Hi !
I have a nook HD+ which has been behaving strangely. Its battery life has reduced lately. I initially had problems with 'media' and 'SDcard' draining it quickly. But I was able to check that by formatting my SD card and deleting two 0 kB files in my internal memory.
However, the battery life, since, has not improved much. Moreover, I have started to see a few spikes in the battery charge chart (like the one in the pictures attached with this post) without having plugged the Nook in.
I am on CM 11 snapshot M8. I have already tried calibrating my battery by charging it to 100% and then removing batterystats.bin system file through PlayStore's 'Battery calibration' app, but the issue still remains unresolved.
Has anyone else faced a similar issue with her or his Nook ?
You cannot calibrate batteries in Android. Those silly apps just delete batterystats.bin and that is an Android file responsible for the statistics seen in your third screenshot. It gets deleted automatically when you unplug the charger at an almost 100% charge level, and it has nothing to do with the reported battery level!
The battery percentage as shown by Android comes from the kernel, the power management unit (PMU) driver to be more specific. The PMU, which usually is a separate chip inside the device, is responsible for monitoring, charging, and discharging the battery, among other things. There are many different PMU models, so this is highly hardware-dependent, and there most likely are no apps out there that can directly talk to all the existing PMUs to do something that's actually meaningful (which deleting batterystats.bin is not).
The only thing you can do is once in a while discharge the battery until the device turns off, then recharge it in one go to full capacity. That way, the PMU hopefully "calibrates" its battery monitoring by itself and should report more accurate state of charge values again. Measuring a battery's state of charge is rather difficult and not an exact science. Those percentage values are only estimates. So, the spikes you see on the battery percentage chart are a result of the imperfect method that is used to calculate the current battery percentage. Maybe this gets worse with aging batteries, I don't know. There's nothing really you can do, other than the complete discharge/recharge cycle you've already tried. Maybe a future firmware will come with a better battery percentage calculation method - but as I said, this is totally independent from Android, it's a low-level hardware and kernel driver thing.
Thanks a lot. A very informative post indeed !
Full battery charge/discharge cycles seems like the only solution then.
How will it affect the battery and its capacity to retain the charge though ?
To prevent any misunderstanding: you should definitely not discharge your lithium-ion based batteries to 0% all the time. Li-ion batteries live longer if they are kept between 40% and 80% charge. At 80% you won't get the full capacity / runtime, of course, but the battery will be able to endure more charge/discharge cycles that way. As I said, discharging to 0% followed by recharing to 100% should only be done occasionally, if you feel that the reported battery percentage has become too inaccurate. It probably won't fix the "ghost recharging" seen on the Nook and other devices. What probably happens here is that the battery's voltage is factored into the state of charge calculation. Li-ion batteries are usually charged to 4.2V per cell, which is "100%", and discharged to some arbitrary voltage, e.g. 3.5V, which would be considered "0%". Inbetween, the voltage curve is not linear. That is, 50% would not necessarily correspond to 3.85V (=(4.2+3.5) / 2). Also, the voltage depends on the power draw to some extent. If the tablet draws a higher current from the battery, the voltage will sag. If you then put the tablet into standby, reducing the current to a very small value, the battery voltage will recover and increase again a bit. This is what might cause those spikes (although they shouldn't be that large).
This and more can be learned on Battery University. And here's a source for the batterystats.bin calibration myth.
Thanks a lot Tzul. You have been very helpful !!
I may have to replace my battery soon. If the battery life does not improve, I guess I will have to buy a replacement battery from a third party replacement battery seller.
My XT1092, recently got updated to Lollipop i.e. Android 5.0
Two of my battery runs, starting from 100% full charge came down to like 5% and the phone shut down automatically as if it was 0%
Also on a side note, i did not put any mode on the battery saver mode for those two runs.
Now to test it, i kept my battery saver to start at 5% but i am not sure if it will run at 5% or just shut down
Anyone got an idea/solution for this issue ??
P.S. Even Motorola care chat, does not have an answer, all they said is to keep my phone in safe mode for a day and check it out....
Mine just did this the other day. When I pressed the power button it showed the battery with a little red fill and a huge yellow triangle with an exclamation mark in it. Also happened last night.
I have also had the same issue xt1092 and on lollipop.
well...
yea man, so the thing is motorola support said that, keep ur phone in safe mode for a day and recheck the issue...
so idk... :/
i am checking my battery use and for now i have kept my battery saver on 5% so i hope it starts on battery saver itself.. rather than shutting down...
My XT1095 does the same thing. Really annoying! Its really lying to you about how much battery is left if its going to do that. I just know that if i'm going below 10% i better run to find a charger ASAP!
M3drvr said:
My XT1095 does the same thing. Really annoying! Its really lying to you about how much battery is left if its going to do that. I just know that if i'm going below 10% i better run to find a charger ASAP!
Click to expand...
Click to collapse
it is quite misleading to say the least..
i did not have this issue with KitKat though..
might be a lollipop thing only
I'll join this list. Really annoying, and never happened on 4.4.4
I've never let my battery get that low honestly, but...
Keep in mind that your battery percentage is completely an estimate. Battery capacity is measured in mAh, but there's no way to measure the current charge capacity in mAh of a battery. The only way to do so would be to run all of the power out of the battery and record the power over time, but then you'd have a dead battery. As a result, the system estimates your remaining battery capacity as a percentage based on the current voltage of the battery. But that can be different depending upon how quickly you've drained the battery and other factors.
So, Android has methods built-in which automatically calibrate the battery, but they only work properly if you fully charge and discharge your device on a regular basis. A battery starts off weak, then it gains strength after a few charging cycles, finally over time it peaks and then begins to taper off as far as battery life goes.
You've likely not taken your device to 0% for a while. The android solution is to fully discharge and recharge your battery a few times to allow it to recalibrate. Slow charging is the best for recalibration. Plug it into a computer for 500mAh charging rather than using a charger. Chargers can charge quicker(1.5A) but do not allow the device to calibrate as well due to the high amperage.
So, just use your device and let it drain fully, and charge fully on a computer USB port and it should recalibrate itself.
InspectifierWrectifier said:
So, Android has methods built-in which automatically calibrate the battery, but they only work properly if you fully charge and discharge your device on a regular basis. A battery starts off weak, then it gains strength after a few charging cycles, finally over time it peaks and then begins to taper off as far as battery life goes.
You've likely not taken your device to 0% for a while. The android solution is to fully discharge and recharge your battery a few times to allow it to recalibrate. Slow charging is the best for recalibration. Plug it into a computer for 500mAh charging rather than using a charger. Chargers can charge quicker(1.5A) but do not allow the device to calibrate as well due to the high amperage.
So, just use your device and let it drain fully, and charge fully on a computer USB port and it should recalibrate itself.
Click to expand...
Click to collapse
While it does help the calibration, it's very bad for your battery to do this deep discharge multiple times.
raptir said:
I've never let my battery get that low honestly, but...
Keep in mind that your battery percentage is completely an estimate. Battery capacity is measured in mAh, but there's no way to measure the current charge capacity in mAh of a battery. The only way to do so would be to run all of the power out of the battery and record the power over time, but then you'd have a dead battery. As a result, the system estimates your remaining battery capacity as a percentage based on the current voltage of the battery. But that can be different depending upon how quickly you've drained the battery and other factors.
Click to expand...
Click to collapse
Sometimes you don't have a choice about letting battery drain get that far.
But regardless, its most definitely an issue with lollipop. Uncountable android devices, and this is the first time I've ever experienced this issue. Happens religiously at 5%. So its never happened before on any device I've used, including this moto x pure on KitKat, and it always happens at 5%.
If it were a true calibration issue, one would think it'd happen at different percentages. However I'm certain this is a bug.
qwerty12601 said:
Sometimes you don't have a choice about letting battery drain get that far.
But regardless, its most definitely an issue with lollipop. Uncountable android devices, and this is the first time I've ever experienced this issue. Happens religiously at 5%. So its never happened before on any device I've used, including this moto x pure on KitKat, and it always happens at 5%.
If it were a true calibration issue, one would think it'd happen at different percentages. However I'm certain this is a bug.
Click to expand...
Click to collapse
I understand that you don't always have a choice, I just meant that I have no insight as to the possible bug since I've never experienced it. And to clarify, it's not really a "calibration" issue, it's a matter of there is no way to accurately measure the charge of the battery.
Honestly, Google could have even implemented this intentionally in order to prevent damage to the battery from a deep discharge.
raptir said:
I understand that you don't always have a choice, I just meant that I have no insight as to the possible bug since I've never experienced it. And to clarify, it's not really a "calibration" issue, it's a matter of there is no way to accurately measure the charge of the battery.
Honestly, Google could have even implemented this intentionally in order to prevent damage to the battery from a deep discharge.
Click to expand...
Click to collapse
But android has been completely accurate in the past. Right down to 1 single percent.
And there's no way google implemented this as a safety feature. If they were legitimately trying to do this, they'd just have the battery monitor read less than actual capacity as to not confuse the operator.
As well as they have what they believed to be a big feature, "battery saver" which has the option to activate at 5%. So them killing your phone at 5% intentionally doesn't hold water.
qwerty12601 said:
But android has been completely accurate in the past. Right down to 1 single percent.
And there's no way google implemented this as a safety feature. If they were legitimately trying to do this, they'd just have the battery monitor read less than actual capacity as to not confuse the operator.
As well as they have what they believed to be a big feature, "battery saver" which has the option to activate at 5%. So them killing your phone at 5% intentionally doesn't hold water.
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Click to collapse
No it hasn't. It may not have shut down until after it read 1%, but it has not been accurate because there is no accurate way to measure the current charge of a battery.
http://batteryuniversity.com/learn/article/how_to_measure_state_of_charge
The fact that it consistently shuts down at 5% does seem like a bug, but it's a very odd bug since it seems like there would have to be some code to specifically tell the phone to shut down.
raptir said:
No it hasn't. It may not have shut down until after it read 1%, but it has not been accurate because there is no accurate way to measure the current charge of a battery.
http://batteryuniversity.com/learn/article/how_to_measure_state_of_charge
The fact that it consistently shuts down at 5% does seem like a bug, but it's a very odd bug since it seems like there would have to be some code to specifically tell the phone to shut down.
Click to expand...
Click to collapse
Every android device I've owned, probably 12, including the 3 still in service with me (moto x before lollipop, nexus 7, nexus 4) all have accurate battery meters right down to 1%. Now are they adjusting on the fly and lowering/raising battery percent to accurately match calculations? Probably. But it adjusts to where the battery meter will read down to the very last percent. No surprises.
The whole point of this thread us that some moto x pures are shutting down at 5%. Maybe the battery really is at 0%, maybe its at 5 or 10%, but its a "bug" that the phone is shutting off at 5%. Its rather a flaw in on the fly calculations where its not accurately adjusting at lower percentages, or a software flaw. But it's a bug either way. That's the complaint here.
raptir said:
Honestly, Google could have even implemented this intentionally in order to prevent damage to the battery from a deep discharge.
Click to expand...
Click to collapse
That is was Microsoft did with their Surface tablets, you can change it, I have mine set to power off at 10%
raptir said:
While it does help the calibration, it's very bad for your battery to do this deep discharge multiple times.
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Click to collapse
Wrong. this is the recommended way to use every mobile phone battery. A full charge and discharge is called a cycle, and cycles are how battery lives are rated.
InspectifierWrectifier said:
Wrong. this is the recommended way to use every mobile phone battery. A full charge and discharge is called a cycle, and cycles are how battery lives are rated.
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Click to collapse
Please don't just post "wrong" without anything to back it up.
http://batteryuniversity.com/learn/article/how_to_prolong_lithium_based_batteries
Table 2 provides details as to why what I said is correct. A 50% discharge will not degrade to 70% capacity for 3-4x as many cycles as a 100% discharge. That amounts to up to double the useful life of the battery assuming your usage stays the same.
InspectifierWrectifier said:
Wrong. this is the recommended way to use every mobile phone battery. A full charge and discharge is called a cycle, and cycles are how battery lives are rated.
Click to expand...
Click to collapse
Have fun killing your battery very quickly by fully discharging all the time
raptir said:
Please don't just post "wrong" without anything to back it up.
http://batteryuniversity.com/learn/article/how_to_prolong_lithium_based_batteries
Table 2 provides details as to why what I said is correct. A 50% discharge will not degrade to 70% capacity for 3-4x as many cycles as a 100% discharge. That amounts to up to double the useful life of the battery assuming your usage stays the same.
Click to expand...
Click to collapse
Mobile device batteries are designed to be "fully" depleted. They are software controlled. You will never discharge a properly controlled battery 100%. This is why your device still has power to turn on and tell you that the battery is too low to turn on.
There are always exceptions to the rule. However, mainstream devices will almost always keep the battery at a safe level.
You cannot use a single chart on all lithium ion batteries. In fact, every one is different due to chemical and annode/cathode changes. This is why every battery has its own MDS for shipping purposes.
The small changes to batteries cause them to react differently to different usage patterns. When designing a battery these reaction patterns are supposed to be accounted for in the battery calibration.
A key engineering principal: a device should never be capable of destroying itself. Full discharge is normal operation for most devices.
Hi,
since there is currently no replacement battery/LiPo-accumulator available (read: I did not find any....) for this tablet
and LiPo accumulators have a limited lifespan - I am interested in prolonging this lifespan.
From reading regarding informations from the internet I found some factors, which "kill LiPo cells":
- Heat
- Excessed charging
- Excessed discharging
One suggestion for a longer lifespan of such cells was: Dont discharge the accumulator till the charging
logic cuts off the current and dont charge the cell until 100%.
I found an app which rings, if the charge reaches a configurable value, but I didnt found one for
alerting me, if the discharge drops below a certain value.
Is there any?
Is there a way to disable charging completely while the tablet is connected via USB and drinking
current from there?
What can I do?
(If someone knows of a source for replacement batteries...this would help too )
Best regards,
tuxic
How do you guys go about your battery usage, as far as charging? Do you let it drain down before charging it? I have a wireless charging pad on my work desk, so I just place the phone on it while working. But this doesn't allow it to ever drain very low. I know in the past, there was a believe in certain battery conditioning, but I'm not sure if that still applies these days.
ledvedder said:
How do you guys go about your battery usage, as far as charging? Do you let it drain down before charging it? I have a wireless charging pad on my work desk, so I just place the phone on it while working. But this doesn't allow it to ever drain very low. I know in the past, there was a believe in certain battery conditioning, but I'm not sure if that still applies these days.
Click to expand...
Click to collapse
I always charge my phone between 40 and 84%. I don't let the battery go below 20% and above 84%; there're loads of research supporting this as this extends battery health (wear) rather than 0-100-0. Wireless charging is absolutely in efficient as it generates heat which is bad for the battery and a substantial portion of the charge transfer is lost in heat. The only good part of wireless charging is it's ease of use.
You don't need to do any battery conditioning as your battery doesn't have any memory as they used to long ago...
my new pixel 7 does not charge all the way up during the night, it usually stops at 40-50%
I'm using a 5v 2A charger and high quality cable (already tried swapping them ).
Do you think it could be an hardware default ?
Power if off and charge.
If it still shows 50% charge return it.
Not acceptable, especially if the actual SOT reflects that.
Nytronx said:
my new pixel 7 does not charge all the way up during the night, it usually stops at 40-50%
I'm using a 5v 2A charger and high quality cable (already tried swapping them ).
Do you think it could be an hardware default ?
Click to expand...
Click to collapse
Did you try turning off adaptive charging?
hi
turn off the adaptive charging
I would return it immediately before you pass the window. I wanted to return mine for fingerprint reader issues, but I waited too long and now my only option is to swap it for a refurb device which is less than ideal.
Thats a good thing. Charging the battery to 100% stresses the battery, as does completely discharging it and reduces the longevity of the battery. I have mine set by ACCA to only charge to 90% and turn off at 5%.
gorilla p said:
Thats a good thing. Charging the battery to 100% stresses the battery, as does completely discharging it and reduces the longevity of the battery. I have mine set by ACCA to only charge to 90% and turn off at 5%.
Click to expand...
Click to collapse
Bump that low to at least 20% especially if you fast charge. It's the higher current load/temperature at the first 20% that causes the stress. It's important the battery is at least 72F at charge start, preferably 82-90F to avoid Li plating which will permanently degrade the cell if it occurs.
I aim for 40-80% usage range. That said on this heavily used device I expect about a 1.5 year battery life. Replacing batteries is just part of routine maintenance, no big deal.
While I always fast charge however I do midrange power cycling, what Li's prefer; it's less stressful. I'll frequently do 20% amounts too. What's convenient for me at the time. Rarely go above 90% as it's rather pointless and disproportionally increases charging time vs usage time.
Yeah, my current setup isnt perfect, but it avoids the extreme stresses while still offering me a charge for a full day.
However, my phones have only ever seen a 5% shutdown on a few occasions so there is no need to set a hard cutoff at 20%. It rarely gets that low and if it does, its because I cant charge it.
Typically I charge it in the car on way home from work, then when I go to bed. So the cycle throughout the day still is pretty ideal.
90->40%->65%->40%->90%
gorilla p said:
Yeah, my current setup isnt perfect, but it avoids the extreme stresses while still offering me a charge for a full day.
However, my phones have only ever seen a 5% shutdown on a few occasions so there is no need to set a hard cutoff at 20%. It rarely gets that low and if it does, its because I cant charge it.
Typically I charge it in the car on way home from work, then when I go to bed. So the cycle throughout the day still is pretty ideal.
90->40%->65%->40%->90%
Click to expand...
Click to collapse
If you resign yourself to changing out the battery when it's degraded (80% of its original capacity) it's not a big deal.
A battery failure is a big deal though; one I had came close to damaging the display on my N10+. That battery was degraded, lasted less then 1.5 years. I got lucky that time... not going to push my luck again especially over a cheap repair like a battery replacement.