# hi What is real a123 20a pouch's C rate?



## Genius Pooh (Dec 23, 2011)

hi What is real a123 20a pouch's C rate?

They keep change their spec..

I will use battery just for condencer 

It's extremely important C rate I will use supercapacitor and battery pack..

My aim is 500~ 1000 hp for 5-10 sec.. battery and capacitor must endure this situation more than 2-3 years... Is it possible?

smaller battery is good for price.. most electronic will obtain by selfgenerator using CNG( natural gas it's extremly cheap in here)

And What is explosion condition?

I hear lifeo is very safe... I suprised volt tester's explosion.. 

How can I prevent it?


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## Ziggythewiz (May 16, 2010)

A123s do a max of 20C

Supercapacitors really aren't that super.

What explosion condition are you talking about? LiFePo4 does not explode. Most batteries don't explode, actually. The only way for them to explode is to create explosive gases in a confined space, then ignite. Many batteries burn under bad conditions, but that's just burning, not exploding. Nearly everything burns under the right conditions. Don't create those conditions.

Don't overcharge. Don't undercharge. Don't place in proximity to high heat. Don't make a short, or leave in presence of leaking fluids.


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## rwaudio (May 22, 2008)

Ziggythewiz said:


> A123s do a max of 20C
> 
> Supercapacitors really aren't that super.


Agreed! 



Ziggythewiz said:


> What explosion condition are you talking about? LiFePo4 does not explode. Most batteries don't explode, actually. The only way for them to explode is to create explosive gases in a confined space, then ignite. Many batteries burn under bad conditions, but that's just burning, not exploding. Nearly everything burns under the right conditions. Don't create those conditions.


Probably the GM research center that "blew up" while testing an A123 cell. There is no confirmation this is a normal production A123 cell that we could get our hands on, or how far past the limits they were testing it.



Ziggythewiz said:


> Don't overcharge. Don't undercharge.


I believe you mean Don't Overcharge. Don't *OVER DISCHARGE*.
As undercharging is completely safe and can be desirable for long cycle life.


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## Ziggythewiz (May 16, 2010)

Yes, thanks. Just play within the specs and you're fine.


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## Genius Pooh (Dec 23, 2011)

Ziggythewiz said:


> A123s do a max of 20C
> 
> Supercapacitors really aren't that super.
> 
> ...


Oh I see bad normal li sell explode in my front... It's just 2/3 size of 18650 quiet hot ... some plastic is melt down... I think it's not so strong explosion but heat is quiet high... Just I think...

Hm.... A123's data sheet say norminal discharge of pouch.. is 1200w 

so they tell nominal rate is 18c .. Am I right??

So I confused Ebay seller said nominal is 3c max is 10c....ah... It's so confusing...

If a123 system answer phone or e mail this problem will be easily solved


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## Genius Pooh (Dec 23, 2011)

rwaudio said:


> Agreed!
> 
> 
> 
> ...


 
Thank you for kind answer ... We don't have enough power testing limit of A123 system... and even they don't answer me... we need about 10 module the biggest one...

GM's case is very shocking I heard lifo is never explode... I really wonder what happend... 

And I wrote above A123's spec is very confuse I wonder everybody in this site well doing with a123's pouch... I saw everybody to use it...


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## Ziggythewiz (May 16, 2010)

A123 does not sell to DIYers. You can't contact them and say qreqwrwer on ebay sold me your cells, what are the specs on them?

There are some people here using A123 pouches, certainly not everybody. There are much fewer due to the complexity of assembling a pack. I don't know if there's anyone even running a full A123 pack in a street car. I know people are building them, but not sure if any are complete.


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## rwaudio (May 22, 2008)

Mavizen is the only authorized distributor that I'm aware of and they quote the following:
_Maximal current discharge rate: 300 cont, 750 peak_

Which is 15C continuous and 37.5C peak


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## Jozzer (Mar 29, 2009)

You will find for anything above 8-10C continuous you will need serious cooling and a very well built pack with decent interconnects that can take heat from the tabs..


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## Genius Pooh (Dec 23, 2011)

Jozzer said:


> You will find for anything above 8-10C continuous you will need serious cooling and a very well built pack with decent interconnects that can take heat from the tabs..


Thank you I will try to use A123's module..42p3s ..

It will need another cool solution ?

Or I must reassemble it??


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## Genius Pooh (Dec 23, 2011)

rwaudio said:


> Mavizen is the only authorized distributor that I'm aware of and they quote the following:
> _Maximal current discharge rate: 300 cont, 750 peak_
> 
> Which is 15C continuous and 37.5C peak


Thank you A123 and Ebay seller and distributer all said it differently..

hahaha... I must use It under as 15c peak at 60 secound


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## LithiumaniacsEVRacing (Oct 9, 2010)

rwaudio said:


> Mavizen is the only authorized distributor that I'm aware of and they quote the following:
> _Maximal current discharge rate: 300 cont, 750 peak_
> 
> Which is 15C continuous and 37.5C peak


I spoke with a tech at Mavizan, he claims they cannot push 750amps. I asked why does your website post this info, his response was long and very loaded with BS.


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## Genius Pooh (Dec 23, 2011)

LithiumaniacsEVRacing said:


> I spoke with a tech at Mavizan, he claims they cannot push 750amps. I asked why does your website post this info, his response was long and very loaded with BS.


 
Oh So what is peak ??? and what is real nominal...

Battery lifetime is big issue 

I doubt real nominal is 15c....hmmm

And what is this is mean?"very loaded with BS." sorry I'm bad english 

And Peak is exactly how much time?? 60 sec?

And they sell 42s3p module? and price??

my email is [email protected]..

I really doubt about Victower's module is geunine one..

I can't trust chinese product ...


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## PStechPaul (May 1, 2012)

Here are the specs on the website:
http://www.mavizen.com/A123.html










That seems to be confusing, misleading, and incorrect. The 300A maximum might be what is sometimes known as cold cranking amps (CCA) which is pretty much the point of maximum possible power output at about 1/2 nominal voltage. At 300 amps the 2mOhm ESR will cause a drop of 0.6 volts, and 600 amps will drop 1.2V or about half the cell voltage. But at 300 amps the ESR will dissipate 180 watts and at 600 amps it will be 720 watts. It would not take long for the cell to melt, self-destruct, and probably explode. 

I think the maximal discharge rates should be considered percentages, so 300% or 60 amps continuous (7.2W), and 750% or 150 amps peak (45W). You need to consider these internal losses when you try to pull lots of extra power from the cells. Eventually you just heat up the cells more and the motor will possibly pull more torque but power will drop and it will go slower, and possibly stall. For smaller overloads you might be able to run for 10 seconds to a minute, and an external temperature sensor on the cells might give you an indication of the overload. But at higher multiples of C the inside of the cell will reach critical temperatures long before the case gets hot, and it will disintegrate violently.


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## IamIan (Mar 29, 2009)

My 2 Bits ... I suspect some of the confusion is from using different test conditions for different specs.

For example in the attached A123 spec sheet snap shot ... the graph for the 10 second pulse power rates shows they are on discharge pulled down to 1.6V in order to get the indicated power at the indicated SoC.

So at 10% SoC they discharge the cell hard enough to pull it down to 1.6V in order to pull out ~1,100 Watts of power for 10 seconds ... that means they are pulling 1,100 / 1.6 = ~687 Amps.

And at 90% SoC when they discharge the cell hard enough to pull it down to 1.6V in order to pull out ~1,450 Watts of power ... that means they are pulling 1,450 / 1.6 = ~906 Amps.

These power rates look mighty impressive ... but they are pulling down the cell really hard in order to get those 10 second power rates... these are not the same test conditions shown for other specs ... continuous discharge rate tests won't push this hard ... cycle life capacity tests won't push this hard ... etc.

If you pull the cells hard enough to get down to 1.6V on discharge and push them hard enough to get up to 3.8V on charge ... you might get the indicated amps ... but it will beat the hell out of the cells ... and it will generate a good bit of heat.

So in short ... keep in mind the test conditions that gave that one specific spec ... do not expect to get all the specs listed under the same test conditions ... If you plan to use or need the cell to perform at or near one specific spec , careful considerations must be made during the planning and construction of the system.


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## LithiumaniacsEVRacing (Oct 9, 2010)

PStechPaul said:


> Here are the specs on the website:
> http://www.mavizen.com/A123.html
> 
> 
> ...


Yes, these numbers are misleading. When I called Mavizan, they explained the numbers and these cells CANNOT produce 750 amps, much lower. Call them, they will explain.


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## Genius Pooh (Dec 23, 2011)

LithiumaniacsEVRacing said:


> Yes, these numbers are misleading. When I called Mavizan, they explained the numbers and these cells CANNOT produce 750 amps, much lower. Call them, they will explain.


Ok I must call them..I think It's best way


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## kishor5466 (May 15, 2012)

rwaudio said:


> Mavizen is the only authorized distributor that I'm aware of and they quote the following:
> _Maximal current discharge rate: 300 cont, 750 peak_
> 
> Which is 15C continuous and 37.5C peak


So who is the battery manufacturer and from whom can we get those batteries ??


provide with the details please


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## major (Apr 4, 2008)

kishor5466 said:


> So who is the battery manufacturer and from whom can we get those batteries ??
> 
> 
> provide with the details please


Been done.



PStechPaul said:


> Here are the specs on the website:
> http://www.mavizen.com/A123.html


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