Root SBC kernels......where are they?

[ocnbrze]

hey guys,
so i stumbled upon this old thread: http://androidforums.com/evo-4g-all-things-root/319636-sbc-no-sbc-kernel.html from the og evo forum. it got me thinking about sbc kernels. i have not seen one in quite some time now. do you think that the devs are steering away from this for a reason? maybe it has to do with ICS or JB?

thoughts?

i would love to have me some sbc on my phone right now

 

[Rxpert83]

When I first got it I brought it up, and I remember Early was VERY against SBC kernels for this phone.

Something about a different technology maybe?

Dear PearlyMon, fill us in again
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The stock HTC kernel already seems to charge up to 100% and stay there. I used to check BMW and it already kept it there.

 

[ocnbrze]

When I first got it I brought it up, and I remember Early was VERY against SBC kernels for this phone.

Something about a different technology maybe?

Dear PearlyMon, fill us in again
-----------------------------------------------------------------------------------------------

The stock HTC kernel already seems to charge up to 100% and stay there. I used to check BMW and it already kept it there.

this is true. i guess, i just miss the good ol days and how i loved sbc kernels like tiamat and netarchy toastmods.

and it does make sense about the new technology with batteries and phones. i was just hopping to hear that they were working on it or something i guess. LOL

 

[EarlyMon]

Superior Battery Charging.

There is no such thing as 10% battery loss after unplugging it. It's just that your battery indicator is misreading the charge. SBC charges your battery above what your indicator can read. So what you see is that it stays at 100% even after significant usage. Once the charge falls to within the thresholds of the indicator, you will see a drop.

SBC also doesn't charge your battery to some "true 100%." You can always crank out more charge by upping the voltage, but at huge detriment on battery longevity. SBC just charges your battery to some point above what your indicator can measure. That's it.

I have a background in Chemical Engineering, which for the current topic I find to be more relevant than electrical engineering. SBC is fine if the voltage is delivered in bursts rather than continuously. The goal here is to avoid plating, which is a chemical pathway where the lithium ions become deposited on the anode as the solid lithium metal. You need Li in ionic form to be able to transfer electricity. A sustained high voltage environment will accelerate plating. This is why modern chargers pull back and shut off voltage as the battery approaches a target charge.

The other contributor to plating is temperature. When the temp of your battery rises, either from charging or use, the chemical reaction starts to favor plating. Charging with higher voltage to get more charge would generate more heat and therefore you lose more Lithium ions in the process. This is also why charging via USB is healthier than a wall A/C charger. The wall charger can do the job MUCH faster, but it also causes the battery temp to spike much higher.

The end result of plating is that you have fewer and fewer cathode ions over time, and your battery capacity reduces. SBC tries to avoid plating by overcharging very slowly in short bursts. That's why it works best during overnight charging where it has the time to slowly build up the extra charge without keeping average voltage high and avoiding peak temperatures.

Despite the precautions, there is a measurable degradation occurring with SBC, but for many, that amount is an acceptable tradeoff for the improved charge. After all, our phone batteries only need to last through our 2-year contract. If a battery under noSBC can last, say 3 years, but a battery under SBC lasts 2 years, we're golden.

That said, I'm not convinced every kernel's implementation of SBC is the same, so results may vary. Likewise, not all batteries are created equal, and some are more susceptible to plating than others. So with all these variables, it's natural for people to observe different results.


-edit-
Forgot to address the exploding battery. The odds of this happening are low. It can happen under a process called thermal runaway. This can be started via several mechanisms including overcharging, but the prerequisite temp of the battery core needs to be around 80C. It's unlikely that any of us have ever gotten battery temps that high. In a poorly implemented overcharge, such as keeping voltage high continuously or using an excessively high voltage, it's very possible to make the battery overheat to 80C. I don't think any current SBC implementation would cause this. But the disclaimer is out there. It COULD happen as a worst case scenario.

If you happen to be holding the phone, or if it's in your pocket, you'll get plenty of warning before the actual explosion, since your phone will become too hot to touch. Temps will reach above boiling (100C) before the explosion occurs. But if your battery ever reaches 80C, consider it a dead battery. It won't ever charge properly again.

Here's an engineering view in very simple terms -

It was a bad idea then, and it became a horrible idea with the battery tech that debuted with the 3vo.

How far down the rabbit hole y'all want me to go on this?

BTW, I heard netarchy was doing fine, working on Samsung kernels or something.

 

[scary alien]

Wow, EM!

Thanks for quoting that excellent post by novox77--very informative and interesting (thanked and bookmarked for future reference!) .

In the same vein, here's a very good thread over at XDA that might be interest to you guys:

Your battery gauge is lying to you (and it's not such a bad thing)

Cheers!

 

[Granite1]

At this point in the game I really don't care about the quest for the 4 day battery anymore. On the OG I was a little obsessive, now not really. I can easily get a whole working day outta this phone even with heavy use. That's all I really need, gooder is always better, but not on my priority list anymore.

On another note, I was fully aware novoxx was intelligent, I wasn't aware he's a chemical engineer!

 

[EarlyMon]

<------ EM, EP is El Presidente lol

Great article, sa, bookmarked!

The takeaway is to not baby your battery, and I agree.

I used to be a big proponent of bump charging. While that worked, I've gone away from that.

We monitored the Evo 3D when it came out, and immediately freaked that it was charging at too high a voltage. The story was picked up by the blogosphere and concerns grew. That kept up until I found the patent describing the new battery and charging technology that explained our observables.

Many new phones have gone to lithium polymer batteries. Tech changes. What worked on your first Evo doesn't necessarily apply here.

I wish I'd bookmarked the long term graph corresponding to the XDA article that was published here on AF. Once a battery hits the low point as defined by the manufacturer, charging starts again. Over the course of hours, it will look like a sine wave - or, like a roller coaster, up, down, up, down. That's why it's really random where the battery will be when you take it off the charger.

Anymore, maybe it's just best to think of your battery like the staff in the first Indiana Jones movie. One side says, the staff is this big, but the other says, take away some, you gotta pay the dues.

So, following that, you get around 90% (a little over, not much) battery to use.

Because the other side not discussed is the bottom end. You don't want to make a habit of taking your battery to zero, it's ok when you must, but don't make it a habit.

So, it comes off charge truly at 100%, you may hit the charger at say, 9%. It comes off charge truly at 96%, you might hit the charger at 5%.

See what I did there?

You can't escape the dues. If you really want that 4% back when you take it off the charger, take it at the back end.

Battery tinkering accomplishes nothing useful, and if you go overboard, it's dangerous. When you finally fail the system to the point of ignition, the battery will not burn like a little cozy fire. It will burn like a blowtorch. The colorful jet will extend quite a ways and the fumes will be toxic. (I know that folks like to make fun of that, my battery didn't, etc etc. Then again, up to 5 guys can win at Russian Roulette.) I ignited a battery under controlled conditions, on purpose, so I guarantee that's how they go.

Anyway, the battery is what it is. If you want to improve it, leave the charging cycle alone and learn all you can about monitoring what your apps are doing so you don't waste what you do have.

 

[ocnbrze]

thanx EM LOL

yeah that does make sense......and i agree with you granite as well. i was not really looking for sbc kernels like i was seeking it for the og evo. i just stumbled upon the earlier thread. i was just wondering about it, since i have not seen any mention of it anywhere for the lte. i to do not mind getting 20-30 hours of battery life now so i'm good.

 

[EarlyMon]

At this point in the game I really don't care about the quest for the 4 day battery anymore. On the OG I was a little obsessive, now not really. I can easily get a whole working day outta this phone even with heavy use. That's all I really need, gooder is always better, but not on my priority list anymore.

On another note, I was fully aware novoxx was intelligent, I wasn't aware he's a chemical engineer!

He's not but he is a man of many parts.

Yeah, I used to get less than 3 hours of intensive screen on time on my Evo. Now, it's 7 to 9.

Good enough for me too.

 

[scary alien]

<------ EM, EP is El Presidente lol

Great article, sa, bookmarked!

LOL, sorry, EM! I try not to do that (I hope that's my first ).

(I keep seeing unforgiven calling me "SE" (first two letters of my first name, so I think he's getting cross-talk ))

Battery tinkering accomplishes nothing useful, and if you go overboard, it's dangerous. When you finally fail the system to the point of ignition, the battery will not burn like a little cozy fire. It will burn like a blowtorch. The colorful jet will extend quite a ways and the fumes will be toxic. (I know that folks like to make fun of that, my battery didn't, etc etc. Then again, up to 5 guys can win at Russian Roulette.) I ignited a battery under controlled conditions, on purpose, so I guarantee that's how they go.

I saw Bear Gryll's (Man vs. Wild) bust open a cell phone battery to start a fire...I think it was because the lithium was exposed to air (not sure) that it started spouting fire and brimstone. Pretty wild.

thanx EM LOL

(<-- not really )