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[Truth][Dev info] Do You Know What's in Your Battery -[Pics] Current Protection Chips

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willy900wonka
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(Last edited by willy900wonka; 14th January 2011 at 06:57 PM.) Reason: Added testing link.
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Default [Truth][Dev info] Do You Know What's in Your Battery -[Pics] Current Protection Chips

Kernel Devs, here's what I found, with pictures to document it.
Li-ion batteries are protected by current limiter chips. SBC kernels cannot exceed safe charging limits because the chips preclude ( stop) it. At the end of the post is a reference to the chip which controls the amperage and voltage, to and from the battery.

I decided to look inside one of my extended $10 3500ma EVO batteries, in order to see how SBC kernels could impact the battery.

I took a series of pictures. Most were 10x and the chip number was 60x. Please be sure to check them.





VV - The four familiar contact pads for the battery.


VV - The picture (at 10x) below is of the chip which controls the operation of the battery.
It is surrounded by the red tape.


VV- The numbers on the controller chip are readable at 60x. Note
it says 8205A, and a mfg (date) code.


What I found was that a 8205 chip is used to provide protection and prevent over charging and over-discharging. Here is a quote from a google search.

Since the batteries are hardware protected, SBC kernels cannot overule and exceed the protection.

Here is a sequel to this thread:http://forum.xda-developers.com/showthread.php?t=913401
It is a test of the battery protection circuit. The concept is one of standard electrons. No magical or invisible electrons allowed. If an electron is added it gets accounted for in any of the possible ways. Usually it's an increase in voltage / heat of the battery.
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CheesyNutz
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Good info thx for taking the time and gather this

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mattykinsx
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I guess my question is... if all this is true... why are we having multiple reports from multiple different people on multiple forums claiming failure with these kernels?


Also, wasn't it shown that the different Evo hardware versions came with different batteries?
So couldn't it be true that these "protection chips" aren't the same across the board?
 
willy900wonka
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Let me explain to you how I came to taking apart my battery.
It might shed some light on your question.

Any time I get a new battery, I always connect it directly to a 6v 2amp charger, with a volt meter across the pos. and neg. terminals.
Here's what I have found: All batteries charge to about 4.33v-4.38v; until they automatically disconnect from the charger ( the voltage goes to 7.2 v ). Judging from this I deduced that all batteries which I tested, stock, 1800ma, 2600ma, and 3500ma all have some hardware protection built in.

I can only guess that maybe some batteries have bad or out of spec. chips and circuits - faulty.



Quote:
Originally Posted by mattykinsx View Post
I guess my question is... if all this is true... why are we having multiple reports from multiple different people on multiple forums claiming failure with these kernels?


Also, wasn't it shown that the different Evo hardware versions came with different batteries?
So couldn't it be true that these "protection chips" aren't the same across the board?
 
housry23
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Good info here. Thanks for taking the time to explore and test these things out. I have been suspecting that it was the battery that failed and not the kernel on these cases of screwed up batteries, Imagine how many people are using these SBC kernels and only 6 failures. I wonder how many battery failures happened that were not reported because no one was paranoid about this SBC kernel thing and just thought to themselves, "hmmm...I got a bad battery" and took it into Sprint and got it replaced. I am suspecting that most of the battery failures were not the stock battery, but a cheap $10 ebay battery which I use by the way. By using this cheap battery I have accepted the fact that it may fail on me and I may have to buy another $10 battery. I keep 2 on hand plus my original battery anyway, just in case. Thanks for you research willy900wonka. I am not saying that this research proves anything and I know this may turn into a flaming war. All I am saying is I don't think the kernel caused these failures, but a bad battery chip inside the battery as the OP stated.
 
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Quote:
Originally Posted by mattykinsx View Post
I guess my question is... if all this is true... why are we having multiple reports from multiple different people on multiple forums claiming failure with these kernels?


Also, wasn't it shown that the different Evo hardware versions came with different batteries?
So couldn't it be true that these "protection chips" aren't the same across the board?
kill them softly... and slowly. These chips are present in all li-ion batteries but can only do so much
 
swatspyder
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http://batteryuniversity.com/index.p..._ion_batteries

No trickle charge is applied because lithium-ion is unable to absorb overcharge. A continuous trickle charge above 4.05V/cell would causes plating of metallic lithium that could lead to instabilities and compromise safety. Instead, a brief topping charge is provided to compensate for the small self-discharge the battery and its protective circuit consume. Depending on the battery, a topping charge may be repeated once every 20 days. Typically, the charge kicks in when the open terminal voltage drops to 4.05V/cell and turns off at a high 4.20V/cell.

What happens if a battery is inadvertently overcharged? lithium-ion is designed to operate safely within their normal operating voltage but become unstable if charged to higher voltages. When charging above 4.30V, the cell causes plating of metallic lithium on the anode; the cathode material becomes an oxidizing agent, loses stability and releases oxygen. Overcharging causes the cell to heat up. If left unattended, the cell could vent with flame.
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HeckNoTechnO
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Quote:
Originally Posted by mattykinsx View Post
I guess my question is... if all this is true... why are we having multiple reports from multiple different people on multiple forums claiming failure with these kernels?


Also, wasn't it shown that the different Evo hardware versions came with different batteries?
So couldn't it be true that these "protection chips" aren't the same across the board?

You say mutiple failures due to what? There have been 6 failures reported. Are they ALL true? Six out of how many EVO's on the market? Lets keep this in check!
HTC EVO OG-Retired
HTC EVO 3D-Passed to Son
HTC EVO 4G LTE-Passed to wife
Nexus 7 (1st gen)
LG G2

 
swatspyder
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Quote:
Originally Posted by mikebeam View Post
You say mutiple failures due to what? There have been 6 failures reported. Are they ALL true? Six out of how many EVO's on the market? Lets keep this in check!
http://forum.xda-developers.com/showthread.php?t=906230
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Quote:
Originally Posted by swatspyder View Post
http://batteryuniversity.com/index.p..._ion_batteries

No trickle charge is applied because lithium-ion is unable to absorb overcharge. A continuous trickle charge above 4.05V/cell would causes plating of metallic lithium that could lead to instabilities and compromise safety. Instead, a brief topping charge is provided to compensate for the small self-discharge the battery and its protective circuit consume. Depending on the battery, a topping charge may be repeated once every 20 days. Typically, the charge kicks in when the open terminal voltage drops to 4.05V/cell and turns off at a high 4.20V/cell.

What happens if a battery is inadvertently overcharged? lithium-ion is designed to operate safely within their normal operating voltage but become unstable if charged to higher voltages. When charging above 4.30V, the cell causes plating of metallic lithium on the anode; the cathode material becomes an oxidizing agent, loses stability and releases oxygen. Overcharging causes the cell to heat up. If left unattended, the cell could vent with flame.

Has anyone reported their battery catching on fire or are people just reporting batteries dying?
Hello, My name is Andrew and I am a Flashaholic

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!truth, 8205a, battery protection chips, big non-bang theory, moot, safe guards, sbc, wrong
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