How are you guys recharging your HD2's? I've been relying on the USB connector at the bottom of the phone, but my concern is that after 'x' number of connects/disconnects that the socket will wear out as it started doing with my Kaiser.
Do you guys know of any pin-based adapter or battery hatch modification with external contacts that would enable us to lay the phone on a stand or platform without having to use the internal USB port on the phone which will eventually wear out? The 'powermat' would be great, but it's not available for the HD2. Does the new HTC car mount recharge the phone too, or is it just a bracket?
I'm thinking of something along the lines of how bluetooth headsets recharge, where the pins are external. It just worries me that the micro USB connector will eventually fail, which on a $700+ phone is not an attractive option.
Your thoughts?
The connector will not fail. At least unless you force/damage it yourself. It has been adopted as a connection/charge connector on ALL new phones now, of any brand, so you can bet they tested it thoroughly before.
If it fails.. well that's what the warranty's there for.
To answer the original question, I charge using USB, and also an external charger for my spares.
kilrah said:
The connector will not fail.
Click to expand...
Click to collapse
I understand your point, but to my way of thinking it's still a physical connector made of metal and plastic. It will fail eventually, trust me. These connectors are tested to withstand a reasonable number of connect/disconnect cycles for the average user. But cell phones tend to get used more, and this phone among other cell phones because of the cpu and screen will need to be recharged even more so.
Also, I'm not talking about the point of failure, but the limit of usability. The connector on my Kaiser got to the point where the cable wouldn't stay lodged in the housing and would drop out of its own weight. Although it still worked, it made for awkward handling while in the car trying to use a coiled charging cable that would drop out on its own.
So what I was looking for was a replacement battery hatch which would connect with the internal contacts, and a corresponding mount/dock of some sort so that it would minimize the physical stress of multiple connections and disconnections.
BillTheCat said:
How are you guys recharging your HD2's? I've been relying on the USB connector at the bottom of the phone, but my concern is that after 'x' number of connects/disconnects that the socket will wear out as it started doing with my Kaiser.
Do you guys know of any pin-based adapter or battery hatch modification with external contacts that would enable us to lay the phone on a stand or platform without having to use the internal USB port on the phone which will eventually wear out? The 'powermat' would be great, but it's not available for the HD2. Does the new HTC car mount recharge the phone too, or is it just a bracket?
I'm thinking of something along the lines of how bluetooth headsets recharge, where the pins are external. It just worries me that the micro USB connector will eventually fail, which on a $700+ phone is not an attractive option.
Your thoughts?
Click to expand...
Click to collapse
I just got the car mount today. It Does recharge the phone - there's a mini usb plug built into the bracket, and a lead plugs into the base of the bracket, and then into your 12v socket. A nice touch, the lead is actually long enough to be able to route it nicely.
ebeam said:
I just got the car mount today. It Does recharge the phone - there's a mini usb plug built into the bracket, and a lead plugs into the base of the bracket, and then into your 12v socket. A nice touch, the lead is actually long enough to be able to route it nicely.
Click to expand...
Click to collapse
Thanks, but what I was really after is a solution that does NOT involve the USB port on the phone.
I've seen battery chargers on Ebay. That's probably the only sensible solution if you're really that worried about the USB connector...
I think I remember reading something about some sort of wireless recharging pad that you can put phones and mp3 players on that would recharge them without any cables but I've got no idea if it would work on the HD2 or if they are even on sale yet.
There was old HTC CU S400 car Update Kit. It has direct conection to the battery throug back cover http://www.slashgear.com/htc-hd2-cu-s400-car-kit-gets-priced-detailed-coming-december-1360143/#entrycontent. New mount have MicroUSB connection http://www.clove.co.uk/viewProduct.aspx?product=53E28901-63DD-4E93-99F6-BF3D0B88BD04
lachutm said:
There was old HTC CU S400 car Update Kit. It has direct conection to the battery throug back cover http://www.slashgear.com/htc-hd2-cu-s400-car-kit-gets-priced-detailed-coming-december-1360143/#entrycontent. New mount have MicroUSB connection http://www.clove.co.uk/viewProduct.aspx?product=53E28901-63DD-4E93-99F6-BF3D0B88BD04
Click to expand...
Click to collapse
Yes, the former is along the lines of what I had in mind. Just surprised that no aftermarket solutions have been developed for the phone to make it easier to charge without wearing out that micro-usb connector.
As the mini USB port is a standard size, (not just used by HTC) if you should ever 'break it', most phone repair shops will be able to replace it quite easily.
A lot less hassle than opening up your phone to plug things in the back.
I have a friend who is visting the US (I'm from Canada) and I asked him to pick me up a nook. Not finding clear info in some of the reviews, mainly concerned about charging.
This charges over usb when hooked up to your computer right? Just want to make sure it doesn't use a proprietary cable for charging. I read on the ipad side, that older computers don't give out enough power to charge over usb, is that an issue with the nook?
What adapters/cables does it come with exactly? And is it just a standard mini-sub for the charging?
Also, this has a headset jack correct? I've read no bluetooth, I guess there's no way to get a mic working on this then.
Micro USB, will charge VERY slowly using a computer. Includes a 2amp wall socket and special cable to quick charge (still micro usb, just more pins). Has a headset port but does not come with a headset.
I've only had a few mobile devices. I read the ipad can charge over usb if the mobo supports giving out that extra juice. Some mobo's have a new firmware update to enable this.
The connector is micro-usb but just more pins. Hmm. so if the cable breaks or I misplace it no other micro-usb will charge it?
edit: i read a little more and found that it's 30 pin proprietary cable to speed up charging. I also read the galaxy tab does something similar.
Does anyone know if they use the same pin configuration? probably not, but I can get tab usb cables here.
I know you didn't ask for it but I'll tell you anyway
In case you are worrying about registering your device (mandatory at initial setup).
I'm NOT in the US and it worked fine.
Good to know. Thanks.
But I'm more concerned about charging it and relying solely on their cables.
I read the ipad can trickle charge on newer computers but some wouldn't provide enough power. Asus et al have released utilities to increase the power to the usb ports.
I can't post the links but endgadget has an article about it providing links to those utilites. They just talk of apple devices but does this work with the nook?
It comes with a charger for US-type sockets and only if you charge your nook with this (and yes, it is proprietary ) it'll charge quickly. It does seem to charge when you connect it to a standard PC USB port but at an extremely low rate.
On the device Micro-USB (not Mini) is used.
You say it does seem to, do you mean from personal experience? How slow? It sounds like that if you do own one it was so slow you didn't let it finish.
Like if it's 8hrs overnight, I can live with that, but I want to confirm that there is a plan b and not solely rely on their cables.
And as I mentioned asus and others released utils to give more power output to the usb (although these seem like their were only created for ipads). Wondering if those utils speed things up.
for ex, google asus ai charger to see what I mean.
I received my nook Color a mere few hours ago so I can't tell you a lot about its charging behavior It "seems" to load slower via standard USB... if you want to know about the details check one of the large threads on the NOOK and its rooting. I remember reading some information about the USB connector and its peculiarities there.
Ah you just got it. I see.
I found this on the root thread:
'
"There are 12 pins coming off the connector. It looks like there are no pins for the standard micro USB portion, only the extended 12 pins. 2 pins are used to bring in +5V, 2 pins are for signal ground providing a hefty circuit for the 2A charging. USB takes up two pins, and as far as I can tell 2 more are for each LED via current limiting resistors. Two more pins go to discretes that I haven't identified, and two more pins are unconnected. I'll take my scope to them when I have some time."
Not sure what he means when he says no pins for the standard micro portion...
Maybe the plug doesn't have standard USB pins, but the NOOK itself does have standard USB pins as well as the proprietary ones. Because I have trouble inserting the original B&N plug, I went out earlier today and bought a standard Micro USB cable...
I connected it to the nook and it said "not charging", so I went out to do some shopping (10-20 minutes max) and left it at 89%... when I came back it was at 93 %.
So it DOES in fact seem to charge albeit slowly.
Thanks. It's weird, lots of comments of its own cable not fitting properly.
As long as it charges with a normal cable I'm good.
I guess it is charging... however there is a slight chance, that it's NOT charging and the battery charge display is lying (de-calibrated). I don't think so, but I'll only know for sure after a few more days of using only the standard USB charger cable.
For the time being this is going to be in Accessories, but eventually it might get moved to Development as I get even more data. It's borderline at the moment.
It's been known for a while that the Nexus 7 is finicky about power supplies. In addition to the usual requirements for a power supply that complies with the USB Battery Charging Standard (D+ and D- shorted by the supply), which makes it VERY hard to find good supplies as most use Apple's nonstandard convention - The Nexus 7 seems to be VERY finicky about supplies which drop their voltage under load. Samsung tablet supplies will charge the N7 faster than the stock supply.
The charger controller chipset in the N7 is a Summit SMB347, same as found in a number of Samsung tablets. No datasheet is available for this chipset, but we do know it has an Automatic Input Current Limiting (AICL) feature - If the power supply "browns out", it will reduce current demand until the supply voltage raises to above the trip threshold.
Previously, I only had the ability to measure battery input current using CurrentWidget, but the top of my Christmas wishlist was an adjustable bench power supply. It has adjustable voltage AND an adjustable current limit - so I can limit the current delivered to the N7 and determine what voltage it settles at. If the voltage kept bouncing between two values, I recorded the voltage as the halfway point. E.g. if it bounced between 5.1 and 5.2, I recorded it as 5.15.
A picture of my setup is at:
https://plus.google.com/u/0/101093310520661581786/posts/gkbHaKKDnj6
Components:
Sinometer HY3005D from Mastech (Adjustable bench supply, 0-30v 0-5A)
22 gauge solid wire (the best USB cables I've seen are only 24 gauge - lower gauge = thicker wire)
Sparkfun MicroUSB breakout with D+ and D- shorted
Here are the results (Bear with me as I try to figure out how to properly format a table here on XDA... The HTML tag doesn't work as expected...):
HTML:
<table border="1">
<tr><td>Amperage Limit</td><td>Voltage</td></tr>
<tr><td>1.85</td><td>5.15</td></tr>
<tr><td>1.80</td><td>5.0</td></tr>
<tr><td>1.70</td><td>4.9</td></tr>
<tr><td>1.60</td><td>4.9</td></tr>
<tr><td>1.50</td><td>4.8</td></tr>
<tr><td>1.40</td><td>4.8</td></tr>
<tr><td>1.30</td><td>4.7</td></tr>
<tr><td>1.20</td><td>4.7</td></tr>
<tr><td>1.10</td><td>4.6</td></tr>
<tr><td>1.00</td><td>4.55</td></tr>
</table>
Below 1A, I think the tablet goes into a more severe AICL mode - it will drop to around 600-650 mA, the power supply will exit current limiting (back up to 5.1 volts), and current will not go up until the device is unplugged and replugged.
One observation here - If the voltage drops 0.2 volts, you lose 400 mA of charge current. Many previous efforts here put an ammeter in series with the power supply - many ammeters drop 0.1-0.2 volts under load! The ammeter used by those previous effort was having SIGNIFICANT effect on the results.
Reserved - future analysis of how various chargers behave under load. Do they REALLY meet their ratings?
May be posted in Hardware Hacking and linked from here instead.
Reserved for work on trying to change the SMB347 AICL behavior.
Even if the amperemeter drops 0.1-0.2 V under various loads, you can stick a voltmeter after the amperemeter (i.e. parallel to the device only) and you should have a pretty accurate reading of the voltage on the device alone since voltmeters are pretty high impedance. And to compensate for the loss, just increase the supply voltage a bit.
Entropy512 said:
Stuff.
Click to expand...
Click to collapse
I think you may be trying to read too far into this.
I charge my Nexus 7 off of a generic 2A/5V X4 output charger, and off the stock charger, and off the woman's kindle fire charger, and off a 2A car adapter. All of it works just fine.
I think the real problem comes from people using chargers that aren't able to produce enough current (thus the voltage drop you're trying to measure for). But honestly, this tablet lasts incredibly long on a charge, and takes almost no time to get back to 100%. Aside from if you're using it in your car as a long term audio/gps/hspa unit, all at once, why even bother taking out your meter?
TLDR: Buy a charger that is rated for 5V, 2A, and go back to having a good holiday instead of trying to measure it. Granted, I understand you're interested in finding out the how's and why's, but I haven't found any issue with charging the Nexus 7 on any charger I own, because I only buy ones that are rated for 2A or above draw. I won't get out the Fluke to test what it's pulling on each one, but it seems to charge very quickly on all of the above. 1%-100% in the time it takes me to not care, anyways.
bladebarrier said:
I think you may be trying to read too far into this.
I charge my Nexus 7 off of a generic 2A/5V X4 output charger, and off the stock charger, and off the woman's kindle fire charger, and off a 2A car adapter. All of it works just fine.
I think the real problem comes from people using chargers that aren't able to produce enough current (thus the voltage drop you're trying to measure for). But honestly, this tablet lasts incredibly long on a charge, and takes almost no time to get back to 100%. Aside from if you're using it in your car as a long term audio/gps/hspa unit, all at once, why even bother taking out your meter?
TLDR: Buy a charger that is rated for 5V, 2A, and go back to having a good holiday instead of trying to measure it. Granted, I understand you're interested in finding out the how's and why's, but I haven't found any issue with charging the Nexus 7 on any charger I own, because I only buy ones that are rated for 2A or above draw. I won't get out the Fluke to test what it's pulling on each one, but it seems to charge very quickly on all of the above. 1%-100% in the time it takes me to not care, anyways.
Click to expand...
Click to collapse
Except that many chargers, even the ONE THAT COMES WITH THE DEVICE, aren't capable of delivering 5v 2A even if they may claim to do so. They may be capable of 4.8v 2A - but as the data I've taken shows, a charger that can only do 4.8v 2A will only charge the N7 at 1.4-1.5 amps. If the charger drops to 4.7v under load, it'll drop to only 1.2A or so.
More data (taken using CurrentWidget):
Idle load with screen at max brightness: 500 mA drain reported by CW
Current entering battery when screen at max brightness: 900-950 mA with stock Asus charger, giving approx. Since system drain under these conditions is 0.5A, that gives 1.4-1.45A into the device, consistent with a charger that is dropping to 4.8v under load.
Current entering battery with a Samsung Galaxy Tab charger: 1300 mA, giving a total of 1.8A into the device (almost the maximum the device will pull given a solid stiff rail)
Current entering battery with the power supply used in the tests above: 1330 mA, giving a total of 1.83A into the device (power supply itself reported 1.86 in this state).
The stock Asus charger that ships with the device underperforms by 400 mA when used with this device. Many "2.1A" chargers underperform even more (I'll run some tests with the Scosche reVIVE II later, but if memory serves me correctly, it's more appropriately rated 1A...)
gokalp said:
Even if the amperemeter drops 0.1-0.2 V under various loads, you can stick a voltmeter after the amperemeter (i.e. parallel to the device only) and you should have a pretty accurate reading of the voltage on the device alone since voltmeters are pretty high impedance. And to compensate for the loss, just increase the supply voltage a bit.
Click to expand...
Click to collapse
Yup. If I didn't have a bench supply with an adjustable current limit, I could've done this. Problem is even a few tenths of a volt difference makes a significant current difference - it's easier to adjust the current limit if you've got a supply that allows it.
Entropy512 said:
Except that many chargers, even the ONE THAT COMES WITH THE DEVICE, aren't capable of delivering 5v 2A even if they may claim to do so. They may be capable of 4.8v 2A - but as the data I've taken shows, a charger that can only do 4.8v 2A will only charge the N7 at 1.4-1.5 amps. If the charger drops to 4.7v under load, it'll drop to only 1.2A or so.
More data (taken using CurrentWidget):
Idle load with screen at max brightness: 500 mA drain reported by CW
Current entering battery when screen at max brightness: 900-950 mA with stock Asus charger, giving approx. Since system drain under these conditions is 0.5A, that gives 1.4-1.45A into the device, consistent with a charger that is dropping to 4.8v under load.
Current entering battery with a Samsung Galaxy Tab charger: 1300 mA, giving a total of 1.8A into the device (almost the maximum the device will pull given a solid stiff rail)
Current entering battery with the power supply used in the tests above: 1330 mA, giving a total of 1.83A into the device (power supply itself reported 1.86 in this state).
The stock Asus charger that ships with the device underperforms by 400 mA when used with this device. Many "2.1A" chargers underperform even more (I'll run some tests with the Scosche reVIVE II later, but if memory serves me correctly, it's more appropriately rated 1A...)
Click to expand...
Click to collapse
Interesting.
Are you getting the same readings when the device is turned off, to ensure there isn't a possible software issue? Is this purely on the stock ROM/kernel, or are you using a custom one?
With the Droid X, there were some concerns that it was unable to charge a fully discharged battery if not on a stock ROM, because Moto implemented measures in the "bloat" that allowed it to do so when it would normally not be capable in pure Android. I remember people having to cut wires to charge batteries externally, if they ran out of juice while trying to flash a ROM that was not Moto based. The whole concept seemed absurd to me, yet that was clearly the case. A dead Droid X could charge normally, if on the Moto software, but could not charge at all, if on AOSP if the battery was completely discharged prior to the attempt.
Just throwing out some ideas. I don't have your level of equipment to test it out at home, but I could take mine into the EE lab and see what one of the students can discern.
Is it possible that some of this is because of the pogo connection, and that may not be sorted out well enough, as such causing complications to the circuit?
EDIT: What is the accuracy of Current Widget? I tried it on my Nexus 7, and it was reporting some absurd numbers that didn't appear to be accurate. I would be charging at normal speed, and it would show me as discharging. The Nexus 7 would go back to 100%, and the whole time it would read as if I was losing power. I uninstalled it, figuring there is a compatibility issue with either JB or the device.
bladebarrier said:
Interesting.
Are you getting the same readings when the device is turned off, to ensure there isn't a possible software issue? Is this purely on the stock ROM/kernel, or are you using a custom one?
With the Droid X, there were some concerns that it was unable to charge a fully discharged battery if not on a stock ROM, because Moto implemented measures in the "bloat" that allowed it to do so when it would normally not be capable in pure Android. I remember people having to cut wires to charge batteries externally, if they ran out of juice while trying to flash a ROM that was not Moto based. The whole concept seemed absurd to me, yet that was clearly the case. A dead Droid X could charge normally, if on the Moto software, but could not charge at all, if on AOSP if the battery was completely discharged prior to the attempt.
Just throwing out some ideas. I don't have your level of equipment to test it out at home, but I could take mine into the EE lab and see what one of the students can discern.
Is it possible that some of this is because of the pogo connection, and that may not be sorted out well enough, as such causing complications to the circuit?
EDIT: What is the accuracy of Current Widget? I tried it on my Nexus 7, and it was reporting some absurd numbers that didn't appear to be accurate. I would be charging at normal speed, and it would show me as discharging. The Nexus 7 would go back to 100%, and the whole time it would read as if I was losing power. I uninstalled it, figuring there is a compatibility issue with either JB or the device.
Click to expand...
Click to collapse
I can only confirm CW works properly on CM10. It is completely nonoperational in stock (as the code was disabled), and they did something in that area in 4.2 that I haven't taken a look at yet. I know the voltage value was off by a factor of 1000 in stock 4.1.
As to software issues - there are none other than whatever nonvolatile defaults are preprogrammed into the SMB347. If you look at the SMB347 driver for grouper you'll see that it does almost nothing in terms of configuring current limits and such, relying on the internal NV defaults. (Very different from Kindle Fire and Note 10.1, which perform quite a lot of configuration of the chip, not relying on internal NV defaults.) I've seen people report similar behavior on multiple kernels and firmwares.
Based on the Kindle Fire sources, there is at least one AICL setting that can be tweaked. However after looking at them further, I think that's the one that hits when the power supply droops to 4.5 volts. The question is whether the charger circuit is doing limiting before hitting that severe AICL threshold. When I get back from my holiday I'm going to try changing the threshold to 4.2 volts to see how things behave.
Entropy512 said:
I can only confirm CW works properly on CM10. It is completely nonoperational in stock (as the code was disabled), and they did something in that area in 4.2 that I haven't taken a look at yet. I know the voltage value was off by a factor of 1000 in stock 4.1.
As to software issues - there are none other than whatever nonvolatile defaults are preprogrammed into the SMB347. If you look at the SMB347 driver for grouper you'll see that it does almost nothing in terms of configuring current limits and such, relying on the internal NV defaults. (Very different from Kindle Fire and Note 10.1, which perform quite a lot of configuration of the chip, not relying on internal NV defaults.) I've seen people report similar behavior on multiple kernels and firmwares.
Based on the Kindle Fire sources, there is at least one AICL setting that can be tweaked. However after looking at them further, I think that's the one that hits when the power supply droops to 4.5 volts. The question is whether the charger circuit is doing limiting before hitting that severe AICL threshold. When I get back from my holiday I'm going to try changing the threshold to 4.2 volts to see how things behave.
Click to expand...
Click to collapse
You're way above my pay grade.... Yet I'll speculate further.
If it's hardware based, to drop the amperage draw, based on a voltage drop, and can be replicated in CM, then it could be an intentional protection circuit in the Lion battery itself. There are many Lion batteries that use protection circuitry these days, yet I don't know of anyone using aftermarket replacements for the Nexus 7, and so testing it could very well be basing the tests purely on the battery itself.
Maybe try running the tests directly to the battery, removed from the Nexus itself, and that will at least exclude the software and the hardware of the Nexus.
I could crack open the body and check the manufacturer, but if it's Panasonic or Sony, there's a reasonable chance that there are built in circuits on the Lion itself.
If you get identical readings, while running leads directly to the battery, the issue will be known immediately. If you don't, we can rule out one of the three options (battery, hardware, software). And you already ruled out most of the software.
bladebarrier said:
You're way above my pay grade.... Yet I'll speculate further.
If it's hardware based, to drop the amperage draw, based on a voltage drop, and can be replicated in CM, then it could be an intentional protection circuit in the Lion battery itself. There are many Lion batteries that use protection circuitry these days, yet I don't know of anyone using aftermarket replacements for the Nexus 7, and so testing it could very well be basing the tests purely on the battery itself.
Maybe try running the tests directly to the battery, removed from the Nexus itself, and that will at least exclude the software and the hardware of the Nexus.
I could crack open the body and check the manufacturer, but if it's Panasonic or Sony, there's a reasonable chance that there are built in circuits on the Lion itself.
If you get identical readings, while running leads directly to the battery, the issue will be known immediately. If you don't, we can rule out one of the three options (battery, hardware, software). And you already ruled out most of the software.
Click to expand...
Click to collapse
No way it's the battery itself. If you ran straight 5v into a LiIon/LiPo battery you'd blow it up (unless the protection circuitry kicked in). Running 5v straight into even a protected LiIon is an extremely bad idea.
It's something in how the SMB347 behaves - http://www.summitmicro.com/prod_select/summary/SMB347/SMB347.htm - Unfortunately there is no public datasheet, just a 1-2 page "product brief" with little detail, other than it does have some sort of automatic input current limiting. The SMB347 is the chip responsible for charging the battery safely, and basically anything related to charging the battery in the N7 is within that chip. Understand that chip and you understand everything about charging the N7.
The only technical detail we have about this chip resides in kernel source code for devices with the same chip - Samsung Note 10.1 and Kindle Fire both have a 347, and unlike the N7 which appears to use nonvolatile defaults burned into the chip, these devices touch the chip's registers. The KFire source has some info on how to change one of the AICL configurations.
Entropy512 said:
No way it's the battery itself. If you ran straight 5v into a LiIon/LiPo battery you'd blow it up (unless the protection circuitry kicked in). Running 5v straight into even a protected LiIon is an extremely bad idea.
Click to expand...
Click to collapse
Without a doubt!
I would never suggest someone use the method for normal charging. You would have to be capable of limiting the current, and be very careful, if testing in that manner.
I don't know how useful this comment will be, since there's no technical data, just empirical evidence, but I've used a friend's Nexus 7 charger several times on my Xperia S, that has fast charging enabled by default, and it charges noticeably faster than the charger that was packed with it (850 mA).
So, I'm inclined to think the culprit is the SMB347 chip.
FenrirMX said:
I don't know how useful this comment will be, since there's no technical data, just empirical evidence, but I've used a friend's Nexus 7 charger several times on my Xperia S, that has fast charging enabled by default, and it charges noticeably faster than the charger that was packed with it (850 mA).
So, I'm inclined to think the culprit is the SMB347 chip.
Click to expand...
Click to collapse
It's the SMB347 combined with the power supply. The PS is drooping a little bit (not significantly), and the SMB347 is being exceptionally finicky about the droop.
Supplies that don't droop (Samsung Tab chargers - FYI, the Note 10.1 also has an SMB347) are OK, that supply is likely OK with less finicky devices.
Next on my project list:
While the setup used here (22 gauge sold wire that is only a foot or so long) is ideal for eliminating voltage drop in the USB cable, I need to whip up a "universal charging adapter" between my bench supply and a female USB port that uses Samsung tablet resistances (which are also OK for most standard devices). That way I can see how my Note 10.1 behaves with a current limited supply.
A power supply tester - PWM out of an AVR microcontroller into an adjustable constant current load, ramp up the current draw and monitor the supply voltage with the uC to get an output I/V curve for various supplies.
current widget
My apologies for reviving such an old thread, but I have been searching for information about how the nexus 7 charges and why of acts so different with different chargers. Your posts have been very informative. I have found that my Verizon car charger will charge my nexus considerably faster than any other charger I have, including the one which came with the tablet.
I am curious to know how you were able to use current widget on this device. I am running cm10. Which kernel has support for current widget so that I may flash it? I am using battery widget for the time being and while of does give me a rough estimate, I would really like a real time reading.
Thank you for your time.
Crystawth said:
My apologies for reviving such an old thread, but I have been searching for information about how the nexus 7 charges and why of acts so different with different chargers. Your posts have been very informative. I have found that my Verizon car charger will charge my nexus considerably faster than any other charger I have, including the one which came with the tablet.
I am curious to know how you were able to use current widget on this device. I am running cm10. Which kernel has support for current widget so that I may flash it? I am using battery widget for the time being and while of does give me a rough estimate, I would really like a real time reading.
Thank you for your time.
Click to expand...
Click to collapse
I actually stumbled on an answer myself.
Franco Kernel r65 for 4.2.2 on CM 10.1 Provides battery current information =)
Here's what I've learned from a hardware perspective...
Posting this in a few places hoping it stimulates an answer to the problem....
We're working on a hardware + firmware + software product that uses an Android tablet, which right now is specifically the Nexus 7. We have found that the standard charge rate of the battery is insufficient to support tablet operation with a few sensors enabled and high screen brightness. Therefore, even if plugged in to a power source, the Nexus 7 discharges during normal use. The charging system cannot keep up with normal power requirements. That is a TERRIBLE hardware design decision.
Rather than guess at what is happening, or jump to conclusions based on various apps that claim to report current, we connected an actual ammeter (current meter) in line with the USB cable plugged in to a 2012-era Nexus 7 and ran a lot of experiments to characterize its behavior.
A few basic things to keep in mind:
* The current rating on a power supply/charger is the max current that device can provide. The device being charged controls how much current is actually drawn from the supply. A higher-current charger cannot, simply by virtue of its higher capacity, force more current into the device.
* USB hardware specs very clearly define the max current that a Portable Device (PD, in this case an N7) can draw from various power sources. Earlier posts in this thread properly referred to the names of the various types of ports including the one that we need, a Charging Downstream Port (CDP), which supports both data and higher charging current. A CDP uses certain voltage levels on its D+ and D- pins to signal the availability of greater current; a "dumb charger" can just short the two data pins together to signal the same thing, but obviously this won't work if you also want to pass data and not just charge the battery. (The "shorted data pins" trick is a documented way to let cheap chargers inform the PD of higher current capacity without having to add intelligence to the charger.)
* USB software specs also define how the PD can negotiate with the upstream port (in our case, a CDP), essentially letting the N7 specify how much current it wants to draw and letting the upstream port respond with approval or disapproval. In this case, the hardware does its thing, and then the software on both ends talks back and forth to agree on a (potentially higher) current rate.
I'll cut to the chase: The N7 never draws more than 440mA. Ever. With any charger, with any cable, with any combination we've tried. This includes the Asus-labeled 5V 2100mA OEM charger and the Asus-labeled OEM cable that came with the tablet. We really, really want it to, but we have not been able to figure out how to convince it to use more current (and thus stop draining the battery while plugged in). Yes, I've read the other comments in this thread that report higher currents and I don't know how to explain what they're seeing. But in a laboratory environment, with real test equipment run by Engineers, 440mA is the number.
On the hardware side, our product has a dedicated 5A 2000mA+ power supply for the N7 connection. This is really clean power - it's a little switching power supply with great filtering that powers nothing but the USB connector. An oscilloscope shows an absolute flat line, no ripple, no noise, nothing, even under load. We have tested its current output capacity and it goes well beyond 2000mA with no degradation of the voltage level nor quality. This power is as clean as its gets. The power is there if the N7 wants it.
On the software side, the N7 does in fact do the "USB software negotiation" for current and we tell the N7 that 2000mA is available. Nevertheless, the N7 always requests 500mA (we've captured and analyzed the USB data), and in reality never draws more than the 440mA mentioned above.
We cannot short D+ and D- since we need to communicate with the N7. But there are other tricks supported by the USB spec, including specific voltage levels on the data lines to indicate that the port to which the N7 is connected is a CDP. Briefly, a PD which takes advantage of a CDP first performs "primary detection" by looking at D- for 0.4-0.8VDC. If a voltage in that range is found, "secondary detection" causes the PD to apply voltage to the D+ pin looking for a pulldown resistance of (nominally) 19.5K.
So we added circuitry to provide this environment, thus indicating we are a CDP. Result: No change at all. The N7 draws 440mA with or without the CDP circuitry.
We kept at it for a long time, because we thought it strange that Asus would ship a 2100mA charger when a 500mA charger would suffice. We figured that was proof the N7 could charge at a higher rate. But after hours and hours of analysis, testing, experiments, etc. we were forced to conclude that the N7 simply never draws more than 440mA. Presumably its onboard charging circuitry cannot handle higher current rates. This is a real shame, because it means the Nexus 7 cannot be used in kiosk mode - it cannot run indefinitely when plugged into external power. It will always require some "down time" to recharge its battery. That's fatal to a lot of applications for this tablet, including ours.
We have not yet tested a 2013 N7, but we're hopeful it has a better charging circuit.
SpokaneNexus said:
We cannot short D+ and D- since we need to communicate with the N7. But there are other tricks supported by the USB spec, including specific voltage levels on the data lines to indicate that the port to which the N7 is connected is a CDP. Briefly, a PD which takes advantage of a CDP first performs "primary detection" by looking at D- for 0.4-0.8VDC. If a voltage in that range is found, "secondary detection" causes the PD to apply voltage to the D+ pin looking for a pulldown resistance of (nominally) 19.5K.
Click to expand...
Click to collapse
I never saw this particular post of yours until trying to find this old post of mine.
N7 does not support CDP (Charging Downstream Port) detection. Few Android devices do. (N7 2012 most definitely does not, and I'm fairly certain N7 2013 doesn't either). If it sees a downstream port, it assumes it's an SDP (Standard Downstream Port) with 500 mA current limit. This is a fundamental requirement of the USB standard - don't pull more than 500 mA from a host unless you support CDP detection and detect a CDP.
N7 does support DCP (Dedicated Charging Port) detection. N7 will ABSOLUTELY pull more than 500 mA from a DCP (this includes the wall supply) when D+ and D- are shorted.
If you want to communicate with the device and supply more than 500 mA, you need either a device that supports CDP detection (rare) or you need to violate the standard. This can be done with kernel modifications that override the current limit when an SDP is detected - this is usually a HORRIBLE idea but is acceptable in a specific case like yours. (Some kernel hackers refer to this as "USB Fast Charging").
Sorry for posting on an old thread, but it is still an issue, and i am determined to find a fix.
I bought a thick 20awg cable, and that seems to do the job, but i don't use my n7 enough to see if it really does.
You referenced the kernel a few times in reference to the chip that controls the charging.
I was wondering if it would be possible to modify kernel sources to change the way the chip behaves, although i dont have many hopes, because i imagine it would have already been done
i was thoroughly engaged in this issue, and even resolved to build my own dock, and bought the pogo pins, but have never used them!
Even if there isn't a way the change the chips behaviour, i was wondering if there was another workaround on the kernel/software side, as i am certainly up for the job, even though not very able as a developer, and always needing to be pointed in the right direction.
Right I am sick of seeing Samsung Battery's die, not the other day I saw at lest 5 note battery's in one of these recycle battery bins and all of them was ballooned just like mine, I want to use the device without a battery this phone is used as a home entertainment device and 3G modem nothing more, its not used as a phone any more, I want to integrate it in to my Bluetooth speaker would look nice and fit very well.
Problem is I have no idea how to go about doing this without the battery, if there a way to to trick the phone to thing it has a battery or has anyone made a factory cable for the Note?
I feel all companies that make these device to run off a battery only are destroying our world faster as there is so much life left in old android devices if we just could power them from mains power only.
I would like to power it from the battery side if I could so I can still use the USB host but this is not 100% important the 11 gig free on the device and the sd slot will do our home music needs.
Any advice would be great but please don't reply 'get a new battery there cheap', the unit once built wont have access to the battery so making it impossible to keep changing the battery when it balloons again.
Thanks, Rex
62 9262248
i think u disrespect our device,
no one accept that
darkangel0077 said:
i think u disrespect our device,
no one accept that
Click to expand...
Click to collapse
For a member with only 5 posts you clearly have no idea what your talking about, how is wanting to give my device a new lease of life
disrespectful? The only thing letting the device down right now is the lag of battery well damaged balloon battery, Housing this with my 50 wat
bluetooth powered speaker would really give new life to this device and how I am using it as a 3G modem I would also like to use the USB host
that this device supports.
I think you should be less disrespectful in your posts next time.
# Back to Topic
I could use wifi to access content on my network but I was hoping to set up RPI to send the phone to the TV making the device able to also stream my videos to the TV, I am not sure that Android or this device could support multi wifi connections if it could I could do that and also have a dedicated stream for my netflix.
If I can find a way to power all this then I think I will also open a build log post later with all the parts and steps
I was going to use our Acer Iconia Windows 8.1 tablet but the USB host on that is like a wet fist out of water, the android is much better at this task then the tablet.
Recap, I would like to power the device without a battery but via the battery pins so I can still use the USB host.
I need to be able to draw enough power for the device, the USB and Wifi + Bluetooth at the same time.
If any ideas on how this could be done it would be great, I was thinking using some kind of meter to find out what the battery gives the battery circet and then find some kind of multi power block to offer that.
rexzooly said:
For a member with only 5 posts you clearly have no idea what your talking about, how is wanting to give my device a new lease of life
disrespectful? The only thing letting the device down right now is the lag of battery well damaged balloon battery, Housing this with my 50 wat
bluetooth powered speaker would really give new life to this device and how I am using it as a 3G modem I would also like to use the USB host
that this device supports.
I think you should be less disrespectful in your posts next time.
# Back to Topic
I could use wifi to access content on my network but I was hoping to set up RPI to send the phone to the TV making the device able to also stream my videos to the TV, I am not sure that Android or this device could support multi wifi connections if it could I could do that and also have a dedicated stream for my netflix.
If I can find a way to power all this then I think I will also open a build log post later with all the parts and steps
I was going to use our Acer Iconia Windows 8.1 tablet but the USB host on that is like a wet fist out of water, the android is much better at this task then the tablet.
Recap, I would like to power the device without a battery but via the battery pins so I can still use the USB host.
I need to be able to draw enough power for the device, the USB and Wifi + Bluetooth at the same time.
If any ideas on how this could be done it would be great, I was thinking using some kind of meter to find out what the battery gives the battery circet and then find some kind of multi power block to offer that.
Click to expand...
Click to collapse
No Android doesn't support Multi-Wi-Fi Connections. (Don't think anything supports that...)
I've tried using Note 2 without charger, doesn't work, probably doesn't for Note either. Though it might work with a socket that supplies loads of power.
Smack that Thanks button if I helped!
KitKat came in on my OmniROM, running on my Note 2.
Sent from a small country called Singapore.
P.S. Time for school, not much time for XDA
Irwenzhao said:
I've tried using Note 2 without charger, doesn't work, probably doesn't for Note either.
Click to expand...
Click to collapse
Yes by default almost all phones don't let your power them on without the battery, but many newer android devices can be powered
by outlet power when in been programmed a factory mode, this is what I am asking people about if anyone has taken the chip of the batter
and provided it outlet power to fool the phone in to thinking its on battery.
You could cheat, find a power adapter and connect it to the battery connectors.
In case OP is still interested I have an idea about this issue. I had exactly the same question, how to power up an android phone without a batery plugged in.
Ignore daedric's post. Smartphones are powered by batteries which, when fully charged, provide 4.2 volts. Power adapter's output is 5 volts, so you would most probably damage your device. Supposing that phone chargers' output was 4.2 volts you would still not be able to use the device because the device draws a lot more current than a charger can provide.
My idea is to use a reliable DC-DC step down converter, and a powerful power adapter. I don't know how much current a Note could draw from its battery but I would try to find a step down converter that could at least handle 3 amps of output without damaging itself. Then I would try to find a reliable power supply like a 12v 2A. The idea is to connect the power supply to the step down converter and the converter to the battery pins on the device. Of course you would also have to set the potentiometer of the converter to output 4.2v.
BUT, there is one more problem. You have to trick the device to make it "think" that there is a battery connected and I don't know exactly how this can be done. I found on the internet a blog where a guy did so by connecting a resistor between the negative battery pin (on the device) with the third pin on the device. So, I don't know if it's possible on the Note, and how to do it. All I'm trying to say is that it might be possible, it just needs more research.
_purple_ said:
In case OP is still interested I have an idea about this issue. I had exactly the same question, how to power up an android phone without a batery plugged in.
Ignore daedric's post. Smartphones are powered by batteries which, when fully charged, provide 4.2 volts. Power adapter's output is 5 volts, so you would most probably damage your device. Supposing that phone chargers' output was 4.2 volts you would still not be able to use the device because the device draws a lot more current than a charger can provide.
My idea is to use a reliable DC-DC step down converter, and a powerful power adapter. I don't know how much current a Note could draw from its battery but I would try to find a step down converter that could at least handle 3 amps of output without damaging itself. Then I would try to find a reliable power supply like a 12v 2A. The idea is to connect the power supply to the step down converter and the converter to the battery pins on the device. Of course you would also have to set the potentiometer of the converter to output 4.2v.
BUT, there is one more problem. You have to trick the device to make it "think" that there is a battery connected and I don't know exactly how this can be done. I found on the internet a blog where a guy did so by connecting a resistor between the negative battery pin (on the device) with the third pin on the device. So, I don't know if it's possible on the Note, and how to do it. All I'm trying to say is that it might be possible, it just needs more research.
Click to expand...
Click to collapse
I was thinking maybe you could take the bust battery and like you said use some kind of step down and psu connected to the battery side of the battery's chip thing so that it would provide the right power to the device.
rexzooly said:
I was thinking maybe you could take the bust battery and like you said use some kind of step down and psu connected to the battery side of the battery's chip thing so that it would provide the right power to the device.
Click to expand...
Click to collapse
That's a very clever idea. Unfortunately, I don't have currently any old smartphone to try it. In case you try it, be cautious not to short the lithium battery. They can be very dangerous. In case it vents, the gases are very dangerous if inhaled. There's also the risk of fire.