Database Users

[Tut] Make car charger behave as "charger" instead of "computer"

As probably several other users, I have set my hd2 to NOT charge when connected to pc, as I often plug the cable to transfer pictures, cabs and the likes. This is useful when I actually plug it to the PC, and it regularly charges with stock/compatible cable if connected to mains charger.
Problems could arise when you connect the microusb cable to the standard carlighter plug with an adapter having a female USB connector in it. It gets recognized as a "pc" and thus the device won't charge unless you re-enable charging when connected to PC.
In case you experience this, as per link found in second post of this thread, you can short the two middle contacts of the USB connector (the data pins) so the phone recognizes the charger as a proper one instead of mistaking it for a PC.

http://www.pocketpc.ch/htc-hd2-sons...en-hoehere-ladestroeme-akku-laed-im-auto.html
desribes modification of car charger, sorry but it´s german. HD2 detects via USB data pins, if it´s connected to PC or charger. If USB data pins are connected like described in above, it will be charged by the car adapter as well. To achive this you´ve to modify your adapter as described.
Regards
Georg

Thank you! Google translate is helping me... and believe me or not, it seems that what I was guessing is actually true: you need to short the data pins of the usb cable... could you confirm please kleiner_onkel? I am not quite so sure of what I am reading with google, as that kind of english is quite far-fetched
n that case I could also avoid messing with the insides of the usb-lighter adapter, and just short the cables inside an external USB hub
EDIT: I just tested it, syhorted the middle data pins of the usb-a plug inside a cheapo usb1 hub, it works and charges the phone when "charge from pc" is disabled.
Will meddle to clean the job and then will update first post

Can you please, for the sake of the slow minded such as I, explain why you would not want to charge from PC/USB?

pa49 said:
Can you please, for the sake of the slow minded such as I, explain why you would not want to charge from PC/USB?
Click to expand...
Click to collapse
+1 for why not.never understood why it would even be an option.I could understand if we still used nickel batteries, but not with li+

Shorting the data pins also tells a device that it can use up to 1.85A of current (versus the 500mA of USB2). Your car charger will have circuitry (of varying complexity, depending on the model) to drop the 12V from the car to something usable by your phone (5V). If the components in your charger can't handle the 1.85A current, you could land up with a pretty hefty repair bill. Be careful out there....
Edit: Need a worst case scenario to see how bad it could be? In the most basic case there'll just be a resistor in the car charger. That resistor is likely 1/4 watt, 1/2 watt tops. Put 1.85A through it and it can pop, potentially going closed (short) circuit leaving your phone with 12V to deal with. The extra current that comes with that means you fry part of your charging circuit at best, your battery (possibly explosively) somewhere in the middle and the entire phone at worst.

samsamuel said:
+1 for why not.never understood why it would even be an option.
Click to expand...
Click to collapse
I do see a use, if you're on a laptop running on batteries, you don't necessarily want to empty your laptop batteries faster by recharging the phone if you don't need to. But that's the only one.
Aterlatus said:
Shorting the data pins also tells a device that it can use up to 1.85A of current (versus the 500mA of USB2).
Click to expand...
Click to collapse
More like 0.85 actually, like what it draws from the original charger.
Aterlatus said:
In the most basic case there'll just be a resistor in the car charger.
Click to expand...
Click to collapse
Then that car charger would NOT work and would fry every device connected to it...
Car chargers have voltage regulators, which have overcurrent and overheat protection, linear ones for older ones, DC/DC switching ones for everything you find today.
I believe there's actually still an extra step from this mod to the phone knowing it is on the original charger. I have both a Chinese USB charger and a car charger, rated at 650mA and 800mA respectively. On both (with soldered pins), the HD2 will charge at 600mA, not 800-900 like with the original charger. But 600 is of course already better than 450.

kilrah said:
More like 0.85 actually, like what it draws from the original charger.
Then that car charger would NOT work and would fry every device connected to it...
Car chargers have voltage regulators, which have overcurrent and overheat protection, linear ones for older ones, DC/DC switching ones for everything you find today.
Click to expand...
Click to collapse
From: ht tp://pinouts.ru/Slots/USB_pinout.shtml
Dedicated charger mode:
A simple USB charger should short the 2 data lines together. The device will then not attempt to transmit or receive data, but can draw up to 1.8A, if the supply can provide it.
Click to expand...
Click to collapse
It's in the spec, and a car battery won't have any problem supplying the current. A cheap (read: chinese off ebay) charger might well employ just a simple resistor. Sure, any decent charger will use a voltage regulator or a buck converter to maintain the correct voltage. That doesn't mean that ALL will, hence the warning to take care.

"If the supply can provide it" is the key. The USB device will see if the supply can't give that much and its voltage starts to drop.
And anyway the HD2 would never draw 1.8A or it would damage its battery.

I noticed much the same thing by accident as reported in this thread
http://forum.xda-developers.com/showthread.php?t=638007
Beware that if your HD2 is set up to detect it, it will turn on Navipanel when plugging in this type of cable

pa49 said:
Can you please, for the sake of the slow minded such as I, explain why you would not want to charge from PC/USB?
Click to expand...
Click to collapse
samsamuel said:
+1 for why not.never understood why it would even be an option.I could understand if we still used nickel batteries, but not with li+
Click to expand...
Click to collapse
I may be the slow minded here. BUT
1) Everyone having had even third-person experience with laptops knows that using one with a battery inserted and "most of the time" attached to the external power unit, makes the battery die pretty soon, and all laptop batteries are Li-Ion based since quite a while; sure, part of that damage comes from the heat generated on the battery both from the charging and the laptop being turned on, but all the rest is caused by the "unnecessary" repeated charges (confront the "battery university" website for this)
2) I often plug/unplug the cable from the pc to move several small files, I just don't feel comfortable doing it if everytime the battery gets a "charging hit", for the aforementioned reasons
3) I want to be able to charge the device when I choose to and not just everytime I plug it somewhere
4) enabling the car charger as "proper charger" lets the device take up more current and charging faster
5) I've always behaved, with all my Li-Ion powered devices, in a way that I would charge the battery when it got to ~20-30% and not before, reducing the number of times I actually charged it; the definition of "recharge cycle" is not the easiest one here, and "battery university" has an interesting one; but since my behaviour until now has given its good results, I'll just keep doing that
Aterlatus said:
Shorting the data pins also tells a device that it can use up to 1.85A of current (versus the 500mA of USB2). Your car charger will have circuitry (of varying complexity, depending on the model) to drop the 12V from the car to something usable by your phone (5V). If the components in your charger can't handle the 1.85A current, you could land up with a pretty hefty repair bill. Be careful out there....
Edit: Need a worst case scenario to see how bad it could be? In the most basic case there'll just be a resistor in the car charger. That resistor is likely 1/4 watt, 1/2 watt tops. Put 1.85A through it and it can pop, potentially going closed (short) circuit leaving your phone with 12V to deal with. The extra current that comes with that means you fry part of your charging circuit at best, your battery (possibly explosively) somewhere in the middle and the entire phone at worst.
Click to expand...
Click to collapse
As kilrah stated, 1.85A may be the max specification, yet the HD2 is NOT going to get that much from a recognized charger. The german thread pointed from the second post of the thread is also specific about it, the intook currents are higher, but not that higher... plus I've peeked inside the car lighter charger, and it's got no single resistor Also, the max 2A is useful when you plug several other things to it for charging purposes other than the HD2, and that's why I connect the HD2 to a USB1 hub connected to the carlighter charger
For a briefly useful reference, my iPaq 214 only took max 200mA from the miniusb plug no matter the charger capacity not the charger "nature", so devices do have a regulator, and it would be reasonable to think that a multihundred euros phone has one, and pretty efficient at it

So aside from hacking the USB cable, is there any other way to make the car usb charger act like a car charger? Or I should save my time and just buy an actual car charger, instead of a universal usb one....?
Thanks!

atagent said:
So aside from hacking the USB cable, is there any other way to make the car usb charger act like a car charger? Or I should save my time and just buy an actual car charger, instead of a universal usb one....?
Thanks!
Click to expand...
Click to collapse
solder together the central pins on the charger output port, it's the exact same principle
Even thought hacking a cable is "safer", as you're playing with a ~2USB asset instead of a ~5USD one, and you have to connect a usb cable to the car charger anyway in order to charge the phone

Faster USB charging?

Just got a new motheboard which has high output USB charging for iPhones, pads etc.
Can this work on N1 ?
http://gigabyte.com/MicroSite/185/on-off-charge.htm
edit: driver link is at the bottom for all the hackers. Hopefully its just changing string from apple to android hehe

kazprotos said:
Just got a new motheboard which has high output USB charging for iPhones, pads etc.
Can this work on N1 ?
http://gigabyte.com/MicroSite/185/on-off-charge.htm
edit: driver link is at the bottom for all the hackers. Hopefully its just changing string from apple to android hehe
Click to expand...
Click to collapse
Hopefully not, I dont want my nexus one to be iphone.
But as you know nexus one is using qualcomm motherboard.
But aslong cyanogen and fm transmitter is working there is no problem wiith your phone.

Dear lord what a crappy reply. Stick to disney mate.

It should, it basically just converts the USB port from .5 amps to 1 amp, like a wall charger.

elkyur said:
Hopefully not, I dont want my nexus one to be iphone.
But as you know nexus one is using qualcomm motherboard.
But aslong cyanogen and fm transmitter is working there is no problem wiith your phone.
Click to expand...
Click to collapse
WTF??? May want to lay off the halucinogenics

elkyur said:
Hopefully not, I dont want my nexus one to be iphone.
But as you know nexus one is using qualcomm motherboard.
But aslong cyanogen and fm transmitter is working there is no problem wiith your phone.
Click to expand...
Click to collapse
lol I seriously hope this is a joke!
I agree with JCopernicus, it should definitely work.

I installed the software in the first post but it still charges very slow compared to wall outlet

Slightly OT, but I've got a USB adapter that plugs into the wall that came with my iphone and when I plug the N1 USB cable into this to charge the N1, it still charges very slowly compared to using the proper wall adapter, why is this? Does this iphone adapter restrict the voltage or something?

Generally, "charger detected" is a circuit that has USB data pins shorted together. So when the phone's USB device probes the lines and detects them shorted, it knows it's connected to a power supply.
But since USB max current spec is 500mA, the current draw is restricted - either by the phone or by the supply.
There might be some other connectivity trick that allows the phone to know it can draw x2 current from the socket and won't damage anything. Most phones probably don't limit the current draw and count on the board to do it. Some boards don't limit the current output, or limit it higher. And the fast chargers provide pulsing voltage - which isn't like USB.
So for the board to be able to charge the device, it needs to detect a device that can use pulsing voltage, and enable such voltage on the socket. It doesn't detect Nexus as such a device, I believe, and that's why the charging is slow.

Faster charging with USB
Building on Jack_R1's response, I believe that the phone is limiting the charge rate. You can make the phone "realize" it is connected to a charger rather than a data connection by shorting the 2 middle USB pins together. I have done this in several car chargers, and the N1 About/Status shows charging (AC), which is the faster charge mode. While you can short the pins in the larger end of a dedicated USB cable, if you can disassemble the connector, I found it much easier to open the charger itself to short the pins.

i also have a gigabyte mobo that has this feature but i havent gotten around to test it out yet. I dont think it would work because the feature is software based and will only bump up the voltage if the program detects an iphone connecting to your computer. Gigabyte doesnt want to be liable if they bump up voltage on every device you plug in and fry something.
btw I have tried charging my n1 from my computer and its extremely slow. started charging at around 5pm on sunday and at 11pm it went from about 23%-97% lol.

Yes, USB charging is very slow. It's actually good for the battery, though.

Maybe someone with some know how can look at the driver files for this 3x tech and see how it checks if its an Apple device. Then fool the check and presto!
Shame I don't know how to do any of this

There is a simple hardware (don't worry, it's on the cable) mod for faster charging; however, make sure the phone has good air vent (it means NO CASE when charging).
1. modify your microUSB cable, disconnect the data connector the A (host) plug, then shorten the data connector to the B plug. (This can charge N900 properly, and speed up n1 charging).
2. modify your powered (with AC adapter plugged) USB hub. Simply shorten the #2 and 3 connectors on USB jack. Make sure you cut the copper strip going to the chip or malfunction may occur.
These modification can greatly speed up the charging, but phone will produce a lot of heat (that's why you must have the phone "naked").

I don't understand this. If the phone + battery are capable of being charged at 1000 mAh from the wall charger then why need extra cooling when asking for 1000 mAh from a PC USB socket?
Mine's still defo getting only 500 mAh from the PC USB despite it being able to give up to 2700 mAh for iPad!!! All I want is my 100 mAh charge.

Because what he suggests isn't a proper charging but rather removal of slot power control, and will damage the battery / phone, if succeeds.
Proper charging at 1000mAh requires pulsing voltage - his hack doesn't provide that. Your MB does, but it requires SW intervention to turn it on.

So can someone brew the intervention ?

martinl1030 said:
i also have a gigabyte mobo that has this feature but i havent gotten around to test it out yet. I dont think it would work because the feature is software based and will only bump up the voltage if the program detects an iphone connecting to your computer. Gigabyte doesnt want to be liable if they bump up voltage on every device you plug in and fry something.
btw I have tried charging my n1 from my computer and its extremely slow. started charging at around 5pm on sunday and at 11pm it went from about 23%-97% lol.
Click to expand...
Click to collapse
They are not doing anything to the voltage, simply allowing more current to pass.
And as said in this thread, any typical data USB cable will charge very slowly. And most standard USB ports charge well less than the max specced 500mAh, in fact my subnote at work I found charged my old phone at around 150mah one time when I was dead and needed to top off and it's all I had available.

i'm not sure of the pinout on the micro USB port but i'm pretty sure that that the Mini USB-B port that was used on phones like the G1 used shorting the -Data pin to the unused 5th pin (actually pin 4 on the connector pinout) to activate AC charge mode. some devices actually require a resister of a certain value to be placed across them to work(i know older motorola phones did like IDEN's)
one thing people often forget but should not forget is that current is drawn from the device using power. its not forced on the device. voltage is forced on a device and while a variance is usually ok for devices depending on how they were designed generally its not a good idea to exceed +1.5v on any low power DC device. 120V AC devices are designed to actually work in a much wider range like 100-130V but thats because of the power supply/nature of AC power. it always varies and in japan they use 100v 60hz AC so many electronics power supplies are designed to work in the full range to save costs and only have to make 1 unit for all (same deal with 220-240 switches on PC power supplies)
the reason why you don't want to do this mod is you could damage you PC's motherboard by pulling too much current from its circuits. USB spec is 500ma. performing this type of mod on a power adapter (car or AC) that does not get recognized as an AC charger by the phone is a safer way to go. worst case senario is you break the charger (unless you mess up on the pinout then you could damage you phone too though)

[Nexus 7] Adding internal USB for other devices (HUB,microSD,FM,flash-storage,etc...)

The project-Adding internal USB for other devices (HUB,micro SD,FM,flash-storage,etc...).
We should have a few deferent options to connect USB internally. This thread should cover them all.
I really want to find a easy solderless method(plug/clips) I have a few ideas but would need to find the female and male connectors for the front camera or maybe soundboard connectors.
or
maybe disconnect the micro USB from the ribbon and run it up to the hub then back to the micro USB connector from the HUB that's one reason for the hub, so we can add a micro SD, a rear camera and the last port (HUB only has 3 ports active, it might be possible to find a different HUB that has 4 ports but this one only had 3) for ether some more flash storage or to hook up the solderless mod to mother board.
We can use the micro USB connection at bottom of the mother board a couple different ways. We could use both the data and power from the connector. We could also just use the data +/- from the micro USB connector and use the power from a different power source like the 7.4V from the battery and drop it down to 5V but none of the wires are 7.4v there is two running at 3.7v, if we could find the 7.4v on the board or a connector somewhere this could be done

Some pics
{
"lightbox_close": "Close",
"lightbox_next": "Next",
"lightbox_previous": "Previous",
"lightbox_error": "The requested content cannot be loaded. Please try again later.",
"lightbox_start_slideshow": "Start slideshow",
"lightbox_stop_slideshow": "Stop slideshow",
"lightbox_full_screen": "Full screen",
"lightbox_thumbnails": "Thumbnails",
"lightbox_download": "Download",
"lightbox_share": "Share",
"lightbox_zoom": "Zoom",
"lightbox_new_window": "New window",
"lightbox_toggle_sidebar": "Toggle sidebar"
}
http://s10.postimage.org/6zg4euc21/N7_cable.jpg

Does this mod actually work or is that last picture just what it might look like?

atticusmas said:
Does this mod actually work or is that last picture just what it might look like?
Click to expand...
Click to collapse
Not yet, Just trying to find some other wiring options and parts before I wire it up.

Would this guy be similar to the nexus tablet?
nabitablet .com/specs/nabi2
amazon. com/Fuhu-NABI-NABI2-NV7A-7-Inch-Tablet/dp/B008DBI5RI/ref=sr_1_4?ie=UTF8&qid=1342981188&sr=8-4&keywords=nabi+2+tablet
Maybe the board could be close, find out how to use the microSD slot on the nexus 7 tablet?
(sorry about the chopped up url's, I guess I can't post links yet)

I Found this little USB HUB and it fits perfect.
This is it before it got striped
Still just in mock up and not connected yet, but it does still close up fine. So I'm pretty sure a hub is a go(for me anyway) and still have room for some flash storage that will go where the rear camera should have gone or just beside the hub

Has anything happened with this project?

Camping for a few days with the family, then back at it.

Wow that's awesome man! Keep on the good work!!
Envoyé depuis mon Nexus 7 avec Tapatalk

What do you mean by an issue with remounting when you use the power from the USB? I had read somewhere about someone shorting two pins to make the mod work but you could no longer charge and would need a switch to deactivate the short to charge it. If any switch is needed to change anything physically then I was thinking the tiny type that you press with a pen head or similar, that is recessed.
I hope you make progress when your back on it. I ordered the usb otg cable and have some tiny micro sdhc readers that slide into a usb slot that are as thin as a reg. sd card. I figured I could solder wires onto one and mount it for the card reader. I was thinking to use hot glue or similar between the soldered connections for safety since it isnt easy to get factory type solder joints all the time on small stuff (even though I am decent at soldering).
I hope someone can come up with the software hack needed to be able to actually mount the micro sd and install to it like any other tablet can.
Thanks for the pictures and work you are doing, I am sure many are watching :good:

Just a few comments on this project:
If you put a hub or device in then it requires that you operate the tablet's USB interface in host mode.
Normally, something supplies power and will not accept power for charging when in host mode.
There are hacks to get around this, but I'd see if I could get this all working externally before I started modifying.
You could end up with your hub idea working find, but you are unable to charge the tablet.
When you do lay the cables in, twist the data pair and leave the two power leads straight.

This looks awesome! Can't wait to see the tutorial if one becomes available, these devices get me in trouble!
Sent from my Nexus 7 using xda app-developers app

Have been watching this thread with great interest as well. Indeed, I always only lurked on XDA, this piqued my interest enough to actually join.
Fingers crossed for OP!
Sent from my Nexus 7 using xda app-developers app

Hub fits I just need to come up with a 5V power somehow got the Data and ground figured. Can someone come up with any ideas to create 5V power, maybe some fancy circuitry to bump the power from battery to 5V?

iAppleDev said:
Hub fits I just need to come up with a 5V power somehow got the Data and ground figured. Can someone come up with any ideas to create 5V power, maybe some fancy circuitry to bump the power from battery to 5V?
Click to expand...
Click to collapse
What model number hub did you use, does that have the USB OTG built in to it?
I am going to ask a few people in another type of forum about the voltage, a few on there know more than I on this topic. What is the battery stock voltage? I first was thinking resisters but I think we would need to know the exact current going through it to determine the right size. I am searching for tiny DC voltage regulators to see what I can find also, but wasn't sure the stock voltage. Here is some info on DC voltage regulators youtube.com/watch?v=GSzVs7_aW-Y&feature=fvwrel I cant post links yet so it doesn't have the www . The video talks about regulating DC voltage to power 5volt usb devices.
Do you think anyone will have a custom ROM or other hack so we can mount and install to the micro SDHC card once this mod is complete? Because that is what I want before I go this far.
Glad your back at it though! Thanks for your work on this.

Normally the 5V power to external devices is fed from a charge pump in the USB PHY interface chipset.
Some non-standard implementations only supply 3.7V battery power.
3.7V may/may not be enough for your hub and SD card.
If you are using 3.7V to a standard USB/SD card adapter, you might try bypassing the LDO in the adapter.
Also, many devices can only host about 100 mA.
Both hubs and USB/SD card adapters can be current hogs.
I think that some actually experimentation is called for before taking a Dremel tool to your tablet.

Renate NST said:
Normally the 5V power to external devices is fed from a charge pump in the USB PHY interface chipset.
Some non-standard implementations only supply 3.7V battery power.
3.7V may/may not be enough for your hub and SD card.
If you are using 3.7V to a standard USB/SD card adapter, you might try bypassing the LDO in the adapter.
Also, many devices can only host about 100 mA.
Both hubs and USB/SD card adapters can be current hogs.
I think that some actually experimentation is called for before taking a Dremel tool to your tablet.
Click to expand...
Click to collapse
Wouldn't it be best to us a non powered usb hub to split the usb connection? I doubt a small keyboard would use much and as far as I go, I would only use the usb for a small case sized keyboard, charging the device and the micro sdhc card/reader.
So is the battery only 3.7 volts? I was thinking it might be more and we needed to step down, so we need to step it up for the micro sdhc reader?

eBandit078 said:
So is the battery only 3.7 volts? I was thinking it might be more and we needed to step down, so we need to step it up for the micro sdhc reader?
Click to expand...
Click to collapse
It's actually two 3.7v Li-Poly cells set up in series for a total of 7.4v. As pointed out (rather rudely) in a prior post, the leads aren't spliced on the pack itself so that a 5v USB input can charge the batteries. My old Acer A100 actually had the batteries spliced so that a 12v charger was needed. It had very weak battery life, but the upside was that the 12V charger would take it from 15% to 100% is a little less than an hour.

Renate NST said:
If you put a hub or device in then it requires that you operate the tablet's USB interface in host mode.
Normally, something supplies power and will not accept power for charging when in host mode.
There are hacks to get around this, but I'd see if I could get this all working externally before I started modifying.
You could end up with your hub idea working find, but you are unable to charge the tablet.
Click to expand...
Click to collapse
Very good points. You may be happy to know that the USB specification recently provided a means for charging an OTG device while in host mode. It's called "Accessory Charger Adapter". See Chapter 6, and in particular Figure 6-2 from the specification:
www.usb.org/developers/devclass_docs/BCv1.2_070312.zip
If you could nail this down, you might solve a bunch of challenges with the +5V supply at once. Not sure what it would take to implement though. A cursory search for dedicated ICs didn't produce anything for me.
Renate NST said:
When you do lay the cables in, twist the data pair and leave the two power leads straight.
Click to expand...
Click to collapse
:good: Second that suggestion.

So this device runs on 7.4V dual Li-ion batteries?
Is there a separate charger input or only over the USB?

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
{
"lightbox_close": "Close",
"lightbox_next": "Next",
"lightbox_previous": "Previous",
"lightbox_error": "The requested content cannot be loaded. Please try again later.",
"lightbox_start_slideshow": "Start slideshow",
"lightbox_stop_slideshow": "Stop slideshow",
"lightbox_full_screen": "Full screen",
"lightbox_thumbnails": "Thumbnails",
"lightbox_download": "Download",
"lightbox_share": "Share",
"lightbox_zoom": "Zoom",
"lightbox_new_window": "New window",
"lightbox_toggle_sidebar": "Toggle sidebar"
}

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.

NST battery voltage shutdown treshold hackable?

Hi,
i use a Nook Simple Touch as typewriter with an usb-keyboard,
which works great thanks to the usb host mode app, or, automated:
an old version of tasker with a plugin to deactivate charging and activate hostmode ( and fastmode...) via shell command after booting.
The problem is, this mode drains the battery really fast,
and charging while using the keyboard, so nececessarily with OTG cable attached, is a bit of a pain in the neck,
because there is only 1 possible sequence of actions how you can enable charging with more than around 100 mA (which would be way too low in this case) while the keyboard is active,
which requires a 16k resistor between GND and ID pin, rebooting, temporarily disconnecting some wires via switch, tapping around etc etc,
(and also does not work well when the nook is completely off ),
so i decided to leave the usb port exclusively for the keyboard,
an remove the internal battery an replace it with a external big 7000mAh or so 1S li-ion pack,
which is charged externally with a lipo module
(while charging, the nook is powered by an ac adapter, power source switching is realised with a relay and a really big capactior to avoid any more complicated possibly failing electronics)
which works great and is very easy to handle,
BUT i really dont like li-ion batterys of any kind because of the fire hazard,
nimh eneloop cant be used because charging in parallel is not a good idea,
so i would like to use lifepo4 chemistry instead,
which has a working woltage between around 3 and 3,6 volts,
but the nook powers down at around 3,65 volts.
A boost/buck converter isnt possible because as the battery drains, the voltage must sink slowly for the nook to make a normal shutdown
and not crash, damage the file system etc, (and also a converter drains quite much battery even if the nook is completely off.)
Question: it would be VERY kind if anyone who has a clue about this could share his opionion on that:
is it possible (if the hardware itself can handle it) to lower the android/nook shutdown voltage to about 3 volts with some rom/software modifications ?

threshold not treshold

Wow, this all seems a bit complicated.
I had never heard of this 16K resistor stuff.
As far as I could tell, the ID pin is only sensed high or low..
Unless I'm mistaken the OMAP3621 ULPI registers only indicate high/low.
The TPS65921B (which is the actual PHY) list 90K as the typical break point.
Of course, there could be a circuit completely external to the ULPI/PHY.
Where did you find out about 16K?
Changing the voltage of everything seems the difficult way to go.
You'd have to modify uboot as well as the charger daemon.
A note: The USB charge pump is pretty inefficient, 55%.
If you were to load the USB to the maximum speced 100mA with a 3V battery, it would be drawing 303mA from the battery!
5V × 100mA / 3v / 55% = 303mA

Oh, you got me confused with your two posts.
When you were talking about ID and 16K did you mean the ID on the battery pack or the ID on the USB OTG?

Renate NST said:
Where did you find out about 16K?
Click to expand...
Click to collapse
wired a 50k pot between gnd and id pin,
in the usb mode app tapped "host" and watched if the led goes an stays on,
if not, lowered the resistance, tried again etc,
as soon it stayed on (at 16k at my device ) used this value as permanent fixed resistor.
with that otg mode keyboard use is possible,
but also at the same time the nook doesnt really believe its in otg mode so charging with 500mA is possible,
if done in this order:
- feed 5v to the + - of the usb cable
- reboot (not always required)
- remove an reinsert usb plug
- hit "host" 2 times, keyboard works and charging with around 500mA works (measured it)
but charging doesnt work when nst ist powered off,
and automount of the keyboard at startup via shell is not possible,
and cable acrobatic is required,
and as you say, usb charging is inefficient.
the other solution with an external battery (at the nst batt terminals) with external charging logic with a relay is a much easyer way,
but depends on a li-ion cell because of the 3,7-4,2 voltages the nook can use,
a lifepo4 ( or 2s li titanate + diode) would be safer and has more cycles but would require the nook
to work with 3 to 3,7 volts, which seems too complicated, changing demons etc whatever that is...
after some research it seems its not really an issue, the newer sanyo/panasonic, samsung, sony, lg powertool/ebike cells seem to be quite safe, as far as youtube shortcircuit etc tests demonstrate.
thanks for the orientational infos

Renate NST said:
Oh, you got me confused with your two posts.
When you were talking about ID and 16K did you mean the ID on the battery pack or the ID on the USB OTG?
Click to expand...
Click to collapse
sorry, i should have used one thread, i suggest ignoring the other one,
where the only request was if the nook battery terminals can survive up to 5v,
here was the request if the nook can be modified to accept at the battery terminals a voltage down to 3v and stay on.
so 3v too complicated, 5v too dangerous,
so i stick with the relay and the li-ion cell, no problem, i was just curious if an improvement would be easily possible.
the battery id resistors have nothing to to with all that, 10k and 30k work fine,
i meant the 5 pin micro usb otg connector, not shorted zero ohms as usual, but 16k.
(but thats obsolete now)

another observation: in some thread you mention you charge the nook while using an usb keyboard,
i tested it and with a normal otg cable, and the usb mode app set to 500 mA oder 1,5 A,
and a 50% charged normal internal battery,
the device draws around 250mA, and the battery gets charged very slowly, or not at all, depending on cpu usage etc.
and if the battery reaches 100% , it continues to draw around 250 mA, which is strange,
because when using a normal, non-otg usb cable,
the device draw only around 100mA when the battery had reached 100%,
so the difference must be used for heating purposes somewhere or overcharge the battery,
which might be a reason for swelling lipos.