Long Term Battery Analysis Results Nov14 to Present

[88horizon5speed]

Hey there guys,

Im sure some of you know that I am running a long term battery analysis of my turbo 64g. I have kept track of every charge cycle since when I bought it in November. I dont account for 100% of the battery use, after running a statistical analysis (multiple regression), by using the screen on time and %, the cell standby percent, time along with no signal % and also talk time and % it is about 75 to 80 percent r2 value which means that battery life is 75-80% correlated or dependent on those factors. I am mostly doing this to be able to see how long the battery degrades in performance over the two or three years I will own the phone.

Attached is the data, if you look at if please be sure to go through all three excel workbook pages.

Let me know what you think guys

 

[Rukbat]

By dropping the battery to 25-30% before charging, you're going to get a shorted life than if you recharge at 40-50% - much shorter. Your math is good, your electronics doesn't match your math. (The Care and Feeding of Lithium Polymer Batteries)

 

[88horizon5speed]

The proper care for batteries is debatable. I have done lots of research and I am performing my test to 25-30% and then charging. What isnt good for them is consistently going to 0 or close to. I can provide plently of sources discussing why its correct, but I realize that many sources say something different. I appreciate your input though, but regardless of what is true, I am going to stick to what I am doing and I guess Ill see in a few years time!?

 

[Rukbat]

I guess. I trust Cadex. They've been in the battery destroying business since before lithium batteries, and they show a distinct drop in lifetime when discharged to 25%.

Going to 0 isn't bad for them, it turns them into industrial waste. Since charging a fully discharged lithium can result in an explosion, the battery commits suicide before it dies completely, disconnecting from the outside world. Discharging to when the phone shuts off, very close to 0, is terrible - it can kill the battery after 300 cycles.

I guess you're right - we'll both see. But my 10 year old V551 batteries are still going strong by doing it my way.

 

[88horizon5speed]

See part of the problem, is if you only discharge a battery to 50%, you may not realize its going bad even though it is. My droid x battery after three years, probably 1000 discharge cycles would go down to 50 normally but then started to jump after that. So you may think the battery is in good shape still but really it may not be able to stretch its legs for as long as it used to be. In my experience, any friend or family member who discharges to 50 or so and back up was charging their phone like twice a day- their batteries would last a year before they were junk.

 

[sharkita]

But my 10 year old V551 batteries are still going strong by doing it my way.

Oh wow - you still have a V551? That was an awesome phone.

Posted via the Android Central App

 

[STEVESKI07]

See part of the problem, is if you only discharge a battery to 50%, you may not realize its going bad even though it is. My droid x battery after three years, probably 1000 discharge cycles would go down to 50 normally but then started to jump after that. So you may think the battery is in good shape still but really it may not be able to stretch its legs for as long as it used to be. In my experience, any friend or family member who discharges to 50 or so and back up was charging their phone like twice a day- their batteries would last a year before they were junk.

Maybe the batteries just need to be calibrated again. A full 100% to 0% cycle. Everything I've read everywhere from scientific studies to just people's hands on experience say the opposite of what you're saying. I've read the keeping your phone between 30-80% is the best you can do to prolong battery life. Battery life is too important to me so I'd probably always charge to 100% to start the day but if I got down to 30-50% during the day and had access to a charger, I'd probably only go up to 80.

 

[88horizon5speed]

from what I have read you should never go down to 0, to calibrate I go down to 7% after every 30 charges. This isnt to calibrate the battery btw, its to calibrate the battery sensor built into the phone, older NiCad batteries had to be calibrated because of the memory affect. Again this is all a very debatable topic of course, everywhere you read says something and has a test proving the best way to care for a battery. Can anyone give more feedback on my long term battery analysis itself? Im curious to see if anyone besides me is interested in results long term and would like to see them?

 

[88horizon5speed]

Ive added another worskeet page with two graphs.

Graph 1) Correlation between the time the battery will last as a function of the time you have the screen on, the cell standby time and the voice call time (again, they make up about 80% of battery drain). Proof of this correlation is seen through the trend lines. As the functions go down the amount of time the phone will last goes up.

Graph 2) Displays the battery % when plugged in for charging, the amount of battery used by screen on time, the % battery use by cell standby time, the % time with no signal and the % battery use through voice call time

 

[JJ Jones]

It's possible that the software is calibrated in such a way to prevent a discharge to "actual 0." What I mean is, if the phone is programmed to read a battery which is at 20% capacity (be it mah or voltage) as 0%, then the battery is never fully discharged anyways.

Sent from my Ballistic Turbo

 

[88horizon5speed]

The phone probably does have a protection from running it to 0 but its more likely 3%, definitely not 20%. Thats a whole lot of battery life that would be sucked out of smartphones!

 

[doogald]

It's possible that the software is calibrated in such a way to prevent a discharge to "actual 0." What I mean is, if the phone is programmed to read a battery which is at 20% capacity (be it mah or voltage) as 0%, then the battery is never fully discharged anyways.

Sent from my Ballistic Turbo

Yes, it absolutely is. I'm not sure what level the pack really is when it's reported to be zero, but it's not actually zero. However, if you discharge to reported zero and then let the phone sit for a long time, that could be a problem.

 

[MA2GA28]

Haven't read it yet, but definitely interested. Will take a look next time I'm on my computer.