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

willy900wonka · Jan 9, 2011

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.

S-8205A/B Series Applications-Optimized-Battery-Protection Circuits.
All contained voltage detectors are of high precision between 15mV and 100mV depending on the function. Overcharge detection voltage is 3.55V..4.4V with 25mV accuracy. Overdischarge detection voltage is 2.0V..3.2V with 80mV accuracy. Discharge overcurrent detection voltage is 0.05V..0.3V with 15mV accuracy and charge overcurrent detection voltage is -0.05V..-0.3V with 30mV accuracy. The detection voltage in short circuit case is 0.5V..1.0V with 100mV accuracy.

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

Here is a sequel to this thread:http://xdaforums.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.

CheesyNutz · Jan 9, 2011

Good info thx for taking the time and gather this

from my phone duh

mattykinsx · Jan 9, 2011

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 · Jan 9, 2011

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.

mattykinsx said:
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 · Jan 9, 2011

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.

xHausx · Jan 9, 2011

mattykinsx said:
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 · Jan 9, 2011

http://batteryuniversity.com/index.php/learn/article/charging_lithium_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.

HeckNoTechnO · Jan 9, 2011

mattykinsx said:
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!

swatspyder · Jan 9, 2011

mikebeam said:
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://xdaforums.com/showthread.php?t=906230

Novarider · Jan 9, 2011

swatspyder said:
http://batteryuniversity.com/index.php/learn/article/charging_lithium_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?

drrtydisko · Jan 9, 2011

Very useful information thanks.

Sent from my PC36100 using XDA App

Shinzul · Jan 9, 2011

So basically, there is a hardware failsafe designed to prevent these batteries from exploding... so what happens when one of the hardware failsafes fails? How many evos have people reported as faulty? Quite a few... we have seen bad screens, bad cases, bad buttons, etc. Who's to say that there haven't also been bad 8205a chips too? Maybe HTC even *gasp* KNEW that these chips were prone to failure and introduced the 90% charge in anticipation of this?

No one can be 100% sure if these "SBC" kernels are to blame. Correlation does not imply causation. But that said, I think that if you understand enough about the electrical engineering involved, you will realize that gaining 10% more battery life isn't worth the risk of a fire hazard and a destroyed phone. It's easy to say "hey, new kernel, cool!" But then if something catastrophic happens all of a sudden it's "oh crap why did I do that?!"

Of course you can do whatever you choose with your phone, it is your choice. I personally am not going to screw around with introducing potential instability to a piece of hardware that already has enough stability problems as it is.

mitchellvii · Jan 9, 2011

mattykinsx said:
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?

Well, you are making the assumption that these batteries would not have failed if not for SBC. It is a post hoc argument (after this therefore because of this). Considering how many people are using SBC and the number of reported failures are tiny compared to the whole, I think it would be safe to say that there is no statistical evidence that SBC is causing the failures. If .01% of SBC users are experiencing failure and 99.99% are not, one has to question if there is a correlation.

If SBC is the problem, why are the vast majority of users experiencing no malfunction whatsoever?

BuddaBelly · Jan 9, 2011

Bottom line is we are messing with something that it took a team of engineers to figure out in the first place. My kids use my phone all the time and I'm just not willing to take a chance however small that might be.

Sent from my PC36100 using XDA App

mitchellvii · Jan 9, 2011

BuddaBelly said:
Bottom line is we are messing with something that it took a team of engineers to figure out in the first place. My kids use my phone all the time and I'm just not willing to take a chance however small that might be.

Sent from my PC36100 using XDA App

Yes, I think this is the most logical way to approach things. Although it is hard to prove that SBC is causing these failures based upon the small number of reported incidents, the potential benefit of using SBC is far outweighed by the potential risk of a lipo fire from an over-loaded battery.

For this reason I personally removed the SBC kernel from my phone and replaced it with a non-SBC kernel - even though I had never experienced any problems at all using SBC.

motenak · Jan 9, 2011

I'm not a battery expert but I can almost guarentee no one has their phone on a charger more than I do. I have a charging dock on my nightstand where it charges overnight everynight. In the morning, I take it off the dock, walk to my garage and plug in a car charger for the drive to work. Once at work, I disconnect it from the car charger and within a few minutes my Evo is sitting in another charging dock on my desk at my office. I would estimate that it is being charged over 20 hours per day. I have done this every day since I got the phone so if the SBC thing is causing the problems described I would think it would have affected my phone by now. I bet every problem reported was with a $10 eBay battery from China which probably don't have any protection chips, probably aren't even Li-ion and so on. IMO, YOU GET WHAT YOU PAY FOR! To sell them so cheap the had to cut some corners somewhere.

lyrical1278 · Jan 9, 2011

Shinzul said:
So basically, there is a hardware failsafe designed to prevent these batteries from exploding... so what happens when one of the hardware failsafes fails? How many evos have people reported as faulty? Quite a few... we have seen bad screens, bad cases, bad buttons, etc. Who's to say that there haven't also been bad 8205a chips too? Maybe HTC even *gasp* KNEW that these chips were prone to failure and introduced the 90% charge in anticipation of this?

No one can be 100% sure if these "SBC" kernels are to blame. Correlation does not imply causation. But that said, I think that if you understand enough about the electrical engineering involved, you will realize that gaining 10% more battery life isn't worth the risk of a fire hazard and a destroyed phone. It's easy to say "hey, new kernel, cool!" But then if something catastrophic happens all of a sudden it's "oh crap why did I do that?!"

Of course you can do whatever you choose with your phone, it is your choice. I personally am not going to screw around with introducing potential instability to a piece of hardware that already has enough stability problems as it is.

See here is my thing with this particular argument. People say they don't want to put anything on their Evos or whatever phone they have that would introduce the possibility of instability. Um, YOUR PHONE IS ROOTED!!!! and you MIGHT NOT have the stock rom on your phone.

So basically you have ALREADY put your phone at risk. I'm not saying USE the trickle charge kernel by any means. It's your phone do what you want to do put what you want to or don't want to put on it. But you can't use that particular argument to justify WHY you wouldn't. If you don't want to risk your phone in any manner, unroot it and return it to stock. Plain and simple.

As for the warnings everyone is given, every kernel and rom has a warning. If someone wants to use it anyway, let em use it. If you don't want to, then YOU don't want to. I paid 300 bucks for my phone (got it brand new from a third party since I wasn't eligible to upgrade) then I paid 30 bucks for an extended battery with case. Would I be mad if my phone "blew up"? Yep

But my phone is often time COOLER while charging than when I am using it. My phone is in mid 80s easy while charing and mid 90s while using it. That's normal considering I am a SERIOUS multi tasker (you should see my visual task switcher sometimes) So maybe, just maybe, I am part of the 99% that isn't having any issues with the SBC kernels. I'll take the extra battery juice, especially since I do travel and I don't sit by an electric outlet all the time.

fixxxer2008 · Jan 9, 2011

as ive said maybe these people with battery issues had cheap knockoff batteries.

spiicytuna · Jan 9, 2011

Shinzul said:
So basically, there is a hardware failsafe designed to prevent these batteries from exploding... so what happens when one of the hardware failsafes fails? How many evos have people reported as faulty? Quite a few... we have seen bad screens, bad cases, bad buttons, etc. Who's to say that there haven't also been bad 8205a chips too? Maybe HTC even *gasp* KNEW that these chips were prone to failure and introduced the 90% charge in anticipation of this?

No one can be 100% sure if these "SBC" kernels are to blame. Correlation does not imply causation. But that said, I think that if you understand enough about the electrical engineering involved, you will realize that gaining 10% more battery life isn't worth the risk of a fire hazard and a destroyed phone. It's easy to say "hey, new kernel, cool!" But then if something catastrophic happens all of a sudden it's "oh crap why did I do that?!"

Of course you can do whatever you choose with your phone, it is your choice. I personally am not going to screw around with introducing potential instability to a piece of hardware that already has enough stability problems as it is.

Agreed. Even though I have insurance, the hassle, etc., is not worth the risk for approximately 10% more battery. With the wimax cm6 kernel I get good battery life under semi-heavy use.

Sent on the go from my HTC EVO

eyeballer · Jan 9, 2011

lyrical1278 said:
See here is my thing with this particular argument. People say they don't want to put anything on their Evos or whatever phone they have that would introduce the possibility of instability. Um, YOUR PHONE IS ROOTED!!!! and you MIGHT NOT have the stock rom on your phone.

So basically you have ALREADY put your phone at risk. I'm not saying USE the trickle charge kernel by any means. It's your phone do what you want to do put what you want to or don't want to put on it. But you can't use that particular argument to justify WHY you wouldn't. If you don't want to risk your phone in any manner, unroot it and return it to stock. Plain and simple.

As for the warnings everyone is given, every kernel and rom has a warning. If someone wants to use it anyway, let em use it. If you don't want to, then YOU don't want to. I paid 300 bucks for my phone (got it brand new from a third party since I wasn't eligible to upgrade) then I paid 30 bucks for an extended battery with case. Would I be mad if my phone "blew up"? Yep

But my phone is often time COOLER while charging than when I am using it. My phone is in mid 80s easy while charing and mid 90s while using it. That's normal considering I am a SERIOUS multi tasker (you should see my visual task switcher sometimes) So maybe, just maybe, I am part of the 99% that isn't having any issues with the SBC kernels. I'll take the extra battery juice, especially since I do travel and I don't sit by an electric outlet all the time.

Rooting your phone and having a custom rom isn't the same kind of instability as potentially over-charging a Li-on battery. A few fc's probably won't blow up your phone.

fixxxer2008 said:
as ive said maybe these people with battery issues had cheap knockoff batteries.

This thread is a report of a stock one.
http://xdaforums.com/showthread.php?t=904577

Again, there's no proof/evidence to show sbc doesn't this, but it's of course within the realm of possibility. And as most people have said.. is that extra few percent worth the risk? That's up to the individual,

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

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