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Discussion Starter · #1 ·
Before I begin with with the topic allow me to make a note about the following:

* When I received my tablet for the first time (more than two months ago), I noticed battery voltage would not go over 3.9V (~3900mV) no matter which charger I used. At that time I thought something was wrong with the tablet or the battery and I just gave up on fixing it. However, after 2-3 weeks I've noticed voltage began to raise with each charge in small steps, and by the end of the week #4 it would reach 4197mV after each overnight charge. Now I have the same issue with the new 5000mAh battery I bought. Currently I can't charge it to more than 3.9V, and every test was run starting from 99% battery charge (3.9V). While I do understand Li-Po / Li-Ion batteries do not need to be "adjusted", these Chinese one obviously do. If someone can enlighten me regarding this issue, I'd appreciate it.

Anyway, here follows the benchmark part. I thought that one of the best ways to put battery under heavy stress is to use it the way anyone of us would do: playing a movie. For this purpose I've decided to use MX Player simply because it's the best video player you can find for Android, and because it has a ton of settings to adjust. Although is offers 3 different playback modes: HW+, HW, and SW, I had to use HW because picture on the HW+ mode was not watchable (probably due to encoding codec of the video).

So, back to the movie. It's a DVDrip (resolution: 720x304) and the size was 1.4GB. I've set the playback to repeat, and let it turn off by itself alone. I've monitored the battery stats with Battery Widget Monitor and Battery apps. I've let only the first cycle to run on the original battery, and all subsequent cycles were ran on the new battery. Here are results


Original battery
Screen brightness: 100%
WiFi: On
Start voltage: 3896mV
End voltage: 3491mV
Battery duration: 1:08 (1 hour, 8 minutes)



(unfortunately I don't have a screenshot from BMW because it had erased the history file which I noticed only after I'd replaced the battery)

5000mAh battery
Screen brightness: 100%
WiFi: On
Start voltage: 3932mV
End voltage: 3513mV
Battery duration: 2:31 (2 hours, 31 minutes)

Battery app:



BMW voltage:



BMW percentage:



5000mAh battery
Screen brightness: 0%
WiFi: Off
Start voltage: 3895mV
End voltage: 3544mV
Battery duration: 4:58 (4 hours, 58 minutes)

Battery app:



BMW voltage:



BMW percentage:



As you can see, there is more than double juice in the new battery (according to my calculations 2.2x more). If you ask me whether to upgrade the battery, my answer would be: hell yeah!


Be sure I'll update this thread after the voltage raises to at least 4.1V when fully charged.
 

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Before I begin with with the topic allow me to make a note about the following:

* When I received my tablet for the first time (more than two months ago), I noticed battery voltage would not go over 3.9V (~3900mV) no matter which charger I used. At that time I thought something was wrong with the tablet or the battery and I just gave up on fixing it. However, after 2-3 weeks I've noticed voltage began to raise with each charge in small steps, and by the end of the week #4 it would reach 4197mV after each overnight charge. Now I have the same issue with the new 5000mAh battery I bought. Currently I can't charge it to more than 3.9V, and every test was run starting from 99% battery charge (3.9V). While I do understand Li-Po / Li-Ion batteries do not need to be "adjusted", these Chinese one obviously do. If someone can enlighten me regarding this issue, I'd appreciate it.
...
As you can see, there is more than double juice in the new battery (according to my calculations 2.2x more). If you ask me whether to upgrade the battery, my answer would be: hell yeah!


Be sure I'll update this thread after the voltage raises to at least 4.1V when fully charged.
Thank you very much for the benchmark.

Almost all Li-Ion batteries require a few full charge/discharge cycles to reach full capacity - having said that, any reasonably worthwhile Li-Ion battery ought to perform reasonably well right from the start - caveat is that it actually reached full charge.

Sometimes it could be the charger - either not delivering enough output current or not having a high enough output voltage to deliver that current -
and it can be the usb cable having too thin a gauge wire to be able to carry/deliver the current. The supplied usb cable was such a case for me (see post #3 link)-
perhaps try a known good usb cable - eg: I used the one supplied and working well with my Android phone.

I also did an ad-hoc battery life test -
please see post #7 (link) in ICOO D70 Pro II - user's perspective
with the original installed battery as-is -
I got 3hours 45mins
playing a 720p video with Wifi On (see post #7 for details and screenshots)
 

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Discussion Starter · #3 ·
Well, trust me I've read every possible thread about battery issues on Android devices on every forum Google could find, and I saw many people stumbled upon these kind of battery issues even with branded products like Samsung or Motorola


Here is what I've learned:
1. never trust battery percentage value which is displayed in Android (or any app dealing with battery monitor)
2. battery calibration is only a myth (confirmed by one of Android developers) and does nothing to fix battery issues
3. Li-Ion/Po batteries do not need priming, and it confirmed by various Li-Ion/Po experts (although it doesn't seem to be so as my original battery showed it's full capacity 3-4 weeks after I got the tablet; it might be the charging electronics within tablet which would track history of charging voltages, and raise it when it got to know the battery, I didn't have time nor capabilities to test the charging using external Li-Ion charger)

I've tried with 3 different chargers (desktop USB port, 700mA and iPod-style 2100mA) and 3 different cables (original that came with the tablet, and two different 2m long cables which charged Kindle 3 without problems). I've discovered the new battery reached 4V+ the first time today (it was 4019mV) which means it's starting to raise voltage, and I expect it will finally reach 4170mV+ in the following few days.

I've tested the original battery more than a month ago (I don't have saved screenshots), and it would play 720p movie with brightness set to 0% and WiFi turned Off for about 3:00-3:15 hours.

I did read your post just before I posted mine, and I'm still wondering how you managed to get so much juice with the original battery while your WiFi was turned On. However you didn't mentioned how was you screen brightness set up? At most times screen will be the main factor (or to be more optimistic: the main killer
) of how much power battery can give you regardless of the WiFi status (if you do not download anything the only activity WiFi will have is to occasionally exchange few packets with the router, and to periodically check for updates for background apps).

It might also be you got tablet with different stock battery. I've seen the capacity fluctuates between 2500-3000mAh depending on when and from where you bought the tablet.
 

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I did read your post just before I posted mine, and I'm still wondering how you managed to get so much juice with the original battery while your WiFi was turned On. However you didn't mentioned how was you screen brightness set up? At most times screen will be the main factor (or to be more optimistic: the main killer
) of how much power battery can give you regardless of the WiFi status (if you do not download anything the only activity WiFi will have is to occasionally exchange few packets with the router, and to periodically check for updates for background apps).
FWIW - my screen brightness was about 75% - ie: I could actually watch the video comfortably,
not that I have to prove anything
here's the screen shot to show it was not at 0% brightness -

I managed a screenshot of the video moments before the tablet shutdown:


shows the time of 3hrs 43mins - with remaining 1% battery charge - WiFi On -
tablet shutdown minutes later at 1:18.
 

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PLease techno.plug...can you tell me where i can buy a 5000mah battery for my D70pro, because i buy a3500mah battery but when i put it the tablet not recognized the battery
. Thank you.
 

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Discussion Starter · #6 ·

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Hi all,

I bought a 5000mah battery from Aliexpress....replaced mine, the tablest start well, after a second charging the tablet didn't start anymore!

I decided to replace the original ......the tablet booted again!!!!ouff!

Any explaination please?
 
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