[Q] Nexus 7 2013 wifi - battery derated/less capacity then 3950mA - Nexus 7 (2013) Q&A

Dear All,
I recently purchase nexus 7 (2013) wifi 16 GB. On the package device was manufactured on 09 2013.
The device is new. It even came with Android 4.3 and was updated to 5.1.1 by me.
When i bought it was not charged. and it was dead.
It was charged and on cpuz it shows battery as 3448 mA instead of 3950 mA,
and now it is even showing less as 3334,
what is happening? Please guide

Amps, milliAmps is current. Current is what drives all electronics. Current and voltage depend on each other, as current drops, so does voltage, as voltage drops, so does current. V=I.R or I=V/R.
Unless of course I am wrong, the more you use your device, the more the charge stored in the battery gets depleted, the voltage starts to drop, which means current drops. As charge moves from the negative side(yes, you can google to verify this) to the positive side of the battery, it tries the get the potential difference(voltage) to 0. And as I just said, as voltage drops, so does current.

Battery capacity is marked in Ah. For smaller capacity this is mAh (milli Ampere Hour) the amount of current it can push per hour. Capacity of batteries goes down with usage and age. It is a rechargeable battery that loses capacity simple by using it. NiMH batteries are notorious for their 'memory' effect, which can be corrected to a certain degree. Lithium based batteries have almost zero memory effect. But all batteries lose capacity over time.
Sent from my Nexus 7 using XDA Free mobile app

Related

[Q] Battery drain application

Hi!
I'm looking for an application, that quickly kills my battery if it's low, so I can do a full charge to improve battery life.
Something, that I launch, I put my phone on the desk, have a tea meanwhile, and it's drained! Something, that turns on wifi, do some downloading, browsing, video playing, or whatever, and does it automatically without supervision. Does such app exists?
I'll second this, it'd be nice to have an app do this for me and maybe even give us some interesting stats from it?
Sent from my mind using telepathy
why would you want an application to destroy your battery?
Adevem said:
why would you want an application to destroy your battery?
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Apparently if you do a full discharge the battery life will be longer.
Soniboy84 said:
Apparently if you do a full discharge the battery life will be longer.
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Click to collapse
not really, you should avoid deep discharges...
Byr0x said:
not really, you should avoid deep discharges...
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+1 If you had been reading around...you would know Lithium Ion batteries are designed to 'maximize' their efficiency within about two weeks of 'top up' charging. Cycle-charging is generally considered a less efficient method of charging. You will need to 'TopUp charge' this means charging as much and as often as possible. If your battery is at 89% for instance and you find yourself near a socket, plug your adapter in and charge it up to 100%. After a few days of doing this you will notice an improvement in the life of your battery when you are not able to charge.
Actually,,,
It is not matter of running your battery down to 0%.
It is ok to run it down till phone does to power on itself.
As you know battery is a single cell Li-Ion @ 3.7v
when it is fully charged it's peak voltage is 4.2v
By the time battery mah is drained down (galaxy s has 1500mah)
battery voltage should be around 3.2~3.4v range. this will depend on condition of the battery.
Battery should never go below 3.2v personally, 3.4v is my cut off.
If your battery voltage goes below 3.2v... it's time for a new battery as this kind of voltage will damage your battery, either it will leak or puff (battery will actually get bloated.
Phone has a voltage cut off so it will not over charge over 4.2v but if it does, it will likely start to smoke and catch fire.
I am sure anyone who is into electric Radio control knows all about these batteries.
Oh btw,,, long time storage voltage should be 3.8v
You'll be asking how do I know what voltage my battery is... I personallly don't know of any apps but GPS Status actually shows the temperature & voltage of your battery.
Soniboy84 said:
I'm looking for an application, that quickly kills my battery if it's low, so I can do a full charge to improve battery life.
Click to expand...
Click to collapse
First, take into consideration the comments above regarding deep discharge of your battery...but, to answer your question, there's an app in the market place called 'Battery Refresh' which attempts to drain your battery quicker.
Well if it's all true above than its a good sign, and thanks for the info! I'm not an expert but in the old times I remember batteries had to discharged completely, maybe even if it's just a few times. Now somebody can also tell me why my battery is discharging when it's plugged in the socket with original charger? All I do is using the internet, and has. nimbuzz and a live wallpaper on. :S
You could probably enable the GPS/BT/WIFI ( connected to a router ) and run the interactive mode on Neocore benchmark.. that should enable most of the hardware components on the phone and stress the GPU/CPU.. probably would see a 25% battery drain for every 35-40mins.
I don't know what has changed with the batteries but as far as I know...
it is good to discharge new batteries 3~4 times down until phone does not power on.
Like I have said... it's about the voltage of the battery, not whether battery has any juice left in it or not.
These batteries have a protective circuitry so that it will not charge over 4.2v,
also as for discharge it is usually down to 3v but usually with a charger/discharger units that can control mah/volts/amps. With typical usage from the phone, it'll likely be discharged down to about 3.2`3.4v. Which is very safe.
You can do whatever you feel but I personally do this to every batteries I have for phone and every batteries I use with my radio controled cars.
For my RC cars, I have about 6 batteries ranging from 1cell to 3cell LiPo packs.
Each cell is 3.7volts.
But you don't have to force discharge and hurry the process.
Just use the phone normally and let it run down to nothing... than recharge to full peak.
Than again, choice is yours.
I'm looking for the same kind of applications. It's very useful for recalibrating your battery. Wipe the battery history then do a full cycle.
Sent from my GT-I9000 using XDA App
The old saying in RC Helicopters was that the difference between discharging 50% and 100% was the difference between getting 500 uses and 5 uses.
You should certainly avoid ever fully dischaging any lithium based battery.
Older nickel batteries (Ni-cd, Ni-MH) required full dischage cycles to get rid of memory the the metals pertained, lithium-ion and lithium-ion-polymer not only do not require this; but doing so will damage them.
And yes, the older ipods came with Nimh cells and they did reccomended full discharge cycles.
Im pretty sure the idea was to try not to let the voltage get below 3.5v/cell and never below 3.3. Dead flat is 3 or 2.85 which is when the battery simply cant produce any real current. The phone should have circuitry though to not let the voltage get above 4.25 or below ~3.5.. If the low battery warning comes on, set the brightness to dim, and stop any activities (unless its a phone call, its not THAT important but if youre playing games or watching a movie...) until yo can get to a charger.
By the way this being my first post (i meant to ages ago) Ill just mention that my galaxy S came with recovery mode and download mode Enabled, i got it just last month, Virgin network, Australia.
draining the battery fully was for the older battery types, new age batteries are not recommended to be drained fully
Thanks!
One more question:
I'm using my phone as a desktop replacement, because I don't have Internet at the moment. I'm using xda, dolphin browser and listening music. It's plugged into the mains and it's not charging. It says 49%, and stuck there. Is it possible I'm using too much battery?
Sent from my GT-I9000 using XDA App
Ok, this will be my last reply.
Fully draining or not is not the issue.
In RC, most modern electronic speed controllers have a built-in battery cut-off which will cut off power once it reaches certain voltage. Because OVER-draining battery without cut off can damage/kill/ or make it unable to hold voltage.
Also, once the battery voltage reach certain point (still within safe range) you will notice the motor being powered slow down. This would also be a recommended time to stop.
Cellular phones have built in safe cut off aswell. As I have said I have measured my battery after being full drained, voltage was around 3.55v or so. Which is very normal considering voltage of the battery is 3.7v only with peak charged voltage of 4.2.
Now, Someone mentioned that fully draining your battery repeatedly will dramatically reduce battery life.
Reducing life of the battery has more to do with the amount of AMP used to charge the battery. Faster charging is usually reduce battery life dramatically.
And without hobby grade chargers, you won't be able to control this charge rate.
Slow charge is better but charging at 1C rating is the normal. But charging at 1C means regardless of batteries mah rating, battery can be charged in about 60 minutes. As we all know, our phone batteries doesn't charge from zero to full in 60minutes, right? just like most of the portable devices it takes nearly 3~4hours to fully recharge. Last 20% usually takes longer because Amp provided to charge slowly lowers. That is why.
For example, if Galaxy S battery is 1500mah, than 1C charge rate is @ 1.5amp.
If battery is 3000Mah, 1C is 3.0Amps and so on.
So like I have said over and over before, drain your battery away if you have to by choice or not. Just use it up, I will bet you your battery will last longer than you keep your phone.
U should avoid draining ur battery to 0% (witch is not possible with ur phone. When it shows 0% the charge of the battery is at 10-15%). Li-ion batteries dont have a memory effect, so it would be usless discharching it completely anyhow. Best for sgs battery is charging it before it goes under 50% that will improve the lifetime of ur battery (not how long it lasts before u have to charge but how long it lasts before u have to go and buy a new one)
How do i know? Simply cause i had to learn that a few weeks ago for the job im learning.
@xxgg: yes ur right, it wont really damage the battery if u runn it till thr phone shows its empty. But using an app to drain battery as quick as possible will, since the app forces the battery to give out more Ampere than its built to give out
Sent from my GT-I9000 using Tapatalk

[Q] Battery Voltage / Charging cutoff

Is the battery one of those new 4.3V chemistries? Fresh from the charger, my battery has a voltage of 4.25V. For standard Lipos that wouldn't be good for battery life at all...
It's definitely a 4.3V chemistry. Running on the charger I see 4.29V using Battery Monitor Widget after the JSS15Q update. Before the update I regularly saw 4.30V. Google may have decreased the max charge voltage slightly trading off a little capacity for a little longer battery lifespan.
I've been very surprised how seldom it gets mentioned. Even the big name reviewers seem to have missed it.
I suspect that the actual battery capacity in Watt-Hours has stayed the same or gone up slightly compared to the 2012 N7 even though the quoted capacity in Amp-Hours (mAH/1000) went down. Most folks don't seem to realize that mAH is a meaningless number for comparisons unless the voltage under load is identical.
Thanks. Looking back at a few reviews, there are some that mention the battery being rated 3.8V instead of the usual 3.7V (missed that before).

Battery messed up?

So I have a zerolemon 10000 mah battery for my note 3, I just switched to cm11 and noticed the battery percentage meter was going wacky and wasn't being accurate (eg. It would jump up 10 percent after a reboot or last hours on 1 percent with heavy use) so I followed the instructions for fixing it, I let it drain completely and then I charged it to 100 percent while the phone was off, then I turned it on and charged it again until it showed full just like it said to do in the instructions, after this I went into my battery status app just out of curiosity, there I saw that the battery had 4250 mv , I am alarmed by this because the battery is only supposed to be 3.9 voltz, is my battery damaged? I always thought that the batteries have circuits in them to prevent overcharge then how come it overcharged my battery??
Sent from my SM-N900T using XDA Free mobile app
Actually battery voltage is a little bit tricky:
first of all it will show higher with no load than with load on it and higher the load, lower the voltage, full charge or not.
Secondly for example my original phone battery is rated 3.8v, but at full charge will be higher than 4 volts.
I don't remember how Li ion batteries are rated, but for example NiCd are rated at 1.2v, which would be the voltage the battery shows when under full load, under no load the voltage will be more than 1.5v and if that NiCd battery shows 1.2 v under no load it usually means it's close to being completely discharged. I don't have specs for your particular battery, but I'm sure fully charged with no load will show more than 4v.
Since the battery has protective circuit, it should still be within specs, before the damage occurs, so I don't think you should worry too much, however if you were doing this all the time, I'm sure you will shorten battery life.
Full charge for lipo is about 4.2V. So the battery is not overcharged. The batteries have a protective board on them, and the charge control on the phone won't allow overcharging either.

Battery capacity calculation

So I bought myself a decent USB multimeter (RuiDeng UM25C) because I was curious about my Mi 6 battery capacity after 20 months of everyday heavy usage.
I was avoiding charging to 100% all this time (max to 70%), only charging to full once a month maybe and never using a phone during charging. I also rarely discharged to less than 30%. The full charge counter in /sys/class/power_supply/bms/cycle_count is showing 642 full accumulated charge cycles, so quite a lot.
USB meter showed 14300 mWh after a full charge 0-100% (which is 110% of the original capacity 12900 mWh, impossible). So I did a search and found an article saying that Quick Charge 3.0 has around 90% charging efficiency.
So I made a quick mathematics and calculated that the battery should have taken in 14300 mAh x 90% = 12870 mAh (the rest of energy dissipated as a heat), which is basically new battery's capacity (which is again quite improbable, even with my special battery treating ).
My question is: is this calculation wrong? And if it is totally wrong - what should I count in additionally to get the more proper mWh estimation?
Thanks for any help

Real battery capacity

Got the phone in december. Never had 5k mAh. From the day one it was about 4.6k mAh. Measured with AccuBattery app, and by measuring charge time. Both not 100% accurate, but supports each other.
Charger output is 1.5A, so it should charge from 0 to 100% in no less than 3hr 20m, but givven that charging slow down above 80% or so, it should be even slower. I don't remember exact charge time of mine phone, but it's somwhere around 2h 50m.
Althogh it still covers all my needs, it's still a little bit dissapointing.
What is your phone real battery capacity?
Failed to insert images as images, so here is the links to AccuBattery stats screenshots
Also failed to insert links to images, so insert dot into prnt sc space
prnt sc/nt7per
prnt sc/nt7p7r
If you don't mind using a custom rom, you can try any custom & get rapidly charge (even with the stock charger). I'm using latest aex 6.5 it has cherry kernel out of the box since the maintainer is the same (aex & cherry kernel). Check the attached pic.
No,the capacity of the battery is 5K
Your doubt is valid that 1.5A of charging should charge in so and so amount of time,but the charging speed even on stock rom soars to about 1.8A depending on device temperature. This is the reason why the phone charges well within the time calculated by you
kanwaljeetsm said:
No,the capacity of the battery is 5K
Your doubt is valid that 1.5A of charging should charge in so and so amount of time,but the charging speed even on stock rom soars to about 1.8A depending on device temperature. This is the reason why the phone charges well within the time calculated by you
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Even if my charging time versus 1.5Amp statement is unrelaible, then the ampermeter in the phone is also shows wrong info. Because AccuBattery calculates capacity based on charging current Ampers * charging time. So, if internal ampermetter is lying, your could lie about 1.8Amp too.

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