[MaryinScotland]

I thought cadmium was the seriously toxic stuff and that therefore the switch from NiCad to NiMH was an improvement in environmental terms. But I haven't researched it. My last e-bike was NiCad, my present one is NiMH, and both seem suitable for the purpose of power-assisting a bike.

I too have been reading the forum about Li-Ion batteries, and I wouldn't be confident in getting a bike which used them. Battery life is one issue; when they quote a lifetime number of recharges, but then tell you to recharge it every time it's used, that seems like a bad combination.

But the real killer is that they cut out on steep hills. In my normal riding area, my bike can cope with the worst hill I meet, if I give reasonable help. If I faced a worse hill, I would expect the bike to slow down, and if speed dropped to around 5 mph, I would consider it unfair on the motor, and I'd get off and walk. (And as I have a bike with a throttle, I could get the bike to pull itself up the hill, even if it couldn't pull me.)

But a bike that cuts out instead of fading away seems to me unacceptable. Add that to the question about battery life, and it gets worse. A test ride on a new bike wouldn't reassure me, because even if hill climbing is okay new, how long would I be using the bike before the cutting-out started? I don't need a motor on the flat; I want an electric bike to help me up hills. If it won't do that, it's no good to me.

We all have our own requirements for an electric bike. I need one light enough that I can carry it upstairs. I have a strong preference for one that can be powered throttle-only on occasion. I would like one that lets me control how much help it's giving. Now, if I decide to shop for a new bike, I need to add NiMH battery to my list.

Mary

 

[Jeremy]

Perhaps that should have read "started a career as a chemist many years ago"..........................

Thankfully I grew out of it and turned to a more interesting area of scientific endeavour!

As has been pointed out, Cadmium is the really nasty stuff. I too believe that the major reason that Lithium has been taken up (before the technology if mature, in my view) is because of the massive hike in global Nickel prices. Now these are slowly falling, perhaps we will see the balance restored, although I have no doubt that Lithium technology certainly has the potential to be a real winner, especially the newer Lithium Iron Phosphate cells.

Jeremy

 

[flecc]

Thanks for the correction, of course nickel is not toxic or even potentially so.

The rest of my post stands as being the background to the present troubles.

Although small NiMh cells have been continuously increasing in size, investment in that area has now reduced to tiny proportions with very few involved, compared to that in lithium techniques.

The D cell size that we are interested in are at a near standstill in development and production is low, the capacity gains and remaining high production being mainly in the widely used AA size.
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[Grizzly Bear]

It would be interesting to do a survey on which lithium powered e-bikes cut out on hills, our bike has never cut out and it's well on the way to covering 1000 miles. I don't think it's fair that owners of one or two models of e-bike are giving bad press to bikes that have been faultless in use. It remains to be seen if our lithium powered machine stands the test of time, but so far so good.

Griz

 

[Jeremy]

I think a lot of this "cutting out" problem has to do with both the particular chemistry and quality of the cells used. The RC model people run LiPo cells at very high discharges rates, yet don't seem to have this problem, similarly, there are many examples of electric bikes with very high performance that similarly don't seem to suffer from it.

My guess is that some manufacturers have used cells with a low maximum discharge rate, which is often accompanied by a high internal resistance. Such cells will give a very marked voltage dip when asked to deliver a high current, so causing the low voltage trip in the controller to operate.

Looking around, it's clear that cheap LiPo cells are only capable of maximum discharge rates of around 2 to 3C, whereas the more expensive ones are good for upwards of 15C rates.

The major remaining problem with Lithium technology seems to be the storage life issue. The relatively high rate of reduction of capacity with age, irrespective of usage, seems to me to be the most significant problem to overcome. Nickel based cells don't suffer from this to any noticeable extent, in fact if operated well within their capacity limits they will last for ten years or more (Toyota guarantee the Prius NiMH pack for 8 years, for example).

I'm hopeful that Lithium Iron Phosphate cells may be significantly better in this regard, although only time will tell. It seems clear that the cordless tool market is one of the major drivers in this area, as both the new Lithium technologies and the very best Nickel based cells seem to be widely available in common cordless tool sizes. In particular, the sub-C cells are far and away the best NiMH ones available, as these are those most commonly used in older power tool packs. There doesn't seem to be a market driver to develop D or F size cells, hence the reason these seem to be sat in the doldrums.

Jeremy

 

[HarryB]

It would be interesting to do a survey on which lithium powered e-bikes cut out on hills, our bike has never cut out and it's well on the way to covering 1000 miles. I don't think it's fair that owners of one or two models of e-bike are giving bad press to bikes that have been faultless in use. It remains to be seen if our lithium powered machine stands the test of time, but so far so good.

Griz

Gris,
remind us of the make of bike you ride as I am interested but have forgotten and cannot be bothered to trawl through previous posts!

 

[flecc]

Also the territory Griz.

The owners of the "cutting out" models who live in moderate territory don't suffer the way those who have to tackle steep or very long hills do.

I can run my Torq/T bike and Quando/Q bike on a fistful of AA cells on the flat, yes really!
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[flecc]

There doesn't seem to be a market driver to develop D or F size cells, hence the reason these seem to be sat in the doldrums.

Jeremy

Absolutely right Jeremy, the requirements of the couple of manufacturers of more powerful e-bikes just don't even justify attention.

The only NiMh cells now available with some reliable consistency at a price suitable for e-bike manufacturing are the 8.5 Ah size used in Powacycle, Urban mover and a number of other e-bikes.

The 10 and 11 Ah ones commonly advertised are proving to be unsuitable, in most cases due to unacceptably high failure rates coupled with a refusal to warranty, in a few cases on price.

One e-bike manufacturer has currently despaired of obtaining the size and type needed for his bikes and is quietly fitting the 8.5 Ah despite the fact that their discharge rates will possibly mean a drop in performance as well as the loss of range.

Hence my original posted remark on the need for investment, not in research but in some production.
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[Grizzly Bear]

Gris,
remind us of the make of bike you ride as I am interested but have forgotten and cannot be bothered to trawl through previous posts!

Hi Harry and Flecc
my missus has a Synergie Mistral, she is not very strong so relies on assistance alot. We live in Wales, in a part of our City called Townhill, as the name suggests we have many (steep)hills, which is why we have electric bikes.

Griz

 

[Footie]

It remains to be seen if our lithium powered machine stands the test of time, but so far so good.

Griz

This is my whole point. Is it right that customers are crossing their fingers and hoping their bike batteries will not cut out on the next hill or even last 12 months - that is ridiculous state of affairs. This has been an ongoing problem that doesn't seem to be any nearer to being resolved. Issues were raised about reliability before I purchased my electric bike and I have had it more than six months now
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[HarryB]

What is interesting is the variation between batteries from the same manufacturers as Flecc points out in his Torq talk webpages. My new battery is a different beast to the old one even when it was spanking new. Fair enough I have only used it for one charge but it is performing in a way that the old battery never did. While the voltage does drop and this shows up as the meter going red, the bike still pulls without cutting out - definitely a different bms in this battery and it shows. Only time will tell if it lasts, and I should get an idea in six weeks or so as this is when the original battery showed its first signs of aging.

 

[Tiberius]

As we've said in another thread, the problem may not be so much that the Li batteries are bad themselves, but more in an unhappy marriage between them and certain bikes. The Torq particularly demands a high current from them in circumstances when a shortfall is most noticeable - hill climbing.

I have to say that since I fitted the Cycle Analyst (ebikes.ca) I'm feeling happier about my Li battery. Now I'm counting charge out and seeing actual voltage, current and power readings instead of relying on 3 coloured LEDs. The battery capacity and performance seems in line with spec - its early days yet and I will report again - but the voltage does droop alarmingly when the bike demands 18 A for a period. I'm providing a reasonable degree of pedal assistance on hills, and its clear that if I wasn't then it would have trouble on the hills.

Nick

 

[ITSPETEINIT]

First deep Discharge

As we've said in another thread, the problem may not be so much that the Li batteries are bad themselves, but more in an unhappy marriage between them and certain bikes. The Torq particularly demands a high current from them in circumstances when a shortfall is most noticeable - hill climbing.

I have to say that since I fitted the Cycle Analyst (ebikes.ca) I'm feeling happier about my Li battery. Now I'm counting charge out and seeing actual voltage, current and power readings instead of relying on 3 coloured LEDs. The battery capacity and performance seems in line with spec - its early days yet and I will report again - but the voltage does droop alarmingly when the bike demands 18 A for a period. I'm providing a reasonable degree of pedal assistance on hills, and its clear that if I wasn't then it would have trouble on the hills.

Nick

I am certain there were several postings after this one, including one of my own, but they seems to have vanished somewhere.
However:
My first deep discharge on my Torq with Li-ion battery carried me more than 30 miles before all three lights went out. I have never achieved as great a mileage on one charge since then.
Now the three batteries I have (li-ion 10Ah/36v) are limited to just about 20 miles each on a Sprint. The oldest of the three is 16 months and 700 miles - but the other two are 5 months and 6 months respectively and 300 miles travelled and each achieves about the same .
My personal profile is: 78 yo; very unfit (except when chased by a rabid dog - wonderful stuff adrenalin); 88 Kgs. The cycle is carrying 2 extra batteries.
The test course is 42 miles and requires 3 batteries on board: there are 7 hills of a grade between 8% and 9% on the outward journey and again on the inward journey, each about 0.5 km long, as well as some very gentler grades.
I have never had a cut out on the Sprint but the battery becomes a bit feeble after 12 miles and definitely does not like up-gradients of any degree after that point.
I usually ride the battery until the red light shows for the first time on a hill. I should probably change the batteries over at 14 miles but I like to keep an eye on the declining capacity of each one. When I rode in late October/early November the capacity for mileage had not changed compared with the summer, but in late November I got the red light on modest hills after 5 or 6 miles.
I wish my batteries were as good as the advertised 'Norms'. I can't see me getting 500 recharge cycles with 80% capacity remaining (the point of uselessness) and I am concerned with the more general declining usefulness that will arrive before that time.
The oldest battery (16 months/700 miles) has had 35 recharge cycles - 465 cycles to go.
Quote from 50Cycles web site 22/04/2007: "Typical Cycling Characteristics. this shows that the cells can go through 500 charge cycles before reaching 80% capacity, at which point the battery will need to be replaced, This equates to a full charge and discharge (with powered cycling of up to 30 miles) every working day for around 2 years (that's 500 x 30 - 15000 miles BUT the decline in capacity is gradual thus after 250 charge cycles the mileage achievable on one charge is much less than 30 - might it be as little as 15 miles? or maybe just 10 miles in my case?
Peter