Iam using the Dell Streak 7 as a sat nav system in the car. Ive tried to charge it up on the usb car adapter but it seems to loose its charge over time, making the D7 unusable for the purpose of a sat nav. Am i doing something wrong or is there a special usb car adapter for the job?
Thanks, David.
Does it say it's charging when plugged in?
Depending on how powerful your charger is it's likely that it's draining faster then the charger can provide. At best on my s5 it's just barely faster then the charger and the s7 needs more power then that.
Thanks for peply, yes it states it is plugged in. I came to the same conclusion. Wonder if there are any other chargers that have more juice.
diddy64 said:
Thanks for peply, yes it states it is plugged in. I came to the same conclusion. Wonder if there are any other chargers that have more juice.
Click to expand...
Click to collapse
There are several that will do the job. Just look for specs that include putting out 5.5 volts and 2 amps. Several of the chargers that are made for the iPad2 will work. And you may want to install a lighter adapter that you can wire directly to the battery that will allow up to 2 or 3 amps from each port
Most standard USB ports do not put out enough power to charge the DS7. The best bet is to use a inverter that plugs into your cigarette lighter and then plug the charger into that, not just the USB cable.
http://www.amazon.com/Power-Inverter-Charger-Portable-SmartPhones/dp/B00144KS6W
I use this setup:
Bestek Adapter
Trans4m lighter adapter
The Bestek I have wired to the battery so I have no fuse problems with lighter, and with that I can charge either my iPad2 or my Streak7, IF I need to charge both, then I plug the Transform adapter into the Bestek and can then charge BOTH devices, the Ipad2 AND the Streak7 and a couple of other things if need be
Thank you guys, this gives me alot of hope. Once again you all get my thanks.
Cheers,
David.
Yea, like they previously stated not all chargers are created equal.
Unless it states it's a tablet/ipad charger you cant assume it's doing 2+ amps. Most phone/lower end ones can only do 500mA/1A.
Realistically you'd prob need at least 2 amps to get a net gain while using gps/anything demanding. But I dont know if it would even try and draw above that if given the chance. [email protected] is what the bundled wall charger does and can accept up to 5.5v (as it's still within the +/-10% tolerence of the usb spec, but just barely)
My fully charged stock S7 WiFi running 514 draws only 45-70mA. Maybe starting fully charged would help?
wptski said:
My fully charged stock S7 WiFi running 514 draws only 45-70mA. Maybe starting fully charged would help?
Click to expand...
Click to collapse
I don't know anything about how it works, but I imagine tablets are wired to know when they are receiving the correct amount of input. For instance, if you connect your Streak 7 to a powered USB hub that only puts out 5 volts, it won't charge nor will it charge when connect via usb to the PC, it has to be receiving 5.5 volts and 2 amps before it will let itself receive charge. I have an iPad that is the same way and have noticed all the tablets I have had my hands on are the same, Galaxy Tabs, Transformers, Xoom... all those have to receive higher numbers to charge. So you have to have a cigarrette lighter adapter that puts that out, if it's for a cell phone it won't do anything for it
cdzo72 said:
I don't know anything about how it works, but I imagine tablets are wired to know when they are receiving the correct amount of input. For instance, if you connect your Streak 7 to a powered USB hub that only puts out 5 volts, it won't charge nor will it charge when connect via usb to the PC, it has to be receiving 5.5 volts and 2 amps before it will let itself receive charge. I have an iPad that is the same way and have noticed all the tablets I have had my hands on are the same, Galaxy Tabs, Transformers, Xoom... all those have to receive higher numbers to charge. So you have to have a cigarrette lighter adapter that puts that out, if it's for a cell phone it won't do anything for it
Click to expand...
Click to collapse
The voltage is constant but current isn't. It won't know how much current is available unless it asks for it. It's like a 2A fuse, you can draw up to 2A, no more.
Even with a fully charged battery it'll show charging at 98% for a short time and that's when I saw the higher 70mA but I'm not sure if it's in the CC or CV part of a Li-Ion charge cycle but I'd guess CV because it's less than 100mA.
My bad thinking measuring AC input current instead of DC current since this thread is about USB power.
Used a cheap ReTrak USB extension cord that loses connections to seperate the wire to measure DC current. My fully charged S7 showing 100% charge still draws 150mA after hours of being plugged in. Since Li-Ion cells normally don't use a constant trickle charge, I "assume" something draws on the battery all the time along with the indicator light and buttons.
Booting up it draws a little over 1A, fully charged while booted up, it draws around 600mA. While charging and powered up, it draws 914mA. Charging while off, it draws 1160mA. Far from 2A.
wptski said:
My bad thinking measuring AC input current instead of DC current since this thread is about USB power.
Used a cheap ReTrak USB extension cord that loses connections to seperate the wire to measure DC current. My fully charged S7 showing 100% charge still draws 150mA after hours of being plugged in. Since Li-Ion cells normally don't use a constant trickle charge, I "assume" something draws on the battery all the time along with the indicator light and buttons.
Booting up it draws a little over 1A, fully charged while booted up, it draws around 600mA. While charging and powered up, it draws 914mA. Charging while off, it draws 1160mA. Far from 2A.
Click to expand...
Click to collapse
I understand that, but you are missing the point, if the internal wiring of these tablets don't receive the 2A they want they WILL NOT even begin to charge. I tried literally dozens of chargers when I first got my S7, spent a couple hundred bucks actually, and none of the chargers not meant for larger devices won't work, and what those chargers all had in common, 2A output
The S7 can and will draw off low capacity ports, it just wont admit to charging unless it's at least 1A as it's just that.
I've had my S7 charge off a 500mA port on my pc at the rate of like 1%/hour while sleeping. As it's barely gaining even while idleing it's not really charging in the literal sense, but it's definitely charging in the technical sense.
Are your data lines shorted together? I believe most high draw devices wont attempt to pull 2A unless it detects that it's on a high draw charger (which I think do this to indicate it as such)
cdzo72 said:
I understand that, but you are missing the point, if the internal wiring of these tablets don't receive the 2A they want they WILL NOT even begin to charge. I tried literally dozens of chargers when I first got my S7, spent a couple hundred bucks actually, and none of the chargers not meant for larger devices won't work, and what those chargers all had in common, 2A output
Click to expand...
Click to collapse
I don't know why your various chargers didn't work but it doesn't seem to be because of current. It didn't charge at 2A or even close to that.
If what your saying correct, why was I able to charge at less than 2A then? Could this be a ROM issue? I only had Froyo for a few hours but I've read that it didn't support USB charging which came with HC but it only charges with the S7 OFF.
It's possible that the demand went higher and I just didn't see on my current clamp meter. I'll have to try a current clamp and a scope to see if I missed a peak level.
Also what we are refering to as the charger might not be a charger but only a power supply and the actual charging circuit is in the S7.
I did notice one odd thing though. The green LED lights up at around 90% battery level and it's still charging. I downloaded a battery app which read the same level.
wptski said:
I don't know why your various chargers didn't work but it doesn't seem to be because of current. It didn't charge at 2A or even close to that.
If what your saying correct, why was I able to charge at less than 2A then? Could this be a ROM issue? I only had Froyo for a few hours but I've read that it didn't support USB charging which came with HC but it only charges with the S7 OFF.
It's possible that the demand went higher and I just didn't see on my current clamp meter. I'll have to try a current clamp and a scope to see if I missed a peak level.
Also what we are refering to as the charger might not be a charger but only a power supply and the actual charging circuit is in the S7.
I did notice one odd thing though. The green LED lights up at around 90% battery level and it's still charging. I downloaded a battery app which read the same level.
Click to expand...
Click to collapse
You were able to charge because your charger was CAPABLE of outputting 2A at least... try charging with one that CAN'T put that out and you should find that the Streak will not charge, on ANY ROM has been my experience, custom or stock
cdzo72 said:
You were able to charge because your charger was CAPABLE of outputting 2A at least... try charging with one that CAN'T put that out and you should find that the Streak will not charge, on ANY ROM has been my experience, custom or stock
Click to expand...
Click to collapse
Capable is the magic word here. The wall wart isn't putting out 2A from what I've seen, unless it does for a split second at the start which I'm going to look into.
Most wall warts at whatever their rating is put out a higher voltage with no load and slightly higher than its marked voltage under a load. If it required [email protected] max., you used a [email protected], S7 needs more current, the voltage would decrease. What's been stated here might be that the voltage was being pulled down and that's why the S7 wouldn't charge, not "really" the 2A issue.
I have a battery pack/cell load testing device used on RC stuff that connects via USB port for its graphic software. There were issues with certain Dell laptops that had a low voltage at their USB ports.
Maybe starting fully charged would help?
I have the OEM T-Mobile car charger and I've found that if I have a full charge before plugging the Streak into the charger it maintains a full charge for as long as I'm driving/using it. Otherwise, with a less than full charge I've watched it slowly discharge even though it's plugged in and is charging.
FYI: I also have a top of the line car charger for an iPad2 that charges the iPad no matter what charge level I plug it in. This iPad charger has a USB port which I have plugged the Streak USB cord into and it also doesn't keep up with the Streak's discharge if the Streak isn't a full charge to begin with. Kind of strange because I would think the iPad would draw more than a Streak. (the iPad isn't plugged in at the same time the Streak is charging)
DCoop said:
Maybe starting fully charged would help?
I have the OEM T-Mobile car charger and I've found that if I have a full charge before plugging the Streak into the charger it maintains a full charge for as long as I'm driving/using it. Otherwise, with a less than full charge I've watched it slowly discharge even though it's plugged in and is charging.
FYI: I also have a top of the line car charger for an iPad2 that charges the iPad no matter what charge level I plug it in. This iPad charger has a USB port which I have plugged the Streak USB cord into and it also doesn't keep up with the Streak's discharge if the Streak isn't a full charge to begin with. Kind of strange because I would think the iPad would draw more than a Streak. (the iPad isn't plugged in at the same time the Streak is charging)
Click to expand...
Click to collapse
The S7 must run some check before it tries to charge . Whatever it is the OEM supplied power supply passes the test.
What's the specs on your two power supplies?
Just remember if you dont have the same 2A for charging in the car. You cannot charge the streak while its TURNED ON. Same with USB charging, just turn the streak OFF, then charge. It will work. =)
Otherwise, Id get a DC to AC converter for the car, plug in your normal adapter.
Related
I'm having problems with kaiser charging when using HSDPA and even slow connections like 3G and EDGE.
Problem is that it charges for about 20-30 minutes (connected to a powered 1Amp USB hub or even with AC charger), then charging light goes off and battery power starts to drop by about 5% every 20-30 minutes.
Have anyone tried 2Amp chargers? It seems like it may be the problem with kaiser itself, since it charges itself but then just stops and will not charge itself until I soft-reset it.
PS: it gets kinda warm, but I wouldn't call it hot. Dunno if its related to temperature.
Any ideas?
Am I the only one with this problem? If so, maybe I should return the phone and exchange it for a working unit?
No, I have the same problem here.
When I use my kaiser in the car (usually navigating) the orange charge light initially lights up, but after a short period goes out. When I disconect and connect the USB-cable, the light temporarily comes on again.
I am using a 1A car charger. I do notice the charger feels a bit hot when in use, so maybe the kaiser is drawing more power than allowed? I can imagine the charger overheating which causes the voltage to drop. Which probably causes the kaiser to stop using USB power. But this is all speculation.
I am planning to use a 5A voltage regulator to 'upgrade' the USB charger, and see if this solves the problem.
--After a bit more reading, I found some info about the kaiser detecting if it is connected to a charger or a USB host device, and regulating it's maximum charge power accordingly. So I will try a modified USB cable to let the kaiser know it can get 1000mA from the car charger.
It's not the USB charger. I have 2A and 3A Olympus Camera chargers that I modified to use as a USB charger. Also cheaper 1A AC chargers. I thought the Olympus chargers would be perfect, because they were high amperage, and built solidly. I had the same charge problems with the TyTn II, and an iPod Nano. They would either charge partially and then stop, or not charge right away, but the charge light would come on after awhile. But still only partially charge.
My guess is that the chargers that work may have a load added in, so that the switching regulator will turn on with any additional load from the device, and stay on. I never found any information on this, though.
What does work: The USB chargers made for any PDA phone. Apple iPod chargers. I bought an 800ma iPod charger (probably a clone). It's a small white cube, with a USB outlet, and interchangeable AC plugs. It charges the Nano, and the TyTn II OK. The Nano last for a week now, instead of 2 days. The TyTn II starts charging right away, and stays charging. So whatever the Apple USB chargers do, they do work.
A thought for the car is to get a car charger made for the iPod, and see if that may work.
To be more accurate, the iPod charger starts charging the TyTn II right away, and the charge light stays lit. I've not actually done a controlled test on it. Just charged for awhile, and verified that the charge light comes on right away, and stays on. Everything looks normal, though. I will try a more controlled test, and post the resutls.
please keep us posted. I've also contaced HTC support about this, I'm waiting the response. Once I found out I will post here.
Hopefully iys not a ksier limitation.
Test results.
Battery at
- 61%, Display off while charging
- 83% - after 70 mins of charging. Then stopped, as was going out.
Started again at:
- 88%, Display off
- 100% - after 60 mins. A little shorter, probably, as I missed when the charge light went green.
I believe the PDA will fast charge up to around 80%, and then slow charge for the remainder. That would explain why it takes 60 mins to charge from 88% to 100%.
So, the iPod charger works great for a PDA, and will start charging right away when it is connected, and it will charge to 100% full charge. It is not the PDA that is stopping the charging. It just has special requirements that only some chargers can handle, so you have to get either a charger built for a PDA, or something like the iPod charger.
So it works quite well as a general purpose charger for iPods, and for the TyTn II, and probably anything that uses a USB charger. It is small, with interchangeable AC plugs. A good travel/general purpose charger. I can bring just this, and different cables for different devices. Phone, MP3, etc.
It is labeled Input:100-240V, Output 5V 1A
Looks like:
Apple MA592LL/A iPod USB Power Adapter
Just as an aside, I have a lithium battery pack 2 7/8" x 2 1/8" x 1/2" thick. It is rated at 2400mAh, input 5V, through a built in retractable USB plug. Output is 5V 450mAh through a female USB plug. Just extend the USB male plug and plug into any USB source to charge it. It works quite well as a small portable battery pack to power/charge a PDA if using GPS steadily. It's flat, and easy to carry.
And it is quite cheap.
ttt123, thanks for your info. I guess I need to get an iPod charger then.
I seem to get a longer battery life (first step down from 100%) if I charge my MDA C4 using the supplied charger as opposed to a charge from a PC using the USB lead.
If I charge using the charger, and just use 2G, I get approx 14 hours before the first drop in the batterymeter. From the PC it happens well before 11 hours.
Is this possible or am I just imagining things?
tmohammad said:
I seem to get a longer battery life (first step down from 100%) if I charge my MDA C4 using the supplied charger as opposed to a charge from a PC using the USB lead.
If I charge using the charger, and just use 2G, I get approx 14 hours before the first drop in the batterymeter. From the PC it happens well before 11 hours.
Is this possible or am I just imagining things?
Click to expand...
Click to collapse
To get full capacity phone needs 5v 1000mA (= 1A) input, which is the charger outputs. If the PC USB output cannot pump that amount it might last shorter....
a PC's standard USB port only outputs 500mA (0.5A)
i think the supplied charger may be 2A (cant check atm), i know the official HTC Car Charger is 2A.
Cheers,
mugglesquop said:
a PC's standard USB port only outputs 500mA (0.5A)
i think the supplied charger may be 2A (cant check atm), i know the official HTC Car Charger is 2A.
Cheers,
Click to expand...
Click to collapse
My original HTC charger (Model: TC P300) outputs 5v 1A
Interesting. I'll check the HTC charger when I get home.
However, Would this not mean that it would just take longer to charge the battery?
(Analagous to having to fill a bucket of water from a 1/2" bore pipe as opposed to a 1" bore pipe).
Artyaw said:
My original HTC charger (Model: TC P300) outputs 5v 1A
Click to expand...
Click to collapse
My original HTC charger is at 5V 2A.
What I did notice is that charging form USB takes much longer than charging off the wall.
Sergio PC said:
What I did notice is that charging form USB takes much longer than charging off the wall.
Click to expand...
Click to collapse
It will do, should not effect the overall charge (as long as it is left long enough!)
tmohammad said:
(Analagous to having to fill a bucket of water from a 1/2" bore pipe as opposed to a 1" bore pipe).
Click to expand...
Click to collapse
Correct, actually water analogy is quite often used here
yes i thought that...
phone charge lasted longer with the mains charger than the usb on pc
and usb pc takes ages to charge full
So I guess we'll all be using our wall chargers now? As the charge is faster and some believe better!
Make no sense to me as to why the charge of the PCs USB cable is not as good as from the wall....
However the slow charge time bit of it makes sense
Car Charger
I have huge problem with my car charger. I use Noname USB car charger, that worked perfectly with my Trinity. Now, when i connect my Diamond it sometimes connects and disconnects the device to USB twice in two seconds and so if the battery is low message about battery fklashes in an out. SOmetimes it does not happen and the battery is charging normally. When i start IGO8 while battery is full and Diamond being charged, it sometimes LOOSES power and after couple of hours it gets out of power even when charged. Sometimes it doesnt happen and the device is charging properly, but very very slowly. When i turn device off, it charges normally. I tried two different chargers and get the same results. But none was HTC original.
It's irrelevent how the phone was charged. If the battery is full, then its full ,and it will last the same period of time irrespective of how it was charged.
Charging rates will vary depending on input current, but once the touch sensor light stays on, then the battery is full.
So I left my NC wall charger and cable in my hotel room in South Korea last weekend, and of course I am back home in TX with no way to charge besides normal microUSB, which takes forever.
Is there any source other than B&N for a high-speed (high current) charger and cable? The B&N one is like $25, which is not too bad, but I still would rather find an alternative if possible.
What you're looking for on the charger is something that's rated at 1.9A or better. Most made for the ipad are 2A. The only alternative I've made use of is a Belkin one they sell at Wallyworld for $20 bucks, (same type deal as you but I still had the cable and was still on the road). With the stock cable I get a full charge in about three hours and with a regular cable I get a full charge overnight. If I had to do it over I might have pushed my schedule a little harder and looked for a B&N so I would have ended up with a "spare" cable out of the deal.
mr72 said:
So I left my NC wall charger and cable in my hotel room in South Korea last weekend, and of course I am back home in TX with no way to charge besides normal microUSB, which takes forever.
Is there any source other than B&N for a high-speed (high current) charger and cable? The B&N one is like $25, which is not too bad, but I still would rather find an alternative if possible.
Click to expand...
Click to collapse
Bummer! I travel to S. Korea regularly in Jan/Feb and in early Aug. Team development programs with Samsung at their Cheonan S1 Training Center. Where do you travel to in S. Korea?
Where as finding an adequate charger seems easy enough, its the cable that's the problem. Has to be an official B&N cable for fast charging. A standard microUSB will charge very slowly. I've yet to find an aftermarket equivalent.
Has anyone checked out a touchpad charger? It looks like it's just a standard micro usb charge that puts out 2A. It seemed to charge my nook reasonably fast but I didn't let it get above 95% since I wasn't sure if it would hurt the battery. I'll have to do a better test to see how long it takes to charge
bitnerd said:
Has anyone checked out a touchpad charger? It looks like it's just a standard micro usb charge that puts out 2A. It seemed to charge my nook reasonably fast but I didn't let it get above 95% since I wasn't sure if it would hurt the battery. I'll have to do a better test to see how long it takes to charge
Click to expand...
Click to collapse
Here are the results of a very quick test that I just performed:
Nook Color running Mirage CM7 latest version (5/18)
Overclocked to 1100Mhz and interactiveX governer
Screen at 100% brightness
Battery Monitor Widget main graph screen displayed entire time
Logging set for every 60 seconds
Test lasted about 5min for each combination
Battery at about 70%
Nook charger & cable
- average reading of +892mA
- mV increased 3844mV to 4053mV
Touchpad cable & charger
- average reading of -335mA
- mV increased 3847mV to 3901mV
Touchpad cable & Nook charger
- average reading of -407mA
- mV increased 3847mV to 3888mV
Nook cable & Touchpad charger
- average reading of +1211mA
- mV increased 3826mV to 4081mV
So it looks like the Nook cable is the key. As long as you have a charger that puts out around 2 amps or so and the Nook cable, the Nook will fast charge. It actually charged faster on the HP charger (2.0A output vs 1.9A for the Nook charger).
I also tried a cheap data cable I had and it stated "USB charging" and the results were similar to using the HP cable but a bit lower on the mA readings.
I plan to run the test again using a high Amp car charger but I think the results will be pretty much the same.
The best combination for a super fast charge is the HP Touchpad wall charger and the Nook cable
Just call B&N, talk nice. They will either give you a new set, or set you up with an order. They gave one to me, 2 day ship too...
My cable broke last weekend. I went to a BN store, and they sell the cable without the charger for $15.
Sent from my NookColor using Tapatalk 2
I don't know about the fast charger, but the charger for a samsung cell phone (not a smart phone just a normal phone) phone will charge the nook. I've accidentally plugged it in and it worked. I've not used it for extended periods so can't speak to its long term ability to work.
joelgrice said:
[...] So it looks like the Nook cable is the key. As long as you have a charger that puts out around 2 amps or so and the Nook cable, the Nook will fast charge. It actually charged faster on the HP charger (2.0A output vs 1.9A for the Nook charger).
Click to expand...
Click to collapse
I've noticed that my NT on B&N firmware 1.4 will charge on a non-B&N charger, but that the charging status shown in settings always says "not charging". My NC on CM7.2 simply indicates it's charging. I don't know if the B&N status really matters or not, but it is finicky about the wall adapter. If/when you re-test, could you please note the battery status?
Meanwhile, I did some testing with a PowerGen 12v adapter. I was able to get the NT showing "charging (AC)" while using the 1A plug on the adapter with the B&N cable. Reading the little booklet that comes with it indicates that "some devices" can pull more than 1A off this plug, including the "HP touchpad, Kindle Fire". While charging, I did get the erratic screen issue while plugged in. With the B&N charger, the same cable didn't cause this behavior on the NT. Not sure what that means, but you basically can't use it while it charges with the adapter. The 2A plug, described as "for the iPad" shows "not charging" (but not discharging). Using a generic microUSB cable also yields "not charging".
I also tested a EZOPower 7800 mAh supplemental battery. I was able to get a NT showing "charging (AC)" while using the "S" plug, described as compatible with the Samsung P1000 (Galaxy Tab) with the B&N cable. The "I" (iPad) plug did not work. The battery itself does charge off any 1A USB source, and will charge external devices at full 2.1A power as it charges. This means you should be able to let this battery power your NC, while the EZOPower battery charges more slowly from a normal 1A USB 12 VDC or AC adapter. Once the NT is fully charged at full rate, the EZOPower battery will itself charge. There were no screen issues with this combination, and I could use the device as it charged (with the usual cautions about the fragile B&N cable, of course.)
I don't know if the distinction between "not charging" and "charging (AC)" actually means anything, but the B&N firmware seems to care, while CM doesn't.
The reason why people notice they need a stock NC cable to 'fast charge' is that While it appears at first glance to be a standard microUSB plug.... it is not. Go ahead, try and plug it into your cell phone (no, it wont hurt your phone). The NC 'microUSB' plug actually has many more pins than the standard 5 (Something up near 20 as I recall). There are the normal 5 upfront, then the rest as further back. When you plug it in to charge, one of the rear pins connects and can supply the 1.9A max charge current. That 1.9A pin is directly connected to the Power Mgmt chip and is the only way to get high current charge.
The <explicitvie delted) whole story
There are three pieces to this puzzle.
1) a high power 2amp / 2000ma USB charger
2) shorting the correct pins in the cable to let the device know it is connected to a high power charger
3) extra long 12 ping next gen micro usb cable.
Some details...
Not all 1.9 / 2amp chargers are actually 2 amps
Some are 2 x 1amp
Some are mis-represented
etc.
I have tried many...
Some are frauds
Some are designed by idiots.
Few actually work
Yes, this is a Ipad spec.
Shorting the data pins (2 to 3) is required.
Go on eBay and look up pwr+ usb filter.
This little USB type a male to female adapter
does just that
shorts the data pins
finally the cable...
There is a new type of micro USB 12 pin connector on the cable.
The other big side is standard 4 pin.
The micro connector is longer than a standard micro USB.
The are some overseas import cables that work.
A standard USB cable WILL NOT WORK.
PS:
using a standard charger and cable will work but takes 4x longer.
Charging while on will run the battery down.
Pretty much stay with genuine OEM parts.
Especially the cable.
Unless you are tech savvy.
Google 12 pin USB
You can source a good 2amp power supply.
You can use OEM Ipad chargers.
HP makes a good 2A charger. PN 157-10157
12V - Scosche big black 4" long job 2 port 2.1a + 1a
However you must short the data pins with the pwr+!
mail at lofthouse dot org
Background
Hi all, I, for a very short period of time was suffering from the problem of my phone DISCHARGING while it was charging. This made no logical sense to me until I did some research, which I will detail below.
How USB Power works (Roughly)
Firstly let's discuss USB power provisioning. Strictly speaking, the specifications say that any given USB port should provide a maximum of 500mA (or 0.5A) at 5 volts. *Don't shoot me electronics guys, I'm simplifying for ease of explanations sake*. Imagine that ampage as the actual force of the charger, how quickly it can ram power into your phone. Like the rate of flow on a pipe.
The beginning of the problem
This was all fine and dandy when all USB was really used for was Keyboards, Mice, Memory, etc, low current draw devices. Something else I should mention here is that the Ampage that a port CAN provide is not the Ampage it DOES provide - the device draws a certain Ampage and if the USB controller agrees it outputs said Ampage. Later, when USB was beginning to be used for more power hungry applications, ie External hard drives, these required more power than the port could (In theory) provide. However, most more modern motherboards/USB controllers were more than capable of supplying plenty more Ampage if it was requested. This was breaking the specification but not in any massively dangerous way so as such nothing bad happens.
This is where we get to the actual issue people are experiencing here. The Nexus 4 is a standards compliant device in the respect that it seems to only draw 500mA from any USB port no matter what it's potential, unless it's an AC Wall wart. If you're experiencing problems with wakelocks (see XDA) and other things, this causes your phone to draw more than 500mA which means your phone actually discharges while it's charging! Terrible!
This is quite easy to get around, but again I'm going into detail so let's explain how the phone tells the difference between a dumb wall wart and a USB controller. Easily! The USB controller obviously makes use of the data pins found within the USB cable, whereas a wallwart just (almost always) shorts them out. The Nexus 4 can detect this short, and as such draw more power *While still in quotation marks staying in spec*.
The root problem is not with how the N4 is charging, it's with the wakelock you're experiencing which is causing the phone to draw so much power while the screen is off. While the screen is off and the phone is in Deepsleep (A CPU state where it uses very little power) - it should draw no more than 50mA leaving 450mA for charging the battery, but you guys are probably experiencing a wakelock of some sort.
Solutions to the problem or How to break a specification for the good of mankind
The simple solution is to install this app: https://play.google.com/store/apps/details?id=com.rootuninstaller.batrsaver
This forces the device into a Deep sleep when the screen goes off by killing applications and turning off all internal chipsets that have wakelock capability, most commonly networking on the Nexus 4. This will allow your phone to charge (slowly) off USB without an issue. Another common wakelock is when the device is picked up by your desktop as a media device. The USB controller inside the Nexus 4 forces a wakelock which keeps it from charging. Stupid design, I know.
* A more hackish solution is to install Francos kernel, buy his app, and tick the Fast charging option in the kernel settings dialog. This will force the phone to think that everything is an AC adaptor and will force the phone to draw as much current as it can from the USB port (which on most modern motherboards is fine, and results in extremely quick charging).
* An even simpler solution than all this is to just use a 'USB Charging cable' - this is simply a cable that does not have the Data pins, and as such does exactly the same as what enabling USB fast charge above does. http://www.ebay.co.uk/itm/Micro-USB...487076?pt=PDA_Accessories&hash=item51a465d124
If you live near a Poundland store here in the UK they sell a 4 in one USB cable type thing which turns 1 USB port into Ipod sync connector, Nokia connector, MicroUSB and MiniUSB, and this doesn't have the data pins and as such is excellent.
One final point, an excellent app for monitoring whether your device is actually charging or not and how quickly is Current widget: https://play.google.com/store/apps/details?id=com.manor.currentwidget&hl=en
This widget will tell you how much Ampage is going into or leaving your battery. If the battery icon is green, then it's discharging, if it's black/white then it's charging. The bigger the number, the faster the discharge/charge. This is an extremely easy way to test speed of chargers too.
Recommendations
Another solution, just use an AC Wall wart - they're cheap as hell and the one supplied with the Nexus 4 is an extremely fast charging one. Shame I've gone and lost mine.
A way to roughly monitor charging current draw
I'd also recommend you install https://play.google.com/store/apps/details?id=com.manor.currentwidget&hl=en and monitor, if the battery is green while charging it's discharging and you need a more powerful charger/to figure out what's causing your phone to use so much power.
General good values in Current Widget
I generally saw a max draw of about 750mA for charging (not including draw for powering the device, the Nexus 4 can draw more power to charge and power the device) on my old Rev10 first generation Nexus 4. On my new Rev12 board I'm noticing this increase to about 850mA.
Are higher amperage chargers any benefit to anyone?
Yes and no. You will not notice faster charging unless you use your device while charging. Your nexus will draw as much power as it needs to power the phone while charging at the fastest rate. For example on the stock 1.2a charger
1200mA | 800mA goes to charging 400mA goes to powering the phone idling
Let's say you start a stability test. Your phone will obviously be using a lot more power so this will happen
1200mA | -600mA goes to charging and 1800mA goes to powering the phone stability testing
That minus value above may look strange! Let me explain. If the phone needs more power than the charger can supply, it will draw from the battery. That's the minus number.
If you have a higher ampage charger like for example a 2.5a charger
2500mA | 800mA goes to charging 400mA goes to powering the device
Stability testing
2500mA | 700mA goes to charging 1800mA goes to powering the device
Can you see the difference?
DISCLAIMER: I am not an electronics engineer nor do I claim to be, I am simply a hobbyist and this is what I've found to be the case. Please correct me if I've made any mistakes, I want to learn.
Thanks!
Thanks so much for this post. It's very helpful.
kn100 said:
Another common wakelock is when the device is picked up by your desktop as a media device. The USB controller inside the Nexus 4 forces a wakelock which keeps it from charging. Stupid design, I know.
Click to expand...
Click to collapse
This isn't true for everyone then as mine connects and charges just fine off of my laptop and desktop when connected as a media device. In fact its on my laptop right now charging, gone from 68% to 81% in about 30 minutes and it shows connected as a portable media player.
Great info! Thanks for writing this!
In certain use cases the Nexus4 discharges faster than it charges and this is a very useful guide.
I use my phone for navigation in my car and having the GPS on and the screen at high brightness
drains the battery faster than the 0.5A car chargers can supply. Car chargers rated for 2.0A work well.
I haven't tried a 'USB charging cable' with the data pins shorted, it may work as well.
-Mindroid- said:
Great info! Thanks for writing this!
In certain use cases the Nexus4 discharges faster than it charges and this is a very useful guide.
I use my phone for navigation in my car and having the GPS on and the screen at high brightness
drains the battery faster than the 0.5A car chargers can supply. Car chargers rated for 2.0A work well.
I haven't tried a 'USB charging cable' with the data pins shorted, it may work as well.
Click to expand...
Click to collapse
was over in Nexus 7 forums and the 4.2.x kernel should have solved the problem at least for having to use shorted cables. have to wait and see if 4.2.2 brings any more changes.
http://forum.xda-developers.com/showthread.php?t=1984838
Section 6 in this link is about power supplied through USB
http://en.wikipedia.org/wiki/Universal_Serial_Bus
I can't tell if we have an updated kernel allowing faster usb charging as I'm limited by the power output of the usb port in my laptop. The output (5V at 500mA max) is controlled by the laptop (USB Standards) and it doesn't matter what the phone or cable is capable of as that's the max it will give out and that's about what I'm charging at. If I had a dedicated charging port in my laptop then it would be different and I could see if its able to draw more power. I have a 1.0 amp port in my car and it does charge at the higher amperage, I would assume it would do the same thing if I had a 2 amp usb port in the car. So I think the stock kernel has the fast usb charge built in it just depends upon if you have a usb port capable of providing a faster charger, it has nothing to do with the cable as I'm using a standard unmodified micro usb cable and its able to draw the max a usb device is able to put out.
thanks
thanks for a great detailed post!!!
I have the same trouble with my N4 when I was charging while using my phone...
I find it very slow... I guess I've been spoiled by my previous iPhone (which charges fairly fast)....
i might be stating the obvious but I find the phone charged "a lot" faster when it's OFF
if you are running low with your battery and need a quick 10 min charge, just do yourself a favour by turning off your phone...
the difference is quite significant!
kzoodroid said:
This isn't true for everyone then as mine connects and charges just fine off of my laptop and desktop when connected as a media device. In fact its on my laptop right now charging, gone from 68% to 81% in about 30 minutes and it shows connected as a portable media player.
Click to expand...
Click to collapse
Yup, me too. It only discharges while charging when I am playing like NFS most wanted.
Sent from my Nexus 4 using xda app-developers app
The issue with cables is with the LG usb wall charger as the one supplied isn't capable of getting the 5 volts at 1.2 amps that the charger is rated at, mine is getting around 300 - 400 mA. The micro usb cable I have in my car and use with my laptop (for charging and data transfer) is able to handle the higher amperage, it gets around 1 amp with the LG plug. There are no specs on these cables so I can't list a definitive difference and I would assume that the cable mod in the OP might help with the LG cable. It also might just be simpler to only buy those cables capable of handling higher amperage as obviously they are out there from my experience.
The cable I'm using is an RCA coiled charging/syncing cable model AH732CBR (has data pins). The maximum I'm getting from this is about 870 mA regardless of the amperage of the usb port, I've tried a 1.0, 1.2 and 2.1 and they are all around 870 mA on current widget. I would suppose if I could find a strictly charging cable I could get higher (link to ebay in OP is outdated) but this is still 2x that which I'm getting from the LG cable supplied with the phone which only puts out 300-400 mA. Our phone also has Qualcomm's quick charge which is supposed to improve battery charging times by 40%.
http://www.droid-life.com/2013/02/1...allows-your-device-to-charge-up-to-40-faster/
How do you measure how much mA the device draw from the charger?
Sent from my Nexus 4 using Tapatalk 2
omrij said:
How do you measure how much mA the device draw from the charger?
Sent from my Nexus 4 using Tapatalk 2
Click to expand...
Click to collapse
current widget, link is in the OP
kzoodroid said:
The cable I'm using is an RCA coiled charging/syncing cable model AH732CBR (has data pins). The maximum I'm getting from this is about 870 mA regardless of the amperage of the usb port, I've tried a 1.0, 1.2 and 2.1 and they are all around 870 mA on current widget. I would suppose if I could find a strictly charging cable I could get higher (link to ebay in OP is outdated) but this is still 2x that which I'm getting from the LG cable supplied with the phone which only puts out 300-400 mA. Our phone also has Qualcomm's quick charge which is supposed to improve battery charging times by 40%.
http://www.droid-life.com/2013/02/1...allows-your-device-to-charge-up-to-40-faster/
Click to expand...
Click to collapse
Bit of a late reply but please bear in mind the Nexus will NOT draw anything more than about 800mAh from the wall for charging alone. That is the absolute max and is a hardware limit - If the cable is transmitting that and it's showing in current widget you've got a good setup. See the added section in OP for more info on higher amperage chargers.
Yesterday I've received my Tab S2 8.0". After the first charge I connected the tablet to my computer to upload some files and I get a red "X" on the battery and the message: "Slow charger connected"
In the notification area I get a constant red "Device charging slowly. To charge faster, use the original charger".
Is this normal? Cause I'm using the USB cable that came with the device and tried with USB3.0 and USB2.0 with the same results.
Oh, extra info! The tablet was bought in France, I'm from Argentina.
XinsaX said:
Yesterday I've received my Tab S2 8.0". After the first charge I connected the tablet to my computer to upload some files and I get a red "X" on the battery and the message: "Slow charger connected"
In the notification area I get a constant red "Device charging slowly. To charge faster, use the original charger".
Is this normal? Cause I'm using the USB cable that came with the device and tried with USB3.0 and USB2.0 with the same results.
Oh, extra info! The tablet was bought in France, I'm from Argentina.
Click to expand...
Click to collapse
Yes it's normal.
USB ports cannot put out as much current as a decent charger (like the one the tablet came with). Hence it charges more slowly using USB (or indeed some inferior or lower powered plug-in chargers), and it's warning you that it is doing so. I think the maximum a USB2 port can provide is about 500mA, with USB3 about 900mA or so.
Compare that to the proper plug-in charger, which is 2A (if I remember correctly).
Some motherboards etc do have higher current USB ports for charging etc, but that's non-standard and they are usually specially labelled as such.
Oh, thanks for the help. I got a little scare with the warning.
I got the same tablet, and also noticed this warning about battery charing slowly, and asking me to use original charger.
It's working resonably ok with original charger, though it charges slow with other chargers with the same AMP rating. E.g. it charges slowly with the larger iPad charger, which is also 2 AMP rated ...
Charing with iPad charger is so slow, that when I use the device with during charging, it drains faster than it charges! Quick unusual ...
Anyone? Any comments?
Theres an excellent app called Ampere which gives you info on the tablets charging and power consumption - useful and interesting.
Cant post links yet so just search for it on Play
Also don't forget that (when not built-into the charger) the cable is also important to the amount of current reaching the tablet.
The best charger in the world may well struggle if a long cable with hair-thin high resistance wiring is used to transfer the power into the tablet.
Lastly even though many chargers are labelled as 5v 2A, they may not actually be able to provide that under load, and if things drop when a hungry device like a tablet is connected then things will slow up.
I have a few 5v 2A chargers which come up as slow charging, whereas others which were more purposefully designed (e.g. the 5v 2A charger from my old Nexus 7) work just as well as the supplied Samsung one.
DarrenHill said:
Also don't forget that (when not built-into the charger) the cable is also important to the amount of current reaching the tablet.
The best charger in the world may well struggle if a long cable with hair-thin high resistance wiring is used to transfer the power into the tablet.
Lastly even though many chargers are labelled as 5v 2A, they may not actually be able to provide that under load, and if things drop when a hungry device like a tablet is connected then things will slow up.
I have a few 5v 2A chargers which come up as slow charging, whereas others which were more purposefully designed (e.g. the 5v 2A charger from my old Nexus 7) work just as well as the supplied Samsung one.
Click to expand...
Click to collapse
this is such onfortunate ongoing issue
i got my Tab S2 - SM-T715Y in Thailand as i am backpacking Asia ..
I know the warranty is per country .. so I can not use it where I am now - in Vietnam .. or back home in USA
I realized that this was a major factor before buying .. so I can go through my credit cards extended warranty ..
in the future I will buy Acer or Asus or alike that have international warranty ..
yesterday I was on a road trip
and I was using my 12V car charger
and then a battery bank .. and I think it rigered this problem or fact that I drained my S2 to 0%
fact is that now it is showing "slow charger connected" .. I am using the original charger and cable
now it is slowly *discharging* when connected to AC!!
also will try to whipe the cache..
this is so terrible
I am losing faith in Samsung :/ (had charging issues with my Note 3 .. 8 months in .. motherboard issue)
I can not find a solution to this problem
I am thinking of putting it in a refrigirator? maybe it will do something to the battery?