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how to charge htc 8125 with no original usb cable and(or) without orig. wall charger

hi there.
shortly-i have this phone with no orig. usb cable and with no wall charger. it was friend of mine phone actualy. given to me with dead battery (i am not sure but i have trouwn it away long time ago)
first I did was to wait until friends of mine from china had sent to me 2 batteries compitable with the phone. what i discovered is that a normal ordinar usb cable cant charge the phone's battery it only can connect to the pc.
second what i did is this: i found my old charger from a very old panasonic cell phone and had a try to make the charging process with the simply contacting corresponding pinouts of the battery to the +&- of this same charger (somehow i dissasembled the plug of that charger and it became more "comfortable" to get in touch to the pinouts of the specific cingular's battery)
that unordinar way i did discovered that i can charge these batteries even not sure how much appropriate that other brand wall charger is. It seems its pretty much the same as a power characteristics.
Meanwhile (as i dont use this phone) i had some free time to search the net and to have better idea about that strange unordinar power charging matter with that model of a phone. The situation is that i cant find a place nearby me to buy a cheap usb and wall charger and become using this nice device finaly.
And also i dont want to buy these cable things before clearly understand why this happens ..
I did try also to charge this phone with a HTC brand wall charger but no sucsess again cause it seems this wall charger is for other htc phone (even same mini usb plug and same characteristics)
What i need is to have answers by someone very informed about that matter and let me know what exactly is the specific power charging matter (need explanations i mean) with this phone. If sharing some good ideas about how to remake others usb cable or wall charger for geting it work along for me in such a case , i will appreciate this very much
thanks

charge
hi ! please forgive me for my bad english! in this case you can charge your phone in 1 way! you need to procure a motorola or any charger with same socket but attention the charger must have 6 volts and no less than 500 mAh(milli amps)! you cut the wires and one wire put on the + of the battery you will see the signs on the battery an one wire at the - no matter which one. and you need stay with the wires 3 - 4 minutes on the battery ! then you put the battery on the phone it will start and then you cand fully charge it with the usb cable ! good luckk ! i hope my inf will help you!

no
no it doesnt work that way.
what i need is the simple answer : what is so special into the pinouts of htc cingular 8125 wall charger?
thats what i need only. Then I might figure out how to proceed
Thanks anyway

I don't know if anyone else has had trouble doing what I have done, but I've got the Cingular 8125 (HTC Wizard 100), which is also known as the HTC 8125.
1. I bought a car charger at a convenience store for $6 that had the mini-USB plug. It worked like a charm. Never any problem there.
2. I also bought a standard USB to mini-USB cable from the local computer store, because I had lost mine, and it also worked fine for both synchronization and for charging.
3. I bought a second wall charger, buying a standard mini-USB wall charger sold pretty much everywhere cellular phone chargers are sold. It's a common charging port, and this generic worked for me as well.
I'd be interested to hear if anyone has had problems with these types of devices not properly charging the unit.
Even my USB cable for my portable USB hard drive will power my unit.
EDIT: About your problem with it not charging. I had that problem about a year ago, when my battery got extremely old. It wouldn't charge even with the original charger. I just needed a new battery. The batteries get old and stop taking a charge after a certain amount of use. How long this takes depends on how heavily the batteries are used. They, like car batteries, do not last forever.

I had this problem when I had my wiz too. The battery died and drained, and my phone refused to charge it. I took it to an AT&T service center, and they had no clue what the problem was, and they wanted to issue me a replacement (it was a G4, I had a G3, I wasn't about to fiddle with that at the time.) So I asked to borrow a demo device they had there to fix it. I charged my battery on their demo device no problem, got it up to 3%, and finished charging it through my USB cable in the car socket.
It appears to be a sort of one-in-every-few-or-so type condition, but I got hit with it.

seems like noone can tell me if something special inside the mini-USB plug.
i realy cant charge. Very nice device, but i cant make it charging up whit cables.
guys, from up there, say that nothing special about the charging cables, but i trust what i see not what i read.

Perhaps there is a problem with your USB port on the device? USB charging has standards, and all devices that need power from a USB port have the same power pin configuration. Otherwise, they can't call it a USB connection. It would have to be called a proprietary connection, and they would have to change the plug size/dimensions and pins.
If there isn't a problem with your battery (which is the most likely source of your problem), then it may be a loose connection on your USB connector. This happens with a number of devices.
If a sync cable connects to the PC but will not charge the battery, then you definitely have an unusual pin detachment of some sort, or a bad battery.

thanks again..
for pity i was writing a lot to make my recent post and finaly it desapeared cause my session was left.. its funny in some case, but now i just dont want to repeat all what was intended to be posted
i give only the link where you might see why i was assuming that this is a kind of a special matter here with that htc 8125 charging
//pinouts.ru/CellularPhones-A-N/razrv3_charger_pinout.shtml
so, any more help will be appreciated a lot
thanks

SOLVED: HTC Wizard (Cingular 8125) Dead Battery Wont Charge
Dozzen said:
hi ! please forgive me for my bad english! in this case you can charge your phone in 1 way! you need to procure a motorola or any charger with same socket but attention the charger must have 6 volts and no less than 500 mAh(milli amps)! you cut the wires and one wire put on the + of the battery you will see the signs on the battery an one wire at the - no matter which one. and you need stay with the wires 3 - 4 minutes on the battery ! then you put the battery on the phone it will start and then you cand fully charge it with the usb cable ! good luckk ! i hope my inf will help you!
Click to expand...
Click to collapse
Hi - Too bad for the OP that asked questions but did not listen to this brilliant post.
I have confirmed that a variation of this method works perfectly! I have an old Cingular 8125 that I have been trying to charge for over a year using various USB chargers and NONE would charge the device.
The reason that this may happen is that the original charger has an output of 1 full amp which is much higher than most chargers. The voltage is the same but you need a charger that can handle such a strong current draw.
Nearly all USB chargers can only handle around 250milliamps - 500milliamps which is about half the power needed to breathe life into a fully discharged battery.
The best solution is to NEVER let the battery fully discharge.
Here are the details of what I did:
1. Find the best match charger of 5-6 DC Volts and ability to put out as close to one amp (1000mA) as possible. I chose an old Sanyo SCP-07ADT that is rated at DC 5.4V at 800mA. The plug can be any type, no need to be USB.
2. Cut the connector off the end of the cable and strip the outer black part up about an inch and then strip the positive and negative (red / black respectively) wires up about a millimeter, just enough to have bare metal ends to touch to a small area.
3. Take your battery out of the phone, look at the back of battery for the + and - marks which correlate to one of the metal connection points on your battery, this is where you will "touch" or "attach" the bare ends of the wires.
4. Plug the charger in making sure not to short your bare leads. Before you do this double check that the OUTPUT of your charger is indeed DC voltage so that you don't hurt yourself. You do not want AC output and it can be dangerous.
Then touch the bare end of the red wire to positive of battery, and black wire to negative terminal of your battery. I held them with my fingers while surfing the web for about five or ten minutes. I had no idea if anything was happening or not but it "felt" like the battery might have gotten just a bit warmer.
5. Unplug the home-made bare wire charger and put battery in your phone. Quickly attach a USB charger or just plug into a USB cable of your computer. I pushed it in and nothing happened at first but finally I heard the standard "bleep" when you plug a USB device in. I knew that I made progress because it never beeped before it took about 30 seconds and several "bleeps" of connecting/disconnecting from USB but eventually the charge light stayed on!
It's been about 30 minutes and I'm up to about 50% charge and been using the phone heavily while charging.
So, in summary... never let your battery discharge below 5% or you can only charge it with an OEM cable rated at 1amp (rare). IF you let it discharge to "dead" then charge for 5-10 minutes with the "wire" method and then charge normally!
Thanks to Dozzen for the original idea!!

Wizard that won't charge
When my Wizard/HTC 8125 goes dead my cure for the battery is to use a 9 volt charger with the wires stripped back also. But, my method is a bit different. I place a standard Christmas Tree light bulb (the newer small ones)in series with the charger wires. Observe the correct polarity. The battery is labeled + and - so that part is easy. By using the small light bulb you are doing 2 things. 1.You can see the slight glow from the bulb and know that proper connection is made. 2. You are limiting the charging current to the battery.
If you get really creative like I did you can solder a couple of small nails or in my case a set of red and black probes to the setup and the points on these nails/probes make for much easier connections. Note.... This method may take a few minutes longer but, is much easier on the battery.
In my experience once the battery is below a certain level NO charger that I plug in will work. I just purchased a used 8125 from eBay and brought it back to life most successfully with this method.

hy there my htc wizard battery whos dead so i charched with a cable with + and - the phone starts but when i try to connect to a usb or a adaptor it doesnt charge anymore it show me the charge icon on the baterry but it doesnt charge the usb works fine it's sync to my pc but it doesnt charge anymore... what sould i do?

So it seems no one touched on what really matters here.
A design flaw, in my opinion. The HTC Wizard cannot recharge via USB unless there is enough power to turn on. The reason is because it requires the OS to charge.
So, what many people already posted are very creative ways to charge your 8125. The easiest and cheapest way, in my opinion, is to use AA batteries.
1) Take two AA batteries and tape together so they are in series. Imagine it like this... [- AA battery #1 +][- AA battery #2 +]
2) Use two wires and tape one to each side of the AA's (one on the + side and another on the other battery's - side since the - of the first battery is connected to the + of the second).
--w-i-r-e--[- AA battery #1 +][- AA battery #2 +]--w-i-r-e--
3) Connect the positive (+) wire to the positive (+) side of the phone. By this I mean the 6 metal pieces that stick out to contact the phone battery. I did it by wrapping the wire around the top most one (or second top most, it's been over a year since I've done this.).
4) Connect the negative (-) wire to the negative (-) side of the phone. Again, bottom most or second bottom most (see #3).
5) Insert phone battery while the wires are still in and connected to the two AAs.
6) Let the power flow for 30 seconds or so and then try turning your phone on. This part is the important part because you cannot use a USB to mini-USB connected to your computer to charge the phone unless the operating system can function. Meaning, it needs to be turned on first.
7) Once the phone is on, plug in the mini-USB part and connect it to a computer. I'd recommend getting at least 5% battery before disconnecting the AAs, seeing as you need to be able to start up your phone long enough for the OS to boot. Once the OS boots, you can fully charge it through a normal USB to mini-USB connection on any computer.

old post but just wanted to say thanks. Used the wire to battery method and got phone turned on after 2 mins of holding wires to battery.

[Q] Battery Connection Voltage/Amperage

ok here's what I want to do.
Permanently integrate a nexus 7 in my car dashboard in the double din radio opening
Remove the battery from the nexus 7 and hardwire to always on power from the car battery
Hardwire the power button to a button installed in the dash
Dashmount a usb port connected via otg for hotswapping media
Hardwire a potentiometer into the dash for volume control
all of the above is fairly simple except for power supply, otg+charging is a possible solution but a car battery wired solution is far better so what i need is information on what the battery pins supply in terms voltage/amperage so i can create a 12v to direct power converter or a device that already does this. any help is appreciated TIA

bump, if someone knows i could really use this info

b22ri22an said:
ok here's what I want to do.
Permanently integrate a nexus 7 in my car dashboard in the double din radio opening
Remove the battery from the nexus 7 and hardwire to always on power from the car battery
Hardwire the power button to a button installed in the dash
Dashmount a usb port connected via otg for hotswapping media
Hardwire a potentiometer into the dash for volume control
all of the above is fairly simple except for power supply, otg+charging is a possible solution but a car battery wired solution is far better so what i need is information on what the battery pins supply in terms voltage/amperage so i can create a 12v to direct power converter or a device that already does this. any help is appreciated TIA
Click to expand...
Click to collapse
Can't you just use the USB port to charge it? it takes 5V, and 2A. With a car battery it should have enough amps, the voltage is what you'd need to regulate.
But if you really want to take out the battery instead...can't you just use a volt meter to see what the N7 draws from the battery? I'd guess it's 3.7v lithium ion but I'm not positive. I couldn't find the specs on google either..

As far as I have read there are some major difficulties getting otg+charging to work at the same time and I need the storage space provided by external storage. Having the car power source replacing the nexus 7 battery would eliminate that problem altogether.
I was hoping that someone here had known the voltages since I don't currently own or have access to a multimeter to test for myself. Knowing the voltages in advance would give me the opportunity to see what would be entailed financially to build the project and determine if its its financially acceptable to me, if the project isn't viable the money spent on the multimeter to do the tests would be wasted as it's not something I need for anything other than this particular project. So in the interest of trying to save $20 I figured I would ask here first and that there was a good chance that someone might have the information I needed.

b22ri22an said:
As far as I have read there are some major difficulties getting otg+charging to work at the same time and I need the storage space provided by external storage. Having the car power source replacing the nexus 7 battery would eliminate that problem altogether.
I was hoping that someone here had known the voltages since I don't currently own or have access to a multimeter to test for myself. Knowing the voltages in advance would give me the opportunity to see what would be entailed financially to build the project and determine if its its financially acceptable to me, if the project isn't viable the money spent on the multimeter to do the tests would be wasted as it's not something I need for anything other than this particular project. So in the interest of trying to save $20 I figured I would ask here first and that there was a good chance that someone might have the information I needed.
Click to expand...
Click to collapse
oh ok..well have you taken a look at the battery? It should just be 3.7v, I don't think it would be too hard to find which pins it is. Maybe take a LED and test it across the pins?
Also, I have heard reports OTG + charging is working fine on CM10 with a patched kernel. you might want to check this thread: http://forum.xda-developers.com/showthread.php?t=1934722

mvmacd said:
oh ok..well have you taken a look at the battery? It should just be 3.7v, I don't think it would be too hard to find which pins it is. Maybe take a LED and test it across the pins?
Also, I have heard reports OTG + charging is working fine on CM10 with a patched kernel. you might want to check this thread: http://forum.xda-developers.com/showthread.php?t=1934722
Click to expand...
Click to collapse
I've been participating heavily in the arena of OTG + charging simultaneously, as well as using USB audio.
To answer the OP's question directly: I have demonstrated (to myself) that I can power down my Nexus 7, disconnect the battery connector, plug in my y-splitting OTG cable with power in one plug, and an unpowered USB hub in the other plug. [Plugged into the USB hub is a flash drive, USB DAC, and I'm sure a keyboard would also be an option.] Then I turn on my Nexus 7, and in the OS it shows the battery at 0%, but charging (obviously it's not actually charging without the battery present...).
I even booted up the Nexus 7 normally, with all the same stuff connected to USB, and then disconnected the battery connector... and the Nexus 7 remained on!
I've thought about integrating some sort of tactile switch that essentially disconnects the battery whenever the switch is depressed. So then part of the car mount could be a little protrusion that presses this switch whenever the tablet is inserted into the car mount. That way whenever the tablet is removed from the car mount, the battery will take over without removing power from the motherboard.

MetalMan2 said:
I've been participating heavily in the arena of OTG + charging simultaneously, as well as using USB audio.
To answer the OP's question directly: I have demonstrated (to myself) that I can power down my Nexus 7, disconnect the battery connector, plug in my y-splitting OTG cable with power in one plug, and an unpowered USB hub in the other plug. [Plugged into the USB hub is a flash drive, USB DAC, and I'm sure a keyboard would also be an option.] Then I turn on my Nexus 7, and in the OS it shows the battery at 0%, but charging (obviously it's not actually charging without the battery present...).
I even booted up the Nexus 7 normally, with all the same stuff connected to USB, and then disconnected the battery connector... and the Nexus 7 remained on!
I've thought about integrating some sort of tactile switch that essentially disconnects the battery whenever the switch is depressed. So then part of the car mount could be a little protrusion that presses this switch whenever the tablet is inserted into the car mount. That way whenever the tablet is removed from the car mount, the battery will take over without removing power from the motherboard.
Click to expand...
Click to collapse
Lol, yes, I think I had you in mind when I said that.. I'm still waiting for my Y cable. I won't get it till at least 1.5 weeks..

MetalMan2 said:
I've been participating heavily in the arena of OTG + charging simultaneously, as well as using USB audio.
To answer the OP's question directly: I have demonstrated (to myself) that I can power down my Nexus 7, disconnect the battery connector, plug in my y-splitting OTG cable with power in one plug, and an unpowered USB hub in the other plug. [Plugged into the USB hub is a flash drive, USB DAC, and I'm sure a keyboard would also be an option.] Then I turn on my Nexus 7, and in the OS it shows the battery at 0%, but charging (obviously it's not actually charging without the battery present...).
I even booted up the Nexus 7 normally, with all the same stuff connected to USB, and then disconnected the battery connector... and the Nexus 7 remained on!
I've thought about integrating some sort of tactile switch that essentially disconnects the battery whenever the switch is depressed. So then part of the car mount could be a little protrusion that presses this switch whenever the tablet is inserted into the car mount. That way whenever the tablet is removed from the car mount, the battery will take over without removing power from the motherboard.
Click to expand...
Click to collapse
Am i understanding you correctly? If i unplug the battery, and just have the OTG cable plug into the charger, it would be able to power on and off and run just fine?

ho9984 said:
Am i understanding you correctly? If i unplug the battery, and just have the OTG cable plug into the charger, it would be able to power on and off and run just fine?
Click to expand...
Click to collapse
This was how it worked while the N7 was running Jelly Bean 4.1.2. I can't guarantee it would operate the same on 4.2.2.

MetalMan2 said:
This was how it worked while the N7 was running Jelly Bean 4.1.2. I can't guarantee it would operate the same on 4.2.2.
Click to expand...
Click to collapse
Someone tried it on Reddit. Removed the battery and tried powering it on with only OEM charger. The screen just flickered. They were on 4.2.2

I am curious about removing the battery and hardwiring as well as I am gathering parts to put my Nexus 7 in my car dash. The problem w/ the OTG route - it gets pretty hot down here and I'm afraid the battery will have some long term issues (ie...could leak/explode). So, hardwiring it would be preferred.
Any ideas for hardwiring?

with the new nexus 7 coming out I am just going to mount the wireless charger behind the tablet dock, now I just hope otg is supported with the slimport on the new nexus 7

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.

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 7 wiring??

Hello all,
First thread here and hoping you guys and girls with more experience can help.
Basically I am fitting my nexus 7 2012 in my car but its got the common charging problem where my battery drains faster than I can charge it.
I have ordered a new USB port strip as I've read that can fix it and fingers crossed with that.
My problem/requirement:
1. I want to charge the tablet via the usb port using a hardwired 5V 2A device this will be plugged into a otg y splitter which is then plugged into the tablet.
2. The USB A side of the splitter I want to connect to my cars ECU (it has a USB port) so I can read the data on that (basically a very expensive memory stick)
I wanted to confirm that this would work and id be able to read data at the same time as charging it.
I also wanted to double check I'm not somehow going to send my 5v 2a power down into my ECU and set it on fire
On a side note, if my new USB port replacement doesn't solve the issue of charging the tablet i will have to remove the battery and hardwire it in, will i still be ok with using the USB port for the ecu while charging hardwired with no battery?
Kind Regards
Tim

Getting any USB 2.0 device to take current while hosting is tricky.
Usually it involves talking directly to the PMIC (power management IC).
If it's a fixed installation, why not remove the battery?
It will avoid the grief of the battery swelling up, which is not too unusual for things plugged in all the time.
I've been using a Nexus 7 (2013) for a few years, but just charging on USB.
It started falling out of its nice holder.
That's when I realized that the battery was all puffed up making the back convex.
I cut off the battery cell itself on the metal tabs and soldered in wires to a 4 V 2 A supply.
I found out that the BMS is a bit balky, it refused to turn on.
So I connected it to USB to "charge" it for about 10 seconds.
Then I could turn it on (without the USB).
Ok, I could have bypassed the BMS entirely but that can be a whole 'nother can of worms too.