Database Users

car charger for XDA Exec

Hello
I had gone out to get a car charger for the XDA Exec. i went to the t-mobile shop and they gave me a car charger for the motorola V3 and said it would work.
i have not tried it, but my brother who has an imate jasjar tried it and it does not seem to work with his device.
both the XDA & V3 use a USB cable from the PC to charge them up, that made me think they could use the same car charger, what do you guys think?

u need to think about the voltage of the charger u have, you should never use a charger that was never designed for your device.
even if it is fractionally dfferent, this could cause anything from failure of your device to fire, etc. you should have got a charger from an o2 shop, I got one and it was only 15 quid. works perfectly and was designed for universal devices.

The main problem here is the current the charger will deliver.
I have 1 exec that will only just charge from an 850 m amp charger the 2nd exec wont charge at all. You really need a charger that will deliver 5v 1 amp to charge effectively.
I stuggled to find such a charger but the active holder from Brodit does the job superbley. i got mine from
www.gpsforless.co.uk
Regards
The Pilgrim

thanks for the replies
so it is the current specifications which is the problem!!
i geuss the voltage spec is nto a problem, since the USB outlet should guarantee volts between 4.75 and 5.25, correct?
i guess the comp based charging works, cause the computer can provided as many amps as required, correct?
but why would one xda charge up and the other wont.
resistor tolerances ??
what about the charging algorithm , once the battery charges up, what prevents the charger to push more juice into the xda exec. likewise with the ccmputerbasec charager?
Can i use a car charger meant for the t-mobile MDA Pro with the O2 XDA EXEC or with the i-mate jasjar, or are the specifications different?

the_pilgrim said:
The main problem here is the current the charger will deliver.
I have 1 exec that will only just charge from an 850 m amp charger the 2nd exec wont charge at all. You really need a charger that will deliver 5v 1 amp to charge effectively.
I stuggled to find such a charger but the active holder from Brodit does the job superbley. i got mine from
Click to expand...
Click to collapse
That's strange, true computer USB ports only deliver 500 mA and it appears to charge just fine, if very slowly, on one of those. Razr chargers are not entirely the same as regular USB chargers, the Razr uses the extra USB pin (mini has 5, regular has 4) to tell it what kind of device is connected, cradle, computer, etc. It's possible that the Uni chokes on that.
As an experiment, I hooked a 400 mA (specced) USB adapter to my MDA Pro, the charge light comes on. It's at 70% battery at 1:00 am local time. I'll check again a bit later to see if it actually charged.
[Edit: It's 22 minutes or so later and I've moved to 76%, while the PDA was otherwise turned off. That confirms that it's very, very slow. Also, the adapter was pretty warm, it may have been running over its rating.]
I'm not sure how much this experiment is worth though, I've got a near duplicate of this adapter with a different colour that's specced at 1000 mA (and in fact they're now selling the same outer plastic with a 2000 mA rating). If the insides are as similar as the outside, the other one's just underrated, but it's possible that the insides are actually different.
Re:Voltage, as far as I know, anything that uses a USB charger is 5V so should be intercompatible. This statement does not come with any express or implied warranty of fitness and I will not be replacing any devices you fry.
Still, though, most devices tend to run on "be liberal in what you accept" -- my Nokias charge on anything from at least 3 to 8 volts. I wouldn't be surprised if the uni is the same, but I won't be testing that out anytime soon. At least not without reloading the original rom first in case I'd need to warranty it.

xda_guy said:
what about the charging algorithm , once the battery charges up, what prevents the charger to push more juice into the xda exec. likewise with the ccmputerbasec charager?
Can i use a car charger meant for the t-mobile MDA Pro with the O2 XDA EXEC or with the i-mate jasjar, or are the specifications different?
Click to expand...
Click to collapse
All the universals are identical to a much closer look than simply charging. The only thing that's different there is the colour, a charger colour coordinated with an MDA Pro isn't with a jasjar.
The name 'charger' is really a misnomer. What 'chargers' actually do is provide a (semi-[1])constant voltage at a certain maximum number of amps, ie, they're *power supplies*. The actual charger which takjes care of the battery charging algorythm is integrated inside the Uni. All the 'charger' needs to do is make electricity of the kind that the *actual* charging chip inside is designed to run on.
[1] Most chargers, even original equipment let alone aftermarket, are highly crappily regulated.

Get one from a local orange store - 10 quid for a spv500 one, works great.

actually i tried to charge a second razr using my comp and it woudl not charge up? does this mean the current spec varies from device to device, even within the same device
if one messes up the uni by charging it using a charger from a different make, it is still under warranty?
hey jasper
The only thing that's different there is the colour, a charger colour coordinated with an MDA Pro isn't with a jasjar.
what do you mean by colour coordinated
The name 'charger' is really a misnomer. What 'chargers' actually do is provide a (semi-[1])constant voltage at a certain maximum number of amps, ie, they're *power supplies*. The actual charger which takjes care of the battery charging algorythm is integrated inside the Uni. All the 'charger' needs to do is make electricity of the kind that the *actual* charging chip inside is designed to run on.
does this mean that charging algorithm is actually within the phone itself, i mean when the phine is 100% charged, how does it know that it should not charge any more?
so there are 2 types of USB sockets, one with 5 pins and the other with 4 pins. did nto the standard USB have 4 pins?
is the 10 quid charger from the orange store meant for an actual spv5000? the t-mobile store gave me 2 chargers which they said were meant for the razr and the ysaid it would work just fine on the razr

re orange 10 quid charger - no idea. i read on a forum that someone else had got one and said it worked, so i got one too and it worked great.
previously I had used the supplied usb cable with a car adaptor and it couldn't keep up with running tomtom, so the battery would go flat. with this charger i can run tomtom and the device charges fine too.

thanks for the reply
you had received a usb cable with a car adaptor ? was this a unit which plugged into the cig lighter socket of the car

hi
this charger works with the exec and charges it quickly
http://cgi.ebay.co.uk/CAR-CHARGER-O...itemZ5849569917QQcategoryZ48674QQcmdZViewItem

xda_guy said:
thanks for the reply
you had received a usb cable with a car adaptor ? was this a unit which plugged into the cig lighter socket of the car
Click to expand...
Click to collapse
The cable was the standard one supplied. the car adaptor does plug into the cigarette lighter socket - one was supplied with a palm t3 car kit, another with an ipaq car kit. both never worked as previously stated (showed charging but failed to keep up with battery drain in use).

xda_guy said:
The only thing that's different there is the colour, a charger colour coordinated with an MDA Pro isn't with a jasjar.
what do you mean by colour coordinated
Click to expand...
Click to collapse
I mean that if you get a silver charger, same colour as the MDA Pro, it will not be a black charger, same as the Jasjar. So it may not look quite as cool, but it'll work just fine.
The name 'charger' is really a misnomer. What 'chargers' actually do is provide a (semi-[1])constant voltage at a certain maximum number of amps, ie, they're *power supplies*. The actual charger which takjes care of the battery charging algorythm is integrated inside the Uni. All the 'charger' needs to do is make electricity of the kind that the *actual* charging chip inside is designed to run on.
does this mean that charging algorithm is actually within the phone itself, i mean when the phine is 100% charged, how does it know that it should not charge any more?
Click to expand...
Click to collapse
There are three components that have to do with charging: First there's the battery. It's got four contacts (+, -, and two others) which means it's probably a smart or at least semi-smart battery, which has internal sensors for temperature etc, either directly wired to outside or with a small chip to multiplex the lot onto just 2 wires, then there's a chip inside the phone which does the actual charging, it probably knows how full the battery is by measuring the output voltage, and regulates charge current based on that and the temperature., and communicates that to the OS. Then there's the so-called 'charger' outside the phone, or the USB cable, which simply provides the raw electricity to work with.
so there are 2 types of USB sockets, one with 5 pins and the other with 4 pins. did nto the standard USB have 4 pins?
Click to expand...
Click to collapse
Standard 'large' USB ports, both the ones found on your PC (long rectangular in crossection, 'type A') and the ones like are on a printer (more squarish in crosssection, 'type-B') have 4 pins. There was at one time a mini-USB with 4 pins as well, bit that was never common and is highly obsolete. And then there's the regular mini-USB we have these days, which has 5 pins. It comes in three variants which look almost the same: Mini-B, which you get on things like digicams, external cardreaders, etc ('slave devices'), and on the end of the USB cables that came with your universal (since it acts as a slave device when hooked to a PC), then there's mini-A, which is for computers that can't fit a fullsize one (rare), and then there's mini-AB, which can be used by both mini-A and mini-B plugs, and is the physical port found on the universal. These should be used by PDAs that provide USB-Host functionality, that is, you can hook them to a PC and they'll act as a slave device, but then you can hook them to a car reader or external hard drive and they'll act as host. Unfortunately, while the Universal has the physical mini-AB port, it doesn't *actually* support USB-Host functionality.

thanks for the info on the usb connectors

I got this.
Works in your car AND in a standard wall outlet in case you dont have a laptop or computer around to do power over usb.
http://www.boxwave.com/products/versacharger/index.htm
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They even have an airplane adaptor in the case that your favorite airline has outlets...
I NEVER leave home w/o this thing...like EVER...

xda_guy said:
does this mean that charging algorithm is actually within the phone itself, i mean when the phine is 100% charged, how does it know that it should not charge any more?
Click to expand...
Click to collapse
When the battery reaches its maximum capacity the voltage dips slightly. the chargers in the phone detect this and stop charging.
Regards
The Pilgrim

xda guy
You can use your V3 car charger to charge your Exec. I do although it doesn't charge as fast as your mains charger or one designed specifically for it. It's something to do with the milli amps output.
However, it won't charge unless you plug it in with the clam Closed and the device OFF. You can subsequently open the clam and/or turn it on (for example if your running TT) and it continues to charge. If you plug the charger in with the device on, switch it off and it will charge (you can then turn it back on).
BTW - The V3 mains charger WON'T charge the Exec !!!

I use the one from Brodit, supplied by www.dsldevelopments.com and it works a treat. Never any problems, and Brodit gear is always top notch!
Ant

thanks for the replies
hey does the versacharger work with all mobile phones?
voltage of the battery dips slightly?
However, it won't charge unless you plug it in with the clam Closed and the device OFF. You can subsequently open the clam and/or turn it on (for example if your running TT) and it continues to charge. If you plug the charger in with the device on, switch it off and it will charge (you can then turn it back on).
Click to expand...
Click to collapse
hey how do you turn the exec off?

hey how do you turn the exec off?
Click to expand...
Click to collapse
ermmm, with the on/off button !

Samsung Galaxy Phone Rapid Charger Mod

This post will show you how to MOD an un-official Samsung USB wall charger into one that will enable full speed charging on Samsung Galaxy S phones.
8 $ ebay cheap wall battery charger power output specs:
350 mA battery charging speed - doesnt matter...
800 mA USB port.. THIS IS WHAT YOU WANT!! more the better. nice if the phone would use all of it... Need AC Mode... (thats what this post is for!)
Samsung wall USB charger is only 750mA! AND it will set AC mode.
The theory behind it is with samsung galaxy phones and "official chargers":
if the middle 2 data pins on the usb, while getting 5v to the outer 2 pins it tells the phone that it is an *official samsung* charger and enables full speed charging.
without the middle 2 pins connected (with or without data flow) will not charge at full speed. even if you supply 800mA it will only charge around 350mA
well there have been posts of cable hacks to do this or adapters... ha! tape and tinfoil... or hack the cable apart! And you cant use the cable with the PC anymore!
heres my mod... bend 2 pins.. DONE! solder if you know how for better connection!
***only use this charger for samsung phones, not all USB devices will like this, -may dammage some- as the samsung phone is PROGRAMMED to know what to do if the 2 data pins are shorted out***
Phone confirms AC charging NOT USB NOW!!
Now i can leave my Samsung Charger upstairs, and this one downstairs.
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You know how long it takes to charge an extended battery on USB mode? almost 5 hours! or at 350 mah in the battery charger? almost 7 hours!
I was able to charge my extended battery (says 2500mah) from 8% to 100% in about 2 hours 45 min over USB cable (AC mode) with the screen off. In the official samsung charger it was a little over 3 hours. just in the battery cradle it takes around 5-6 hours. Very much improved!

Good guide. I did the same modification to my Verizon car charging cable. I don't have Verizon, but I swapped an iPhone car charger with a verizon user who got rid of his Motorola Android.
This mod works on any charger. The device will always display "Charging(AC)" and this enables full charging capability.
I modded my cable by taking apart the microUSB connector and dropping a bit of solder between pins 2 and 3 on the back side of the connector. It works great.
Do not do this on a cable which may be connected to a PC. If the PC is older and does not have overcurrent protection, it may fry the USB Power Supply.

You could also use one of those short usb extender cables that come with some usb dongles. I did that with one of mine and it works great. Don't even have to take the cable apart just carve out a small part of the plastic connector between the pins and bridge it with solder. Or use a conductive pen- haven't tried that though.

Wow i'm so lost, so does this apply to the vibrant...
You know maybe I have had my foot up my ass for sometime then..
I ALWAYS charge my phone with the USB charger connected to the computer and it seems to take forever...
You must forgive me but I always leave my phone charging on my PC everynight and have actually lost the AC power wall plug portion...
Will connecting this through the USB of the computer also only supply the 350mA instead of the full 800mA like your saying, or will the computer always deliver the sexy amount?
Thank you sir, you are a genius?

jwleonhart said:
Wow i'm so lost, so does this apply to the vibrant...
You know maybe I have had my foot up my ass for sometime then..
I ALWAYS charge my phone with the USB charger connected to the computer and it seems to take forever...
You must forgive me but I always leave my phone charging on my PC everynight and have actually lost the AC power wall plug portion...
Will connecting this through the USB of the computer also only supply the 350mA instead of the full 800mA like your saying, or will the computer always deliver the sexy amount?
Thank you sir, you are a genius?
Click to expand...
Click to collapse
Most of PCs provide up to 500mA on single USB port or on pair of ports, haven't heard about mainboard which doesn't throotle it and let power drain go higher.
However, you can mod usb cable with 2 male and 1female connectors, that kind for powering external hard drives.

Here is a picture of the pinouts in a usb cable..
Now obviously you have the 5V, Ground, and data, but then where would you add in more power?

jwleonhart said:
Now obviously you have the 5V, Ground, and data, but then where would you add in more power?
Click to expand...
Click to collapse
The talk about connecting the pins 2 and 3 is only an indication to the phone. Normally, usb ports from computers, etc. will only provide 500 mA of current. Typical wall adapters provide 1000 mA of current. Samsung phones will normally only draw the smaller amount of current, unless pins 2 and 3 are shorted, which tells the phone to charge at the full rate of 1000 mA.
So pin 1 still carriers power, it just carries more power when connected to a source capable of providing the power (e.g. most wall adapters), and pins 2 and 3 tell the phone to accept the increased power.

jwleonhart said:
Wow i'm so lost, so does this apply to the vibrant...
You know maybe I have had my foot up my ass for sometime then..
I ALWAYS charge my phone with the USB charger connected to the computer and it seems to take forever...
You must forgive me but I always leave my phone charging on my PC everynight and have actually lost the AC power wall plug portion...
Will connecting this through the USB of the computer also only supply the 350mA instead of the full 800mA like your saying, or will the computer always deliver the sexy amount?
Thank you sir, you are a genius?
Click to expand...
Click to collapse
if the 2 data pins arent joined the phone WILL NOT receive anymore than 350. this tells the phone "im an official charger, take more!"
if you are going to mod a cable to have the 2 data pins joined, make sure the 2 pins shorted on the phone end and NOT THE PC END of the cable, and NOT BOTH EITHER. shorting the data pins on the computer side can blow your usb port.... or more.

Thanks
Thanks, Worked For Me!

Same thing you can make via kernel by adjusting max8998 regulator driver. I've done it in my Galaxian kernel

Do you mean to build a kernel that has different settings for the USB resistor input? What/where was the specific change you made?

TRusselo said:
Do you mean to build a kernel that has different settings for the USB resistor input? What/where was the specific change you made?
Click to expand...
Click to collapse
Voltage regulator and the charging current part: max8998-private.h, a file that contains charging values in mA:
Code:
#define MAX8998_ICHG_90 0
#define MAX8998_ICHG_380 1
#define MAX8998_ICHG_475 2
#define MAX8998_ICHG_550 3
#define MAX8998_ICHG_570 4
#define MAX8998_ICHG_600 5
#define MAX8998_ICHG_700 6
#define MAX8998_ICHG_800 7
Battery driver part: s5pc110_battery.c and defined AC and USB charging rates (modified by me to 800mA when on AC and 550mA on USB):
Code:
if (chg->cable_status == CABLE_TYPE_AC)
max8998_write_reg(i2c, MAX8998_REG_CHGR1,
(MAX8998_TOPOFF_10 << MAX8998_SHIFT_TOPOFF) |
(MAX8998_RSTR_DISABLE << MAX8998_SHIFT_RSTR) |
(MAX8998_ICHG_800 << MAX8998_SHIFT_ICHG));
else if (chg->cable_status == CABLE_TYPE_USB)
max8998_write_reg(i2c, MAX8998_REG_CHGR1,
(MAX8998_TOPOFF_25 << MAX8998_SHIFT_TOPOFF) |
(MAX8998_RSTR_DISABLE << MAX8998_SHIFT_RSTR) |
(MAX8998_ICHG_550 << MAX8998_SHIFT_ICHG));
One more thing in i9000 kernel sources: drivers/usb/gadget/android.c
Code:
#ifdef CONFIG_USB_ANDROID_SAMSUNG_COMPOSITE
/* soonyong.cho : This value of max power is referred from S1 */
[COLOR="Red"].bMaxPower = 0x30, /* 96ma */[/COLOR]
#else /* original */
[COLOR="YellowGreen"].bMaxPower = 0xFA, /* 500ma */[/COLOR]
#endif /* CONFIG_USB_ANDROID_SAMSUNG_COMPOSITE
from where I removed the condition to make it look like that:
Code:
[COLOR="YellowGreen"].bMaxPower = 0xFA, /* 500ma */[/COLOR]
BEFORE:
AFTER:

Now that's the kind of stuff we like to see!
NOW ENGLISH IMAGE (non android related)...

Is there any particular reason why you did not move USB speed to match the PC speed? Was it to avoid drawing too much power from your USB port?

TRusselo said:
Is there any particular reason why you did not move USB speed to match the PC speed? Was it to avoid drawing too much power from your USB port?
Click to expand...
Click to collapse
Yes and no, because single USB port cannot deliver more than 500mA, but if you use two ports simultaneously, you are able to use full 800mA charging current which is limited by the kernel driver so there is no way to charm the phone.

If you have any USB 3.0 ports those are able to go up to 900mA from a single port

I just tried this and it worked perfectly, thanks! Very easy soldering job.
EDIT: Used my $8 radioshack iron, it was plenty. No need to break out the Hakko station for this.

some kernel devs on ICS SGS project seem to think the above kernel change to up the USB mode to 500mah (less than AC mode) could cause the battery to explode, or damage the phone, or fry the USB ports of the computer..... and the batteries *like* being charged slower anyway... lithium ion batteries... but its all "simple chemistry" according to "one of them".. ignoring simple electronics...
i dont know where to start on how many things are wrong with what they think.... but I am not a kernel compiling god like them..... so I am no-one to tell them different.... (in their eyes).
making the suggestion of the above kernel change. led to a 20 minute bashing session of how i am wrong.
i just wanted to suggest, and leave. not really caring if they liked it or not. but ignorance is a powerful foe.
anyone wanna explain for me?
makes me re-think donating to people i dont know.

TRusselo said:
some kernel devs on ICS SGS project seem to think the above kernel change to up the USB mode to 500mah (less than AC mode) could cause the battery to explode, or damage the phone, or fry the USB ports of the computer..... and the batteries *like* being charged slower anyway... lithium ion batteries... but its all "simple chemistry" according to "one of them".. ignoring simple electronics...
i dont know where to start on how many things are wrong with what they think.... but I am not a kernel compiling god like them..... so I am no-one to tell them different.... (in their eyes).
making the suggestion of the above kernel change. led to a 20 minute bashing session of how i am wrong.
i just wanted to suggest, and leave. not really caring if they liked it or not. but ignorance is a powerful foe.
anyone wanna explain for me?
makes me re-think donating to people i dont know.
Click to expand...
Click to collapse
So now you know why you didn't saw any info about my interesting finding... ^^
Sent from my GT-I9000 using Tapatalk

we need to have software devs that understand hardware...
im too much in the middle. lol

Need some help from someone who knows legit electronics(diodes, resistors, etc.)

So, i'm trying to add in a usb microsd adapter to my Kindle Fire.
Threads before I started, just discussing ideas:
KF forum: http://forum.xda-developers.com/showthread.php?t=1615055
Hardware hacking forum: http://forum.xda-developers.com/showthread.php?t=1615059
Now, I just about completed the project, but I dropped the motherboard and broke it while soldering a wire onto it. I've just bought another KF off of ebay and will continue at that point, but while i'm waiting I need some advice/help.
I've made a diagram of what i'm going to do. It's pretty horrible, but I think it's understandable.
Few questions that go with the diagram:
*DC only flows one way, do I need the diodes?
*If I should use the diodes will these work? (max output they would need to withstand would be 7v and 1A cause of the wall charger)
*The wall charger puts out 1000mA(1A) when charging. USB puts out 100mA, would that 1A ruin the adapter since it's designed for USB? If so, should I use some resistors?(Unsure cause they would change the regular, lower output to the adapter)(Or the resistors could be put into the charger)
*More questions/concerns on the diagram
Diagram:
Taken off because it was incorrect.

I'm still a bit fuzzy on what's going on here.
I'm not sure what the (2) 3.7V batteries and the 4.4V boards are.
Is that the stock Kindle Fire power supply that you are showing?
Th first question: Have you gotten the USB SD card to work normally plugged in externally?
If not, have you gotten the USB SD card to work through a powered hub?
All the diodes on the black lines are drawn backwards.
You don't need any diodes there or even a reed switch on the black line.
You might have a problem activating the 4 (remaining) reed switches simultaneously and reliably.
If you've never seen voltage out of the KF USB connector, that means that you've not gotten it into USB host mode.
Oh, of course the KF has a single 3.7V battery so I don't know what that whole right side is doing.

Renate NST said:
I'm still a bit fuzzy on what's going on here.
I'm not sure what the (2) 3.7V batteries and the 4.4V boards are.
Is that the stock Kindle Fire power supply that you are showing?
Th first question: Have you gotten the USB SD card to work normally plugged in externally?
If not, have you gotten the USB SD card to work through a powered hub?
All the diodes on the black lines are drawn backwards.
You don't need any diodes there or even a reed switch on the black line.
You might have a problem activating the 4 (remaining) reed switches simultaneously and reliably.
If you've never seen voltage out of the KF USB connector, that means that you've not gotten it into USB host mode.
Oh, of course the KF has a single 3.7V battery so I don't know what that whole right side is doing.
Click to expand...
Click to collapse
The battery is made up of two 3.7v batteries, they just stuck them together and put a board there to control the power flow or whatever. I said it's lowered to 4.4v cause normally when two batteries are put together their voltage gets added together, but that 4.4v is coming from the very end pins, there are 10 total. I get 4.4v when trying the other pins too, so since i'm only connecting it to one set of pins i'm just going with 4.4v.
No, I haven't. I have not been able to successfully get USB host working at all, even with a USB host cable. I don't have a powered hub, but I tried taking the power from a USB port on my computer and that didn't work either. Other people have it working though, some with powered hubs, and a few without.
It might have just been my Kindle, so i'll see when I get the other Kindle I ordered.
I thought I was doing them backwards, I know how they go on physically, but I wasn't sure about on paper.
I'm not sure that i'll need all the reed switches, I may just need two; one to disconnect the ID(blue wire) from the back, and one to disconnect one of the data lines. I wasn't able to experiment though since I never got USB host working.
I tried measuring the voltage directly on the board and from the USB host cable and didn't a reading from either.(When I measured on the board I shorted out the ID an GND wires like they are on a USB host cable)
What I was trying to do with the battery there was prevent power from the charger going directly to the battery, that would be bad. So I do need at least one diode on each line there, but the other two I added cause I didn't want any extra power to be wasted. Of course, it doesn't make much sense to me(not sure what I was thinking), that's why I asked if it was necessary.
Picture of the battery and the board connected to it. I took it apart and removed the second one to move it over and resolder it so there was space down the middle for the wires. The adapter will be at the top where the speakers are.
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This whole idea has lots of problems.
Taking power directly off the battery is not a good idea for many reasons,
the least of which is that many (most?) USB devices won't work on 4.4 volt.
Throw in a silicon diode and you're down a further 0.7 volts.
Ok, you could make it a Schottky diode if you want.
You're still going to have to disconnect both data lines to get this to work,
unless you are planning to only use the external USB connector for charging.
Using host mode, the power should be coming out of the USB interface.
As mentioned, if you don't have it there, it's not working.
Here's a sequence of a Kindle Fire teardown: http://www.ifixit.com/Teardown/Kindle-Fire-Teardown/7099/1

Renate NST said:
This whole idea has lots of problems.
Taking power directly off the battery is not a good idea for many reasons,
the least of which is that many (most?) USB devices won't work on 4.4 volt.
Throw in a silicon diode and you're down a further 0.7 volts.
Ok, you could make it a Schottky diode if you want.
You're still going to have to disconnect both data lines to get this to work,
unless you are planning to only use the external USB connector for charging.
Using host mode, the power should be coming out of the USB interface.
As mentioned, if you don't have it there, it's not working.
Here's a sequence of a Kindle Fire teardown: http://www.ifixit.com/Teardown/Kindle-Fire-Teardown/7099/1
Click to expand...
Click to collapse
Taking power straight from the battery is only a temporary solution, the devs working on the 3.0 kernel is working on fixing the OTG issues and trying to remove the kernel limit of 3v. Also, from what I understand there are other issues that the KF is having regulating the voltage out, people report that below 50% battery USB host stops working.
So, if the issues get fixed i'll just disconnect the battery, or, as I said before, it may have just been my Kindle. I got it used & broken and fixed it myself, so it may have been damaged more than I was aware. I would be able to provide more definitive answers if I had something to experiment with, but I won't have the other Kindle for a few days.
Also, since i'll have a second battery now, i'm not as worried about the battery being damaged.
I do realize that the diodes drop the voltage by .7v, but people who have USB host working report that the KF is putting out 3.3v, and some people have gotten certain flash drives and other devices to work off of that. I believe the microsd adapter I have will work off of that lower voltage.
I only charge using a wall adapter, and charging did work for me as long as the ID and GND cables were separated. My main concern is that adb and fastboot work since i'll just be transferring files to the Kindle and the sdcard with FTP. Which, if adb works so will mass storage, so...
Without using the battery it's just and internal OTG USB host set up with a switch/es, so in theory it should work.
I also don't need and diodes if it's not connected to the battery. I was just hooking it up to the battery cause I wasn't getting any power from the Kindle.
As for the reed switches not working reliably, I did read something before that said that they might screw each other up if they were all right next to each other. What if they were lined up end to end, would they interfere with each other like that? If they do work properly end to end all I need is a custom, long, slender, and rectangular neodymium magnet.
Again, I didn't really have much time to experiment since gravity and I screwed up my motherboard. I had just done some physical modding to the housing and framing to make space for everything, and done some testing on the voltages that it was putting out.
Also, thanks for the help and advice

Ok, here's what I was planning on doing without the battery, any problems now, besides the potential issues with the reed switches?

Ok, the TWL6030 used in the KF uses an LDO regulator for VBUS on USB for OTG
and is speced for 3.3V at 35 mA
http://www.ti.com/lit/ds/symlink/twl6030.pdf
The Nook Touch that I have uses a TPS65921 (a/k/a TWL4030) which uses a charge pump
and is speced for 5.0V and guaranteed for 50 to 100 mA depending on battery voltage.
http://www.ti.com/lit/ds/swcs048f/swcs048f.pdf page 16
I've seen some devices that won't even work at 4.5V
Keyboards generally draw about 5mA.
I've seen audio adapters at 25 mA.
Some thumb drives take a lot of current.
Keeping the red connected all the time may or may not be a problem.
An inactive USB device should not be drawing much (any?) current, but you can never tell.
Bottom line, I don't think that the KF is a very good candidate for stand-alone OTG.
I'd use a powered (and back-powering) hub if I owned a KF.

I don't know what's going on here.. but I corrected your power supply in the schematic above.

Renate NST said:
Ok, the TWL6030 used in the KF uses an LDO regulator for VBUS on USB for OTG
and is speced for 3.3V at 35 mA
http://www.ti.com/lit/ds/symlink/twl6030.pdf
The Nook Touch that I have uses a TPS65921 (a/k/a TWL4030) which uses a charge pump
and is speced for 5.0V and guaranteed for 50 to 100 mA depending on battery voltage.
http://www.ti.com/lit/ds/swcs048f/swcs048f.pdf page 16
I've seen some devices that won't even work at 4.5V
Keyboards generally draw about 5mA.
I've seen audio adapters at 25 mA.
Some thumb drives take a lot of current.
Keeping the red connected all the time may or may not be a problem.
An inactive USB device should not be drawing much (any?) current, but you can never tell.
Bottom line, I don't think that the KF is a very good candidate for stand-alone OTG.
I'd use a powered (and back-powering) hub if I owned a KF.
Click to expand...
Click to collapse
Thanks for the info, I cut open a cable and plugged it into my computer with a resistor hooked up to it and got the voltage down to about 3.4v and the adapter that i'm using still ran and was recognized. I'm unsure about the current though.
It's not really OTG if it has to be hooked up to a separate power supply :/
AdamOutler said:
I don't know what's going on here.. but I corrected your power supply in the schematic above.
Click to expand...
Click to collapse
I don't understand why i'd need a 5v regulator on the battery when it's only putting out 4.4v? (Again, current-wise i'm unsure)
Also, the ID wire(blue) needs to be connected to the GND to activate USB host mode, it tells the device that it's a master and not a slave.
And I don't know if you read my previous posts, but I may not even be using the battery if I can get USB host working like everyone else. And the diodes were there cause I didn't want power going directly to the battery since it could mess it up.

Well, your circuit is wrong in a bunch of different ways so I redesigned it.
0. USB requires 5V regulated power.
1. the ground diodes are pointing the wrong way so the power would not flow.
2. When charging the battery you'd kill your device
3. zener diodes breakover at a certain voltage, not regulate. Those zener would just prevent any voltage from flowing. You'd want a Silicone Controlled Rectifier.
4. The 2 extra diodes do nothing at all in your circuit.
5. Each diode drops .7V. Your circuit effectively uses 4 of them between power and ground from the battery. so, by the end of your circuit, the microSD adapter gets 1.6 volts.... no where near what's required to run the device.
So, I corrected the circuit.
Didn't read that you were using any other method, still havn't.. Just wanted to correct the circuit in case someone else tries to do it.

I built my own car charger using a similar circuit. It's the same thing you'll find in a powered usb hub, although they may use diodes to prevent a backflow of power into the computer.

AdamOutler said:
Well, your circuit is wrong in a bunch of different ways so I redesigned it.
0. USB requires 5V regulated power.
1. the ground diodes are pointing the wrong way so the power would not flow.
2. When charging the battery you'd kill your device
3. zener diodes breakover at a certain voltage, not regulate. Those zener would just prevent any voltage from flowing. You'd want a Silicone Controlled Rectifier.
4. The 2 extra diodes do nothing at all in your circuit.
5. Each diode drops .7V. Your circuit effectively uses 4 of them between power and ground from the battery. so, by the end of your circuit, the microSD adapter gets 1.6 volts.... no where near what's required to run the device.
So, I corrected the circuit.
Didn't read that you were using any other method, still havn't.. Just wanted to correct the circuit in case someone else tries to do it.
Click to expand...
Click to collapse
AdamOutler said:
I built my own car charger using a similar circuit. It's the same thing you'll find in a powered usb hub, although they may use diodes to prevent a backflow of power into the computer.
Click to expand...
Click to collapse
*If it requires 5v then how do devices run with less with USB host on other people's KFs?
*I'm aware that the ground diodes are the wrong way, I asked in my og diagram, and mentioned in a previous post that I know how they go on physically, just not in a diagram.
*That's why I had the diodes, to prevent messing up the battery and device
*I still don't understand how/why it needs to be regulated when it's only 4.4v, it's not over 5v.
I know what zener diodes are, all I would need is to prevent power going straight into the battery, and that's what the diodes would do.
*I wasn't going to use those extra two diodes on each battery line unless someone said that it did something, it was suggested to me by someone who has less electronical knowledge than me and I figured it doesn't hurt to ask.
*And with the 3.3v from the Kindle and 4.4v from the battery minus the 2.8v required for four diodes it equals 4.9v, which should work, but hopefully I don't have to use the battery.
Also, if you look at the picture in my post here it shows exactly what a OTG USB host cable does minus the switches. All I did was add the battery and diodes to prevent power from the charger going into the battery and power from the battery going into the charge port. In theory that should work out. And like I said before, hopefully I don't need to use the battery at all.
I removed the picture in the first post since it was incorrect; while I doubt anyone is going to try it at this point, I understand your sentiment.

Look, im not saying my way is totally up to standards, but it comes much closer than yours with fewer parts, less work and i gaurantee it will work. The proper way is to buy a powered hub and connect to that. If you dont want feedback, dont post in a discussion forum.
Im done wasting my time on this thread. Youre doing it wrong.

AdamOutler said:
Look, im not saying my way is totally up to standards, but it comes much closer than yours with fewer parts, less work and i gaurantee it will work. The proper way is to buy a powered hub and connect to that. If you dont want feedback, dont post in a discussion forum.
Im done wasting my time on this thread. Youre doing it wrong.
Click to expand...
Click to collapse
No need to get all upset bro, i'm just replying to what you've said(Like you said, discussion forum). You said you didn't read any previous posts, and it was obvious, you kept saying things that had already been brought up. And you say things like "Those zener would just prevent any voltage from flowing" when I was saying that was what I was trying to do anyways. Your comment implies that you think that I shouldn't use them, but with no explanation as to why not.
It's not that I don't want feedback, but you keep saying i'm doing it wrong, but you're not answering the questions that I ask. You're just saying "My way is right, your way is wrong," basically.
I repeatedly asked why it needs to be regulated when it's already less than 5v.
I also asked "If it requires 5v then how do devices run with less with USB host on other people's KFs?"
And I realize I didn't post this, but my next question was going to be, with the regulator there I would still need to put the diodes in to prevent power from the battery from going into the charge port and power from the charger going directly into the battery, correct?
Tl;dr:
You're right, you're wasting your and my time because you're not answering my questions, you're not explaining why your way is correct, and you keep bringing up things that were already discussed that I know about.

aaricchavez said:
If it requires 5v then how do devices run with less with USB host on other people's KFs?
Click to expand...
Click to collapse
Um, luck? Sure, a lot of devices are not picky about power.
The specification for USB is 5.0 V
Some devices may not have enough voltage to run at 3.3 V
Some devices may not have enough current to run at 35 mA
Some may simply not detect the presence until it rises over a threshold of 4.5 V
An SD card all by itself uses a nominal 3.3 V
The USB interface circuit is a separate issue.
aaricchavez said:
And with the 3.3v from the Kindle and 4.4v from the battery minus the 2.8v required for four diodes it equals 4.9v
Click to expand...
Click to collapse
The math may be correct, but unfortunately the circuit is not in series.
The voltages just don't add up that way.
You'd need a "floating" battery (not the built-in one) to make the voltages add.
Getting a higher voltage from somewhere and using a 5 V voltage regulator would work.
However, you might need up to 7 V input because your garden-variety regulator has a "dropout voltage" of about 2.0 at full current.
That's why there are special "low dropout" (LDO) regulators designed for such cases.
Still, they can't make more voltage than what they take in.
For that we use charge pumps or boost regulators.
Both of those are active switching devices.

aaricchavez said:
I repeatedly asked why it needs to be regulated when it's already less than 5v.
I also asked "If it requires 5v then how do devices run with less with USB host on other people's KFs?"
Click to expand...
Click to collapse
Sorry didnt read all of the posts, butfor this you can use simple step-up converter.
I have solar charger also with li-ion battery which can provide max 4,22 V and I need 5 Volts.
I bought this module on ebay:
http://www.ebay.com/itm/DC-DC-Conve...175?pt=LH_DefaultDomain_0&hash=item4165891a1f
Works great, provides nice clean 5V output, max is about 2 Amps, even they are telling more... Could also post my complete solution photo if you want

Renate NST said:
The math may be correct, but unfortunately the circuit is not in series.
The voltages just don't add up that way.
You'd need a "floating" battery (not the built-in one) to make the voltages add.
Getting a higher voltage from somewhere and using a 5 V voltage regulator would work.
However, you might need up to 7 V input because your garden-variety regulator has a "dropout voltage" of about 2.0 at full current.
That's why there are special "low dropout" (LDO) regulators designed for such cases.
Still, they can't make more voltage than what they take in.
For that we use charge pumps or boost regulators.
Both of those are active switching devices.
Click to expand...
Click to collapse
What's the difference between the built in battery vs an outside battery that would make it add up?
Adding another power source would basically end up being the same as getting a powered hub.
So what Helium, the poster below you, said should work with the 3.3v that the KF already puts out?
HeliumX10 said:
Sorry didnt read all of the posts, butfor this you can use simple step-up converter.
I have solar charger also with li-ion battery which can provide max 4,22 V and I need 5 Volts.
I bought this module on ebay:
http://www.ebay.com/itm/DC-DC-Conve...175?pt=LH_DefaultDomain_0&hash=item4165891a1f
Works great, provides nice clean 5V output, max is about 2 Amps, even they are telling more... Could also post my complete solution photo if you want
Click to expand...
Click to collapse
I would like to see the photo, if you don't mind.
This one should work as well, correct? http://www.ebay.com/itm/DC-DC-3V-to...932?pt=LH_DefaultDomain_0&hash=item3a722f7ccc

aaricchavez said:
What's the difference between the built in battery vs an outside battery that would make it add up?
Click to expand...
Click to collapse
Many many ..
Power outputs form every mobile devices are not designed to provide big current. It is many times about 50-100 mA, which is sufficient for flash sticks,keyboards or mouses but not for e .g. hard drives.
If you connect step-up converter to for example 3,3V and 100mA, on output you will get 5V 50mA - this is really not sufficien for even mouse...
But if you use battery insted, it can provide huge current - normally 2000mA max. So if you connect battery to converter you will get 3,7V 2000mA and on output 5V 1400mA. Which could be usable even for low power 2,5" hard driver. Also battery has bigger voltage, so it means, that efficiency will rise up a little.
aaricchavez said:
So what Helium, the poster below you, said should work with the 3.3v that the KF already puts out?
Click to expand...
Click to collapse
Yes, look up in this post
aaricchavez said:
I would like to see the photo, if you don't mind.
Click to expand...
Click to collapse
Here there are - as you can see. I am charging my phone from standart li-ion battery from GPS with standart 5V USB
aaricchavez said:
This one should work as well, correct?
Click to expand...
Click to collapse
Yes, could. But I recommend that I posted before - it has bigger mosfet package, which allows about 0,5W thermal dissipation. On your module are SMD transistors, which can dissipate only 0,1W and are very sensitive to aḿbient temperature. I dont trust SMD components in power solutions.

I'd actually recommend keeping the boost regulator on the smaller side.
Besides the space consideration, it would be nice if there were some current limiting.
I just measured the current draw on a 4GB microSD in a IOGear USB adapter and it was 45 mA.
The wireless mouse dongle that I measured was 15 mA.
I don't have any wired mice to measure, but I'd guess that they would all be around that.

Renate NST said:
I'd actually recommend keeping the boost regulator on the smaller side.
Besides the space consideration, it would be nice if there were some current limiting.
I just measured the current draw on a 4GB microSD in a IOGear USB adapter and it was 45 mA.
Click to expand...
Click to collapse
Sure, but you wrote, that his device provides 35 mA max, so it wont be enought for most flash drives. Besides that - you measured in low power (3,3V) or high power (5V) USB mode? Because I expect 5V mode so it means than in 3,3V will be much more miliamps...
Anyway, with boost module it will enable him to use almost everything which has drivers. Not only tiny consumption devices, it will be full equipped active host hub also could be connected with switch as emergency charger...

Building a dummy battery

Hello,
i would like to measure the current consumed by my mobile phone while operating. I've already built a current meter using arduino however i'm having some troubles in interfacing it with the mobile phone.
At the beginning I thought that it would enough to insert the meter on the ac charger right before the usb port and then removing the battery. However I discoverd that the mobile phone does not work without battery.
It seems that a dummy battery would do the work however I do not know how to mechanically build it. I mean the electrical part should be trivial (a simple voltage regulator should do the trick), but what I would need is a sort of empty battery case with the pins.
Any hints?

Dummy Battery
Hi,
I´ve seen a camera hack with a dummy battery made of wood. In that case the dummy had to replace an AA-Battery, so it was made of a wood needle with pushpins at the ends for contacts.

Remove battery and connect current meter between positive battery terminal and corresponding terminal on your phone, then use some wire to connect other battery terminals with their corresponding terminals. It may be a bit difficult, since terminals are probably relatively small. Also, be extra careful and don't make a short circuit! Just be sure that you know what you're doing.

Many phones use a 3 pin battery, one pin is V+, one pin is ground and the other pin is usually used to monitor the battery's temperature via an internal thermistor that is tied to V+ since it reads a slightly lower voltage proportional to V+. I imagine the phone then uses a simple voltage divider with an internal resistor to calculate the temperature.
Like you've already discovered most phones won't run on the charger without a battery, and most phones will begin to boot but then shut down before if the thermistor doesn't give off a correct reading.
Is there a reason you want to run it without a battery. If you just want to measure current with a meter you could solder some jumper wires to the battery terminals so that you could get a amp meter between the battery and the phone.

I've run into the same problem.
Although the power management ICs (at least mine) are designed to work with a missing/dead/shorted battery, it never works out that way.
My battery on the Nook has six wires, doubled ground, doubled plus and two one for temperature sensor and one for battery pack identification.
One of the tricky thing about determining what % the battery is, is that normally you can only measure the voltage and temperature of the battery.
You'd really like to know the actual current flowing out of the battery.
The Android system has a whole chunk of code that looks at the status of the system and tries to "guesstimate" the amount of current flowing out of the battery.
The % full for a battery at 4.000 volts with no load is a lot less that a battery reading 4.000 volts with a hefty load on it.
Since lithium batteries are so persnickety you want to make sure that whatever you insert into a line is very sensitive and has a minimal voltage drop.
I think the best solution for forensic current monitoring is to build a 4 volt supply with current monitoring.
When you are done playing, it's best to clear the statistics for the "battery".

Renate NST said:
I think the best solution for forensic current monitoring is to build a 4 volt supply with current monitoring.
When you are done playing, it's best to clear the statistics for the "battery".
Click to expand...
Click to collapse
This is a pretty big item on my "todo" list.
TBH the hardest part (depending on the phone) is the physical connections.
If you build a constant voltage 4.0 volt supply with current monitoring, you'll be able to replace the battery with your power supply, instead of faking the device into thinking it has a battery and monitoring charger current.
If you want an accurate high-resolution picture of device power usage (e.g. high enough resolution to see stuff like cpuidle kicking on/off), you need to use the "dummy battery as power supply" approach. Any approach that merely monitors current into the device via its charging port is going to give very coarse results.
Obviously, many batteries have "special" additional stuff that can be difficult to emulate. 3-pin Samsungs are probably the easiest - the middle "pin" is just an ID resistor to ground.

OT
:silly:

Hi,
maybe this could help you building your own external battery measuring device
Due to the ****ty 10 post rule i cant post a link so just google for "[Info] Akkuverbraucher des Galaxy S2", it is a German android board.

Entropy512 said:
If you build a constant voltage 4.0 volt supply with current monitoring, you'll be able to replace the battery with your power supply, instead of faking the device into thinking it has a battery and monitoring charger current.
Click to expand...
Click to collapse
This should not be that complex a simple power supply with a current sensor (e.g. the acs 712) and an arduino should do the trick. A resistor on the temperature pin should also fool my galaxy2. The problem is that I do not want to solder anyhthing to the mobile phone. I will try to make a dummy battery out of wood.

If this helps to anyone, I didn't remove the battery but I used a 5V 2A power supply and connected V+ to positive and gnd to negative. The battery has internal circuit to protect from overvoltaje and overcurrent. This way the device keeps running from "battery" and you have the charge port free to connect something through otg or mhl
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qubas said:
Remove battery and connect current meter between positive battery terminal and corresponding terminal on your phone, then use some wire to connect other battery terminals with their corresponding terminals. It may be a bit difficult, since terminals are probably relatively small. Also, be extra careful and don't make a short circuit! Just be sure that you know what you're doing.
Click to expand...
Click to collapse
Then use those results to check calibration on an apk like Accubattery. This whole idea seems awkward at best and may end up frying something.
It be interesting how accurate the onboard milliamp monitoring is. I suspect it's better than most think it is.

If somebody still interested then just remove circuit from battery and connect power supply directly to the battery protection circuit board(without battery ofc ). Check the nominal voltage on the battery and set it on your lab power supply. Voltages are most commonly 3.7V-4.2V. Keep note that nowadays smartphone can consume a lot of current. For example Samsung device may consume even 2.8A while connected to Anyway blue jig while booting without battery. According to that make sure that your power supply can deliver at least 3A of current

ProfessorM_ said:
If somebody still interested then just remove circuit from battery and connect power supply directly to the battery protection circuit board(without battery ofc ). Check the nominal voltage on the battery and set it on your lab power supply. Voltages are most commonly 3.7V-4.2V. Keep note that nowadays smartphone can consume a lot of current. For example Samsung device may consume even 2.8A while connected to Anyway blue jig while booting without battery. According to that make sure that your power supply can deliver at least 3A of current
Click to expand...
Click to collapse
I was thinking the same but bumped into a strange problem with this workaround. If I connect the dummy battery to the phone, nothing happens. I cannot turn it on.
If I leave the dummy battery connected AND also connect a charger via the USB port, the screen comes alive and the phone displays the charging animation (depending on the voltage level I set for the dummy battery). Then I can unplug the charging cable, and can also turn the phone on. It's working fine, and it's also possible to turn it off and on again any times as long as the dummy battery is connected.
But as soon as I disconnect and reconnect the dummy battery I need the charger cable plugged in to be able to turn the phone on for the first time again.
What would be the reason for this behavior? I would like to use the phone as a touch screen for my 3D printer, so for me the optimal solution would be to turn the phone on automatically as soon as the power is connected, but I'm ok with turning it on manually, but would like to avoid messing with the charging cable each time.
The phone is an old OnePlus 2.

meszarosi said:
If I connect the dummy battery to the phone, nothing happens. I cannot turn it on.
Click to expand...
Click to collapse
It could be that the power supply is not sufficient for startup.
Or it could be that the thermistor and/or battery pack identification resistor wiring is wrong.
How many wires in the connection?
As somebody said, the most fail-proof is using the old BMS PCB out of the battery pack and connecting where the cell was.
The last time I posted on this thread was a decade ago!
Some years ago I did build a power supply with a USB interface,
Initially it had a TI INA219 high side current monitor.
Eventually I updated it to a TI INA226.
Here's a plot of some handy booting up (I forget which).
Minor X divisions are 5 seconds, major X divisions are 30 seconds.

Renate said:
It could be that the power supply is not sufficient for startup.
Or it could be that the thermistor and/or battery pack identification resistor wiring is wrong.
How many wires in the connection?
As somebody said, the most fail-proof is using the old BMS PCB out of the battery pack and connecting where the cell was.
The last time I posted on this thread was a decade ago!
Some years ago I did build a power supply with a USB interface,
Initially it had a TI INA219 high side current monitor.
Eventually I updated it to a TI INA226.
Here's a plot of some handy booting up (I forget which).
Minor X divisions are 5 seconds, major X divisions are 30 seconds.
Click to expand...
Click to collapse
Hi! Thanks for your reply. I actually did use the BMS board form the original battery, I connected my PSU (set to ~4.2V) where the battery cell was connected to the BMS.
The PSU can supply up to 5 amps, so I don't think thats the issue. The phone runs perfectly fine from the dummy battery, the charger cable is only necessary for the very first startup. Then I can unplug and forget it. The phone works, I can even turn it off and on again. But as soon as I remove then re-attach the dummy battery, I need the charger cable again for the first power-on.

meszarosi said:
I need the charger cable again for the first power-on.
Click to expand...
Click to collapse
Oh, ok.
It seems that the MOSFETS are shut off until they see some power from the device side.
If this is still a barrier, you can bypass that.
If there is no intelligent control to the BMS you can replace the BMS with a few resistors.
Check how many wires there are to the BMS, with everything disconnected measure from all the non-red wires to black.
There should be 10k and maybe another wire.

[Q] Tegra note 7 wireless charging?.

Hello.Does TN7 have wireless charging module inside if not then can it be installed?.

subzero82 said:
Hello.Does TN7 have wireless charging module inside if not then can it be installed?.
Click to expand...
Click to collapse
I would like to know if this is possible also as the micro USB connector in mine has gotten crushed when I accidentally pushed the connector in the wrong way up. I need to find some way of charging it and nobody seems to be able to offer a repair for it.

Stargazer Optimus said:
I would like to know if this is possible also as the micro USB connector in mine has gotten crushed when I accidentally pushed the connector in the wrong way up. I need to find some way of charging it and nobody seems to be able to offer a repair for it.
Click to expand...
Click to collapse
wireless charging does work if you get a 1000ma output plate, the hassle is it has to go behind the copper foil plate under the cover.
you can patch a usb cable to the battery and use a smart charger to keep it safe or get clever and solder to a live input like the fuse on the IO board. thread it through the stylus hole
you can if carefull patch a USB extension cable into it and mod the case to get a proper socket back or maybe see if a phone repair ship will fit a usb b socket to it.

The easy answer is no. It does not have this built-in, and the battery is non-removeable. There may be some fancy hacker way to do it that involves taking the thing apart and soldering stuff, but there's no consumer-oriented way to do it.

as a non fancy hacker type I have been picking these up with bad ports on purpose.
if you understand a soldering iron and can make 4 joints then its a simple enough fix to get a cheap high power tablet.
chargers such as the QI wireless units or powermats are intelligent so you wont run the risk of burning the house down as they switch off when charged although the unit wont tell you it is on charge the battery level will creep up.
the powermat kits are going dirt cheap for phones like the blackberry torch or iphone 3, you strip out the receiver, connect it to the battery and place between the foil and back plate.
the only issue per se is not being able to charge through a case like the fintie despite the 7mm claims for the chargers which pick up the device but fail to lock and charge. however it is possible to split the fintie case putting the QI charger internals inside it so you can plug the case in instead and charge semi normally.
the main difference between the QI and powermat is the latter is a bit thicker and has magnets in the receiver to allow a positive connection it beeps when connected and comes with its own dedicated charger, the QI unit needs a standard micro usb one.
the usb port is replacable but not at home and the wireless option at least keeps you up and running if it fails. trimming a bit out of the case will allow a proper socket to be fitted instead of the badly designed original. it will just stick out the case a few mm but hold the plug the right way round and more securely.
one issue is that like the last one I picked up is that you need a charged device to test the socket properly incase it is just the usual below minimum charge problem android devices seem to suffer from
if the device is rooted then it should be possible to do everything required even with bad ota by using recovery and the sd card.
so it is fixable for under 20 pounds and I've been buying them for around 25 off ebay. :highfive:

I have managed to get wireless charging installed on my device so it is now useable again. I have connected a QI charging card to some contacts on the IO board so you get the lightening bolt when it is charging. I have also installed a charging coil into a case so that it can be charged by plugging a charger into the case.
If the device goes completely flat however, the power from it is insufficient and you get stuck in a state of the battery icon on the screen which can consume more power than the card can deliver so it won't get going again.
I'll post with pictures of what I have done so other interested parties can give it a go if they like when I get them all together.

To add QI standard wireless charging to my TN7, first I took out the IO board, used my multimeter to find to contacts to the + and - 5V DC supply from the microusb on the board and soldered some wires to them as below:
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The wires I took out of a spare usb cable. The other ends of the wires I soldered to the contacts of a QI reciever from which I had cut the microusb connector off and exposed some of the wires:
There is of course some tape applied to the soldered contacts on the QI receiver to prevent short circuits. I then peeled the sponge tape pads from the battery and repositioned them to allow the receiver coil to sit against the battery so that it would not cause a bulge in the device:
Finally I cut a section out of the copper heat spreader in the back cover:
All in all not a big job. The wires pass by the volume switches when the case is snapped back together in this case. The QI receiver used in this case can only charge the battery at about 15% per hour when the screen is off.

Awesome walkthrough! I'm still never coming near any of my devices with a soldering iron though... every time I've tried to solder anything, I end up with a mess and a broken gadget.

Question?
Stargazer Optimus said:
Finally I cut a section out of the copper heat spreader in the back cover:
Click to expand...
Click to collapse
Can I ask you one thing? From the picture below, which part is the battery? Can you highlight it? It'd be a big help.

Torajirou said:
Can I ask you one thing? From the picture below, which part is the battery? Can you highlight it? It'd be a big help.
Click to expand...
Click to collapse
The battery is underneath the wireless reciever is in the picture. It is almost the full width of the unit and goes up to the electronics which is almost the top half of the unit. It has the black tape on it either side of and below the wireless reciever.

Okay, so could those two solder points be used to solder a cable to charge the device, like say a USB cable, solder the power wires from the cable to the solder points, obviously making sure not to reverse the polarity, and then use that as a replacement to charge a unit with a broken micro usb port, and not have to worry about using a smart charger or anything??? If so this tutorial would be a life saver!

CapeNick said:
Okay, so could those two solder points be used to solder a cable to charge the device, like say a USB cable, solder the power wires from the cable to the solder points, obviously making sure not to reverse the polarity, and then use that as a replacement to charge a unit with a broken micro usb port, and not have to worry about using a smart charger or anything??? If so this tutorial would be a life saver!
Click to expand...
Click to collapse
Yes, I have used that method to charge the device in the past before installing the wireless system. Be aware however that when you bypass the charging circuitry, there is the potential for overcharging...
The battery has red and black wires on the solder contact points so pretty obvious if you want to do that.

I've soldered QI universal wireless charger to my tn7 and its not charging anyways , same as for micro usb anyone have any ideas about whats going in my tablet ?

Nameitis said:
I've soldered QI universal wireless charger to my tn7 and its not charging anyways , same as for micro usb anyone have any ideas about whats going in my tablet ?
Click to expand...
Click to collapse
Can you provide some information about how and where you have soldered the charger? and did you check the polarity?

What kind of charger are you using, Stargazer Optimus? I was thinking about buying the Nexus charger because it's rated at 1.8A output.

Stargazer Optimus said:
Can you provide some information about how and where you have soldered the charger? and did you check the polarity?
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Click to collapse
The module I've bought and the pad are attached as images
And for polarity I was referring to your post and for QI module I checked usb wiki.
To note when I soldered and put QI module on pad it switched from red (not charging) to blue (charging) but tablet was not charging.
I was checking with original tn7 charger 5v 2a, 5v 1a iphone charger and tried with pc usb port all three were doing same stuff.
I did detach io module from main board before soldering.

You will need to check that the receiver is delivering the required voltage and current with a multimeter. Ideally you will do this at the ends of the wires that get soldered on the IO board.

Stargazer Optimus said:
You will need to check that the receiver is delivering the required voltage and current with a multimeter. Ideally you will do this at the ends of the wires that get soldered on the IO board.
Click to expand...
Click to collapse
If this helps, before cutting QI module I've tested on Samsung alpha smartphone and it did charge the phone, could it be cause of amps ? and yes when I'll get hand on a multimeter I will test.
Thanks for help!

I just tried this out but made a big mistake that some of you may make as well. I assumed the 5V wire was 5V and the ground was ground. Boy, was I wrong. They're switched! But I only found this out after hooking everything up and putting the receiver on the charger to bench test before piecing things back together. It's been about an hour since I've finished up and all it shows is the battery signal with the lightning bolt in the middle and then it switches to an empty battery and keeps alternating like that. I'll keep it on the charger all day and hope it works out.
I'm using an Anker qi charger and a universal receiver sold on Amazon by Buboon, I think. Charger is rated at 1A output and receiver is rated at 500mA - 1A.

MRunabout said:
I just tried this out but made a big mistake that some of you may make as well. I assumed the 5V wire was 5V and the ground was ground. Boy, was I wrong. They're switched! But I only found this out after hooking everything up and putting the receiver on the charger to bench test before piecing things back together. It's been about an hour since I've finished up and all it shows is the battery signal with the lightning bolt in the middle and then it switches to an empty battery and keeps alternating like that. I'll keep it on the charger all day and hope it works out.
I'm using an Anker qi charger and a universal receiver sold on Amazon by Buboon, I think. Charger is rated at 1A output and receiver is rated at 500mA - 1A.
Click to expand...
Click to collapse
Hey, did you figure it out? Mine's doing the same thing, though it's wired with usb cable, not a QI charger, though that may be the next step. I'm gonna leave it for now, and just keep an eye on it. Fingers crossed.