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#11 (permalink)      12/9/2014 1:53:12 PM US Central   quote/reply + tips
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mccmick
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for 1 second bursts, you really can take authentic VTC5 cells to around 60A ;-)


I've seen various figures for sony batteries. The problem is that nobody has published the rest time or pauses between bursts. My guess is that it is dependant on internal temperature and also to give the chemistry time to stabilise again.

When you are pulsing above max continuous discharge be aware that you are dramatically shortening their life span. If you have to do it then best to do it on new batteries rather than old.

When I was younger I used to go skinny dipping. Now, all I can do is chunky dunking.
#12 (permalink)      12/9/2014 2:10:00 PM US Central   quote/reply + tips
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johnny_469
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mccmick wrote:


I've seen various figures for sony batteries. The problem is that nobody has published the rest time or pauses between bursts. My guess is that it is dependant on internal temperature and also to give the chemistry time to stabilise again.

When you are pulsing above max continuous discharge be aware that you are dramatically shortening their life span. If you have to do it then best to do it on new batteries rather than old.



Absolutely right ;-)

Monitoring the heat produced by the cell itself is the best and really only way to actively diagnose their health in use, especially at low resistance. When you get the cells above 105-115 deg F, you start to degrade their internal components.

If you notice a drop in capacity, extra volt sag, or heat coming form the cell on a build that didn't heat them up before, it's time to stop abusing them, and likely even bin them.


Edited on 12/9/2014 at 2:10 PM. Reason:
Woah, mama!
#13 (permalink)      12/9/2014 2:19:11 PM US Central   quote/reply + tips
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mccmick
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If you notice a drop in capacity, extra volt sag, or heat coming form the cell on a build that didn't heat them up before, it's time to stop abusing them, and likely even bin them.


Alternatively measure the battery's internal resistance. As the resistance rises with age and abuse then its capability to deliver max amps discharge decreases. Hence I said earlier that if you are going above max levels then it is safest on newer batteries with low internal resistance.

When I was younger I used to go skinny dipping. Now, all I can do is chunky dunking.
#14 (permalink)      12/9/2014 2:28:19 PM US Central   quote/reply + tips
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johnny_469
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I would like to add, that if you do go above the continuous limit of your cells, make sure that for safety, you don't activate the circuit for longer than you let it rest between puffs.

We don't know much about the required rest period in pulsed applications, so better safe than sorry In my opinion here, make sure you give the cells ample time to recover after firing. I recommend at least an equal amount of time to how long you fired it, and, of course, longer is better in that case too.
Woah, mama!
#15 (permalink)      12/9/2014 2:36:03 PM US Central   quote/reply + tips
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mccmick
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One other thing you should be aware of. The batteries in image #2 have a date code of VK03 as far as I can make out. This translates to manufacturing date of 3rd November 2013.
When I was younger I used to go skinny dipping. Now, all I can do is chunky dunking.
#16 (permalink)      12/9/2014 3:08:36 PM US Central   quote/reply + tips
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johnny_469
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mccmick wrote:

One other thing you should be aware of. The batteries in image #2 have a date code of VK03 as far as I can make out. This translates to manufacturing date of 3rd November 2013.


I'd imagine that all the Nov 2013 manufactured cells have long since been sold ;-) They can't keep them on the shelves long enough to get that old... lol

Woah, mama!
#17 (permalink)      12/9/2014 3:18:04 PM US Central   quote/reply + tips
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mccmick
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They can't keep them on the shelves long enough to get that old... lol

VK03:
V = year (a = 1992, b= 1993, ..... v = 2013 etc)
K = month (a = jan, b= feb ... etc)
03 = day of month

If I was getting these batteries I would hope that they were using a stock image rather than an actual image but who knows.

A 1 year old lithium can have degrade between 20 and 60 percent depending on what temperature it has stored at and at what charge.

Most optimistic is 20% which mean you are buying a 1680 mah battery with 24A max continuous discharge.

At 40% you are buying a 1260 mah battery with 18A max continuous discharge.

If I was buying I would be putting in a pre-sale ticket to clarify lol

When I was younger I used to go skinny dipping. Now, all I can do is chunky dunking.