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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 !
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...
Hi all,
I have had my 7 for a while however I left it for several days after it ran out of juice and I'm now experiencing the issue where it cannot charge via usb. I have an appropriate battery charger and intend to juice the battery up slightly whilst disconnected from the pad to give it enough power to rise from the dead and charge normally.
Has anyone looked into which of the 6 connections coming from the battery do what? There are obviously 2 red, 2 black, a yellow and a white. Is there something like a 5v, 12v and data connection??
Can someone educate me to which connections I can apply voltage to, to charge it please?
I would rather go down this route if possible rather than going through warranty as I have no backup of the items currently on my nexus.
Any help would be very appreciated.
Cheers,
Rob
What little I know about Li Po cells/batteries is:
The nexus 7 has a single cell battery rated at 3.7v - no 5v or 12v
Charging outside the Nexus is DANGEROUS. Protective bags are used to hold LiPo cells whilst charging (and transporting them).
Where the wires enter the cell there is a thin section that will be a PCB with protective electronics that will monitor the temperature of the cell.
Your red/black pairs COULD be a pair for charging and a pair to power the Nexus and the white and yellow ???????
Your charger should have this info in its instructions.
Two remarks to finish DON'T DO IT and search Youtube for "LiPo overcharge"
I've done it with phone batteries when I've been at a mates or something and I've ran out of battery and not had my charger.
Its safe, provided you give it the correct voltage, to the correct pins lol, and don't try and fully charge. Give it 50% of its normal charge time max. But since you only need to get into the boot loader to properly power off so it will charge again you're only speaking about a quick ten minute charge..
As for the two pairs, its maybe a 2 cell battery.
White and yellow are likely temperature sensor.
Sent from my Nexus 7 using Tapatalk HD
knuckles1978 said:
I've done it with phone batteries when I've been at a mates or something and I've ran out of battery and not had my charger.
Its safe, provided you give it the correct voltage, to the correct pins lol, and don't try and fully charge. Give it 50% of its normal charge time max. But since you only need to get into the boot loader to properly power off so it will charge again you're only speaking about a quick ten minute charge..
As for the two pairs, its maybe a 2 cell battery.
White and yellow are likely temperature sensor.
Sent from my Nexus 7 using Tapatalk HD
Click to expand...
Click to collapse
I'm facing exactly the same problem, and no "normal" work-arounds seem to be working for me, I just can't get into the bootloader. So it is either trying to recharge it myself or buying a battery..
So given the fact that you have done it with other devices, could you please explane how you would start with all this? Here is a picture of of the nexus 7 battery connector, if it would help you:
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(the picture is from ifixit).
I was thinking about molesting the usb cable of my htc and use the black and red cables to charge the battery (I suppose that a USB output can not put a to high voltage to the battery?), but I do not know which red/black poles to use on the battery connector..
Thank you very much in advance!
Erwin
Ive never done one with two pairs like that, but here's what I'd do to get enough charge to boot at least. I would connect my positive from the charger to one of the battery connectors reds, and connect the negative to one of the blacks (obviously lol). Give it 5 minutes only, then swap your negative charger wire onto the other black of the nexus. Give it 5 minutes only again.
Then swap your positive charger wire over to the other red of the nexus and repeat the process, keeping the positive on that red and connecting the negative to each black for 5 minutes.
You only need enough charge to boot, so this will be fine. Also, keeping it to 5 minutes each keeps it safe.
An even better way to do it would be wait until tomorrow until I can get a hold of a multimeter and i would check to see how the pairing is, then you could do it without the guesswork. But if you can't wait, I've told you the way that i would do it.
Sent from my Nexus 7 using Tapatalk HD
knuckles1978 said:
Ive never done one with two pairs like that, but here's what I'd do to get enough charge to boot at least. I would connect my positive from the charger to one of the battery connectors reds, and connect the negative to one of the blacks (obviously lol). Give it 5 minutes only, then swap your negative charger wire onto the other black of the nexus. Give it 5 minutes only again.
Then swap your positive charger wire over to the other red of the nexus and repeat the process, keeping the positive on that red and connecting the negative to each black for 5 minutes.
You only need enough charge to boot, so this will be fine. Also, keeping it to 5 minutes each keeps it safe.
An even better way to do it would be wait until tomorrow until I can get a hold of a multimeter and i would check to see how the pairing is, then you could do it without the guesswork. But if you can't wait, I've told you the way that i would do it.
Sent from my Nexus 7 using Tapatalk HD
Click to expand...
Click to collapse
I'm trying to be patient for almost a week now, so one day (or more, if you need them) will not be a problem Take as much time as you need, I'm already thankfull that you are willing to look into it!
All the best,
Erwin
ErwinP said:
I'm trying to be patient for almost a week now, so one day (or more, if you need them) will not be a problem Take as much time as you need, I'm already thankfull that you are willing to look into it!
All the best,
Erwin
Click to expand...
Click to collapse
I'll be able to get a multimeter tomorrow for sure, that way i can check it out properly for you. The other way is safe and would definitely work though, but its no problem for me to check it out.
Sent from my Nexus 7 using Tapatalk HD
Again, thank you already in advance, I hope this gets me out of trouble. What an inacceptable bug, bah.
One additional question though, if you don't mind. What are your thoughts of using the stripped usb cable an my laptop to deliver that little bit of battery juice? I'm good with my hands, can replace every part of your bike and am able place a new smartphone screen with my eyes closed, but I just don't know anything about the real hardcore electronics
All the best,
Erwin
ErwinP said:
Again, thank you already in advance, I hope this gets me out of trouble. What an inacceptable bug, bah.
One additional question though, if you don't mind. What are your thoughts of using the stripped usb cable an my laptop to deliver that little bit of battery juice? I'm good with my hands, can replace every part of your bike and am able place a new smartphone screen with my eyes closed, but I just don't know anything about the real hardcore electronics
All the best,
Erwin
Click to expand...
Click to collapse
It is not a bug. Your tablet has entered a sleep mode to prevent t the battery from being damaged. I have previously posted the procedure to enable it to charge and wake again. Search through my recent posts for the fix- I unfortunately can't link it right now due to time constraints.
ETA: Plug your N7 into the charger and immediately press power and volume down to get into the bootloader. Once there, use the volume key to scroll to Power Off Device and then press the power button. After it powers off, unplug it and then plug it back in. It should then charge normally.
Sent from my Nexus 7 using Tapatalk HD
najaboy said:
It is not a bug. Your tablet has entered a sleep mode to prevent t the battery from being damaged. I have previously posted the procedure to enable it to charge and wake again. Search through my recent posts for the fix- I unfortunately can't link it right now due to time constraints.
Click to expand...
Click to collapse
I'm sorry, but this is a bug and not a feature of the device protecting you. If the device runs out of battery, it should do what every other tablet and smartphone does: shut down. And it should shut down 'way before' the battery is completely out of power, so that it still has a fair amount of battery capacity to at least once initate startup, notice that the battery is too low to continue and shut down properly. Of course, if you try to restart the device several times whilst it doesn't have any battery power left, then you are damaging your device. But than you are an idiot as well
Look at wat happens when you are working on your N7 and power comes to 0%. Indeed: it will shut down properly and you will be able to charge it without any problems. However, if battery comes to about 10% and you do not shut it down manually but leave it just sitting there, the device will do what it normally does: it goes to (deep?) sleep. However, even deep sleep consumes battery and inevitably you will reach the point where the battery is at 0% (seen by the android device). But instead of waking up and shutting down the device properly, it just stays into its deep sleep, consuming power and finally undercharging your battery making the device totally irresponsive. This is what I call, a bug.
I know now that I should either shut down or recharge my N7 when I come to the point of 10-15% battery. But hey, once you learn that, it is too late, this is why I'm here
najaboy said:
ETA: Plug your N7 into the charger and immediately press power and volume down to get into the bootloader. Once there, use the volume key to scroll to Power Off Device and then press the power button. After it powers off, unplug it and then plug it back in. It should then charge normally.
Click to expand...
Click to collapse
Thank you very kindly for your help, but as stated before, I have tried everything already. Including a whole evening trying to get the timing right to see the android bootloader following the solution you mention. But it doesn't give anything but frustration. So I understand why you point to that solution, but that is one of the first solutions that comes up if you google my N7 phenotype. Again, thank you kindly, but for now I do not see any other solution than trying to get an inital voltage in that battery manually.
Best regards,
Erwin
Same issue has happened to me and I can not even enter the bootloader...
What is your status on this issue?
SubZero5 said:
Same issue has happened to me and I can not even enter the bootloader...
What is your status on this issue?
Click to expand...
Click to collapse
did anyone charge it manually out of the nexus ? I've verified that the black is - and the red is + with a multimeter. battery reads .47 with multimeter. If you guys are going to charge it 5 minutes per pair, definitely get a multimeter to read the positive and negative coming out of the 5v chargers.. also, make sure that it's about 5 volts cuz some are about 6? I dont' know if having too high of a voltage will fry it.. i do know from experience that some usb chargers are 5 and some are 6 volts and some are even slightly more. I'm talking about getting a transformer that goes from usb to the circular out put head..
Same problem here. Someone on another thread was suspecting the magnetic cover causing problem and I'm using one too. Anyone having this problem NOT using a magnetic cover?
I know this is thread is a few months old.
donnygg said:
Same problem here. Someone on another thread was suspecting the magnetic cover causing problem and I'm using one too. Anyone having this problem NOT using a magnetic cover?
Click to expand...
Click to collapse
I have a similar problem and my n7 has never had a case.
Update
I hooked the battery up to a usb port using the out side read and black wires, red was + black was - charged for about 1 minute via pc usb power while monitoring with a dmm. the tablet now charges normally.
Charge manually
chevyowner said:
I know this is thread is a few months old.
I have a similar problem and my n7 has never had a case.
Update
I hooked the battery up to a usb port using the out side read and black wires, red was + black was - charged for about 1 minute via pc usb power while monitoring with a dmm. the tablet now charges normally.
Click to expand...
Click to collapse
I did charged the battery manually.
For about 1 minute for each pair of red/black.
Not to bump an old thread but manually charging indeed fixes this problem. Used a multimeter to take a reading from one nexus 7 and then cut up an old usb and hooked it up to the ends of the multimeter and placed them on the first 2 points. Charging manually up to about 3.7ish should be enough to accept a charge.
Thanks guys saved buying a new battery.
i have a bit of life after manually charging, is it important to do both pairs of black and red? I have 2 batteries and now the nexus flashes an empty battery logo up when i hold the power button, its better than before as nothing came up at all but still wont boot up
I just charged my battery up manually using a proper Li-Po battery charging unit, left it charging at 2.5A until it hit 4.0V. No problems.
I did not charge up both pairs. I believe this is unnecessary: see first image in this thread: http://forum.xda-developers.com/showthread.php?t=2311799
The pairs of red and black are actually soldered together, so it doesn't make a difference which pin you apply the voltage to.
I would be worried about charging the battery directly with a 5.0V supply (ie. USB voltage). Don't do it if you can avoid it.
If at any point when charging a battery directly you notice it getting hot, stop immediately.
External charging nexus 7 batteries
Use the black - and the red + wires to charge .Charge the outer red and black wires ,I use a 5 volt charger since these batteries are rated at 3.7 v + or - .5v Charge the batteries to a voltage reading of 4.2 volts this will be a full charge.Please Note you will be charging this battery with out a protection over voltage or temp sensor system. If the battery is bad ,will not take charge due to damaged cells, or is overheated while charging they will burst apart.Charging with out protection circuits can damage batteries and also harm yourself.You do this at your own RISK.
@knuckles1978, @androiddeveloperg, @mr portugal, @chevyowner, @VanquishUK
Thanks guys!!
You saved my Nexus 7!
I charged the battery with my computer's usb port and a multimeter connected, let it charge to 3.90V (with power), and it booted up again
Now I have to get it to 100%, as it still shuts down after booting..
Sent using my nexus⁴ running Mahdi 2.8 with Xposed and hells-Core B64
Bitcoin donation address
Intro
I do not take any responsibility for any damaged, bricked, burned devices or electric shock caused by your doing. You need basic knowledge of electicity before doing something.
I got my N5X a few weeks ago, and unfortunately found out that all my powerbanks are useless - N5X takes about 400-500 mAh from the battery pack ( via a normal USB -> TypeC cable) and it is not even enough to keep the battery charging - if the screen is on, the phonejust slooooowly discharges
Ideas
So I had a few Ideas of how to fix the problem:
1) Buy a compatible USB Type-C powerpack on Amazon/Aliexpress, wait for it for like 2 month ( I live neither in USA nor in China ) and hope that Fast Charging, oh wait, at least, normal charging will work.
2) Try out all powerpacks I can find in hope that some will have a compatible DATA+/- chip/resistor/shortcircuit combination.
3) Read USB Type-C charging specs and find out what ICs support the so called "Fast charging" like the Qualcomm QuickCharge ( remember, you need a special IC doing voltage negotiation between charger and phone )
Thoughts
Number 1 was not a solution for me because I have LOTS of 18650 lithium batteries ( and also some LiPos my friend gave me) and paying $50 for a compatible battery pack is OMGTOOMUCH :laugh:
Nubmer 2 was a partial solution for me ( and I did find A LOT of powerpacks and tried them out, no result )
Number 3 made me really sad, after reading the specs I found out that you really do need an IC, because Type-C has a special data pin for power negotiations, and it has a special protocol.
Solution
Turned out to be simpler than I thought.
Logic behind my solution: We got a phone that has a special pin in Type-C usb port, that waits for the charger to tell " heeey I am strong,I am legit made by LG, you can take up to 3A from me".
But it is difficult to buy 2-3 additional original chargers ( 1 for work, 1 for home, 1 to be in your backpack), not because they are expensive, but because they just dont sell them in Russia ( the phone is legitimately sold here though). So there should be some other way for the phone to charge rapidly.
So I started experimenting, I thought, that the biggest problem is not the missing IC and negotiation data on USBA-USBTypeC, but the low quality of the cable itself, in other words, its resistanse measured by Ohms is too high. There is one way to compensate the voltage drop on the cable - make the charger voltage cover it, make the charger voltage higher. I took an oscilloscope, a multimeter and a alternate current transformator to measure sudden current drops and spikes.
Experiment
At first I tried 5,2V. Did not help
Then I tried 5,4V. Wow, here it comes better, already charging @ 1,2A ( it was like 400 mA before)
Then I tried 5,6V. The current stayed about 1,2-1,4A ( measured by Ampere App and a physical real current meter)
In all of the experiments I left the DATA pins soldered together - a standart simple way for most phones to think they are connected to a charger.
Then I remembered, that some phones by Sony, some by Nokia and other brands sometimes had a resistor between the DATA pins in the charger, so that, for example you could fast charge a sony from a sony charger, but not from a nokia's one, because sony's had 56kOhm resistor, and nokia had 5kOhm ( values are for example, I dont really remember how it was back then).
So I took the first resistor I found in the box, turned to be 3,2kOhm and soldered it between DATA pins.
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And it worked!
At first I saw a fast current spike on the oscilloscope ( could not take a picture, but it was for about 0,3 seconds ), I think the phone was checking capabilities of the charger by giving a load and watching if the voltage drops. The voltage did not drop below normal value ( 5V ). Output voltage of my charger is stabilised and not depending on the load given, so the phone figured that it fits for fast charging, as the voltage did not drop below 5V ( 5,6V on the charger minus about 0,5V at 2A on the cable leaves 5-5,1V at the phone)
Proof:
Charging current as reported by Ampere app ( real current meter said 1,8A, but it is not a precise one )
What you need to do this:
1) A multimeter ( a good one )
2) An output with voltage above 5,5V but below 5,7V. to compensate voltage drop on a cable ( depends on the cable, measure your cable's resistanse, then you can count voltage drop using Ohm's law)
I got mine first on a laboratory power supply, later on a LM2596 board, ( you can buy it here . You just have to adjust the output voltage to 5,6V. Be careful, you must know what you are doing, for this IC to work, input voltage has to be higher than output voltage for like if you need an output of 5,6V, you need about 7V input ( for better effecancy you need about 12V input )
2) A resistor about 3kOhm between DATA pins of the USB cable on the side of the charger
Conclusion
So by these simple manipulations you can charge a N5X ( and possibly N6P) rapidly with a cheap DIY powerbank/charger.
In a few days I will try to reach 3A charging current cap, I will post results
I would be glad to answer your questions and post the detailed schematics if nesessary.
Cheers!
nikozzzzzz said:
Intro
I do not take any responsibility for any damaged, bricked, burned devices or electric shock caused by your doing. You need basic knowledge of electicity before doing something.
I got my N5X a few weeks ago, and unfortunately found out that all my powerbanks are useless - N5X takes about 400-500 mAh from the battery pack ( via a normal USB -> TypeC cable) and it is not even enough to keep the battery charging - if the screen is on, the phonejust slooooowly discharges
Ideas
So I had a few Ideas of how to fix the problem:
1) Buy a compatible USB Type-C powerpack on Amazon/Aliexpress, wait for it for like 2 month ( I live neither in USA nor in China ) and hope that Fast Charging, oh wait, at least, normal charging will work.
2) Try out all powerpacks I can find in hope that some will have a compatible DATA+/- chip/resistor/shortcircuit combination.
3) Read USB Type-C charging specs and find out what ICs support the so called "Fast charging" like the Qualcomm QuickCharge ( remember, you need a special IC doing voltage negotiation between charger and phone )
Thoughts
Number 1 was not a solution for me because I have LOTS of 18650 lithium batteries ( and also some LiPos my friend gave me) and paying $50 for a compatible battery pack is OMGTOOMUCH :laugh:
Nubmer 2 was a partial solution for me ( and I did find A LOT of powerpacks and tried them out, no result )
Number 3 made me really sad, after reading the specs I found out that you really do need an IC, because Type-C has a special data pin for power negotiations, and it has a special protocol.
Solution
Turned out to be simpler than I thought.
Logic behind my solution: We got a phone that has a special pin in Type-C usb port, that waits for the charger to tell " heeey I am strong,I am legit made by LG, you can take up to 3A from me".
But it is difficult to buy 2-3 additional original chargers ( 1 for work, 1 for home, 1 to be in your backpack), not because they are expensive, but because they just dont sell them in Russia ( the phone is legitimately sold here though). So there should be some other way for the phone to charge rapidly.
So I started experimenting, I thought, that the biggest problem is not the missing IC and negotiation data on USBA-USBTypeC, but the low quality of the cable itself, in other words, its resistanse measured by Ohms is too high. There is one way to compensate the voltage drop on the cable - make the charger voltage cover it, make the charger voltage higher. I took an oscilloscope, a multimeter and a alternate current transformator to measure sudden current drops and spikes.
Experiment
At first I tried 5,2V. Did not help
Then I tried 5,4V. Wow, here it comes better, already charging @ 1,2A ( it was like 400 mA before)
Then I tried 5,6V. The current stayed about 1,2-1,4A ( measured by Ampere App and a physical real current meter)
In all of the experiments I left the DATA pins soldered together - a standart simple way for most phones to think they are connected to a charger.
Then I remembered, that some phones by Sony, some by Nokia and other brands sometimes had a resistor between the DATA pins in the charger, so that, for example you could fast charge a sony from a sony charger, but not from a nokia's one, because sony's had 56kOhm resistor, and nokia had 5kOhm ( values are for example, I dont really remember how it was back then).
So I took the first resistor I found in the box, turned to be 3,2kOhm and soldered it between DATA pins.
And it worked!
At first I saw a fast current spike on the oscilloscope ( could not take a picture, but it was for about 0,3 seconds ), I think the phone was checking capabilities of the charger by giving a load and watching if the voltage drops. The voltage did not drop below normal value ( 5V ). Output voltage of my charger is stabilised and not depending on the load given, so the phone figured that it fits for fast charging, as the voltage did not drop below 5V ( 5,6V on the charger minus about 0,5V at 2A on the cable leaves 5-5,1V at the phone)
Proof:
Charging current as reported by Ampere app ( real current meter said 1,8A, but it is not a precise one )
What you need to do this:
1) A multimeter ( a good one )
2) An output with voltage above 5,5V but below 5,7V. to compensate voltage drop on a cable ( depends on the cable, measure your cable's resistanse, then you can count voltage drop using Ohm's law)
I got mine first on a laboratory power supply, later on a LM2596 board, ( you can buy it here . You just have to adjust the output voltage to 5,6V. Be careful, you must know what you are doing, for this IC to work, input voltage has to be higher than output voltage for like if you need an output of 5,6V, you need about 7V input ( for better effecancy you need about 12V input )
2) A resistor about 3kOhm between DATA pins of the USB cable on the side of the charger
Conclusion
So by these simple manipulations you can charge a N5X ( and possibly N6P) rapidly with a cheap DIY powerbank/charger.
In a few days I will try to reach 3A charging current cap, I will post results
I would be glad to answer your questions and post the detailed schematics if nesessary.
Cheers!
Click to expand...
Click to collapse
So you're doing this to circumvent the limitation that prevents it from charging full speed from a non factory charger? Because I find that the phone refuses to use the full power available to it if it's connected with a USB type A to C cable or if the screen is on it will not charge fast.
Yes, exactly, check voltage output of your charger, if it's more than 5,5V under load, then you have a good chance
Sounds so interesting!!! Glad you're able to achieve it.. Great write up! Any updates on your work?
What If i Buy a 5V/3A Charger? Is it perfect for Fast Charging?
Does it damage the Board or not?
I accidentally did connect 5v for a second or so,
it did power on, i disconnected immediately, and after that it didnt power on for several hours,
but not sure if it was because of the interruption during boot, or overvoltage.
Can somebody confirm?
(i cant use a diode for voltage reduction, its a bit complicated, i use a load sharing capable solar charger board etc)
its a nook simple touch
Yow, don't do that!
Ok, it should be able to take it, but still.
I've often fed 4V to devices which had their battery blow up.
In worst cases I've used a diode for drop, but the voltage can be pretty variable over load.
The uboot on most things will not continue if there is zero voltage on the battery.
Also, the peak current of a device can go up to 600 mA or more at times.
That kind of current often can't come in through the USB connector.
Finally, battery packs have ID connections and thermistor.
Entirely disconnecting a battery pack will often prevent booting even when voltage is present.
If you have a dead battery pack always keep the the connector, cable and tiny PCB inside.
Attach a power supply to where the naked cells used to connect to the PCB.
For wiring of the battery pack see: https://forum.xda-developers.com/showpost.php?p=42552349&postcount=5
thanks, 2 weeks ago i prepared to measure possible resistors but did a google search before, found your description...
i use the protection board with a 18650 3000mAh lithium manganese (to prevent blow (up)) etc cell and charge it externally,
which requires switching between charging the batt + powering the nook over the batt terminals,
and using the batt for powering the nook , all that while the usb keyboard is connected and in use,
this is done via relay and a really big capacitor, which works great but is a bit ghettostyle.
i tried to use another charger board with load sharing circuitry instead,
but the only easy available module requires 5v minimum input, passes this 5v to load if the ac adapter is plugged in,
if not, it passes the battery voltage to load,
so a diode(+ parallel resistor to maintain voltage drop) or LDO doesnt work because it would at least steal around 0,5 v,
which is to much reduction for the battery voltage, because the nst powers off at ~ 3,7v,
easiest would be to just let the 5v to the nook but seems no good idea.
anyways, it works with the relay