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ClockworkMod (CWM) Recovery easy install for RK3066 and RK3188 -- TWRP/CWM Flash-Tool and root for RK3288
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Contributor
2013/07/09

As I just explained to Andy I just pulled out my tablet, haven't used it in about one to two weeks and noticed a significant bulge that was not there before. I immediately panic and came on the board in hopes of trying to find and answer or two. I came across some post regarding batteries bulging. After reading these I decided the best course was to open my tablet and check. Apparently battery number two (2), closest to antenna, was bloated, bulging. I decided I could not leave it in the tablet and risk it exploding so I cut its connection to the other battery and took it out. I also ordered a battery as per Andyffoo posted. Just letting you folks know, especially if you are going on three or four years with the tablet and you have not pulled it out of the closet and played with it that perhaps you should!
I still love this tablet and will try that battery Andyffoo posted about in the hopes of saving it.
In the mean time can I get an update from people who bought a new battery? How long ago, which battery and what rom are you currently running. It may help me decide whether to downgrade to a lesser power rom, or leave it as is or just go back to 4.2.2.
So if you can please let me know when you are able. I figure I got a month before the new battery arrives.

2013/10/23

Looks like my cube battery ballooning out is not an isolated incident.
Still happy with my new battery. Same specs as previously mentioned.
On installation I totally removed the old red and black wires. I soldered the new battery in as it came with plenty of wire length that were also red and black wires. Just make sure you remember which way round the wires go before removing the old wires.
The following users say thank you to andyffoo for this useful post:
maikal

Contributor
2013/07/09

andyffoo said
Looks like my cube battery ballooning out is not an isolated incident.Still happy with my new battery. Same specs as previously mentioned.
On installation I totally removed the old red and black wires. I soldered the new battery in as it came with plenty of wire length that were also red and black wires. Just make sure you remember which way round the wires go before removing the old wires.
Thank Andy. Yes, I don't know if its do to age and usage, I used it almost everyday to read kindle and update any apps that needed it. It has always run hotter than with the 4.4.2, but it otherwise was fine. So I can't tell whether it was its longevity being cut short do to the Kitkat upgrades or that it was already at 3 years old maybe! In any case, yes I ordered from the link you provided and the battery was like $22 on special or so they claim on special, but its already on its way and I will take it in and get it soldered by someone with experience in soldering these things on.
One more thing Andy, are you still using the same power cable that came with the tablet? I read somewhere on the forum about someone having trouble charging with the original cable after replacing their battery! I need to replace mine too so I wanted to know whether I need to order an original or a similar one from ebay.
Again thanks for your posts on the battery issues, ordering and updates!


Contributor
2013/05/25

I've installed a new battery. First time i spilled to much solder on the positive connector, causing a shortcircuit through the backplate. Got weird things like the battery, while loading, jumping from 2 to 4 to 2%. Got rid of the solder, measured the voltage(about 8 volt) and the battery was immedeately at 70% in android. Now is working just fine.
Cube u30gt2 tab

2013/08/18

Mark06 said
I've installed a new battery. First time i spilled to much solder on the positive connector, causing a shortcircuit through the backplate. Got weird things like the battery, while loading, jumping from 2 to 4 to 2%. Got rid of the solder, measured the voltage(about 8 volt) and the battery was immedeately at 70% in android. Now is working just fine.
Nice one, let us know how its doing after a couple of weeks

2013/10/23

maikal said
andyffoo said
Looks like my cube battery ballooning out is not an isolated incident.Still happy with my new battery. Same specs as previously mentioned.
On installation I totally removed the old red and black wires. I soldered the new battery in as it came with plenty of wire length that were also red and black wires. Just make sure you remember which way round the wires go before removing the old wires.
Thank Andy. Yes, I don't know if its do to age and usage, I used it almost everyday to read kindle and update any apps that needed it. It has always run hotter than with the 4.4.2, but it otherwise was fine. So I can't tell whether it was its longevity being cut short do to the Kitkat upgrades or that it was already at 3 years old maybe! In any case, yes I ordered from the link you provided and the battery was like $22 on special or so they claim on special, but its already on its way and I will take it in and get it soldered by someone with experience in soldering these things on.
One more thing Andy, are you still using the same power cable that came with the tablet? I read somewhere on the forum about someone having trouble charging with the original cable after replacing their battery! I need to replace mine too so I wanted to know whether I need to order an original or a similar one from ebay.
Again thanks for your posts on the battery issues, ordering and updates!
I am still using the original charger with a plug adapter as I live in the UK. Tablet charges fine. Takes a few hours to charge, similar period of time as my moto g phone.


Contributor
2013/07/09

Got new batteries, had them installed and the cube charged right up and it was a beautiful thing to see. However, the removed bloated battery may have done some damage to lcd with the pressure. I'm not sure. I am taking it back to me repair guy for a check again to see. I haven't done any battery test yet, but I do want to downgrade a bit on the kernel because it does get hot and that may have caused the battery to die/bloat prematurely, I don't know but don't want to take the chance again. I'll return to post after testing further after kernel change. I am optimistic though after reading Andy's updates.


Contributor
2013/05/25

My 13000 mah battery shows only 4,78 volts in battery app. Isbthis normal? Measured it with a volt meter and yes 7,4 volt or something like that, so that's normal. However that story of after use like 6 times recharge the battery downgrades a bit. Think my battery now only has a capacity of like 4000mah ):
it doesn't matter if i use rom 4.2 or 4.4.2, from 100 to 90 in about half an hour/45 mins with just setting up the cube and listening/streaming some music to my stereo.
Du battery saver pro gives 5625 mah for my 13000mah battery, so not really right buy.
Cube u30gt2 tab


Contributor
2013/05/25

If my theory is right, next thing:
13000mah at 7.4 volt. However when the cube is on it drops to about 4 volts due to the resistance. Now if you calculate that you get 7000mah at 4 volt. So guess all the new batteries you can order at chinese stores give about the original capacity of the cube battery.
ps. last reply was at 80 percent of battery capacity.
Cube u30gt2 tab


Contributor
2013/05/25

Wastes said
I tested both batteries you are talking about:Rated "11000 mAh":
Measured capacity after 6 cycles: 4600 mAh
Rated "12000 mAh":
Measured capacity after 3 cycles: 3900 mAh
The one I removed from my Cube after 8 months use and +- 4h working time: 3000 mAh
So the first one is better. I installed it and currently testing it.
The problem I had is the first battery is a little bit thicker than the original one, that leads to increased pressure on the back of the screen, giving a slight dull white stain in the middle of the screen (like a light leaking). However this is very faint and only noticeable with backlight at maximum and black screen.
Did you notice that Kellbain?
For the second battery I doubt the seller will tell you: "No, I isn't a LG battery, it's a fake…"
![]()
All 7.4 Lipo batteries are fitting the U30GT2, the tablet is regulating the charging voltage/current.
How do you measure the capacity of the battery?
Cube u30gt2 tab

2013/09/03

I think I will take a chance on the 13000mAh batteries. I will get back with you if my charger will test the capacity of two batteries in series (8.4v) if not, I will desolder one and test it.
I tested the stock battery in my cube and got an average of 2850 after three cycles.
I believe the values are false, if they say 12000mAh, they should be 12000mAh, not two 6000mAh in series.
In Series you double the voltage and keep the capacity so for example two 4.2v 6000mAh in Series is equal to 8.4v 6000mAh.
In Parallel you keep the voltage and double the capacity so for example two 4.2v 6000mAh in Parallel is equal to 4.2v 12000mAh.
This tablet must require 8.4v otherwise the batteries would be in parallel, we would have twice the run time and we wouldn't need a charge cord running 12v 2A.
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