Sky Energy LiFePO4 Bulk Buy this Week

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Post by Powered By DC » Thu, 07 May 2009, 09:43

For those that were not aware we just finished a bulk buy from Thundersky of over 150,000AH . It went very well and we had several requests for the Sky Energy cells so we have decided to make the same offer on the Sky Energy cells as we did for the Thundersky cells.

We have started a Sky Energy bulk order that is being submitted to China this week.

Sky Energy has discontinued the "TK" cells that they were making for Thundersky.
As of this month they are now making the SE cells that have a slightly better discharge rating of 4C vs the TS cells at 3C and 12C pulse vs the TS cells at 10C

We are ordering 100,000+ amp hours to get a lower $/Ah price from Sky Energy.
Over 1/3 is already committed to individuals.

The price available is $1.10 USD per Ah. We can have the cells shipped to your nearest port for only the actual shipping costs. You will be responsible for all taxes or duties.

Here are the remaining cells that are not yet committed and still available:

100 of the SE 60 Ah cells at $66 each plus shipping and customs

312 of the SE 100Ah at $110 each plus shipping and customs

150 of the SE 180Ah at $198 each plus shipping and customs

Sky Energy has these sizes available in the SE cell. 40 Ah, 60 Ah, 90 Ah, 100 Ah, 120 Ah, 160 Ah and 180 Ah.
The 120 Ah is on the list, but not in regular production yet.

If you want one of the sizes that is not currently part of our extra cells in the order, I need to know ASAP to add it to the purchase order.
We don't need payment this week, but we do need a firm committment if you are requesting a size other than those on our extras list.
We selected 60 Ah, 100 Ah and 180 Ah because those are the most popular.

The SE 180 Ah cells are interesting because they have the same physical dimensions as the Thundersky 160 Ah cells but are more energy dense at 102 wh/kg and 159.48wh/l compared to 91.43wh/kg and 144.16 wh/l on the 160ah TS cells

The 100ah and the 180ah are the most energy dense large format LiFePO4 cells on the market that I am aware of.

Last edited by Powered By DC on Thu, 07 May 2009, 06:41, edited 1 time in total.
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Post by coulomb » Thu, 07 May 2009, 18:15

Weber and I are interested in this. But we are concerned about the cost of the double shipping (China to Seattle, then Seattle to Brisbane). I believe that there is someone from Australia that is part of this buy (or maybe the last buy, of Thunder Sky cells). If you are an AEVA member, what is/was the shipping arrangement?

Are any other Aussies interested? Maybe we could get them to split the shipping, part to an Australian port, and we can road frieght to other cities from that port.

We'd be ordering 40 Ah cells, so it sounds like we need to be quick with this.
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Post by coulomb » Thu, 07 May 2009, 18:25

The other question is, does anyone know if this Powered by DC mob are Fair Dinkum? For example, none of the photos of their only conversion to date shows the motor or battery. There are also very few details on their web site.
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Post by Powered By DC » Thu, 07 May 2009, 18:40

We would be shipping the cells for AEVA members directly from China to your nearest port. If several of you end up purchasing them we can probably combine the shipping. Yes there was 1 person from Australia that was part of our TS buy. The shipping quote for that order was under $300 USD.

I know that we did not put much info on our conversion website. I put it together myself and I am certainly not a web designer. We are currently having a web designer build the parts website. I can provide pictures of what ever you want from the conversions we have done if requested. We have done several Rav4's with TS batteries and we ae currently Working on converting the first of 7 2009 Rav4 EV's I used the BMS from Rod Dilkes for the Rav that is on the website.

We can also Provide references to anyone who needs them.

We also just purchased 30+ AC55 motors and inverters, several Enova 90KW inverters hundreds of Kilovac contactors, fuses and fuse holders etc from a bankrupt company and will be able to give very good pricing on this stuff.

We are providing a 1 year warranty with the purchase of the bateries
2years if you purchaes the BMS from us. The BMS we are offering is from Elithion www.elithion.com

Last edited by Powered By DC on Thu, 07 May 2009, 08:44, edited 1 time in total.
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Post by zeva » Thu, 07 May 2009, 21:08

I'm really looking forward to hearing people's feedback on these Sky Energy batteries. Kudos to everyone who's taking the plunge with a different manufacturer, I hope the cells perform well.

Seems like ThunderSky have enjoyed a bit of a monopoly for a few years because they're the only brand to have earned much of a reputation, which is a bit of a "chicken and egg" problem for other manufacturers! But some healthy competition could do wonders for the industry.

PS: Sorry, I myself don't need any more batteries right now Image
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Post by coulomb » Thu, 07 May 2009, 21:32

Powered By DC wrote: We would be shipping the cells for AEVA members directly from China to your nearest port.
Ah, excellent.
... We also just purchased 30+ AC55 motors and inverters, several Enova 90KW inverters hundreds of Kilovac contactors, fuses and fuse holders etc from a bankrupt company and will be able to give very good pricing on this stuff.
Wow, cool.
We are providing a 1 year warranty with the purchase of the bateries
Ah, that answers another question. Thanks for the assurances!
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Post by antiscab » Fri, 08 May 2009, 01:57

hi Guys,

I was the one who participated in the TS bulk buy.

the shipping for me should be done through China Post.
for larger orders, this probably wont be possible (each package has a weight limit of 20kg).

Matt
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Post by weber » Fri, 08 May 2009, 06:49

Powered By DC wrote: Sky Energy has discontinued the "TK" cells that they were making for Thundersky.
As of this month they are now making the SE cells that have a slightly better discharge rating of 4C vs the TS cells at 3C and 12C pulse vs the TS cells at 10C

Dave, I note that the SE cells say charge 3.6 V and discharge 2.0 V while the TK cells say charge 3.9 V and discharge 2.5 V (very similar to TS). Can you explain why these differ so much? Are the SE still LiFePO4? Do they still have a no-load voltage at mid-charge of around 3.3 V? Is the 12 C pulse rating based on the cell voltage falling to 2.0 V rather than 2.5 V? If so, it wouldn't be a fair comparison with the TK or TS 10 C pulse rating.

Do clamping plates and straps and screws come with the cells, included in the price? If so, are they for a fixed number of cells per block? If so, how many?

Are electrical links and their screws and washers included?

Sorry for all the questions.
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Post by weber » Fri, 08 May 2009, 07:30

Apparently some Sky Energy factory photos here
http://www.evdl.org/archive/index.html# ... td23251023

Also some discharge curves that look mighty strange when they go below about 2.3 V. I don't think I'd be taking them down there, and if this is how they get their higher capacity figures I think it's a bit dodgy.
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Post by Powered By DC » Fri, 08 May 2009, 23:36

The SE cells are still the LiFePO4 chemestry just changed a bit. They are a step closer to being a large format nano phosphate battery. If anyone wants more info about this please contact me off list.

We have been testing the 100ah cells and they have been impressive. The cells we have tested had more than the rated capacity.

The clamping plates, straps and screws come with the cells and are included in the price. They will package them to your requirements. for the smaller cells I have seen as high as 18 packed together.

The electrical links and their screws and washers are included in the price.
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Post by Powered By DC » Sun, 10 May 2009, 20:31


Update on the bulk buy:

We have two bulk orders from China currently in process.
One with Thundersky and one with Sky Energy.
Delivery is expected in late June or July.
The price on both is $1.10 per AH plus customs and shipping.

On the Thundersky order:
What have ordered 144,000 AHs of cells.
92% of this order is sold and committed to individuals.

It is too late to change the quantity and sizes of the cells.
Here are the remaining extras from Thundersky that are available and on the way.

49 of the 100 AH cells at $110 each

http://www.thunder- sky.com/pdf/ 20092201189. pdf

44 of the 160 AH cells at $176 each

http://www.thunder- sky.com/pdf/ 200871782241. pdf

On the Sky Energy order:

We have ordered 100,000 Ahs of cells.
About 75% of the order is already committed to individuals.
The first payment has been wired to Sky Energy in China.
We have about another week to adjust the mix of the different sizes and quantities in the extras that are uncommitted, then that windows closes and we have to pick sizes that we believe are in demand.

We are planning on just filling up the extras with the SE 100 Ah and SE 180 Ah cells.
Those sizes have been most popular.

If you need a different size, 40 Ah 60 Ah, we need to know ASAP before our window closes on adjustments that can be made to the order.

Even if you are not ready to pull the trigger yet, try to give us an idea of what you are looking for down the road so that we can plan accordingly with our extras that we order.

Delivery is expected in late June or July.



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Post by Powered By DC » Fri, 15 May 2009, 00:01

Both the Thunder Sky and Sky Energy LiFePO4 battery orders have been finalized.

95% of the Thunder Sky order is committed to buyers.
78% of the Sky Energy order is committed to buyers.

Here is the list of extras that we included in the orders. The estimated arrival date in the port of Seattle is late June or early July. If you are interested in any of these cells let me know ASAP so that I can arrange to have them Shipped diretly to your nearest Port.

Thunder Sky available cells:
101 of the 60 Ah cells
5 of the 100 Ah cells
44 of the 160 Ah cells

Sky Energy available cells:
140 of the 100 Ah cells
48 of the 180 Ah cells

The price available is $1.10 per Ah plus customs, container shipping, etc. Expect about 10% extra for those costs. There is also shipping from our location in the Seattle area to your location unless you are local to us. Delivery is expected in late June or July.

The SE 180 Ah cells are interesting because they have the same physical dimensions as the Thundersky 160 Ah cells but are more energy dense at 102 wh/kg and 159.48wh/l compared to 91.43wh/kg and 144.16 wh/l on the 160ah TS cells

The Sky Energy 100 Ah and the 180 Ah are the most energy dense large format LiFePO4 cells on the market that I am aware of.

If you have any questions, please contact:

Dave Kois
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Last edited by Powered By DC on Thu, 14 May 2009, 14:18, edited 1 time in total.

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Post by coulomb » Tue, 23 Jun 2009, 05:12

I finally found a name for the Sky Energy "magic sauce":

Aleees LFP NCO cathode material (nanococrystelline olivine)

Edit: See http://www.aleees.com/en/product/LFP-NCO.htm

Edit 2: But this is contended; see next 2 posts.

Edit 3: Arrgh! I was also confusing Blue Sky and Sky Energy (which make blue coloured cells). So whatever Sky Energy have, it's probably not this Aleees stuff. Or at least, there is nothing to indicate whether it is or it isn't.

From http://www.diyelectriccar.com/forums/sh ... post125627
Last edited by coulomb on Tue, 23 Jun 2009, 08:54, edited 1 time in total.
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Post by weber » Tue, 23 Jun 2009, 06:06

I don't believe it. I can't find anywhere that Sky Energy (China) or Aleees (Taiwan) claim that Sky Energy is using Alees cathode material.

The source of the claims seems to be
http://www.forsenusa.com/batteries.html
which some people think is not trustworthy. See
http://visforvoltage.org/forum/4683-fal ... -hub-motor
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Post by coulomb » Tue, 23 Jun 2009, 14:08

weber wrote: I don't believe it. I can't find anywhere that Sky Energy (China) or Aleees (Taiwan) claim that Sky Energy is using Alees cathode material.

The source of the claims seems to be
http://www.forsenusa.com/batteries.html
which some people think is not trustworthy. See
http://visforvoltage.org/forum/4683-fal ... -hub-motor


Ah, you mean the source (that web site) is not trustworthy, not the sauce (cathode material).

Ok, I agree that if this is the source of the link between Sky Energy and this cathode material, then it's highly suspect. Oh well.
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Post by Nevilleh » Tue, 23 Jun 2009, 14:09

I ordered a set of Sky Energy cells and just received the factory quality test report. Each cell is individually tested and serial numbered and they are matched within quite close parameters.
The report includes a table showing the performance of every cell.
eg, the first one in the table shows an internal resistance of .58 mOhms, a voltage of 3.309V and a capacity of 48 AH.
The internal resistance ranges from .51 mOhms to .66 mOhms, the spread of voltage is 3.304 to 3.310 and the capacity is 47 - 48 AH. (That's at 60% SOC)
I am looking forward to their arrival!

My intention is to put 3 cells in parallel to get 45 packs which will be placed in series to give a nominal 144v and 120 AH capacity. (I didn't use 120 AH cells as they are too tall to fit where I want to put them.)
Interesting that the cell capacity exceeds the 40AH spec by quite a margin, so if I use 47 AH as the pack capacity, 80% DOD still gives me a usable 37.6 AHs which is 16.25 kW-Hrs.
If I take the average internal res of about .58 mOhms, put 3 in parallel to get .20 mOhm and then 45 in series, the pack should have an internal res of about 9 mOhm which will give a voltage drop of 9v at 1000A discharge! If the pack voltage was 3.3 x 45 = 148.5 at no load, then its 139.5 at full load giving an output of 139.5 kW!
The voltage drop at 3C ie 360A discharge is only 3.24v.

These things appear to be much better than TS in both performance and price, but we won't really know until they "start work".

I will be using them to power my 1988 BMW with two ADC L91 motors and a LogiSystems controller.
Last edited by Nevilleh on Tue, 23 Jun 2009, 04:12, edited 1 time in total.

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Post by Gow864 » Tue, 23 Jun 2009, 16:29

Nelivveh What BMS will you be using for the Sky Energy cells?

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Post by coulomb » Tue, 23 Jun 2009, 19:00

When I posted a few messages back that I found a link between Sky Energy and Aleees cathode material, I was confusing "BlueSky SE" (whatever they are) and Sky Energy's SE cells. Hey, they both have "sky" in the name, and Sky Energy make cells that are a distinctive blue in colour. Plus, he said "BlueSky SE in 100 Ah form factor", which happens to be a size available from Sky Energy. Image

So I demand that there may, or may not, be a connection between Sky Energy and the Aleees cathode material. (With apologies to Douglas Adams).
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Post by Powered By DC » Wed, 24 Jun 2009, 03:13

I have been told by Sky Energy that they do indeed use the Materials from Aleese in the cathode otf their batteries. I have a document from them that shows that they are using the LFP-NCOTEC material in their cathodes but it doesnt actually mention Aleese. If anyone wants to see the document just email me or Skype me.

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Post by coulomb » Wed, 24 Jun 2009, 19:30

weber wrote: Apparently some Sky Energy factory photos here
http://www.evdl.org/archive/index.html# ... td23251023

Also some discharge curves that look mighty strange when they go below about 2.3 V. I don't think I'd be taking them down there, and if this is how they get their higher capacity figures I think it's a bit dodgy.

Sorry for the late reply. I think you might be thinking about the -20°C discharge test:
Image
(Edit: The above is from the EVDL archive that you linked to).

This is like a demonstration that things aren't too bad even at this extreme (for our climate) temperature. The TK cell that they compare against looks pretty strange too. So would I, at that temperature. Image
Last edited by coulomb on Wed, 24 Jun 2009, 09:31, edited 1 time in total.
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Post by Nevilleh » Thu, 25 Jun 2009, 13:18

Gow864 wrote: Nelivveh What BMS will you be using for the Sky Energy cells?

Thanks,
Gow.


I'm using my own BMS. I use an Atmel microcontroller to monitor each cell's voltage in blocks of four and also the temperature of that block. This is in conjunction with a shunt set to conduct at 3.65v and bypass the cell. The voltage monitor shuts the charger back to 2A when it detects any cell reaching 3.65v ie its shunt is conducting and also shuts down the charger when all cells reach 3.65v.
Under load, it generates an alarm should any cell drop to 2.5v. I figure it is better to allow the driver to make the decision about possibly damaging the cells due to low voltage rather than having the thing cut power in what could be a dangerous situation.
Being mostly software driven, I can program in any voltages I like.
I need one shunt pcb per cell and one MCU pcb per 4 cells plus a "master" unit (another Atmel micro) which has opto coupled comms to all the others and an LCD to show voltages.
The charger is a switch-mode unit putting out 162v (for my 45 cell pack) at 20A with two inputs: one to cut it back to 2A and one to shut it off.
I will add load current monitoring to the master unit when I get time so I can see how many AHs have been used.

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Post by weber » Thu, 25 Jun 2009, 15:14

Hi Nevilleh, Have you tested your BMS in a running EV yet?
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Post by Nevilleh » Thu, 25 Jun 2009, 16:28

weber wrote: Hi Nevilleh, Have you tested your BMS in a running EV yet?


I've built a smaller version and run it in my EVT scooter with 16 TS cells. I used 4.2v for the shunts in this case, because I believed the manufacturer's specification! I now think that 3.65v which is the ES spec would also be better for the TS cells. I haven't yet modified them for 3.65v (I did one only to check its operation). Also the charger is a lot smaller, 6A switching down to 2A.
2A is the most I can put through the shunt with the heatsink I used.
If I ever get time to get my car finished, I'll need the bigger version!

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Post by coulomb » Wed, 15 Jul 2009, 14:56

An update from Powered by DC:

http://www.nabble.com/forum/ViewPost.jt ... 1&framed=y

Sounds like there is another Sky Energy bulk purchase about to close.
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Post by Mesuge » Thu, 16 Jul 2009, 04:43

coulomb wrote:
weber wrote: Apparently some Sky Energy factory photos here
http://www.evdl.org/archive/index.html# ... td23251023

2. the cells chemistery are same as ferrous phosphate-LFP at surface look if you bought from different manufacturers, but these cells are completely different. Ours is the promotion ones, with higher capacity, higher energy density, longer cycle life etc. Even the performance is more than 10~30% than other's

Name                                           SE180Ah                          TS160Ah
Energy-Density                             100Wh/kg                                  90Wh/kg
Discharge Performance under -20℃ 85% rated capacity      60% rated capacity
Safety          Resist Compression of the shell is 0.35MPA     Resist Compression of the shell is 0.3MPA
        Opening pressure of Safety valve is 0.1MPA Opening pressure of Safety valve is over 0.1MPA. Possibility of explosion exists.
Cycles Attenuation @80%DOD 0.3C 100 cycles   <3%                           >8%


How shall we read it?
That after 1000cycles at shallow .3C discharges suddenly <30% of the capacity is gone, also provided the cells/pack are not abused during the charge/discharge/storage operation of the car at all (hard to achieve in reality)? On the other hand, good for them publishing the info at all, most of the manufs. have been obfuscating the "laboratory conditions" at which they rate their cycle life claims for ever, I'm still very suspicious about the longevity of <$1/Wh grade LiFePO4 cells anyway.

Color me unimpressed, I think that the lithium tech. at the moment (and per todays $/Wh) is limited to high milage drivers like *fleet clients, where the ~6yrs lifespan can be "justified" in completely abused car and amortized over >150K miles or more. However, the large format NiMH has proven slower degradation in >10yrs operation even for casual/individual drivers. If anything is certain about the future, it's the end of spendy days of new car replacement every ~3yrs for the middle class.

*also I hate to be on a cell phone lease like plan for batteries
as Renault-Nissan/Mitsu/PBP and others seem to be pushing, instead
of trizillionizing their batt. production capacity, exactly what they should be focusing on if they are serious about EVs for the longterm.

/rant off - sorry too much heat today
ImageCzech EV Club | blog, gallery, video | http://old.elektromobily.org

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