wb9k
10 kW
bigmoose said:
Wouldn't it ultimately be the same as the area of the thick part of whatever cells you're using?
A123 20AHr Pouch Cell Battery Build & Info Thread
- Thread starter bigmoose
- Start date
Wouldn't it ultimately be the same as the area of the thick part of whatever cells you're using?
999zip999
100 TW
If you are just putting persure on the flat's of the cells. Will it not just blow out on the sides.
wb9k
10 kW
If you abuse them, yes. So will any other battery, just via a different escape route. But if you don't compress them, they'll swell up even without abuse.
bigmoose
1 MW
wb9k said:
Not quite and the reason for the clarification. The flat area of a cell is abut 57 square inches. Now say we have a one inch diameter air cylinder attached to a ram plate that is the size of the cell. The area of that ram piston is 3.14/4* dia^2 or 0.78 sq inches of piston area. Force exerted is psi * piston area in sq in. Pressurize that piston at 10 psi and it exerts 7.8 lbs of Force upon our 57 square inch ram. That would only result in 7.8/57 or 0.14 lb/sq inch on the pouch. Sort of a significant difference in preload.
Now if it might be a 2 inch piston pressurized to 10 psi. That would give a force of F=(10psi)*3.14/4*2^2 =31.4 lb force against the cells or a cell loading of 0.55lb. Interesting number... engineers like round numbers like 0.5 or 1.0...
yokneamcity
1 W
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- May 9, 2011
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Hi guys !999zip999 said:
I'm doing a battery for Vectrix electric scooters from A123 prismatic packages.
The battery boxes I did as it did in the OSN company. box in a box.
Matreial for the box is pertenaks.
The ends of the box are connected by adhesive tape.
Lego set for connection, I also bought from the OSN company.
BMS-modules is mini-BMS. The new version.
Do not just find another BMS for 42S configuration .
I will be glad to answer your questions about my project.
Attachments
yokneamcity
1 W
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Yes. Are new version of Mini-BMS modules.cwah said:
cwah
100 MW
Thanks for your answer. Do you know where we can buy these Mini-BMS?
yokneamcity
1 W
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of course !cwah said:
http://minibms.mybigcommerce.com/
cwah
100 MW
Thanks, looking into it. It seems it's for lifepo4 only?
I decided to stop A123 20AH since your feedback from OSN power. Going back to old lipo
I decided to stop A123 20AH since your feedback from OSN power. Going back to old lipo
yokneamcity
1 W
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maybe my packages swelled because I don't pressed them.cwah said:Thanks, looking into it. It seems it's for lifepo4 only?
I decided to stop A123 20AH since your feedback from OSN power. Going back to old lipo
cwah
100 MW
Are you going to keep buying more A123 20AH?
You'll need a lot of spare :lol:
Make me think that lipo probably also need compression
You'll need a lot of spare :lol:
Make me think that lipo probably also need compression
999zip999
100 TW
What A123 cells ?
A123 for 32usd full tabs
half tab korean 22usd.
half tab USA ??
A123 for 32usd full tabs
half tab korean 22usd.
half tab USA ??
etriker
100 kW
999zip999 said:
Real ones new from A123 here, coming soon ?
http://www.buya123batteries.com/AMP20M1HD_A_Lithium_Ion_Prismatic_Pouch_p/amp20m1hd-a.htm
agniusm
1 MW
I would like to ask wb9k as the insider in A123, what would be a prognosed price on legit cells to us hobbyists? At least rough estimate
jonescg
100 MW
Agnius, try Mavizen. Apparently they are still stocking the legit A123 cells.
agniusm
1 MW
For 99 a pop? No, thank you. The price is out of the sky, cant justifyjonescg said:
etriker
100 kW
agniusm said:
And some A123 stickers to put on my bike and some A123 baseball caps and t shirts !
agniusm
1 MW
... with every purchase: 12S - sticker, 16S - a cap, 24S t-shirtetriker said:agniusm said:
And some A123 stickers to put on my bike and some A123 baseball caps and t shirts !
aug brought up an interesting question- for w9- i do wonder what the real cost is for a 20ah cell
on another note it seems like evdm might actually be able to actually source these (that would be interesting).....70 per cell is better than mavi's rip off price who knows there might even be a discount for quantity- for now though i am on the enerdel wagon- the cells are at a fair price and you get a professionally built module with it
on another note it seems like evdm might actually be able to actually source these (that would be interesting).....70 per cell is better than mavi's rip off price who knows there might even be a discount for quantity- for now though i am on the enerdel wagon- the cells are at a fair price and you get a professionally built module with it
cwah
100 MW
yokneamcity said:
Do you stress the cells at high C rate during discharge? Because at low power the cells shouldn't get hot or inflate a lot.
wb9k
10 kW
cwah said:
Not if they're compressed properly. No abuse or high current is needed to puff an uncompressed cell.
yokneamcity
1 W
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Continue current is 40-60amp
Peack current is 100amp
for 42S-2P config.
Peack current is 100amp
for 42S-2P config.
cwah
100 MW
Does this rule also apply to all cells without case? lipo from hobby king never compress their cells:
http://www.hobbyking.com/hobbyking/store/__21387__ZIPPY_Compact_5800mAh_10S_25C_Lipo_Pack.html
http://www.hobbyking.com/hobbyking/store/__21387__ZIPPY_Compact_5800mAh_10S_25C_Lipo_Pack.html
ambroseliao
100 kW
Isn't that shrink wrap on that pack? Doesn't that count?
megacycle
100 kW
cwah said:
Seen this happen to a very small, wrapped, heli lipo pack, i accidently abused.
Wrapping did'nt restrict it puffing on one of the outer cells of the three cells.
Though it went back in shape and appears to still works ok.
Hav'nt tested it only cellog.