Database Users

[Q] Nook Simple Touch - DOA Wont charge/turn on

Got a new nook simple touch- charged in for 24 hours - will not power up- has the same screen all the time "fully charge before first use".
Tried 4 different charges, cables and different PC's. Contacted Barnes & Noble support - talked me through all various software resets pressing buttons - nothing worked - then told me take it back to store. I cannot return the thing as live outside uk.
I have tried removing the battery by taking the thing apart , leaving battery disconnected for a few hours - reconnecting it but nothing works.
The LED light is always green when plugged into charger, from what i gather it should be orange when charging?
The battery also does not seem to be heating up when charging, i have touched it a few times to test its stone cold
Nothing happens when connected to PC either.
Does anyone know any reset procedure that i can try please as i am getting to the stage of throwing this thing into the bin?
it may just be a bad unit

If you have a voltmeter, see if you can measure a voltage across the red and black leads out of the battery.
The Nook will not boot up without a battery (on the USB obviously).
I haven't looked into whether it's a safety on the thermistor or what.

Renate NST said:
If you have a voltmeter, see if you can measure a voltage across the red and black leads out of the battery.
The Nook will not boot up without a battery (on the USB obviously).
I haven't looked into whether it's a safety on the thermistor or what.
Click to expand...
Click to collapse
Thanks i do have a voltmeter but there is no red black lead, there are 6 wires as in the image attached, do you know what the six wires are or is there anyway to find a pinout from them so i could meter it?
There's no other tricks to reset the battery is there i have heard sometimes the battery needs to be left unconnected for a few hours then reconnected but that didn't do nothing for me
Thanks

I see red, I see black.
The two red wires on the connector are positive.
The two black leads on the connector are negative.
The yellow and the green are for the thermistor to measure battery temperature.

A truly frozen Nook.
I finally got around to investigating fully the whole battery wiring on the Nook.
Some people have expressed interest in running a Nook without a battery.
Removing the battery and using USB power does not work.
As stated above, of the 6 wires, the two red are positive and the two black are negative.
The green wire is a battery ID.
This is a 30K ohm resistance to ground to indicate that the battery is plugged in.
The yellow wire is for battery temperature.
This is a NTC (Negative Temperature Coefficient) thermistor.
It has a resistance of about 10K ohms at room temperature, decreasing as the temperature goes up.
You can run your Nook without the yellow wire (thermistor).
(The battery temperature will be off.)
You do need the green wire (battery ID) to get the Nook to power.
If you want to run your Nook without a battery,
connect a 30K from green to ground (27K seems to work fine) and
connect a 10K from yellow to ground (just to be nice) and
feed the V+ battery with around 4V.
You might try feeding that with a diode voltage drop off the USB connector.
(I didn't try that.)
The screen shot indicates -40C for open and +40C for 5K ohms.
(Thanks to 160thehaven for the photo. I have no macro lens.)

Renate NST said:
If you have a voltmeter, see if you can measure a voltage across the red and black leads out of the battery.
The Nook will not boot up without a battery (on the USB obviously).
I haven't looked into whether it's a safety on the thermistor or what.
Click to expand...
Click to collapse
okay close to throwing this thing away, the light is always green. I think the battery is not charging. even though when plugged in i seem to be getting a voltage swing on the red and black wires.
Should i measure the voltage across the red and black wires when booting up the nook? with the usb disconnected

To make life easy, grab the ground off the metal cage for the SD card.
What's the voltage on the red with no USB connection?
When you connect the Nook to your PC does it ever say, "Found new device OMAP3630"?
The question, is the processor powering up at all?
Is it doing the primary bootloader?
Is it doing the secondary bootloader?
If you had a kernel console, it might tell you what's up.
Just for yucks, what's the voltage on the yellow and green test points?
Does it pulse every few seconds?

his eedolsi
Renate NST said:
To make life easy, grab the ground off the metal cage for the SD card.
What's the voltage on the red with no USB connection? i will test this now
When you connect the Nook to your PC does it ever say, "Found new device OMAP3630"?
yes it does and it looks for the driver and keeps connecting and reconnecting
The question, is the processor powering up at all? how would i know this
Is it doing the primary bootloader? how would i know this
Is it doing the secondary bootloader? how would i know this
If you had a kernel console, it might tell you what's up.
Just for yucks, what's the voltage on the yellow and green test points?
Does it pulse every few seconds?
Click to expand...
Click to collapse
yes when plugged in the light is solid green but then pulses orange every few seconds

160thehaven said:
yes when plugged in the light is solid green but then pulses orange every few seconds
Click to expand...
Click to collapse
Oh, I was asking if the green and yellow test points pulse.
What's the voltage on them?

Mdevai 155
Renate NST said:
Oh, I was asking if the green and yellow test points pulse.
What's the voltage on them?
Click to expand...
Click to collapse
i give up no voltage anywhere, i think the battery is defective
thanks for you help its going to go in scrap heap- only useful debug feature it does is flash the orange light the odd time when connected to charger- prob means something to barnes and noble
im sorry i purchased this

Aw, don't give up so easily.
I hate an unsolved mystery.
You're sure that your voltmeter is working correctly?
You can't measure anything from the V+ test point to the SD card metal frame?
There's no way to exchange it with B&N?
If you are really giving up, I'll take a look/keep it/fix it/return it/something.
Send me a PM for details.

I'm actually having the same problem. It started a couple of days ago. I tried using this method (http://forum.xda-developers.com/showthread.php?t=1813384) and I was able to at least boot it. However, after only one day (without using it much) it started failing again and now when I use that trick it lasts a few minutes.
I will try measuring the battery voltage and I wonder if it would be a good idea to try to re-root it. However, I don't know if I should try in case it freezes half way through the flashing and I end up with a nice black brick.
I think this issue is happening quite a lot. I hope we can all work together to find a solution.
--Update--
I checked the voltage on the battery and it shows 40mV. So it's definitely depleted. However, when I do the trick and manage to boot the device, it says that the battery is 100% charged and the green LED is on. Conclusion, the device is preventing the battery from getting charged :/ Any ideas how to fix this? Is there any other way I can charge the battery?

40 mV?
If your voltmeter is working and on the correct place, then your battery is way dead, as in broken.
We can argue about whether you should discharge Li ion to 3.5 V, 3.3 V, 3.0 or even 2.5V,
but if any time it's reading a lot less than that, then you have a deceased battery.
If it's open or high resistance, a charging circuit can take it up to 4.1 V easily.
It would show as 100% charged but have no actual charge to backup that statistic.
It's interesting, because the BQ24072 should be able to power up the Nook without a battery.
I think it's that pesky MSP430F2272 that is not allowing the Nook to go on without a battery.
This calls for more experimenting!

Renate NST said:
40 mV?
If your voltmeter is working and on the correct place, then your battery is way dead, as in broken.
We can argue about whether you should discharge Li ion to 3.5 V, 3.3 V, 3.0 or even 2.5V,
but if any time it's reading a lot less than that, then you have a deceased battery.
If it's open or high resistance, a charging circuit can take it up to 4.1 V easily.
It would show as 100% charged but have no actual charge to backup that statistic.
Click to expand...
Click to collapse
First of all thank you for your help.
Maybe I measured it wrong?... I was checking the voltage between the red cable (or so I think) and the metallic frame where you put the micro SD card. I also checked it from there to the black cable and it said 0 V, as I was expecting.
Renate NST said:
It's interesting, because the BQ24072 should be able to power up the Nook without a battery.
I think it's that pesky MSP430F2272 that is not allowing the Nook to go on without a battery.
This calls for more experimenting!
Click to expand...
Click to collapse
Definitely! I'm up for it!

Look, Ma, no battery!
The Nook seems pretty idiosyncratic how it will turn on.
I was trying to make it work just USB powered.
At the least, that gives the people with battery problems a reference point.
On the photo above there are two points labelled "V+ Battery.
Solder the cathode (the stripey end) of a 1N4001 (or better) diode to one of these points.
Connect the anode of the diode to the red wire of a spare, gutted USB cable.
Connect the black wire of the USB cable to the gold border on the circuit board.
Plug in the USB cable. The Nook should boot.
I've tried just stealing the 5V off the Nook's USB connector, but the Nook refuses to boot when both the USB and battery come up at the same time.
The ID and the thermistor circuits don't seem to be that necessary.

i have same DOA device (Simple Touch with Glowlight) , wont power on , green led on usb charger or pc usb cable , quickly reappeared 3630 omap device in device manager when pressed power button
i disassembled device - accu show 2.4v , i recharged accu in turnigy charger - it normally charged about 3 hours and show capacity 1550mah but when i connected it back to the nook it wont power up again and same green light on charger and usb cable , i try all reset combinations - no luck

It is possible for your battery to accept current, charge and still not be able to supply any current.
This would be the case if the charge circuit is working but the discharge circuit is open.
Did you measure the battery voltage after charging?
Can you measure it with some sort of load on it?
50 to 100 ohms would be fine.
If anybody has gotten far enough to tear a battery down any identifying photos of the battery protection module would be appreciated.

i find another working nook (without glow) , tomorrow i check battery (but battery is ok - i try it in charger . internal resistance is low an discharge on 1A corrent is ok )
but now i solder wires from regulated power supply to battery tp - i find nook consumption is 160 mA current on 4.2 v supply and it reacted on power button - if i press pw about 20 - 30 sec is 0 ma current press again and 160 mA still here

battery is ok . screen is ok , mainboard is not ok
working nook eat 150 mA current on start , working nook not start when regulated power supply connected on battery tp - press power button , 150 mA . depress button - 0mA

replaced mainboard ( from nook gl with broken screen) - all working ok

dead nook ST!

Hi!
I bought a brand new NST on ebay, when i plugged to charger the led light up as green, dont orange. few hours later i coudnt turn on, i disassembled the nook. the battery case was torn, the voltmeter show 0,3 V, my multicharger coudnt see as a lipo battery. i bought a 3,7V 1500mAh lipo cell, i cut the "charger pcb" from the old battery, soldered to the new cell. but not working. when i plug to charger or usb the led light up green. but green without battery too. the pc show as a "omap 3630 device, but nothing too.
the new battery show :3,99V on black-red wire.
9,2 K resistance on black-yellow
99,8K resist. on the green-black with the original wiring, but nothing.
I try to solder a 10K to yellow and 30K to green resistance to ground (black) but not working this method!!! the led is green when i plug to charger with or without battery. i thing the nook cant see the battery is plugged.
can anyone measure and tell me the original battery good parameters???? yellow-black, green-black,etc. or what can i do that the nook see the battery. the original battery was LICO, china!!!!
I m live in hungary, i bought from uk, the delivery cost was 1/3 price of the nook, the re-send and re-delivery cost not return...
thanks!!!!
update: if i try to charge the battery pack via 6pin outlet with my lipo charger (red-black wire),it identify as a 3,7V lipo cell but say the "connection break" after 2 second charging. if i try to charge directly on the cell pinouts its everything ok!!!!
i cant buy a new battery in hungary now. if i soldering 10K,30K,+ and ground directly to the battery without "charging pcb" it s good idea or other solutions???
thanks

More people seem to have problems with batteries.
I'd like to see if we could get a handle on this.
Some background info:
If you plug a USB host (like a PC) into the Nook with or without a battery it should do the inital power up.
The processor finds itself powered up somehow and starts executing internal bootstrap code in ROM.
It identifies on USB as OMAP3630.
It waits around a few seconds for a command then continues.
Depending on which jumper resistors are soldered in (I'm still looking for this info),
it tries to find the primary boot loader on the SD card or the internal NAND.
The file it looks for is MLO on a FAT disk.
This file is actually x-loader, a very simple loader.
x-loader will load u-boot.bin
Here is where things get complicated.
Up until this point the processor only knows that it seems to have power.
It has not engaged enough peripherals to figure out what or how.
It's at this point that u-boot checks to see if a battery is connected,
what the temperature and voltage is.
Although from a technical point of view the Nook could boot up Android now
without a problem u-boot does not allow it.
Everybody has had that annoying situation of a dead Nook plugged into
a charger and wants to read their book but u-boot digs its heals in and says,
"No, you have to wait while I do some charging."
If you have the battery disconnected but the two sources of identification
wired around (the thermistor and the ID resistance) the Nook will try to charge.
See: http://forum.xda-developers.com/showthread.php?p=42552349#post42552349
It will pulse on and off at about a one second cycle the charging on the battery.
If you connect an LED and a 220-1000 ohm resistor between the battery connection
point and ground you should see it flashing.
If at this point you connect just for a moment the two wires of an external LiPo battery
the display should be activated and go through the charging animation.
Remove the battery and the animation will continue.
This is proof that the Nook could be happy without any battery.
So where does this leave you with your specific problem?
The first question is whether your original battery really has a problem or just discharged.
If you tore the battery apart and couldn't even charge it without the battery protection module that might be something.
Note: I am not advocating the permanent removal of the battery protection module.
I'm just saying for the purpose of testing when you have your eyes right on the battery it's ok.
Check to see if you can get the LED above to flash.
Check if your hacking resistors are correct.
You had a McNair battery pack and the ID resistance was 100K?
I was trying to get my kernel console on the Nook working but something is screwy with it right now.
I would have liked to see if some of the printf's in u-boot were saying something.
Edit:
I just realized that you reused the old BPM from the old battery.
We haven't yet ruled that out as the problem.
Try (as an experiment) using the new battery without the BPM.
Make sure that the voltage on the battery stays between 3.5 and 4.0 V
Do not permanently install anything without the BPM!

Ok,
i cut the battery pcb (protection module) from the new cell and the 6 pin outlet.
connected the wires directly to the lipo cell as follows:
2X red wire to batt +
2x black wire to batt - (ground)
yellow wire to ground via 10K resistor
green wire to ground via 30K resistor
i connected the 6pin plug to the nook and it turned on!!!!!
i do not know that i get or make other protection module for the battery. Anyone can measure the values of R and C? I do not dare to use without module via usb or charger. i can charge the battery separated from the nook, but not the best...
i dont know whats the MCNair battery pack.
on the old battery label:
Model No.:s11ND018A REV: B
LICO, made in China
and yes, the green-ground resistance is 100K on protection module.
i cant discharge the battery with my multicharger if i connect via module. (i try 0,1 and 0,5A too,not discharge)
many thanks

Need help troubleshooting, dead rk3066 tablet

Hello,
I need help with my new tablet.
Model is Allfine Fine10 Yoy.
Specs:
Rockchip RK3066, 1.6GHz, Cortex A9 dual core; GPU: Mali 400 MP4
Android 4.1
1GB (DDR3)
16GB Nand Flash
10.1 Inch / IPS
Battery: 7800mAh
It is not so old, about 5 months. Few days ago I have left it to charge overnight (it usually takes 4-5 hours to charge so I always charge it overnight) and in the morning it could not turn on. It is dead, no signs of life. I checked maybe it did not charge, so I changed power socket and tried again.
I can not charge it via USB so I can't test that.
There is not sign of life when connected to PC, adb list's no devices.
There is no sign of life after holding power/lock button for a long time and there is not signs after holding restart button.
It came factory rooted, I've never updated/flashed or anything.
I have not noticed any troubles so far, no lags, no freezing, no overheating.
Are you familiar with debug method for this kind of tablet?
What should I do, what test to make?
Can you help me debug this, please.
Thank you.

cheap china tablets are easy to open up. just pry the back cover off carefully and put a volt meter on the battery. its probably dead.
check your power supply first, it might have croaked too.

Would it be possible to run tablet with removed battery, straight off adapter to check is it working?

mrnjau said:
Would it be possible to run tablet with removed battery, straight off adapter to check is it working?
Click to expand...
Click to collapse
Possibly, at least some part of startup.
Most device processors will start up if they notice power coming from somewhere.
At some point try will try to access the state and source of power.
If they notices that the battery is really dead (that is, the power is only from USB) they will shut down and go into charge-only mode.
It may be more likely that your battery is charged and the processor got wedged somehow.
Disconnect from USB, open the back, disconnect the battery and reconnect it.

Renate NST said:
Possibly, at least some part of startup.
Most device processors will start up if they notice power coming from somewhere.
At some point try will try to access the state and source of power.
If they notices that the battery is really dead (that is, the power is only from USB) they will shut down and go into charge-only mode.
It may be more likely that your battery is charged and the processor got wedged somehow.
Disconnect from USB, open the back, disconnect the battery and reconnect it.
Click to expand...
Click to collapse
Thank you for your reply,
I've precedeed as you sugested.
Solder is pretty hard on battery connection, so I unsoldered just one (negative wire, red one) and pluged it to charger and try to start it. I undsolderd just one because I don't want heat to ruin something and I guessed it should be enough to try this.
It still shows no signs of life.
However I've noticed something, when re-soldering red wire I have noticed that there is a spark when wire is near the solder point. So, there is some power in battery.
Any idea how to proceed? I still don't have multimeter to test battery voltage so that will have to wait.
Thanks once again.

Oh, sorry, I thought that the battery was on a connector.
That makes life easier than soldering.
The red wire(s) are always the positive.
The black wire(s) are always the negative (ground).
Any other color wires on a battery are thermistor, id sense or communication.
Yes, finding/borrowing a voltmeter is the next step.

Renate NST said:
Oh, sorry, I thought that the battery was on a connector.
That makes life easier than soldering.
The red wire(s) are always the positive.
The black wire(s) are always the negative (ground).
Any other color wires on a battery are thermistor, id sense or communication.
Yes, finding/borrowing a voltmeter is the next step.
Click to expand...
Click to collapse
Renate, I hope you still follow this topic.
I'm sorry for 2 months without updates, I've waited for some time for parts from China.
So, what have I done so far...
1) Get multimeter.
2) Test battery.
Battery is designated as 3.7V, however output is 4.15 - 4.16 V.
I've presumed this is fine.
3) Test the charger.
Charger is designated on 5V and 3A. I've tested voltage, it is fine. However ampers dance between 0.5A and 3.5A. I've presumed that charger is faulty, so I've ordered new one. Generic 5V, 3A charger.
4) Put it back together, re-solder the battery and connect charger. Test again.
Voltage on battery connectory is same as before - 4.15V.
After 20min there is no change in battery temperature (source: my fingers), however power jack where new charger is connected is getting warm, but not too warm.
Tried to power it on, no signs of life. Tried holding restart button for forewer, no sign of life.
I'm out of ideas.

3 Amps is a heck of a charger.
Where did that come from? Is it stock?
You have a little round coaxial connector for the charging input on the tablet?
There's no reason that it should be drawing 3 amps or anything getting warm.
The battery is fully charged.
There could be a high resistance in the battery protection module so that it looks charged but can't actually supply any current when called upon.
There's a USB connector on this too?
And nothing appears when you connect a USB cable to it?
I wouldn't expect ADB, but maybe a bootloader.
Run devmgmt.msc when plugging it in and see if anything at all shows up.

Renate NST said:
3 Amps is a heck of a charger.
Where did that come from? Is it stock?
You have a little round coaxial connector for the charging input on the tablet?
There's no reason that it should be drawing 3 amps or anything getting warm.
The battery is fully charged.
There could be a high resistance in the battery protection module so that it looks charged but can't actually supply any current when called upon.
There's a USB connector on this too?
And nothing appears when you connect a USB cable to it?
I wouldn't expect ADB, but maybe a bootloader.
Run devmgmt.msc when plugging it in and see if anything at all shows up.
Click to expand...
Click to collapse
Stock charger is 3A, so I bought with indetical specs. My research showed that a lot of chinese tabs use 3A chargers (Ainol Hero, etc..)
Yes, charger connector is 2.5mm "needle".
Some 30min after I posted this area around connector and speaker on motherboard got very very hot, I almost injured myself by touching it. So I've disconnected it.
No, nothing on USB. I've mentioned it in my first post, there are no signs of life on adb. Or "dmesg", which should list something even if device was bricked.

Um, are you sure that the polarity of the supply is correct?
For coaxial plugs the center is usually positive.
If it got that hot you probably have blown something.

Renate NST said:
Um, are you sure that the polarity of the supply is correct?
For coaxial plugs the center is usually positive.
If it got that hot you probably have blown something.
Click to expand...
Click to collapse
http://www.amazon.com/2000mah-Adapt...6-6172141?ie=UTF8&refRID=1AED4Q5XRX7QS8JJ91Y9
This is that kind of power connector, 2.5mm. Are we talking about the same thing? Is is possible for this kind of connectors to have non-standard polarity.
Maybe nothing is blown, I would smell that. Maybe there just hi resistance somewhere along the line.

Well, if it's the same charger and it used to charge then the polarity must be ok.
Still, something is not happy.
You should have been able to get it working with just the battery.
The DC input should not be getting hot.
I can only say so much from this distance.

Renate NST said:
Well, if it's the same charger and it used to charge then the polarity must be ok.
Still, something is not happy.
You should have been able to get it working with just the battery.
The DC input should not be getting hot.
I can only say so much from this distance.
Click to expand...
Click to collapse
I can't find any info on ampers and battery. I can't measure any amps coming out of battery, that's strange. I don't know much about this but should not battery put up some ampers?
Yeah, I understand that DC port should not get hot. Only 2 options.
1) Charger (the new one) is putting up too much electricity, to many amps that is.
2) There is something faulty on DC port or around it and causes too much resistance and thus heat.

Black screen with white streaks when powering up then black

I have been reading all the posts regarding the dreaded "black screen" issue. However mine doesn't seem to fit the bill
It has been left to discharge and wouldn't boot up. i plugged it in (wall charger) and left it for 24hrs. I tried to boot it up but all that comes on is the Google logo then i see some white video streaks then it turns black again
It is rooted and i tried to boot into TWRP but it shows the same streaks then it turns black again. I did press on the back where the connector was supposed to be and thinking would fix it but no success
I do not know what else to do.
Do i need a new screen? I wouldn't mind to replace it if i knew that was the problem but i am not sure if that is the case
Is there anyone that had a similar experience and can maybe share some ideas?
I would really appreciate it!!
Thank you

rainfactor said:
...regarding the dreaded "black screen" issue. However mine doesn't seem to fit the bill
It has been left to discharge and wouldn't boot up.
Click to expand...
Click to collapse
I was under the impression that that scenario is exactly the bill - the battery drains off to such a low voltage that the internal charge controller circuit doesn't work correctly at that low voltage, even when you put the device back on the charger, so you are stuck with a not-dead unit that won't turn on, and also won't take a charge. (But that hardware isn't dead - you just need a partial charge on the battery to get the charge circuit to start working again.)
The only recourse really is to get a *small* amount of charge on the battery by some means other than the built in charger, and then reconnect the battery to the tablet and put it on the charger to complete the charging.
There are disassembly instructions on here that take you through the steps necessary to get to the battery connector (it detaches and has a short run of wire between that connector & the battery so that should be convenient for attaching the battery to something else without removing the battery from the tablet). Use the search functions.
If you can borrow a voltmeter, the symptom will be obvious: a very discharged battery will have a terminal voltage around 3.0v (maybe less). Under normal conditions the battery voltage will rise to about 4.05v when fully charged (measured when disconnected from the charger) and be somewhere around 3v when completely discharged.
Don't do anything stupid (there are examples of that on here too). The charger that you use needs to limit the amount of current to a reasonable value, say less than 500 mA. The battery can tolerate up to about 1.8 Amps of charging current but you should use something far more conservative than that for safety reasons. And you are only trying to put a small charge on the battery (not completely charge it) so you don't need to use the fastest possible charging rate anyway.
Something incredibly cheap would be a USB cable (with the micro-B connector cut off) and a 1/4 watt, 100 ohm resistor connected to the positive supply line coming from a 5 volt USB wall wart charger. Even if the battery was a dead short, only 50 mA of current would flow and the resistor wouldn't burn up. If the battery was good but heavily discharged, you'd only be charging at a 20 mA rate - that would put a 10% charge on the battery in ~30 hours.
If you initially measured the battery and found it had a voltage of 2.5v or higher, you could use a 22 ohm, 1/4 watt resistor safely and charge the battery 10% in only 8 hours or so.
You can charge faster by using a resistor of a higher wattage rating, but 1/4 watt size are readily available and cheap.
The equation for power dissipated in the resistor is
P > V^2/R or
R > V^2/P = (Vs- Vb)^2/P
So for example in our case with Vs = 5, Vb = 3 and a 1/4 Watt (P) resistor, we would get
R > V^2/P = (Vs- Vb)^2/P = (5-3)^2/0.25 = 16 ohms.
The "dead shorted battery" worst case would be Vb=0 or
R > (5-0)^2/0.25 = 100 ohms
(so you can see where the numbers came from)
Anyway, that's my recommendation
- disassemble to the point of exposing the battery connector
-disconnect battery from tablet
- put battery on simple & safe charging circuit (+ terminal to resistor to + terminal, and - terminal to - terminal)
- let it sit for a while*
- reconnect to tablet and finish charging
- profit
* if you leave a live circuit unattended, even if it is only a 5v circuit, please please no exposed wiring or loose connections. Use tape and plastic straws for temporary insulation... or shrink wrap if you prefer a neater look.

bftb0 said:
I was under the impression that that scenario is exactly the bill - the battery drains off to such a low voltage that the internal charge controller circuit doesn't work correctly at that low voltage, even when you put the device back on the charger, so you are stuck with a not-dead unit that won't turn on, and also won't take a charge. (But that hardware isn't dead - you just need a partial charge on the battery to get the charge circuit to start working again.)
The only recourse really is to get a *small* amount of charge on the battery by some means other than the built in charger, and then reconnect the battery to the tablet and put it on the charger to complete the charging.
There are disassembly instructions on here that take you through the steps necessary to get to the battery connector (it detaches and has a short run of wire between that connector & the battery so that should be convenient for attaching the battery to something else without removing the battery from the tablet). Use the search functions.
If you can borrow a voltmeter, the symptom will be obvious: a very discharged battery will have a terminal voltage around 3.0v (maybe less). Under normal conditions the battery voltage will rise to about 4.05v when fully charged (measured when disconnected from the charger) and be somewhere around 3v when completely discharged.
Don't do anything stupid (there are examples of that on here too). The charger that you use needs to limit the amount of current to a reasonable value, say less than 500 mA. The battery can tolerate up to about 1.8 Amps of charging current but you should use something far more conservative than that for safety reasons. And you are only trying to put a small charge on the battery (not completely charge it) so you don't need to use the fastest possible charging rate anyway.
Something incredibly cheap would be a USB cable (with the micro-B connector cut off) and a 1/4 watt, 100 ohm resistor connected to the positive supply line coming from a 5 volt USB wall wart charger. Even if the battery was a dead short, only 50 mA of current would flow and the resistor wouldn't burn up. If the battery was good but heavily discharged, you'd only be charging at a 20 mA rate - that would put a 10% charge on the battery in ~30 hours.
If you initially measured the battery and found it had a voltage of 2.5v or higher, you could use a 22 ohm, 1/4 watt resistor safely and charge the battery 10% in only 8 hours or so.
You can charge faster by using a resistor of a higher wattage rating, but 1/4 watt size are readily available and cheap.
The equation for power dissipated in the resistor is
P > V^2/R or
R > V^2/P = (Vs- Vb)^2/P
So for example in our case with Vs = 5, Vb = 3 and a 1/4 Watt (P) resistor, we would get
R > V^2/P = (Vs- Vb)^2/P = (5-3)^2/0.25 = 16 ohms.
The "dead shorted battery" worst case would be Vb=0 or
R > (5-0)^2/0.25 = 100 ohms
(so you can see where the numbers came from)
Anyway, that's my recommendation
- disassemble to the point of exposing the battery connector
-disconnect battery from tablet
- put battery on simple & safe charging circuit (+ terminal to resistor to + terminal, and - terminal to - terminal)
- let it sit for a while*
- reconnect to tablet and finish charging
- profit
* if you leave a live circuit unattended, even if it is only a 5v circuit, please please no exposed wiring or loose connections. Use tape and plastic straws for temporary insulation... or shrink wrap if you prefer a neater look.
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Wow! THANK YOU VERY MUCH !! I did not expect such a detailed answer.
I REALLY appreciate for taking the time to answer me!
I will try the things you recommended:good::good::good:

rainfactor said:
Wow! THANK YOU VERY MUCH !! I did not expect such a detailed answer.
I REALLY appreciate for taking the time to answer me!
I will try the things you recommended:good::good::good:
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Click to collapse
The more information you can collect before you begin the more confidence you will have. Hopefully you have a voltmeter or can borrow one to insure you are getting the wiring polarity correct and you are not going to damage anything or cause a fire.
If the battery voltage is closer to 4v when you first crack open the device, then this hypothesis about an overly-discharged battery is not correct, and you should assume that some other mechanism is involved.
The resistor values I used as examples are just barely big enough to meet their own thermal rating (1/4 watt in the examples), so that means that they can get hot. I'm pretty sure their thermal rating is for "natural convection", meaning that you don't need to put a fan on them to keep them cool, but you shouldn't cover their bodies up with any insulation or shrink-wrap. Nor should you leave them in that state next to a pile of papers or a jug of gasoline
A more sophisticated approach would involve using an adjustable battery charger that operates near 5v (the normal wall-wart USB voltage) and will let you set the current level, but almost nobody owns one of those. (But I have plenty of dodgy USB cables that the cats have chewed on that can be sacrificed for a quick-n-dirty trickle charge exercise.)
good luck.

Has anyone tried connecting 5 Volts directly to the internal battery terminals ?

Does it damage the Board or not?
I accidentally did connect 5v for a second or so,
it did power on, i disconnected immediately, and after that it didnt power on for several hours,
but not sure if it was because of the interruption during boot, or overvoltage.
Can somebody confirm?
(i cant use a diode for voltage reduction, its a bit complicated, i use a load sharing capable solar charger board etc)

its a nook simple touch

Yow, don't do that!
Ok, it should be able to take it, but still.
I've often fed 4V to devices which had their battery blow up.
In worst cases I've used a diode for drop, but the voltage can be pretty variable over load.
The uboot on most things will not continue if there is zero voltage on the battery.
Also, the peak current of a device can go up to 600 mA or more at times.
That kind of current often can't come in through the USB connector.
Finally, battery packs have ID connections and thermistor.
Entirely disconnecting a battery pack will often prevent booting even when voltage is present.
If you have a dead battery pack always keep the the connector, cable and tiny PCB inside.
Attach a power supply to where the naked cells used to connect to the PCB.
For wiring of the battery pack see: https://forum.xda-developers.com/showpost.php?p=42552349&postcount=5

thanks, 2 weeks ago i prepared to measure possible resistors but did a google search before, found your description...
i use the protection board with a 18650 3000mAh lithium manganese (to prevent blow (up)) etc cell and charge it externally,
which requires switching between charging the batt + powering the nook over the batt terminals,
and using the batt for powering the nook , all that while the usb keyboard is connected and in use,
this is done via relay and a really big capacitor, which works great but is a bit ghettostyle.
i tried to use another charger board with load sharing circuitry instead,
but the only easy available module requires 5v minimum input, passes this 5v to load if the ac adapter is plugged in,
if not, it passes the battery voltage to load,
so a diode(+ parallel resistor to maintain voltage drop) or LDO doesnt work because it would at least steal around 0,5 v,
which is to much reduction for the battery voltage, because the nst powers off at ~ 3,7v,
easiest would be to just let the 5v to the nook but seems no good idea.
anyways, it works with the relay