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Hey Guys,
I have a Nook Simple Touch.
And the Battery is acting up.
Need to put a clip on it for it to work.
Does anyone know where i can get a replacement battery from?
I stay in India so there is no B&N support here.
Also sending mine back will cost as much as a new one.
And i have already opened mine up.
Update: Fixed
there is a small PCB [wrapped in blue tape] that is connected to the battery.
one of the connections here for some reason had come off [the one further away from the connecting wire].
I soldered it back on.
so far so good.
Did U solved your problem with Nook's battery
Battery for my nook is swollen...Really bad
I am trying to find replacement battery....
Any help would be appreciated...
dhananjay1287 said:
Battery for my nook is swollen...Really bad
I am trying to find replacement battery....
Any help would be appreciated...
Click to expand...
Click to collapse
If you're in the US here's the one that I have, right around $5 shipped: http://pages.ebay.com/link/?nav=item.view&id=251406061206
OB
Sent from my SPH-D710VMUB using Tapatalk 2
Trying to make my own power supply...
I am India....
So doomed, No shipment
I am currently trying to create my own supply using 4 AA battery cells.
As I i could not get my hands on any compatible Lipo-battery.
I was able to power my nook with Bench power supply at 4.3V and putting 10K, 27K resistance between ground (blck) & yellow, green wires resp.
Now I am currently working on creating 4.3V supply from 4 AA cells.
What do u think...
Any suggestions....
3 alkaline cells should be plenty.
That gives you an open circuit voltage of 4.8V
When it gets to mostly dead it's 3.6V
Do I need to regulate that supply....
Renate NST said:
3 alkaline cells should be plenty.
That gives you an open circuit voltage of 4.8V
When it gets to mostly dead it's 3.6V
Click to expand...
Click to collapse
Is it necessary for me to put some sort of circuit to regulate the supply.
I mean can nook handle 4.5-4.8V supply from 3 cells.
And thanks again...
One more doubt...
Why this setup is not working when supply voltage is between 3.7-4.2.
Which is the operating voltage of the 3.7V lipo battery.
I can't tell from here why it's not working.
Double check your wiring.
Peak current can exceed 600 mA. Are you supplying that?
I wouldn't bother with a regulator on 3 alkaline cells.
I might throw a 1N4001 diode in series to drop down 0.7V just to be safe-ish.
If you had a level shifter on UART1 you could see what is happening.
Normally without a battery you can't see anything happening.
Here's an edited startup with the battery disconnected:
Code:
bq27520 status 0xc07
Get DATE: 0-01-01 (wday=0) TIME: 18:82:83 2257335851
Initial voltage 627 mV charge 0 %
BBLOG: 2257335851 627 0 0 1055 0 263
usb detected
bq24073: not safe to change current
It's the u-boot that is picky and wants a battery.
Connecting a battery, even at this point allows a normal boot.
Here's a normal boot with battery (actually my battery eliminator):
Code:
bq27520 status 0x138
Get DATE: 0-01-01 (wday=0) TIME: 0:07:05 2257266473
Initial voltage 4019 mV charge 93 %
BBLOG: 2257266473 4019 -21 93 1301 1195 202
usb detected
charge current request 500
Renate NST said:
I can't tell from here why it's not working.
Double check your wiring.
Peak current can exceed 600 mA. Are you supplying that?
I wouldn't bother with a regulator on 3 alkaline cells.
I might throw a 1N4001 diode in series to drop down 0.7V just to be safe-ish.
[/code]
Click to expand...
Click to collapse
This part I understood and will try it and get back to you.
next part can you explain a bit, I did not understand it
I'm just saying that the Nook will boot up a bit with no battery connector plugged in and just the USB for power.
It will load the MLO and the u-boot.bin
At that point is when the boot process will stop if there is no battery.
Externally, you won't have seen anything happening.
If you have a terminal on UART1 (with the proper 1.8V to TTL to RS-232 converter) you can see the above logs.
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
Lately – I’m not sure when this stated, my Nexus 7 (running 4.4.2) has been charging absurdly slow. I’m talking 20%-30% in a span of 24 hours. It’s like it’s hooked up to a trickle-charge. I’ve tried 2 different OEM cables and 2 different OEM chargers (I had the one that came with it, and I ordered an official Asus OEM replacement charger with cable as well, to have as a spare).
I downloaded Battery Monitor Widget and while it sees it as plugged in via AC, the charge rate is -9ma (in other words, while plugged in, running nothing but the battery monitor, instead of actually charging, it simply reduced the discharge rate from negative 718ma to negative 9ma).
The only thing I can think of is this: as I understand it, USB AC adapters capable of “fast charge” (2ma) first test the device to see if it’s compatible, to avoid potentially over-charging the unit. Perhaps my device is not properly responding to this test? Perhaps that’s why it’s not providing enough juice?
Or maybe someone else has some better insight and can educate me. I’m certainly open to learning. Any ideas?
WraithTDK said:
The only thing I can think of is this: as I understand it, USB AC adapters capable of “fast charge” (2ma) first test the device to see if it’s compatible, to avoid potentially over-charging the unit. Perhaps my device is not properly responding to this test? Perhaps that’s why it’s not providing enough juice?
Or maybe someone else has some better insight and can educate me. I’m certainly open to learning. Any ideas?
Click to expand...
Click to collapse
[apologies in advance for a long-winded reply; hopefully some of it will be useful to you]
The OEM charger should be capable of 2 A (not 2mA).
Dumb chargers don't "talk" to the tablet. (Well, except for Apple USB dumb chargers - Apple violates the USB spec with their proprietary hardware, and that raises the meaning of "dumb" to a whole new level).
The tablet tries to draw what it wants, and if the wall charger is capable of supplying that current, everything will be fine - meaning, that the output voltage of the charger will be stable (near to 5V). If the tablet tries to draw more current from a charger than the charger is designed for, what usually happens is that the output voltage of the charger will start to droop down. (Sometimes, even worse things can happen, such as the voltage coming from the charger will start to oscillate.) This will have the effect that the voltage drops down to the point where it is barely larger than the voltage from the battery, and so the current flowing out of the charger gets limited that way.
But you shouldn't have this problem as you have at least two OEM chargers, and more than one cable, suggesting that your difficulty is with the tablet somehow.
I note (from your post) that you can observe the actual charging current; this suggests that you have a custom kernel on your tablet, as the stock kernel doesn't have the BQ27541 patches which allow current monitoring (only battery voltage and percent charge).
Here's the reason why I mention this. (Oh boy, get yourself a beverage, this is a long story).
I was going to be making some long drives (>13 hr) and I wanted my N7 in the vehicle, WiFi tethered and active (Google Nav and so forth) As you have observed, when you have the tablet running and are poking away at the screen, it can draw anywhere from 300 mA to more than 1000 mA, depending on how many cores are alive, which CPU frequency is in use, the screen brightness, streaming activity, etc.
And unfortunately...I was in a hurry: I couldn't wait for a car charger to be delivered following an online purchase. And all the local electronics stores seem to only sell high-capacity car chargers that are "Apple Compatible", which is marketing speak for "violates the USB spec". The N7 expects compliant behavior from chargers.
So, I bought two of those "Apple Compatible" car chargers from different manufacturers, and also bought a micro-USB cable that I could hack. I opened up the cable, clipped the D+/D- wires, connecting them together on the "Nexus 7" end of the cable, and left them open on the charger side (open but insulated of course). This has the effect of preventing the N7 from thinking there is a data connection present - the Apple chargers twiddle those D+/D- lines a little bit, and that prevents the (USB spec-compliant) N7 from thinking there is a dumb charger on the other end of the cable.
I wanted to be sure that what I had was actually working correctly, and if either of those two car chargers really would provide enough current, so I installed a dev kernel that has the BQ27451 battery current monitor patches in it. I think several of the dev kernels have this; I used M-kernel.
OK, so far so good.
The next step was to crank both the min and max CPU clock limits way down (300 Mhz iirc), turn on the "performance" governor and turn the screen brightness all the way down. I may have even used Trickster Mod to set Max_Cores to only 1. This was done so that the tablet would draw a smallish and constant current. That way, when I plugged in the car charger, I would actually know what the total charger current was - the sum of the (absolute) values between the unplugged state (discharging) and plugged in (charging)** If you leave the CPU frequency controls in their normal state, the amount of current the tablet draws can jump all over the place depending on tablet activity, and then it would be hard to know the total current the charger is actually producing. (It is the SUM of the battery current displayed plus whatever the tablet is drawing).
When I did the above, my N7 (grouper, WiFi off) was drawing just under 300 mA of current from the battery in the unplugged condition.
Still with me? (it gets better, trust me).
So, what I observed was that, yes, one of the two chargers was better than the other; I could get get the monitored battery charging current up to 1400 mA with one, and maybe 1100 mA with the other. (That's total current from each charger of about 1.7A or 1.4A respectively after adding in the 300 mA the tablet is drawing)
Finally though, an explanation of why this is relevant to you:
When the tablet was plugged in to either charger, the current would not immediately jump up to the maximum value; instead, it would sometimes takes minutes or more for the current to jump up to that maximum value!
It would, however immediately jump up to about 800 mA total current right after plugging the charger. That's better than a 500 mA computer USB connection, but if the tablet is active, it's no guarantee that the tablet will gain any charge - as in your situation.
So why the delay? To be honest, I don't really know. In my panic to get ready for my travel, I only spent a little bit of time fooling with it - for a while I had a hypothesis that the kernel was doing *something* that made the current pop up to its full 1.7A value only after the tablet had left a deep sleep state. The good thing was that once the current stepped up to the full value, it would stay there despite the level of activity on the tablet.
[size=+1]The point is that the maximum charging current condition seems to be dependent on some condition(s) happening which is under control of the kernel - it is not just an "analog" behavior that happens as soon as you plug the charger in.[/size].
So I suppose it is possible that you simply have a configuration where the operating trajectory that your tablet passes through does not trigger the right conditions in the kernel to command the SMB chip (USB interface controller) to max the current out close to the 2A limit.
You might want to try an experiment where you:
- Observe the charging rate with the tablet completely turned off. Should be about 100% in 150 minutes (2.5 hrs) or about 6-7% every ten minutes. Note that because the battery is 4.235 A-h capacity, that works out to a charging current of at least (4.235 A-hr / 2.5 hr) = 1.7 A. (It is probably greater than that due to charging losses).
If your tablet charges at about this rate when it is off, then nothing is wrong with your charger, cable, battery, or SMB chip, and it points a finger at your kernel's code - and possibly other things like applications holding wakelocks which prevent the tablet from entering deep sleep.
I won't go so far as to claim that it is "coming out of deep sleep" that triggered the M-kernel to twiddle the SMB chip so it would draw 2A; in all my experimentation, I couldn't faithfully reproduce the behavior. The good news was that that it would eventually (within a few minutes, possibly due to the tablet sleeping) ramp completely up and then stay there.
Anyway, I hope this gives you some food for thought and maybe some experiments you can run to narrow down the problem.
- What kernel are you using?
- Does your tablet ever enter deep sleep? (I don't mean simply that the screen is off - it is a state where the hardware is placed in a low-power state where even the memory bus is no longer operating. A wakelock might prevent this from happening, but in any event you should be able to observe this in the kernel log - the clock values get wonky and you might see a message about "G" state)
- Does your tablet charge even a little bit when the screen is off?
** I sort of recall that that "Current Widget" app always displays a positive value for current, but changes the display color red/green depending on whether the tablet is discharging (red) or charging (green). Something to watch out for.
.
Kernel: It's rooted, but otherwise completely stock. Battery Monitor Widget doesn't seem to have an issue display the charging rate (and yes, I meant 2A, not 2ma).
Sleep mode: It should; I have one of those cases whose covers are supposed to put it in sleep mode. It DOES charge; but it does it at a snail's pace; a battery info app has it at 30% over the span of 24 hours with it never being touched during that time.
I turned it completely off 3 hours ago at 37% and I just turned it on to 76%
Unfortunately, Current Widget is not compatible with the N7.
WraithTDK said:
Kernel: It's rooted, but otherwise completely stock. Battery Monitor Widget doesn't seem to have an issue display the charging rate (and yes, I meant 2A, not 2ma).
Click to expand...
Click to collapse
It actually displays instantaneous current? Maybe I should restore a 4.4.2 ROM and see if the newer stock kernel has those BQ27541 patches.
WraithTDK said:
Sleep mode: It should; I have one of those cases whose covers are supposed to put it in sleep mode.
Click to expand...
Click to collapse
Well, "screen off" is not equal to "deep sleep". The tegra3 has multiple low-power modes, but the one I am thinking of is really low power - kind of like a "suspend" state for PCs. If there is an application holding a wakelock, the tablet will never enter deep sleep. (As I mentioned, the "deep sleep" mode is very near to the tablet being completely off - the lpRAM is still drawing a little bit of current (it is in self-refresh mode) ). When my N7 sleeps, it charges nearly at the same rate as when it is turned off. (But, see below; in light of that I don't think this is your problem)
WraithTDK said:
It DOES charge; but it does it at a snail's pace; a battery info app has it at 30% over the span of 24 hours with it never being touched during that time.
I turned it completely off 3 hours ago at 37% and I just turned it on to 76%
Click to expand...
Click to collapse
39% in 3 hrs? Hmmm. If things were linear, that would be: 0.39*4.235 / 3 = 551 mA.
You are right, that isn't very good at all. Your tablet will discharge if you are using it even though it is plugged in.
Well - that "tablet off" charging test is pretty diagnostic - the kernel and OS are not even running, so they can't be altering anything. So maybe they can't be blamed for anything either.
But, that Summit Microsystems SMB347 chip is sitting there acting as the battery charger, even when the tablet is "off". Maybe it has something stateful in it (like a few non-volatile memory registers) that could have been altered by past activity on the tablet. Summit doesn't allow datasheet downloads without a NDA, so I don't know.
When the N7 is fully turned off, there is still something tiny running - otherwise, how would that "charging animation" get painted on the screen when you plug the tablet in when it is off? I don't know if that is something in the tegra3 miniloader or just a low-power personality of the bootloader; hard to know really. I guess I am speculating whether something in the bootloader could have "programmed" the SMB chip, but the only thing I remember seeing here (on XDA) is a toggle via a fastboot OEM command that causes the tablet to boot up as soon as power is applied - the guys who do car installs use that.
Well, I'm sort of out of ideas. It sounds like you have tried the obvious stuff already. Do you have any reason to believe the USB port has an intermittent connetion? Or maybe that the battery itself has an intermittent or resistive connection at its power connector?
cheers
Had a very similar problem on my s3 and the problem was the microusb port on the phone
Sent from my SPH-L710 using Tapatalk
WraithTDK said:
Lately – I’m not sure when this stated, my Nexus 7 (running 4.4.2) has been charging absurdly slow. I’m talking 20%-30% in a span of 24 hours. It’s like it’s hooked up to a trickle-charge. I’ve tried 2 different OEM cables and 2 different OEM chargers (I had the one that came with it, and I ordered an official Asus OEM replacement charger with cable as well, to have as a spare).
I downloaded Battery Monitor Widget and while it sees it as plugged in via AC, the charge rate is -9ma (in other words, while plugged in, running nothing but the battery monitor, instead of actually charging, it simply reduced the discharge rate from negative 718ma to negative 9ma).
The only thing I can think of is this: as I understand it, USB AC adapters capable of “fast charge” (2ma) first test the device to see if it’s compatible, to avoid potentially over-charging the unit. Perhaps my device is not properly responding to this test? Perhaps that’s why it’s not providing enough juice?
Or maybe someone else has some better insight and can educate me. I’m certainly open to learning. Any ideas?
Click to expand...
Click to collapse
You might have an issue with your USB on your device. Mine was starting to charge slow but not quite to the degree as yours. I also found that my device would no longer communicate to any computer. If you have tried different cables & charger then you may have to RMA your device.
Asus Nexus 7 draining while plugged in to charge
My Nexus 7 was totally dead. Hit the power button and five blinks of a white LED. Plugged it in it went to 68% then next day it was 28% - 19% and on down. Before it got to zero I turned it off and took off the back. I noticed with the aid of a magnifying glass, that the soldered connections of the mini USB charging port were very possibly fractured. Having had experience at soldering, I added solder and reflowed the connections (about 4 or 5). I then plugged it in. For the first time since the beginning of this mystery I saw the battery icon actually indicating that it was charging. It was 100% within three hours. Haven't had a problem since.
I have been searching all over and found many ideas from - try another charger to - install another charging board. When you think about it, that connecter sees a lot of push and pull. If it is not soldered well and sturdy it's no wonder that it will fracture. I don't think there was enough solder on there to begin with.
If you do not know someone who can solder on a very small scale and want to brave this yourself, make sure you have a very small tip on the iron, not more than 700 degrees and some extra flux. You will most likely bridge a few connectors but keep brushing the tip of the iron away from the connections with flux added. You will get it eventually. Just don't burn the board. And clean it all with a brush and alcohol. Good luck.
Hi,
i use a Nook Simple Touch as typewriter with an usb-keyboard,
which works great thanks to the usb host mode app, or, automated:
an old version of tasker with a plugin to deactivate charging and activate hostmode ( and fastmode...) via shell command after booting.
The problem is, this mode drains the battery really fast,
and charging while using the keyboard, so nececessarily with OTG cable attached, is a bit of a pain in the neck,
because there is only 1 possible sequence of actions how you can enable charging with more than around 100 mA (which would be way too low in this case) while the keyboard is active,
which requires a 16k resistor between GND and ID pin, rebooting, temporarily disconnecting some wires via switch, tapping around etc etc,
(and also does not work well when the nook is completely off ),
so i decided to leave the usb port exclusively for the keyboard,
an remove the internal battery an replace it with a external big 7000mAh or so 1S li-ion pack,
which is charged externally with a lipo module
(while charging, the nook is powered by an ac adapter, power source switching is realised with a relay and a really big capactior to avoid any more complicated possibly failing electronics)
which works great and is very easy to handle,
BUT i really dont like li-ion batterys of any kind because of the fire hazard,
nimh eneloop cant be used because charging in parallel is not a good idea,
so i would like to use lifepo4 chemistry instead,
which has a working woltage between around 3 and 3,6 volts,
but the nook powers down at around 3,65 volts.
A boost/buck converter isnt possible because as the battery drains, the voltage must sink slowly for the nook to make a normal shutdown
and not crash, damage the file system etc, (and also a converter drains quite much battery even if the nook is completely off.)
Question: it would be VERY kind if anyone who has a clue about this could share his opionion on that:
is it possible (if the hardware itself can handle it) to lower the android/nook shutdown voltage to about 3 volts with some rom/software modifications ?
threshold not treshold
Wow, this all seems a bit complicated.
I had never heard of this 16K resistor stuff.
As far as I could tell, the ID pin is only sensed high or low..
Unless I'm mistaken the OMAP3621 ULPI registers only indicate high/low.
The TPS65921B (which is the actual PHY) list 90K as the typical break point.
Of course, there could be a circuit completely external to the ULPI/PHY.
Where did you find out about 16K?
Changing the voltage of everything seems the difficult way to go.
You'd have to modify uboot as well as the charger daemon.
A note: The USB charge pump is pretty inefficient, 55%.
If you were to load the USB to the maximum speced 100mA with a 3V battery, it would be drawing 303mA from the battery!
5V × 100mA / 3v / 55% = 303mA
Oh, you got me confused with your two posts.
When you were talking about ID and 16K did you mean the ID on the battery pack or the ID on the USB OTG?
Renate NST said:
Where did you find out about 16K?
Click to expand...
Click to collapse
wired a 50k pot between gnd and id pin,
in the usb mode app tapped "host" and watched if the led goes an stays on,
if not, lowered the resistance, tried again etc,
as soon it stayed on (at 16k at my device ) used this value as permanent fixed resistor.
with that otg mode keyboard use is possible,
but also at the same time the nook doesnt really believe its in otg mode so charging with 500mA is possible,
if done in this order:
- feed 5v to the + - of the usb cable
- reboot (not always required)
- remove an reinsert usb plug
- hit "host" 2 times, keyboard works and charging with around 500mA works (measured it)
but charging doesnt work when nst ist powered off,
and automount of the keyboard at startup via shell is not possible,
and cable acrobatic is required,
and as you say, usb charging is inefficient.
the other solution with an external battery (at the nst batt terminals) with external charging logic with a relay is a much easyer way,
but depends on a li-ion cell because of the 3,7-4,2 voltages the nook can use,
a lifepo4 ( or 2s li titanate + diode) would be safer and has more cycles but would require the nook
to work with 3 to 3,7 volts, which seems too complicated, changing demons etc whatever that is...
after some research it seems its not really an issue, the newer sanyo/panasonic, samsung, sony, lg powertool/ebike cells seem to be quite safe, as far as youtube shortcircuit etc tests demonstrate.
thanks for the orientational infos
Renate NST said:
Oh, you got me confused with your two posts.
When you were talking about ID and 16K did you mean the ID on the battery pack or the ID on the USB OTG?
Click to expand...
Click to collapse
sorry, i should have used one thread, i suggest ignoring the other one,
where the only request was if the nook battery terminals can survive up to 5v,
here was the request if the nook can be modified to accept at the battery terminals a voltage down to 3v and stay on.
so 3v too complicated, 5v too dangerous,
so i stick with the relay and the li-ion cell, no problem, i was just curious if an improvement would be easily possible.
the battery id resistors have nothing to to with all that, 10k and 30k work fine,
i meant the 5 pin micro usb otg connector, not shorted zero ohms as usual, but 16k.
(but thats obsolete now)
another observation: in some thread you mention you charge the nook while using an usb keyboard,
i tested it and with a normal otg cable, and the usb mode app set to 500 mA oder 1,5 A,
and a 50% charged normal internal battery,
the device draws around 250mA, and the battery gets charged very slowly, or not at all, depending on cpu usage etc.
and if the battery reaches 100% , it continues to draw around 250 mA, which is strange,
because when using a normal, non-otg usb cable,
the device draw only around 100mA when the battery had reached 100%,
so the difference must be used for heating purposes somewhere or overcharge the battery,
which might be a reason for swelling lipos.
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