Group Buy: Dow Kokam LiPo Cells

[cassschr1]

Can I see some pics of the cell inter connect boards.
Also talk about balance wire connect points. Thank you

[LI-ghtcycle]

WOw, another great choice for our battery needs! Just when I thought I knew what I would be buying next!

Thank you so much for making these "unobtainium" cells available for us here at ES!

Gonna have to see which pouch cells (these or A123's) the best in my cargo pods based mainly on size.

Sounds like the 25 AH High Energy would be a good fit hmmmm.

[FFR Trikes]

Can I see some pics of the cell inter connect boards.
Also talk about balance wire connect points. Thank you

The cell interconnect boards are not yet available, we're just providing bare cells to folks who are doing direct tab-tab connections, or mechanical builds using clamping buss-bars at this point. Balance wires will connect just as they do as the Turnigy packs, with a connection at the most positive, and most negative point, as well as every interface between tabs. The 16Ah and 25Ah boards will basically be scaled up versions of these, to allow folks the option of manual offboard balancing, or a centralized BMS.

WOw, another great choice for our battery needs! Just when I thought I knew what I would be buying next!

Thank you so much for making these "unobtainium" cells available for us here at ES!

Gonna have to see which pouch cells (these or A123's) the best in my cargo pods based mainly on size.

Sounds like the 25 AH High Energy would be a good fit hmmmm.

The 25Ah HE cells are some of the most volumetrically efficient cells available, our finished 22.2V 25Ah pack will be roughly 9x9x1.5".

-Tommy

[countermeasure]

The cell interconnect boards are not yet available, we're just providing bare cells to folks who are doing direct tab-tab connections, or mechanical builds using clamping buss-bars at this point. Balance wires will connect just as they do as the Turnigy packs, with a connection at the most positive, and most negative point, as well as every interface between tabs. The 16Ah and 25Ah boards will basically be scaled up versions of these, to allow folks the option of manual offboard balancing, or a centralized BMS.

Hey Tommy,
I am interested in the clamping buss-bar. Are these parts from DowKokam? Or do you have to make your own clamping bars?

I want to build 1S3P, 25 Ah. Is there MSDS sheet available for the 25 Ah?

How do you solder to the battery tabs? Is it aluminum like A123 20Ah?

Thanks.

[cassschr1]

Can you show me a picture of a clamping bus barPLEASE How can I buy em, if I can't assemble the cells. Cass

[Whiplash]

I may have missed it, but do these cells need to be "clamped" for best performance, or is it not a concern??

[amberwolf]

There are a number of different clamping bar designs here on ES that you can make (I'm not aware of any commercially available ones yet, except for the ones EIG seems to be using with their own mounting hardware for their own cells, based on the pics that have been posted of such packs). Most of these are beign used on 15/20Ah A123 pouch cells, and are in threads about the A123 cells, some of them are older threads (more than a year) and some more recent (a few months, I think).

[FFR Trikes]

I am interested in the clamping buss-bar. Are these parts from DowKokam? Or do you have to make your own clamping bars?

I want to build 1S3P, 25 Ah. Is there MSDS sheet available for the 25 Ah?

How do you solder to the battery tabs? Is it aluminum like A123 20Ah?

Thanks.

Can you show me a picture of a clamping bus barPLEASE How can I buy em, if I can't assemble the cells. Cass

The manufacturing of the clamping buss-bar pieces is up to you guys, they're relatively simple by design. Here's a great example from the folks at Plasma Boy Racing:


Obviously, they're handling a ton more amperage, so the copper or aluminum bars don't need to be nearly as thick for these applications. There's a lot more photos of their setup here: http://photos.plasmaboyracing.com/LiPol-Module?page=1

Do you mean 12S3P? What total pack voltage and Ah are you shooting for? The positive tabs are aluminum, the negative tabs are nickel. They can be soldered directly to one another with a standard high-heat iron, if you don't want to do the assembly mechanically.

I may have missed it, but do these cells need to be "clamped" for best performance, or is it not a concern??

Whip,

Do you mean as far as tab assembly goes? Or are you talking about keeping the cell's walls under pressure? They will perform almost identically whether assembled with solder, or mechanically. Some LiPo cells perform marginally better if the cell stack is under slight pressure, a simple wrap of heatshrink, or a similar binding wrap will do the trick.

[cassschr1]

I thought of a way to clamp them. How high do the tabs stick above the cells. ALSO how thick are the tabs....in thousandths.

[FFR Trikes]

Hey Cass,

Tabs are 1.25" tall, 0.01" thick on the 25Ah cell.



The tech sheet for the 25Ah cell is attached. Thanks

-Tommy

[sangesf]

Can you give us cycle life for the majority of these cells at 2C and up?

I keep seeing 1C and .5C charge and discharge cycle life, really interested in the higher C-rate cycle life (to 80% of capacity left).

[FFR Trikes]

Can you give us cycle life for the majority of these cells at 2C and up?

I keep seeing 1C and .5C charge and discharge cycle life, really interested in the higher C-rate cycle life (to 80% of capacity left).

I haven't been able to get a hold of that info. The closest I can get is 1C/1C. Here's the specs for the 31Ah HP:



-Tommy

[spkpn]

Hey FFR trikes,

thanks so much for making these cells available. Unfortunately (well ok, price was great and cells look good, so unfortunaltely might be the wrong term ) I just bought a batch of a123s so I dont need cells right now but if Ill need more, I would be happy to buy from a company that actually is willing to sell their product to us!

[countermeasure]

Thanks for the info on the tabs.

What are the safety design parameters? Has the cells passed EUCAR or SAE destructive testing?

[Warren]

Brain Richardson has been running 32, Kokam, 100 Ah cells, in his Norton, since 2009, racing, and road riding. He has worked through two frames, three fairings, and two motors, but the same pack. Two cells were physically damaged, in a wreck, but the pack is still going strong, I believe. He is not a techie, but I suspect he would be glad to tell you his experience with them. He won't be hanging out typing on this, or any other site. He is pretty quiet, and focused.

http://www.facebook.com/photo.php?fbid= ... =1&theater

http://motoelectra.com/

[FFR Trikes]

Hey FFR trikes,

thanks so much for making these cells available. Unfortunately (well ok, price was great and cells look good, so unfortunaltely might be the wrong term ) I just bought a batch of a123s so I dont need cells right now but if Ill need more, I would be happy to buy from a company that actually is willing to sell their product to us!

Sounds great!

Thanks for the info on the tabs.

What are the safety design parameters? Has the cells passed EUCAR or SAE destructive testing?

Brain Richardson has been running 32, Kokam, 100 Ah cells, in his Norton, since 2009, racing, and road riding. He has worked through two frames, three fairings, and two motors, but the same pack. Two cells were physically damaged, in a wreck, but the pack is still going strong, I believe. He is not a techie, but I suspect he would be glad to tell you his experience with them. He won't be hanging out typing on this, or any other site. He is pretty quiet, and focused.

http://www.facebook.com/photo.php?fbid= ... =1&theater

http://motoelectra.com/

Very cool!

-Tommy

[FFR Trikes]

All orders must be confirmed and paid for by noon on Friday!!

Update: please note that $1/watt-hour pricing is only available on cells 16Ah and larger!!

Here's the updated stock status from Dow Kokam as of this morning.


8Ah HP (SLPB75106100): 8-10 weeks $49.82
13Ah HP (SLPB6205130h): 8-10 weeks $67.33
16Ah HP (SLPB78205130H): In Stock $59.20
25Ah HE (SLPB60216216): In Stock $92.50
31Ah HP (SLPB78216216H) In Stock $114.70
100Ah HP (SLPB80460330): In Stock $370
200Ah HE (SLPB160460330H): 13-15 weeks $740

Here's the status on the packs we plan to build:
22.2V 6S 8Ah High Power-Uncertain due to price change
22.2V 6S 13Ah High Power-Uncertain due to price change
22.2V 6S 16Ah High Power- Definitely building
22.2V 6S 25Ah High Energy- Definitely building
These packs can be connected in series to meet your desired voltage.

If you'd like us to build you a pack for you, you must order the cells that your pack will require. Each pack will require 6 cells.

These packs will be built just like the Turnigy 6S packs are, with JST-XH leads so they can be balanced manually, or with a BMS.

Please confirm your order via PM.

Thank you!
Tommy

[FFR Trikes]

I just wanted to confirm with everyone that we will be building the following packs:

6S 22.2V 16Ah High Power
6S 22.2V 25Ah High Energy
6S 22.2V 31Ah High Power (note: there are only 66 cells left in stock at this point)

These can be connected in series for 44.4V, 66.6V, 88.8V, etc.

At this point, we will not be building the following packs unless significant interest is shown within the next 12 hours:

6S 22.2V 8Ah High Power
6S 22.2V 13Ah High Power

Pack assembly fee is $100 per 6S pack, if you'd like us to assemble your pack for you. Average shipping cost has ranged from $40-100 (because of FedEx's battery shipping surcharge) in the lower 48 so far, but PM me for a specific shipping quote.

Remember, all orders must be confirmed and paid for by noon tomorrow!

Thanks!
Tommy

[nachty]

Could someone please upload the datasheet from the 53 Ah High energy cell?

Thx alot

[hillzofvalp]

WHere does one get Kokam cells these days.. is there another group buy?

[recumpence]

FFR stocks them. The group buy may be finished, but they still sell them.

Matt