[Q] USB charging difficulties - Nexus 7 Q&A, Help & Troubleshooting

Nexus 7 2012. CM 11 M2 Grouper, - 3-5 hours use daily - Unit is 20 months old.
Until for the first time while playing a game, allowed the device to attempt recharge while continuing with the game after getting a 14% low Battery warning flash on screen.
Factory Charger and connection cable..(this is a 2100 mA strength charger)
The device went dead despite being connected to a charger.
the device went totally dead as the battery drained completely.
the problem appeared to be that the device stayed on and drained the battery.
Opened up the device and charged the battery with a home-made cable - good to go..(98%)
the process involved using 4 sewing needles inserted into the battery connection and crocodile clips to attach, this ensures that the battery is receiving equal current to each side.
this can be done with any type of standard charger but will take longer. the beauty of using the factory charger is that the recharge will only take 3 hours verses 10 hours for a 500 mA type charger. the chargers stop automatically when the battery is fully charged, this would lead one to deduce that any control circuitry related to battery charge levels is inside the charger.
reconnected battery and assembled the unit.
Followed google instructions and used boot menu to switch off device.
turned on device as normal.
Did a factory data reset and wiped all user information.
Set screen brightness to minimum & set battery % inside the charging icon.
Turned off the wi-fi and nfc and everything that could affect battery life.
the device is showing a charging icon when powered off but the battery is not increasing in charge
the device makes a nice noise when the charger is connected.
the device shows the charging symbol in the status bar
the device is not charging and a computer cannot recognise the device.
the device makes charging noises and indications when connected to the computer
the device is not actually charging at all.
there is no apps that could be using unnecessary power. I have stopped the google play service etc. there is only 3 services running.
the loss of power is continuous, even when powered off the device battery continues to loose power.
I am presuming that there is a short circuit within the power sub assembly that is causing this continuous power loss. My reasoning for this is that the operating system is functioning and capable. A fault within the micro usb could cause the effects mentioned above.
the only possible faults are the micro usb port and or the cable that connects the power sub circuit to the motherboard. the cable runs under the battery and the pins are micro size. (it would take 2 people to properly analyse this cable.)
regardless of my particular fault, the advice that i would seek is in regard to any test that I should do to prove either way which part I need to replace.
is there a way to bypass the micro usb connection and power the device via the cable that connects to the motherboard
I have used many different micro usb leads and chargers. The factory charger and lead will charge other devices.
windows 7, windows 8.1, linux mint and ubuntu 14.04 are the different computer systems that will not recognise the device although they will appear to be charging the device without actually increasing the charge at the battery.
I have not found any other nexus users with a similar problem.
Using a moto g, samsung GT9305i, Samsung 5380i, Samsung 5570, all rooted and custom roms.
I will Bluetooth a ROM to the nexus and attempt installation.
Just to eliminate any doubts that could be related to using the m2 version of CyanogenMod 11

Related

battery draining when I charge phone. Alerts me to change it

For some reason, every couple of days when I plug my phone in to charge the battery overnight I end up getting an alert (about 4 in the morning!) to change the battery because mine is dead, along with the back up battery, and then the phone shuts off within about a minute. Luckily I have another battery, which I then put in, and then put the dead battery in the "back up battery" slot in the cradle to charge, which it does. I don't know why this happens but it is very frustrating. I am afraid of this happening on a trip out of town where I won't have the ability to use my cradle, unless I bring it which is a big hassle. I don't know what to do.
This IS vexing. By the fact that it charges the extra battery - we know that the power transformer is connected. Since the device does not seem to be charging (possibly even discharging?) - it seems that either the connector on the charging base or the connector on the device itself are bad.
Have you used the power dongle connected to the power transformer to attempt to charge the device? This would tell you if it's the charging base or the device. If it charges outside of the base, it's the base - if not, it's the device.
Best of luck!
How are you charging the battery - from mains power or through the USB?
I had a situation where I was only using USB power to the cradle and although this worked most of the time, I noticed that if the battery was already low (<50%) then the battery seemed to discharge rather than charge.
So the trigger in your case may be the amount of charge left in the battery before you start re-charging it.
I think other people have reported similar discharging situations, so some other ideas might emerge from a search of other threads.

[Q] Low charge rate after some installations

The device is charging at such a low rate that when at idle the battery level remains the same. This began after trying three different applications which are supposed to enable UMS, but which all fail to do so for the N900V. I also just recently installed SafeStrap, but I think this problem began before SafeStrap and it continues after uninstalling SafeStrap. I had also installed TWRP earlier in the day, but that was later replaced by SafeStrap. All of these applications have been uninstalled.
Yesterday I had it plugged into the laptop for several hours while I was away from home and experimenting with the UMS applications, then I made a 10 minute journey home and saw that the level was 95%. It should have been 100%. I plugged it into an external lithium battery and the charge finished while I was installing SafeStrap. Today I've had it plugged into the laptop for a couple of hours and the charge has remained at 93%. I got it to increase by a couple percent after being powered down for 10 minutes with a USB 3.0 cable into the externally powered laptop. Powered up with the screen off it increased 1% after 15 minutes, but after a couple seconds of screen on it lost that 1%.
It there something in the root that could have been altered which controls the charge rate? With the external lithium battery the transmit/receive lines are not used; could this be related?
EDIT 09:48:
I've confirmed that the external battery has a normal charge rate. The low charge rate is on the laptop and I'm certain it was as fast at the external battery until yesterday.
EDIT 2013-11-23 1259:
After some research I see that the PC's USB port does not normally output sufficient current to charge the Note 3, only a sufficient quantity to power it while it is in use. The statements I struck were confusion between my Note and Note 3. It seems to me though that when the Note 3 is powered off and plugged into the PC's USB port that the PC should output the higher current for battery charging, but I don't think this is happening on my laptop (with fully charged battery and on external power). This is unsatisfactory. I have a growing list of unsatisfactory Verizon Note 3 issues*.
Frank
* The Unsatisfactory List (items greater than simply undesirable)
1. Boot locked.
2. No UMS.
3. No USB battery charging (even if it is a PC issue).

Dead charging circuit?

Hi everyone;
I've having an interesting time with my nexus 7 (2012 wifi 32gb).
Before I left on vacation I couldn't get the thing to charge. Looking at the usb port I thought it had become to damaged to make a good connection. So while I was away I ordered a new port assembly. Installed that and still no charging.
Oh the battery cell voltage had gone down to 2.2V so it's in a sleep mode. No problem used a proper lion charger to trickle charge it back to life then further to about 3.8V.
At that point it boots up though the optimization took the charge down to 2% so couldn't do more testing but clearly it worked just fine. However the thing won't charge. Plugging it in to USB it does detect the connection but does not draw any current (as shown by a usb voltage/current monitor). It will show the charge screen, go through 3 cycles of the battery filling animation then shut off.
I check and the voltage is getting from the usb cable into the connector. I traced the ribbon cable from the IO board up to the motherboard and at the other end I also get a nice 5V reading. Clearly the connection from the USB to the device is being made no problem.
At this point I am thinking that maybe I blew the charging circuit. When I was orignally trying to get it to charge before leaving I was applying all kinds of stress to the connector to get it to charge and there was a few times where I think I shorted it (usb monitor showed >3A and the device reset).
Anybody have another theory?
At this point I can't really use it as charging the cell externally is dangerous and not convenient. At this point from what I have seen with my testing and on here if I want to use it I would have to apply 5V to the battery connector (sans battery) which I haven't tried yet.

Nexus 10 battery draining faster than charging when in use - fixable?

Hi,
I just picked up a used Nexus 10 for an app I'm building. I specifically needed this tablet as it an NFC reader both on the front and back of the device. Everything was great until I realized that the battery drains faster than it charges with the screen on and in use. I am using the POGO charger with what I believe is the stock Samsung plug (output 2A).
I've done some searching and it seems that this is a known issue with this tablet. Are there any known solutions?
Will buying and installing a new battery remedy this? I don't even necessarily need it to charge back up, I just need it to hold steady at its current charge while the screen is on and in use. Thank you!
OK, I realized this is because I simultaneously have a micro USB cable plugged in to a serial device and am using the Nexus 10 as an OTG host device - so even though it shows charging, it's actually not charging at all it appears hence the draining. If I unplug the micro USB device (which supplies its own power, even), the Nexus 10 begins incrementing battery %, slowly but surely.
I will try getting a Y cable for the micro USB portion per a thread I found on androidcentral.

SGS7 not charging after software update fail

Hey everyone, it's my first post here and I'm glad to meet you all.
Recently, I updated my SGS7 edge using OTA updates and it failed to turn on after(stuck on bootloop on samsung logo). While i managed to turn it on after wipe in recovery mode, battery percentage decided to drop to low percentage (not sure what exacly, but to the point I decided to charge it). It shows alert about wet USB port, and I'm sure it wasn't wet at all, but I decide to stop charging and let it dry for few hours. Battery lost its charge completly while it was drying. After few hours i pluged it again, and it was charging (at least i thought so). After 2 hours of charging it managed to charge 1% of battery and then it turn off. When I measure the current flow to the battery it shows 90mA when I plug charger, then it drops to 0 mA after few seconds. When I press buttons it shows that current is flowingh again, but never more than 90mA. Anyone knows what can be a reason for such behavior? Is it charger port broken, or firmware malfunction?
EDIT: I've trierd to charge it for a bit with power button pressed. Now it shows that current is equal to 170mA and it keeps flowing without button pressed.
EqRazzielson said:
Hey everyone, it's my first post here and I'm glad to meet you all.
Recently, I updated my SGS7 edge using OTA updates and it failed to turn on after(stuck on bootloop on samsung logo). While i managed to turn it on after wipe in recovery mode, battery percentage decided to drop to low percentage (not sure what exacly, but to the point I decided to charge it). It shows alert about wet USB port, and I'm sure it wasn't wet at all, but I decide to stop charging and let it dry for few hours. Battery lost its charge completly while it was drying. After few hours i pluged it again, and it was charging (at least i thought so). After 2 hours of charging it managed to charge 1% of battery and then it turn off. When I measure the current flow to the battery it shows 90mA when I plug charger, then it drops to 0 mA after few seconds. When I press buttons it shows that current is flowingh again, but never more than 90mA. Anyone knows what can be a reason for such behavior? Is it charger port broken, or firmware malfunction?
EDIT: I've trierd to charge it for a bit with power button pressed. Now it shows that current is equal to 170mA and it keeps flowing without button pressed.
Click to expand...
Click to collapse
The way you've described it almost sounds like a short. It may also explain the difficulty with OTA (short). The S7 USB charging port may be suspect but also the battery may be at end of life. To eliminate the other usual suspects, have you tried a different USB cord and/or charger? Does your S7 show as connected when plugged into PC (either through adb commands or file explorer)? Have you tried charging using a wireless charger?
If needed, the good news is charging port isn't too difficult to replace, granted you have a heat gun and a few tools (google S7 teardown -- iFixit or youtube). If you're convinced the port is bad and decide to replace it, might as well replace battery too (OEM only). After the above mentioned process of elimination you're left thinking software, maybe download model specific required firmware (matching current binary) and familiarize yourself with ODIN flashing.
Aimless Rambler said:
The way you've described it almost sounds like a short. It may also explain the difficulty with OTA (short). The S7 USB charging port may be suspect but also the battery may be at end of life. To eliminate the other usual suspects, have you tried a different USB cord and/or charger? Does your S7 show as connected when plugged into PC (either through adb commands or file explorer)? Have you tried charging using a wireless charger?
If needed, the good news is charging port isn't too difficult to replace, granted you have a heat gun and a few tools (google S7 teardown -- iFixit or youtube). If you're convinced the port is bad and decide to replace it, might as well replace battery too (OEM only). After the above mentioned process of elimination you're left thinking software, maybe download model specific required firmware (matching current binary) and familiarize yourself with ODIN flashing.
Click to expand...
Click to collapse
I managed to charge the device, I left it plugged into charger with power button pressed and it started after ~2 hours. Now, I'm trying to charge it to 100% just to backup my data. Really appreciate your help tho.
I was trying 4 different USB cables, 2 chargers and powerbank. Device wasn't recognized by computer by any means. I have no access to wireless charger unfortunately. I'm not gonna replace any part of it becouse it is time to change it to newer model I guess.
EqRazzielson said:
I managed to charge the device, I left it plugged into charger with power button pressed and it started after ~2 hours. Now, I'm trying to charge it to 100% just to backup my data. Really appreciate your help tho.
I was trying 4 different USB cables, 2 chargers and powerbank. Device wasn't recognized by computer by any means. I have no access to wireless charger unfortunately. I'm not gonna replace any part of it becouse it is time to change it to newer model I guess.
Click to expand...
Click to collapse
Hopefully all is well then. I wouldn't rule out repairing the S7E, it's still a competitive device. Newer phones are fine if you can afford it but I prefer proven devices with development and software support. Granted, it is a personal preference. For the same price of a new flagship phone I can justify to the wife fiddling around with 5 or 6 old ones (ha):laugh:. Other than an LCD/digitizer most parts can be gotten pretty cheap and there's always [insert any online sales (ebay/swappa/amazon)] in order to acquire a salvage device for parts.

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