Alternative charge points - Nexus 7 (2013) Q&A

I ripped up the usb pads on my nexus 7 removing the usb port. I plan to mount it in my dash so I cannot use wireless charging. Probing the back cover wireless charging pads I get 0 volts. Anyone know if I can directly solder onto them and hook them upto 5v on the nexus 7 side? Or are there any other easy points to connect to?

Freeloader247 said:
I ripped up the usb pads on my nexus 7 removing the usb port. I plan to mount it in my dash so I cannot use wireless charging. Probing the back cover wireless charging pads I get 0 volts. Anyone know if I can directly solder onto them and hook them upto 5v on the nexus 7 side? Or are there any other easy points to connect to?
Click to expand...
Click to collapse
Do not connect anything to the wireless pads. In the situation you have described, the no-battery mod is the perfect solution https://www.youtube.com/watch?v=9N2Bh4fI8Bo

I thought about doing this the battery mod, however I wont really have access to the power switch in my setup, hopfully there is a auto start kernal but then the boot times kind of kill the experiance.

Freeloader247 said:
I thought about doing this the battery mod, however I wont really have access to the power switch in my setup, hopfully there is a auto start kernal but then the boot times kind of kill the experiance.
Click to expand...
Click to collapse
I believe the change to auto-start is easy. I did so on the 2012 nexus. I'll check my notes and update if i find anything.
You can also get a momentary switch and solder two wire under the power button switch cap(outer, and inner ring) to remotely mount the power/volume buttons.
I have done the battery bypass, i use a 12v DC - 5v 3a DC power supply from linkswell i think. It registers the tablet as being 100% full, but still allows it to "charge" i only use the "charge" to trigger turning on/off the tablet. can use either wireless or usb to trigger the tablet. In either case, it's nice to have an external power button, especially if the unit is encased.

To start the tablet when power is detected:
In adb run this command:
fastboot oem-off-mode charge 0
to force the tablet to power on if under power (plugged in and charging).

Related

CDMA Touch Pro 2 - Charge from PC/Laptop?

Sorry if this is a duplicate thread, I searched quite a bit for a solution but only found stuff for the TP, not the TP2.
Ok, so I know with the original TP you could charge it from a computer, but it was not as fast as a wall charger unless you had the fix that allowed it to charger faster on the computer.
Well on my TP2, it really won't charge the phone, and if I am using something like wifi router that uses a lot of power, it will actually lose power while charging off my computer...
Is there a fix to bypass this so I can have my phone plugged into my computer and charge it???
make sure in your battery settings the box that says "when device is turned on, do not charge the battery when connected to the PC" is unchecked. meaning an empty box. if its checked off, uncheck it. also, this might help, when plugged up to ur computer, cut ur backlight all the way down or low. the phone will use less battery that way and will charge faster when hooked up. either way though, charging thru a pc is trickle charging, meaning its gonna b slower than wall charger anyways. i havent came across the fix u mentioned for the TP.
trickle charging is when battery is fully charged and is still pluged on charger, then charging change to trickle power charge, around 20mA+actual request of the phone. this way if you have phone/any electronic in general on charger for a month, it's still kept fully charged.
---
htc have two modes of charging slow 500mA and fast 1A (1000mA)
to say to the phone that charger is fast, you need to have one pin on mini-USB connected to ground. this pin is unused by mini-usb specifications but htc is using it for this trigger.
---
cut open mini usb connector on usb to mini usb cable and wire the unused PIN to power ground (get pinouts pics or use multimeter!!!!! don't guess try it)
then you still facing another problem, USB is strictly specified to not exceed 500mA (with 10% toleration) no trick to get more then this from one usb. some computers are not so precise with rules though and could give slightly over 550mA
to get 1A you need to use two usb ports in parallel. like some china made usb harddrives enclosures
get an additional USB connector and add it to your cable.
NOTE: DON'T CONNECT DATA LINES ON THIS SECOND CONNECTOR!!!!!
data = inner 2 pins
power = outer 2 pins
* you can get an USB extension cable, wire 2 power lines out of it, connect to your usb - miniusb cable... this way you still can use the other usb for other device
NOTE: this is not a standard though accepted solution. I haven't saw or heard of any burned computers cos of this but wouldn't be surprised to see one.
anyway if I had that need, I would go for it
when making this cable, be very sure 5v wire is not touching data lines!!! Test it properly before plugging to PC! I have brand new laptop now, the old one is lying with DEAD usb host below table just because I believed there have to be protection against this. There IS NOT.
NOTE: NEVER LAUGH ON MY PAINTINGS!!
Or you can buy one for $4
http://eshop.macsales.com/item/Othe...medium=shoppingengine&utm_campaign=googlebase
actually NOT.
without grounding the special pin on mini USB side of the cable, mobile would charge by 500mA no matter if you put 100A charger in. or paralleling 20 USBs
Wow...I'm pretty tech savy but that was a bit confusing...so I get the gist of that, but how is it that all it takes is plugging the usb chord into the htc ac power supply will fix that? why isn't it required for all that jazz of rewiring crap on the ac adapter as well, since it comes from the same usb chord...?
eh, have mercy with that english slang we are mostly not englishers here
What you meant was, why htc AC (wall) charger charges on hi power without those tricks?
Because the connection is already made there.
That's not a hidden trick anyway. Not even trick. It's a standart feature.
HTC is, not like other manufacturers, sticking to specs and mobile would not demand more then 500mA from standart usb connection.
usb is defined to be max 500mA
if you want a connector which is based on standart (htc's usb-hub can use usb cables), and you want a fast charging without violating standarts than this was the best resolution, to use pin which is generaly unused to trigger-detect 1A charger.
But as htc didn't made computer fast-charge cables. A serious company will not release such a cable. Connecting power from two usb hosts together - I feel pain by doing it, but it proved computer stabilizators don't mind it and though I don't think it's giving really double, it's giving more then 500mA.
But here you have to "imitate" original htc AC charger by shortwiring that trigger pin the way as it is there.
hope this was your question about.
Just final note in red when making this cable, be very sure 5v wire is not touching data lines!!! Test it properly before plugging to PC! I have brand new laptop now, the old one is lying with DEAD usb host below table just because I believed there have to be protection against this. There IS NOT.

charging and USB OTG/Host

I've seen people complaining that the i747 doesn't charage when your using USB OTG. I was watching a 720p mkv movie off my wd-750gb hd and noticed my battery was going up not down. I seem to have gotten it working with the following combo: Generic USB OTG L shaped cable, D-link usb2.0 hub that I hardwired the positive 5vdc rail to the host upstream power rail and [ROM] AOKP(Jellybean) Task & Ktoonsez 9/11. I had previously modded the usb hub to work with my Atrix as it needs 5vdc on the host rail in order to activate host mode.
There are a few ways to get the charging working. I have one of these
http://www.dealextreme.com/p/usb-2-0-4-port-hub-with-splitter-cable-black-18cm-125451?item=30
and if I plug the black line in and the red line into a USB port, I get charging. It just seems to have to do with if you're on a powered hub and if the 5v rail is hot.
Now I need to get an MHL adapter.
Yeah that's my next thing to test. I have one in the mail now.
Sent from my SGH-I747 using xda premium
When I used OTG cable, stuff I plug into it get power from my i747... In theory, I can charge other devices from my i747.
However, I suppose if the device connected to the i747 via OTG actually is hot (supplies power instead of getting power), it would then charge the phone instead...
Just a theory,.... A powered hub (with it's own power supply), might be able to charge the phone and power the devices connected to it... But a non-powered hub will get power from the i747 and power devices connected to the hub from the phone's battery... Do note that some devices require a certain amount of power to switch on and actually work... the power supplied by the phone is limited, so using a hub will divide the power across the connected devices to it...
This is the most finicky phone I've had in regards to the USB cable. I've never had an issue in the past with any of the mini usb cables I have on hand, but half of them don't work on this phone. Caused me problems with odin flashing, transfering files, etc - so I wouldn't rule out the cable as a possibility for your problems. Also, if you have a higher rated charger (more amp rating on the label) you might see if you get the same behavior. Also, I find that once in a while, my phone is hot after being 'off'. When I go into battery usage I find that 'Android System' is chomping the battery up. I haven't figured out if it's rom specific or just a 'feature'. Maybe that's drawing some extra current - check your task manager when you're watching your show to see if something might be getting busy in the background.
Ozark_8125 said:
This is the most finicky phone I've had in regards to the USB cable. I've never had an issue in the past with any of the mini usb cables I have on hand, but half of them don't work on this phone. Caused me problems with odin flashing, transfering files, etc - so I wouldn't rule out the cable as a possibility for your problems. Also, if you have a higher rated charger (more amp rating on the label) you might see if you get the same behavior. Also, I find that once in a while, my phone is hot after being 'off'. When I go into battery usage I find that 'Android System' is chomping the battery up. I haven't figured out if it's rom specific or just a 'feature'. Maybe that's drawing some extra current - check your task manager when you're watching your show to see if something might be getting busy in the background.
Click to expand...
Click to collapse
My moto atrix was way worse for cables and chargers. At least I can over ride the 500mah draw with the sgs3. Unless it was made by moto or you crossed the d+ d- lines it refused to go into fast mode.

auto power on when charging?

is there a way to have the tablet automatically power on if the battery dies? or to force a reset without getting to the power button?
i use my nexus 7 as a in dash h/u and atm have the fiberglass mold with a small hole for a needle or stick to go threw to hit the power buttong when/if it freezes or dies. but i would like to just skip that.
darkmage1991 said:
is there a way to have the tablet automatically power on if the battery dies? or to force a reset without getting to the power button?
i use my nexus 7 as a in dash h/u and atm have the fiberglass mold with a small hole for a needle or stick to go threw to hit the power buttong when/if it freezes or dies. but i would like to just skip that.
Click to expand...
Click to collapse
there is a fastboot command for auto power on:
http://forum.xda-developers.com/showthread.php?t=2496079
don't know for the reset.
i also have my nexus mounted in my car, and the fastboot trick works for me.
what I'm wondering now is if it works but when using a Qi charger.
JebyDroid said:
there is a fastboot command for auto power on:
http://forum.xda-developers.com/showthread.php?t=2496079
don't know for the reset.
Click to expand...
Click to collapse
thanks will try it out.
schlager said:
i also have my nexus mounted in my car, and the fastboot trick works for me.
what I'm wondering now is if it works but when using a Qi charger.
Click to expand...
Click to collapse
thats a very good question. i have a qi charger here. i will try it out. after i do this patch.
cool let us know. i already put an order for it earlier today, so i'll cancel it if its not any better than my otg+charge cable.
also do you have any temperature issues with the qi charger? just saw some posts on that on the forums
schlager said:
cool let us know. i already put an order for it earlier today, so i'll cancel it if its not any better than my otg+charge cable.
also do you have any temperature issues with the qi charger? just saw some posts on that on the forums
Click to expand...
Click to collapse
just tested the patch, works great in the car. the qi charger does indeed turn the tablet on as well and no heat issues for me. i do have my tab underclocked to 1ghz and undervolted. not sure if that makes a difference in bat temp though
darkmage1991 said:
just tested the patch, works great in the car. the qi charger does indeed turn the tablet on as well and no heat issues for me. i do have my tab underclocked to 1ghz and undervolted. not sure if that makes a difference in bat temp though
Click to expand...
Click to collapse
when it auto powers on with the qi and otg cable plugged in, does the tablet also show the "charging" symbol?
schlager said:
when it auto powers on with the qi and otg cable plugged in, does the tablet also show the "charging" symbol?
Click to expand...
Click to collapse
yes. says its charging just like normal.
i wanted to go ahead and throw this out there but it seems that when charging with wireless charger and it hits the full marker and the tablet stops accepting a charge, the wireless charger will not start charging again unless its unplugged and plugged back in. idk whats up with that. im assuming the tablet just rejects a charge after reaching full and it cant tell the wireless charger to start again? or maybe the charger never actually quits but the tablet doesnt know the wireless charger is still there to continue taking a charge? not sure but either way its pretty annoying seeing as how i have it glued to the back on the tablet and the power is in behind my dash so i cant just unplug it very easy.
for me it seems really tricky to find the sweet spot where it starts charging.
also, i couldn't get it to charge with any charger/adapter without the official wall plug
is yours working with a car charger?
schlager said:
for me it seems really tricky to find the sweet spot where it starts charging.
also, i couldn't get it to charge with any charger/adapter without the official wall plug
is yours working with a car charger?
Click to expand...
Click to collapse
yea. using a dual usb car charger, with 1 output being 1A output and the other being 2.1A. i have the wireless charger connected to the 2.1 and a bluetooth hands free connected to the other. charger works fine until its done charging. i have mine directly in the middle of the tablet. idk if it really differs charger to charger but i use http://www.amazon.com/UPGRADED-Wireless-Charger-Charging-Qi-Enabled/dp/B00C40OG22 maybe the charger your using in the car doesnt have enough juice? try maybe a 1A or higher charger.

Nexus 7 2013 (wifi) no battery mod - car install - otg - power problem

Hi there everyone,
I have been trying to get my Nexus 7 2013 installed into my car seamlessly without problems since December 2015. I have Timur's Kernel v4 (6.0.1) running on it, and it was working flawlessly.
However, I decided that the no battery mod needed to be done as I just could not leave that battery inside a hot car - way too risky.
So, I did the Kevdav no battery mod - with success.
However, once the battery connection was receiving 5v via a usb car charger the OTG cable connected to the tablet's mini usb port would not wake/suspend the tablet properly. It would wake it up, but once it was awake the little battery icon at the top would forever show that it was 'charging' and once power was cut to the otg y cable / mini usb, it would not suspend (would still show as charging).
I did research, and bought a Drok DC-DC step down converter. I lowered the voltage to the battery mod connection to 3.7v (and tested up to 4.7v) and this alleviated the problem of suspend/wake. I think since the original battery gave out less voltage then the otg/charging connection, this needed to be replicated in order for the otg to work.
However, I now have a new problem that I cannot seem to fix. This problem only seems to happen in the car and does not occur when testing it in the house using normal wall chargers.
For clarity, this is how everything is wired up in the car.
Nexus 7 battery mod side of things:
Nexus 7 battery terminals > 22awg usb cable > drok dc dc step down power supply (this board has a female usb port for output) set at 3.7v (tested up to 4.7v) > input is connected to car's constant 12v connected directly to battery on a fused wire.
Nexus 7 mini usb port side of things:
Nexus 7 mini usb port > usb otg y cable > mini usb cable > 2.4a usb car cig adapter hardwired to car's switched 12v accessory wire.
The link to the drok dc dc step down is this - https://www.amazon.co.uk/dp/B01FDBY66Y/ref=twister_B01GO268W6?_encoding=UTF8&psc=1
I turn on acc ignition to send power to the otg connection. It'll power up. However, if left in standby overnight the tablet won't power up. If I physically press the tablet's power button it'll wake up, show the wake up animation, and react as normal (including any subsequent power downs). However, if I don't press the power button and I turn off the ign again, an icon on my car's instrument cluster will be faintly illuminated - this is odd behaviour and should be completely out. When this is the case, if I get out and try to lock the car the remote central locking doesn't work.
This light will go out if I physically disconnect the otg y cable from the tablet, and low and behold the remote central locking works.
I'm no expert on electronics and such, but it seems to me that power may be flooding back into the OTG connection from the no battery mod power?
Does this make sense? Sorry for the long question, but I was wondering if anyone had any experience with troubleshooting or any advice? I've this one problem and then I'm set but I just can't seem to figure anything out and need someone's advice who is in the know rather than take wild stabs in the dark using my own logic because if I do the latter, not only will I waste money on needless components but I'll more than likely break something. I've read stuff about diodes or something in order to regulate power flow but I'm not even sure I'm using the correct terminology here so if anyone can tell me I'm onto something here or I'm talking complete nonsense then anything is appreciated!
I did search these forums and google but I really cannot find anything that is similar to my problem.
Thanks for any input guys, whether it be any tips on what I'm missing or what I need to change (software or hardware, electrical, etc) - it's all very much appreciated.
Antony
Edit: so sorry I think I posted this is the wrong n7 2013 sub section. I can't delete the post but if a mod could please kindly move it to the relevant forum I'd appreciate it. Thanks!
antc101 said:
it seems to me that power may be flooding back into the OTG connection from the no battery mod power?
Click to expand...
Click to collapse
Hi, indeed, and your "2.4a usb car cig adapter hardwired to car's switched 12v accessory wire" requires a small mod to prevent the power feedback. It needs an extra 1A+ diode connected directly to 12V input. You could modify the adapter's PCB or simply replace the fuse's internal wire with a diode where its cathode goes to the spring and its anode to 12V input. Or just place the diode somewhere along the adapter's hardwire. $0.16 1N4001 is good enough ([email protected] is OK for [email protected]).
Not sure if thread is still active but I also have the same symptom with tablet turning off completely overnight. I am running constant 12v to 3.7v dc to dc on battery input and car adapter 12v to 5v on microusb cable in. Tablet will work fine with on and off but after car is shutdown for the night it will not turn on in the morning. It shows me battery charge icon only. I dont have diode installed either. Not sure if thats the cause. Anyone know why it would completly shutdown overnight?
Neo2020Marz said:
Not sure if thread is still active but I also have the same symptom with tablet turning off completely overnight. I am running constant 12v to 3.7v dc to dc on battery input and car adapter 12v to 5v on microusb cable in. Tablet will work fine with on and off but after car is shutdown for the night it will not turn on in the morning. It shows me battery charge icon only. I dont have diode installed either. Not sure if thats the cause. Anyone know why it would completly shutdown overnight?
Click to expand...
Click to collapse
Hi there,
Been a while since I posted on this thread but just wanted to update on what I have done so far.
Since my last post, I don't have any issues. I placed a diode as mentioned above on the +12v for the accessory power. This seemed to have fixed any back flow of power.
Concerning the power off over night, I'm pretty sure this was something to do with Timur's kernel. I forever had issues with that thing - eg, suspect and wake issues, accessories connected to my usb hub..
I switched to a stock version of android 6.0.1 - MOB30X if memory serves... and installed Elemental X version 5.16. No issues with this setup what so ever.
Huh.
I run my Nexus 7 on my car with the battery, mounted just above the dashboard, with direct sunlight exposition and no UV film on the windshield. It's been a whole year without issues, thank God.
https://i.imgur.com/cPNhDDc.jpg
I live in the Northeast of Brazil, where's 30C to 40C through the year. Sometimes I come up to the car and the tablet shut off due to the heat.
Battery still lasts wonders and there's no signs of damage.. yet.
Is it really adamant to remove the battery, or is it just a precautionary measure?
GTMoraes said:
Huh.
I run my Nexus 7 on my car with the battery, mounted just above the dashboard, with direct sunlight exposition and no UV film on the windshield. It's been a whole year without issues, thank God.
https://i.imgur.com/cPNhDDc.jpg
I live in the Northeast of Brazil, where's 30C to 40C through the year. Sometimes I come up to the car and the tablet shut off due to the heat.
Battery still lasts wonders and there's no signs of damage.. yet.
Is it really adamant to remove the battery, or is it just a precautionary measure?
Click to expand...
Click to collapse
You better have more luck.
My nexus was put under the dash and was fine for around 3 years. And it became expanded in just 2 days, separating the screen and the case. So I have urgently remove the battery.

car tablet power options

A few years ago, I installed a Verizon Samsung Tab 2 in the dash of my Cadillac. I have this tied into the sound system and use it mostly for streaming music and google maps. I had it set up so that the power (cigarette adapter) would shut off whenever the car turned off. Then I used the Tasker app to detect when the tablet was not getting power and put the tablet into Airplane mode, turn the screen off, and pause any music. This would cause it to conserve enough power that it could last a long time until I started the car again. (I cannot reach the tablet's power button once it's installed in the dash). This worked fine for years. However, this tablet was so slow due to no OS updates ever that I couldn't stand it any longer.
I recently decided to upgrade to the Verizon Asus Zenpad Z8. The issue I am now having is that no matter what I do, the tablet dies when the car is sitting. I cannot keep up with its power demands. Tasker does not have the options available to put it into airplane mode. But I have gone into the developer mode menu and set it so that the screen goes off whenever the tablet is not receiving power and it goes into super saving mode during the night. It still dies. It cannot get enough power from the cigarette adaptor to charge it fast enough to recharge what it has lost when it was parked. I have upgraded to the fastest cigarette charger I could find (3A). The battery life barely moves while the car is on, it charges soooo slowly. But the battery drains very quickly when off. This means that every time I get in the car, the tablet is off and I have to pop the panels off the dash to turn it back on.
I recently tried to use a small power inverter (powered from the cigarette adapter). This caused a massive feedback loop that was unbearable (and not fixed by an inline noise filter). I then tried a true sin wave inverter, same result. Although this did solve the power problem, it charged fast enough that there would be enough battery life that the car could sit overnight and not completely die.
I had to go back to the cig adapter. This tablet is thus far, un-rootable. That limits my options with shuttings things down and limits the features available in Tasker.
If I switch the cig adapter to power the tablet all the time, then I don't have a way to tell the tablet when to shut the screen down (so that people walking by don't see a tablet in my car and break in). I'd like some way for the tablet to know when the car is off so that it can shut things down. The easiest way to do that was by making the cig lighter turn off when the car turns off.
If anyone has any other ideas, I'm open to about anything at this point. This is getting really frustrating. Thanks.
I bought this tablet because my whole family has USB-C devices. No more stupid micro USB what an abortion that connector was. At any rate at first we used USB-A to USB-C adapter cables with USB-A charging devices. I noticed right away that most of my chargers would overheat quickly or simply charge quite slowly...the charger could not keep up with the demand if you were trying to stream video to the phone or whatever. Then I bought Google Pixel phones for me and my wife and noticed that the supplied charger has a USB-C port on it and the supplied charging cable is USB-C to USB-C. These Google supplied chargers would completely charge a dead pixel phone in 20 minutes. After reviewing the USB-C standard on Wikipedia I noticed a much higher ampacity available using USB-C to USB-C devices. So for my car I bought an LM317T integrated circuit and with a resistor and a heat sink I cobbled a little 3.5 amp 5v charging port in my dash. You could also use an LM7805 if you wanted and insert a small value resistor on the ground reference if you really want the extra .5 volts. Make sure and attach the ic to a small heat sink with heatsink compound. You will need to solder your female port to a female USB-C and use a USB-C to USB-C cable as the USB-A connector on the Asus supplied cable cannot pass enough current.
ninasmith said:
I recently decided to upgrade to the Verizon Asus Zenpad Z8. The issue I am now having is that no matter what I do, the tablet dies when the car is sitting. I cannot keep up with its power demands. Tasker does not have the options available to put it into airplane mode. But I have gone into the developer mode menu and set it so that the screen goes off whenever the tablet is not receiving power and it goes into super saving mode during the night. It still dies. It cannot get enough power from the cigarette adaptor to charge it fast enough to recharge what it has lost when it was parked. I have upgraded to the fastest cigarette charger I could find (3A). The battery life barely moves while the car is on, it charges soooo slowly. But the battery drains very quickly when off. This means that every time I get in the car, the tablet is off and I have to pop the panels off the dash to turn it back on.
I had to go back to the cig adapter. This tablet is thus far, un-rootable. That limits my options with shuttings things down and limits the features available in Tasker.
If I switch the cig adapter to power the tablet all the time, then I don't have a way to tell the tablet when to shut the screen down (so that people walking by don't see a tablet in my car and break in). I'd like some way for the tablet to know when the car is off so that it can shut things down. The easiest way to do that was by making the cig lighter turn off when the car turns off.
If anyone has any other ideas, I'm open to about anything at this point. This is getting really frustrating. Thanks.
Click to expand...
Click to collapse
Here's something you can try:
Use a different signal to trigger sleep mode, like WiFI. You could use a cheap 3G router and have the tablet connect to it via WiFi. When you exit the car take the router with you = no WiFi = tablet goes to sleep.

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