Advances in battery technology

[flecc]

These are the ones that kraeuterbutter is always speaking of, and has a high opinion of. They don't say what chemistry though, which is odd.

Assuming a lithium variant, they should be fine on bike use since with that large capacity the voltage drop under load wouldn't be likely to cause cut out. They are generally quite expensive though, and with lithium's short life, very expensive.

They claim 800 charge cycles, but I don't believe it, and bet they wouldn't guarantee that. Probably more like 400 cycles in typical bike usage, or 500 for a short trip person who recharged every short trip.
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[Ian]

They certainly look interesting John, but as always with lithium there's the essential battery management electronics to consider. With a potential incendiary bomb under your saddle it's vitally important such batteries are used correctly otherwise it's not only your pocket that will get burnt!

That brochure probably came from a Chinese manufacturer with a minimum order quantity of a container load, so it's likely there would be problems obtaining such cells anyway.

 

[coops]

If they were to do 'what they say on the tin'

What? They come in a tin? .

Something odd about the specs there John I think. I've heard the name kokam quite a lot, well known & considered "more reliable" rolleyes: nuff said!), but the 25Ah looks suss, and I think the 0.5C in the small print is saying something, but I don't know.

I think what flecc's been saying is that, put those together in series to make a battery & the current can't be maintained, so you get cut-outs. Deep discharge regularly, and you get short life: so its short, useless life or long, useless life, its your decision

But I could be wrong .

Stuart.

 

[JohnInStockie]

Thanks Flecc. I am just trying to calculate the costs to me. I am recharging my 6.5Ah NiMH each way on my work trip, how many cycles do you think I can get out of that battery, 2 charges a day, 5 days a week and a refresh every weekend.

As you know the cost of the replacement is £250 and again it would only give me 6.5 Ah.

If the Nimh gives me 800 cycles, then thats 80 weeks. It the Lithiums give me 400 cycles, but average 20AH (down from the 25Ah) over say 450 cycles, then does that mean I would only have to recharge every 2 days, or 3 times a week, meaning that I would get 150 weeks out of them?

So my math is:

2 x 6.5Ah Nimh = 1600 cycles or 160 weeks
1 x 25Ah LiPo = 400 cycles or 150 weeks

If that stacks up then its all down to the cost I think.

John

 

[JohnInStockie]

COOPS - not sure but I think Flecc said the opposite.

IAN - Bang for my Buck?? (or Butt) Yes that is a serious consideration, but if all current models of e-bike have them...well...they should be safe I guess

Other considerations are of course the weight reduction on the trip of not carrying a charger with me wherever I go, (minor, but annoying)

John

 

[flecc]

Don't forget that if you use lithium batteries like that John, the life is shortened. Fully discharging them can lead to 66% loss of capacity in a week.

The odds are that your NiMh could last longer than you think, they are quite resilient.

Also, recelling to 8 Ah for £99 plus P & P for the battery that the cells come from is better than a new Giant battery at £250.
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[Ian]

IAN - Bang for my Buck?? (or Butt) Yes that is a serious consideration, but if all current models of e-bike have them...well...they should be safe I guess

John, That's true of commercially made battery packs which all incorporate battery management electronics and have been independantly tested for CE compliance, but DIY packs are a different matter and not something I'd want to be sitting on.

Then theres the cost of the charging bunker to consider.....

 

[JohnInStockie]

Don't forget that if you use lithium batteries like that John, the life is shortened. Fully discharging them can lead to 66% loss of capacity in a week.

The odds are that your NiMh could last longer than you think, they are quite resilient.

Also, recelling to 8 Ah for £99 plus P & P for the battery that the cells come from is better than a new Giant battery at £250.
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Yes when you put it like that it makes sense to stick with NiMH, but I need to have a 10Ah I think. On my Giant battery, 10.5 miles into work uses half the battery (down-hill), the return journay flattens it to the last flashing led on the battery. So I take that as meaning that I need 150% of what I have or nigh on 9.75Ah for the full trip.

Any ideas how I can recell to that for a 'reasonable' price?

Thanks

john

 

[coops]

Am I the only one that finds the energy density of those batteries a little incredible: 25Ah and 26.9V is almost 575Wh, for 4.5kg? I suppose once you've cased them & included any battery management electronics though, it'll be about 1.5 times the capacity of NiMH for the same weight .

 

[flecc]

Mistype there John, I meant 66% in a year, not a week!

Not at the moment for recelling to 10 Ah.

Batteryspace have those packs but their prices have almost doubled and we've had reports that their quality control has been failing with dud cells being sent out in made up packs.

Several suppliers of loose cells around, but your case won't take those, it's got to be a welded prepack like the Powacycle 8 Ah ones.
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[flecc]

Am I the only one that finds the energy density of those batteries a little incredible: 25Ah and 26.9V is almost 575Wh, for 4.5kg? I suppose once you've cased them & included any battery management electronics though, it'll be about 1/5 times the capacity of NiMH for the same weight .

That's what I keep saying to kraeuterbutter, but he dismisses my critical attitude to these sort of figures with graphs of the performance. If the graphs are right, they will be ok. If.
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[Ian]

Am I the only one that finds the energy density of those batteries a little incredible: 25Ah and 26.9V is almost 575Wh, for 4.5kg? I suppose once you've cased them & included any battery management electronics though, it'll be about 1.5 times the capacity of NiMH for the same weight .

Which makes them about the same as the normal Li batteries used in bikes. But only when new. Despite the claims of huge cycle life, like you I'm not convinced and would expect them to deteriorate and a similar rate to other lithium types.

 

[ITSPETEINIT]

Lithium-ion or Phylion or Lithium Manganese

Canany tell me, in words of one syllable, the difference between a battery marked "Phylion Battery", a battery know as "Lithium -ion" and a battery I recently come across on e-bike specifications "Lithium Manganese".

They are probably interchangeable and would be recharged using the same type of charger, but is one more efficient than another and has other advantages over another?

Thanks
Peter

 

[coops]

Its all Greek to me...

Sorry Pete, not me! I must admit I'm confused which are Lithium polymer & which Lithium ion, and of those two which deteriorates fastest over time...

I think Li-manganese is a safe type of Li-ion Pete, as is the less safe Li-cobalt which was previously used; phylion rings a bell, but I can't place it - is it a brand name?

I also think that "normal" Li-polymer decays faster than Li-ion?

Not sure though .

Stuart.

 

[flecc]

Phylion is in fact just the Lithium Ion batteries that we have in the eZee models and other bikes, also abbreviated to Li-ion, and they are manufactured by the Phylion Battery Co. Ltd of Beijing, hence the "Phy" prefix. These are also Lithium Ion Manganese, as opposed to the older Lithium Ion Cobalt types which were prone to internal shorts causing fires. The Manganese and Cobalt refer to the cell chemistry and constituent type.

You'll also see LiPol, Li-polymer, Lithium Polymer, but those are all the same thing, abbreviations for Lithium Ion Polymer. This is a newer cell type which has the potential to permit faster charging, though that's often not exploited for e-bike use.
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[coops]

Cheers flecc, I knew I'd heard it somewhere .

Are there different types of Lithium ion polymer too? With different cathode chemistries?

Actually, to be honest, it doesn't really matter to me unless they offer an effective, lasting & good value ebike battery, which they don't seem to .

Stuart.

 

[flecc]

They can have the same chemistries Stuart, the only difference being in the use of ion exchanging plastic film and gel electrolytes. They aren't likely to be any better performing than the other types, but can be a bit more compact for a given capacity.

The real reason for their development was to provide a lightning fast charging battery for electric cars. Since these would never have very long range, the concept was for them to stop for a 1 or 2 minute full recharge every 100 miles or so.

Sharp and Toshiba have been leading in that research, but although prototypes show promise, the market realisation has been delayed a couple of years so far.
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[coops]

The "konion" and "nanophosphate" batteries, are they Li-ion or Li-ion polymer?

 

[ITSPETEINIT]

Li-ion or what have you?

Phylion is in fact just the Lithium Ion batteries that we have in the eZee models and other bikes, also abbreviated to Li-ion, and they are manufactured by the Phylion Battery Co. Ltd of Beijing, hence the "Phy" prefix. These are also Lithium Ion Manganese, as opposed to the older Lithium Ion Cobalt types which were prone to internal shorts causing fires. The Manganese and Cobalt refer to the cell chemistry and constituent type.

You'll also see LiPol, Li-polymer, Lithium Polymer, but those are all the same thing, abbreviations for Lithium Ion Polymer. This is a newer cell type which has the potential to permit faster charging, though that's often not exploited for e-bike use.
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Thanks Flecc and Coop for your help.
My confusion arose because batteries recently supplied are Pylion (on a sticker inside the battery slide fixer). These are marked with nothing else to indicate which type they are.
On the 50 Cycles web site which details cycle specification it says "Battery : Lithium Manganese 37 V 10 Ah..........."
Down the bottom, same page, it says "Lithium ion option from £995".
Hence my confusion.
Peter

 

[flecc]

The "konion" and "nanophosphate" batteries, are they Li-ion or Li-ion polymer?

I think konion is either a trade name or a language difference. Nano phosphate just refers to the trend towards smaller particulates to increase cell content density. One of the costs of moving to the polymer construction was initially a reduction in capacity, but this was and continues to be overcome with the use of ever smaller particulates.

There's a downside though. As before, the finer the particulate and denser the structure, the more difficult it becomes for charge to drain from large cell volumes. This could be why eZee expressed themselves as "terribly disappointed" in polymer, since high demand motors like theirs would be the most likely to suffer from a battery's reluctance to give up it's content.
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