Wisper Battery Failure x 2

[karl101]

Does not the price of an item have a 'reasonableness' value? A perception that you are paying the right and fair price for something. As an item turns from an luxury into a consumable then the competitive market reduces the price, like Laptop PC's for example, in the early 90's the prices were silly, now you can get one cheap as chips.

But what we, the consumer, need is a universal standard so that I can go and buy a "type b" battery that will fit into the "type b" battery slot. This would be made by any battery manufacturer. Price difference would be determined by build quality, weight, battery life, brand name, etc..

Karl.

 

[bazwaldo]

But what we, the consumer, need is a universal standard so that I can go and buy a "type b" battery that will fit into the "type b" battery slot. This would be made by any battery manufacturer. Price difference would be determined by build quality, weight, battery life, brand name, etc..

This is right I think,
My Bearprint Ebike similar to a Freego or Juicy Bike shares a very standard looking behind the seat battery box usually in 2 sizes small or large.
I went for the larger 16ah size and recently searched on the internet looking for a replacement Chinese battery.
I felt sure it ought to be possible to find a slot in replacement easily as the battery had to be a common size with some sort of industry standard.
After emailing a few Chinese Alibaba vendors I got no where with my questions about "Industry Standards" falling on deaf ears.
To replace my battery with a cheaper import it has to have the same dimension box with the same bottom connector, 3 pin charging connector and the same size locking button at the same height near the top of the battery.
How hard can it be to find this?

Barry.

 

[Deleted member 4366]

I noticed that those very similar Chinese batteries don't use the connector in the bottom, but instead have a kettle type socket in the top, so be careful, but having said that, the case is the same size so you could remove the cells and BMS and put them in your case or use the top and bottom off your case and re-route the output wires to the bottom.

Asking the Chinese sellers questions is normally a waste of time: They never seem to be able to understand what you mean and they never say "no". They just repeat stuff from their advertising material. Li Ping is an exception.

 

[bazwaldo]

I noticed that those very similar Chinese batteries don't use the connector in the bottom, but instead have a kettle type socket in the top, so be careful, but having said that, the case is the same size so you could remove the cells and BMS and put them in your case or use the top and bottom off your case and re-route the output wires to the bottom.

Probably like many other Ebike users I feel that I do not have the necessary skills or electrical knowledge to safely take my battery apart. It would invalidate the warranty as well.
I would love to have a 2nd battery case to experiment with if I could do so safely.
Most of the available cases/batteries seem to be the rack mounted type.
My battery which slots behind the seat post appears to be quite a common design so I am surprised that they are not more readily available.

Barry.

 

[jerrysimon]

Asking the Chinese sellers questions is normally a waste of time: They never seem to be able to understand what you mean and they never say "no". They just repeat stuff from their advertising material. Li Ping is an exception.

I wonder in their business practises that must be a cultural thing about never saying no or I don't know ?

Regards

Jerry

 

[JuicyBike]

Here you go Barry

 

[flecc]

But what we, the consumer, need is a universal standard so that I can go and buy a "type b" battery that will fit into the "type b" battery slot. This would be made by any battery manufacturer. Price difference would be determined by build quality, weight, battery life, brand name, etc..

This sort of thing only comes with standards set in large markets by standards bodies supported by trade organisations, and the e-bike industry doesn't fit any of the requirements yet. There's no agreement on what is an e-bike yet, the world having three very different views on that, and each view further fragmented into various forms. For example, what the Chinese view as an e-bike for their own use we in Europe call a scooter or moped. Nor is there any agreement on what types of battery to use, and the battery chemistries and technologies are as yet completely unsettled.

We may get there one day, but the market will have to grow much bigger and have more elements of design stability before it will happen.

 

[JuicyBike]

The vast majority of the 30 million electric bikes produced in China each year share less than 20 battery case designs. It makes sense, as a UK importer, to choose the most popular. We took a decision to adjust frames and suppliers to arrive at a range (excluding kits) that all share the same baseplate and slider profile, allowing interchangeability. We also selected one of the more popular cases from one of the largest suppliers. I hope we have it right for the mid-term and keep an eye on the trends.

 

[Wisper Bikes]

I think diversification is the missing word in this tantalising little teaser! Are you thinking about floating the company any time soon David as I'd like a few shares?

Jack Cohen started small and very quickly became Britain's biggest. I'm sure you're driven in exactly the same way.

Indalo

Thanks Indalo, I will keep you informed!

All the best

David

 

[Kudoscycles]

We are trying to standardise our batteries-Our King,Tourer,City, Liberty and new Eco bike all use same 10Ah x 36v LifePo4,price £208.80. Our Duke,Duchess and new Safari bike will use a different mount battery,still 10Ah x 36v LifePo4,price £267.37. For future bikes we will try to use either of these batteries.Our experience so far is that both these batteries are performing well and represent fair value for money.
Dave
KudosCycles

 

[Wisper Bikes]

Thanks Dave, we will look into them.

All the best

David

 

[jerrysimon]

We are trying to standardise our batteries-Our King,Tourer,City, Liberty and new Eco bike all use same 10Ah x 36v LifePo4,price £208.80.

That seems like a decent price for that battery.

Regards

Jerry

 

[z0mb13e]

Hi Scatty, we can of course supply cheap 360Wh batteries as can everyone else, maybe you are correct and we should give this some consideration. There are so many Asian suppliers desperate to sell them that we get several offers every day of the week. These batteries are the standard now for China and are manufactured by the hundred thousand hence the low price, I don't think there is anything wrong with them they are simply considerably cheaper than the type of battery we currently sell.

The more I consider this the more I feel it may be worth bringing out a super eco LiFePo4 for those who would like such a battery, we could easily fit them into our cases. Thanks Scatty for your patience, you have certainly given me cause to think!

All the best

David

Much as I liked the high capacity battery on the Wisper, I will be forced into getting a cheap replacement when the current battery dies. Though when that will actually happen is becoming a mystery! I would estimate (based on observation and nothing else) that the current capacity after 2 years and 4 months is less than 60% but the weather is playing a much bigger part in all of this than I ever considered (the cold really didn't affect the battery for the first year), and it may well perk up again next summer. On the other hand it may die completely this winter.

So if Wisper were to offer a 36v 10Ah LiFePo4 for a price comparable to other UK suppliers then I would be more inclined to go that route than trying to shoe horn a DIY pack into the original case.

If this were an option would the original charger work ok with the lower capacity battery?

Oh and while I'm here, and completely unrelated - A direct question for David@Wisper: Can I get spare battery keys? My second key is broken, i'm left with just the blade. This always seems to happen in the winter - it happened on the Cyclamatic key which is the same design - I guess the plastic gets brittle in the cold weather.

 

[Wisper Bikes]

Hi Z0mb13e

I do understand your point, but do remember when choosing a new battery that our latest batteries will have a 20% maximum current drop in two years so will last even longer. After two years the battery will still have at least a whopping 460Wh, 100Wh more than a brand new 36V 10Ah and only 54Wh down on our older batteries when they were new. Even after three years hard use they will still have more capacity than a brand new 36V 10Ah.

The batteries we use now really are 16Ah not simply rated 16Ah, they are testing at on average 16.4Ah +-. Other batteries we have tested fall short of the published capacity by as much as 15% even when they are brand new. The battery you are using now is one of our older 36V 14Ah batteries or 504Wh. If it is down to 60% of original capacity that means you still have over 300Wh remaining, a maximum of 60Wh down on a brand new 10Ah battery.

We can go back over 6 years with our batteries and give 100% guaranteed feedback. The new cheaper 36v 10Ah batteries have not been about for more than a few months and no one really know what to expect. At half the price of a powerful Wisper battery they may seem good value but it is worth noting that you are getting much more than a third more capacity with a decent battery. It's similar to buying 16 litres of fuel instead of 10.

Using decent powerful batteries is one of the main reasons Wisper bikes feel more powerful than many others and maintain that power for more miles.

All said though we are all restrained by budgets and there is nothing at all wrong with buying what can be afforded short term. Hence the reason I will be looking at the new cheaper batteries as an option.

All the best

David

 

[celedep]

An interesting thread posted earlier by Kudos

http://www.pedelecs.co.uk/forum/electric-bicycles/10206-voltage-drop-lifepo4-v-limn2o4.html

LiFePO4 versus LiMn204
We have a number of bikes in our warehouse that are under test – some have LiFePO4 batteries and some have LiMn2O4 batteries (manganese spinel based lithium-ion polymer or lithium-ion batteries). We have noticed that the 10AH LiFePO4 battery has a sustained voltage up to 30-35 miles and then drops suddenly. Whereas the 14AH and 20AH LiMn2O4 batteries, whilst having a potentially longer range, the fall off of voltage is progressive from O miles and becomes critical at about 35 miles for the 14AH battery and 45 miles for the 20AH battery. These figures are not merely theoretical, if you read reports of Kudos users on Pedelec they all report strong performance from the LiFePO4 battery up to the point when the battery is technically exhausted.
However, if you look on my graph the 14AH and 20AH LiMn2O4 batteries start to experience critical voltage drop off at 34 miles and 47 miles respectively – in practice at this point the bike will start to become sluggish to ride in assist mode. Whilst a total mileage of 50 plus miles (14AH) and 80 plus miles (20AH) is potentially possible, the last 16 miles of the 14AH and 30 miles of the 20AH will be unpleasant to ride – someone elsewhere on this forum described it as ‘like riding through treacle’!
The LiFePO4 equipped bike never experiences this sluggish riding except in the last few yards before the battery is exhausted.
Therefore if you use (2) LiFePO4 batteries you can expect 70 miles of almost full power riding.
The effect is exaggerated with storage life – the LiFePO4 on average experiences only 2% drop in capacity in the first year and 3% drop in the second year, whereas the LiMn2O4 battery loses on average 14% capacity in each year. If you move point A and B some 20% back it is now easy to see why this LiMn2O4 type of battery loses working range rapidly after 2 years of usage, coupled with the high cost of replacement I just cannot understand why this battery type is preferred over the LiFePO4 battery.
Dave
Kudos Cycles

 

[jasono]

Hi Mick

We will not be using this new Tech to increase range on our 2013/14 bikes, we will simply be reducing the size and weight of the battery whilst retaining a 500Wh capacity, we may even reduct to 36V 10A or a 360Wh capacity, this way we believe we can get our bike weight down to under 16kg. Our target for the new bike is -16kg, 60 mile range and a very discreet sports bike like design, that said we will be continuing with our current bikes but will be offering huge range touring bikes as an option. Yesterday I learned that this amazing new chemistry will enable batteries to be delivered without any charge whatsoever, they come to life during the first charge performed by the customer. This means the batteries will have a shelf life massively better than any of the current lithium cells on offer.

All very exciting!

Best regards

David

This sounds great, can't wait!

 

[Wisper Bikes]

Cheers Jasono, I will post updates here.

We are all massively excited about the project and will keep Pedelecs updated.

All the best

David

 

[Wisper Bikes]

Thanks for the info Celedep

To answer Dave's question, I think there are several reasons that the major ebike and electric car manufactures are not using LiFePo4, the primary reason of course is the very low energy density (Wh/kg or Wh/L) compared with other battery chemistry which means the batteries are bulky and heavy especially compared to Li(NiCoMn)O2 (Wisper does not use LiMn2O4 as suggested). Li(NiCoMn)O2 is safe, has superb energy density (up to 160Wh/kg) and over the last few years cycle life has increased from about 700 to 1200-1400.

Other reasons for sticking with Li(NiCoMn)O2....

1. Rated cell voltage for Li(NiCoMn)O2 is 3.7V whereas LiFePO4 is only 3.2V. So to achieve 36v LiFePO4 needs to employ at least 11 cells (35.2V). Li(NiCoMn)O2 needs only 10 cells, 37V which gives us significantly more power and makes voltage control more consistent.

2. LiFePO4 battery cryogenic properties are poor. At -10℃ capacity drops to about 50% of normal temperature capacity.

3. LiFePO4 battery technology not yet mature, and there are patent dispute problems. Due to these factors I have been informed it is difficult to source consistently high quality product.

All good for the science, the truth of the pudding of course is in the eating, we have experimented with both and we find LiFePO4 simply is not as good and is certainly less powerful.

Lastly, why would we use a more expensive battery if we could get away with using the cheapies? If we sold cheap batteries in our bikes we would no doubt considerably increase our unit sales whilst maintaining margins.

All said, I will look into selling a cheap battery especially for people who want to replace their existing. I am off to China tomorrow for a week, during the trip we are meeting our battery manufacturers (who make both) to discuss. I will report back to the forum.

Best regards

David

 

[karl101]

Do we get a trade in on our old batteries? It'd make the purchase of a new one a little less painful.

Karl.

 

[Wisper Bikes]

Hi Karle, yes you do, as a part of our recycling scheme we will discount a new 16Ah battery by £50 when the old 14Ah battery is returned.

This of course reduces our price per Wh to about 80p against about 70p for a phosphate battery.

Best regards

David