Related
(Yes I mention android development but this is regarding a 'general' topic)
As an android app developer, it's pretty much mandatory that I have my devices plugged into the computer for ADB. However, with wifi / bluetooth / GPS / screen brightness turned on or cranked up, I also need to have the device plugged into something that provides more than the measly 500mA that the computer's USB port can provide. From what I've been able to gather, the USB standard requires that USB hubs and ports cannot supply more than 500mA to a connected device. However, I suspect that there are manufacturers out there that are aware of the need for simultaneous charging + connectivity and have made special cables specifically for this (What I'm thinking of is a Y usb cable where one end plugs into the device, one plugs into the computer and only uses the data wires, and the other plugs into the charger which feeds and charges the device.) Do any of you know if something like this exists and where I can find one? I've definitely tried to Google for it but the phrases I'm using are long and not producing the right results. I obviously don't know the correct term(s) to search for.
If I knew a bit more about circuitry in general and the USB standard specifically, I could probably solder together a cable like this with a couple diodes to prevent the charger from zapping the motherboard's USB, or perhaps, as mentioned, not connect the power wires at all. I do have 6-8 spare cables laying around but I'd rather not start chopping and black-taping unless I get some confirmation Plus I only have one female end to mangle, so... yeah ;p
My idea for the splice & solder (in case no commercially available alternative exists):
Code:
computer - 2 data -----\
|----------------- device
charger - 2 power -----/
Most chargers and phones have some kind of regulator circuit built-in anyway, at least that's the impression I'm under. Generally if you crack open a charger there are only two cables black and red (+/-) which makes things considerably easier but that's assuming you have a charger that's just for charging and not one that requires you already have a usb cable to plug into it (like some that come with phones now). Standard wiring color schemes applied to all the cables I've cut open and spliced so as long as you go black/black red/red from the charger and leave the other wires untouched you should be ok. You'll know if something's wrong quickly because your phone will get quite a bit hotter than normal and do so faster, and you shouldn't need to add any components as they're already in the charger circuit (diodes to prevent current flow-back, resistors and the transformer to convert to dc, capacitors to smooth the current, etc). Just use common sense when working with this, don't solder until you test, don't splice wires together that don't seem right, use a multimeter to make sure you're getting the proper wires, don't work on anything while it's live unless you're properly insulated and even then not if you can help it, all that jazz.
Yeah, my biggest concern would be that I was told that some USB devices negotiate current requirements with the motherboard, which I'd assume goes over the two data wires, but I remember landline phones have 2 wires but both power and data flow over it, so I wasn't completely confident that the two power wires weren't passing data as well. If I run the 2 data to the computer and the 2 power to the charger, and it turns out that the negotiation requires all 4 wires be connected from the device to the computer, then I've just ruined two good cables.
I just am not so super confident in my logic and theorizing that I'd want to risk frying circuitry If I can nab a commercially available accessory that does this for $30 it's a lot less than having to buy another $700 device and a new $200 motherboard (at the least)
I don't think you really have to worry, but I wouldn't replace the charger wires, I'd connect the wires from the charger to the power lines inside the usb cable that way even when the charger isn't plugged in the phone is still getting some power and it'd basically be hooking them up in parallel when the usb and charger are plugged in. You could always go buy a $20/$30 cheapo phone that connects through microusb-to-usb and test the cable on that through a USB hub. that way if something goes wrong you're only losing a cheapo phone and a usb hub, but honestly things shouldn't fry as long as you get the wiring right and don't try to do something like black to red because then you're feeding power from the charger back into the usb socket which is where things get ugly.
I think i've found something on the interwebs, that will actually save you the wire-splicing and soldering
It is actually just what you described, it uses 2 USB ports in order to provide 1000mA to a device.
dealextreme.com/p/cable-style-dual-power-1000ma-usb-2-0-4-port-hub-13526
Sorry for the inconvience with the url, atm i'm not yet allowed to post links directly... :/
Xadro said:
I think i've found something on the interwebs, that will actually save you the wire-splicing and soldering
It is actually just what you described, it uses 2 USB ports in order to provide 1000mA to a device.
dealextreme.com/p/cable-style-dual-power-1000ma-usb-2-0-4-port-hub-13526
Sorry for the inconvience with the url, atm i'm not yet allowed to post links directly... :/
Click to expand...
Click to collapse
I know that some of the smaller usb external drives have a cable that has 2 "type-a" connectorsto allow data connection/enough power for the drive. I have not seen these in micro-usb form, only mini-usb. SO, I do not see why it would not work.
papabear said:
I know that some of the smaller usb external drives have a cable that has 2 "type-a" connectorsto allow data connection/enough power for the drive. I have not seen these in micro-usb form, only mini-usb. SO, I do not see why it would not work.
Click to expand...
Click to collapse
Agreed, USB offers about 2.5v of charge aswell as data connectivity of course, I don't understand why it wouldn't work... I can tell you from experence through that it does take about 40% longer, and will suck the life out of a laptop if you are using it on battery mode.
The reason I was thinking about cutting the power wires from the computer entirely is I don't know what dumping 1-2 amps into the computer's USB port is going to do ;p
Edit: Looks like newegg.com/Product/Product.aspx?Item=N82E16817707145&cm_re=2a_output_usb-_-17-707-145-_-Product should do what I'm interested in, if the details are legitimate. Who knew finding a hub with full details would be so hard? ><
LycaonX said:
The reason I was thinking about cutting the power wires from the computer entirely is I don't know what dumping 1-2 amps into the computer's USB port is going to do ;p
Edit: Looks like newegg.com/Product/Product.aspx?Item=N82E16817707145&cm_re=2a_output_usb-_-17-707-145-_-Product should do what I'm interested in, if the details are legitimate. Who knew finding a hub with full details would be so hard? ><
Click to expand...
Click to collapse
just as papabear already said, there are also external hdd, that use this kind of wire.. so it should be no problem. If the ports arent't capable of delivering that power (but as far as i know they are designed for 500mA each), simply you will not get the the full 1 A.
And i must agree, hardware vendors rarely add detailed power info -.-
OK so I need help clearing up some things about charging my phone. I have searched forums and google and I keep finding conflicting responses. I figured XDA may have plenty of knowledgeable people to clear things up. Here is what I think is correct. Please correct me if I'm wrong. I want to find a faster way to charge my phone.
USB data cables (with the exception of some that come from our phone manufacturers) are limited to 500mA because the data pins limit the current that goes through regardless of the rating of the wall adapter.
Example: you have a 1A AC adapter but your phone is only drawing 500mA when charging because you are using a data cable.
Charging cables have the data pins shorted (or missing) and will charge your phone at whatever mA the AC (or DC) adapter is rated at.
Your phone will also have a built in regulator to draw a certain amount of mA's regardless of what the adapter/cable are rated at.
Keeping all these things in mind, I have an AC adapter rated at 5V (standard for these phones) and 2.1A (2100 mA), and my factory samsung micro usb cable that is capable of data transfer as well. Since it is used for data transfer as well I wanted to buy a charging usb cable (with the data pins missing). My theory is this will remove all bottlenecks for charging speed and let the phone's battery pull what it needs, uninhibited by the usb cable and with more than enough current to keep a fast charging rate even when the phone is being used (light usage of course, I dont want to overheat the battery).
If anyone knows about this please clear things up for me, this would make it so much less inconvenient to give my phone a quick charge when needed.
This is my understanding, i might be incorrect:
The 500mA limit doesn't come from the cable but from the mainboard usb specifications.
USB2 can deliver upto 500mA, USB3 upto 900mA.
The different between the "charging" and "data" cables are most likely missing pines, but this has no influence on the current delivered via the cable.
I believe the phones uses the missing connections on a "charge" cable to detect it as charging from an outlet instead of a computer.
I would find it interesting to know if the phones charging routines differ depending on which power source, it thinks, it is connected to.
Probably some typos, but i'm tired ;-).
I guess only thing left to do is buy the usb cable without the data pins and see if it makes a difference. I'll post the results here.
Sent from my rooted GameBoy Color
As Dark3n stated, the limitation is with the USB port capabilities.
Ok you said you want to know the fastest way to charge. The fastest is with the phone off of couse. 2nd. Having a phone in airplane mode will charge fast.
Sent From Space Using My ICS Flavored Sensation
Ohh ok took a while to understand what he meant. Makes sense, thanks all this clears it up
Sent from my rooted GameBoy Color
The fastest method is to have a second battery and an external charger. A battery is much more portable than a charger if you are just out for a day, and if you are traveling, the extra battery & it's charger are not much more bulk than the phone charger alone. I go this route whenever possible as the benefits are inestimable.
With the advent of the S4, and its higher capacity battery, one could understand a higher charging current. However, I seem to have uncovered some findings that the charging system on the S4 is a bit more complex than first thought!
This is a bit techy, and assumes you have a basic amount of electrical knowledge, ie voltages, currents, resistance etc., but I'll try and keep it as simple as possible for anyone who may not!
To explain: The mains charger supplied with the S4 is a model number ETA-U90UWE, rated 5V @ 2A. However, the phone will ONLY charge at full current (which as I have measured so far, depending on what the phone regulates it to, typically sits in the region of 1.2 - 1.5A), when using the supplied charger (or possibly one of equal or higher current rating, depending on how it's configured internally), AND the supplied usb cable, OR any other usb cable, provided its shielding (the metal outer surface of the connectors) is connected at BOTH ends of the cable. Use a cable that doesn't have this shielding, and the charge current drops, regardless of whether there is plenty of current available or not. Use a different charger with an unshielded cable and the current drops even more, again regardless of whether it can supply plenty more current.
My assumption on this, is possibly an effort by Samsung to avoid the scenario of sticking 1.5 amps down a flimsy cheapo cable, the wires of which will likely be too thin to carry it.
After doing some probing around with a meter, I have managed to find a slight difference with the charger itself, compared to a generic one. In a generic one, the two data pins are usually just shorted together, which tells most phones that it's a mains charger rather than a USB port. On the Samsung one on the other hand, the pins appear to be shorted together, and also connected via resistors across the supply line (known as a potential divider), which holds these shorted data pins at a certain voltage. This is what tells the phone what sort of charger it's connected to.
Attached are a couple of diagrams to show the difference between the two chargers. There are in fact various setups of resistors that different manufacturers use to set the charging current, so it's quite easy to run into compatibility issues!
To make this a little less confusing I have done some preliminary experimenting, and I set out my results here.
For the test, I used combinations of 4 different usb style mains chargers: an apple iPhone one rated at 1A, an iPad one rated 2.4A, an HTC 1A one, and the genuine S4 one. With these I used two cables - the supplied Samsung S4 one (which is shielded), and a cheap generic one (which isn't). I started by measured the charging current directly with a meter, by using a very short usb breakout lead I've made, enabling me to interrupt the 5V line. However, I soon noticed that the use of any extension cables, even shielded, can lessen the chance of maintaining a good shielding connection, so I continued the exercise relying on the "galaxy charging current" app to get a reading.
Charger.................... Cable................ Current (A)
=====================================
HTC 1A.................Generic..................... 0.5
HTC 1A.................Samsung S4..............1.0
Apple 1A...............Generic......................0.5
Apple 1A...............Samsung S4..............1.0
Apple 2.4A............Generic......................0.6
Apple 2.4A............Samsung S4..............1.3
Samsung S4.........Generic...................... 0.8
Samsung S4.........Samsung S4...............1.3
So as you can see from these results, the original charger makes a difference, and the supplied cable (or a good quality shielded one) makes a further difference. If you have any further findings please feel free to add them here.
I can see that this is going to confuse some people, as it has me, as I'm sure some will inevitably try charging up their phone on generic chargers/leads at some point, with potentially long charging times resulting!
.
Very nice findings! Thanks for sharing them.
Not only what you say about longer charging time, but also discharging may occur (it has with me) while connected to the USB. I left my phone with USB tethering and it shut itself down after a couple of hours (it was low on battery already). I wanted to keep all the accessories in "new condition" in case I sell the phone in a few months, but I guess this justifies using the official charger and usb lead.
I hope someone can shed some light on the detection mechanism or the particular characteristics of the official cable so it can be replicated in generic ones.
From your findings, also Appe 2,4A charger has some control on the cable used, thanks.
Yes, but you won't be able to get more than about 0.75A out of it even with the samsung s4 cable.
You could try to add an extension cable to check if the charging system needs exclusively an original samsung cable from the charger to the phone.
Original samsung charger => extension cable male/female => original samsung cable => phone
PS: is there an app to check the charging current?
My experiments used an extension cable, that's the one I made into a breakout cable. So no it doesn't change by adding a cable.
There is an app, called galaxy charging current, which I tried also. In the 0.75A results above it showed a max permissible current of 1000mA, with the fully samsung setup it showed 1900mA. In the lower scenarios is showed up as 460mA. Other than that it doesn't tell you anything, it literally just shows you a max possible current, not the actual current it's drawing.
I've found out what the issue was, my generic cable was obviously a cheap one and wasn't shielded! I have edited my original post to re-explain.
Also I did a further test on a PC usb port - the Samsung cable allowed for 500mA, but the unshielded cheap one only allowed about 350mA, so (as pintycar found out), the phone actually carries on discharging in this case!
Interesting post.
I've been trying to mod a car charger so that the s4 draws more than 300mA so far unsucessful. I'm going to add in the 82K resistance and see what happens.
demusss said:
Interesting post.
I've been trying to mod a car charger so that the s4 draws more than 300mA so far unsucessful. I'm going to add in the 82K resistance and see what happens.
Click to expand...
Click to collapse
Hi,
Using a 5a digital bench power supply, I took a normal micro USB cable, cut it in two, added in the 82k resistors and tested.
Before: 450ma, after 1.73a
Then using a clamp meter I tested it with a 2amp Asus tablet charger - it varied between 1.48 and 1.61 amp.
I have since built a few more cables - one to use in my car (again 2 amp charger).
All in all, it works very effectively. Thanks for the initial research (saved me having to open my charger.)
BTW I suspect it is the charger where the resistors are, not the cable, otherwise the phone would try to pull 1.5a + from a laptop if you connected it.
Left my samsung cable at work so will test it tomorrow (if I remember)!
W.
Interesting. So basically for us laymen, you are telling us to use the original charger and cables to the extent possible ... right?
Can you clarify to me what an unshielded cable is? Maybe with a picture? I've got a blackberry's cable at work connected to my PC.
At home, I also have a cable and charger that I got with my Nexus S (I think this says Output 5.0V ~ 0.7A).
Would this be a problem or can I get by with these?
Thanks
I've been using the Samsung cable+charger+USB extension cable and charging the S4 usually takes about 4 hours, I'm going to try with just the Samsung cable next time and see if it makes any difference since people are saying that theirs can be fully charged within less than 3 hours.
Paparasee said:
Interesting. So basically for us laymen, you are telling us to use the original charger and cables to the extent possible ... right?
Can you clarify to me what an unshielded cable is? Maybe with a picture? I've got a blackberry's cable at work connected to my PC.
At home, I also have a cable and charger that I got with my Nexus S (I think this says Output 5.0V ~ 0.7A).
Would this be a problem or can I get by with these?
Thanks
Click to expand...
Click to collapse
Hi,
I believe (guess work here ) that only the original charger "needs" a shielded cable - could be checked by shorting the ground and shield on one side and see if it works at the higher current - if I am bored I may do it - it probably checks the shield and limits the current if it is not there (note I have not tested this so only going by the first posters findings).
BTW a shielded cable has a wire mesh around the 4 internal cables - this mesh avoids external interference messing with the signals. Can't see it affecting the charging though BUT shielded cables tend to have thicker internal cables so could be related to this.
I have it charging at 1.7a on an unshielded cable (thought he power strands are thicker than average) Shielding should only affect the data transfer speed, not the charging current.
If the Nexus S has only a 700mah charger then this will not be able to provide enough current for high speed charging and could easily burn out - nice smell, dead charger, not much else. therefore only use a normal unmodified usb cable (and it will charge at about 450mah).
W.
all this would eexplian why the charger that camewith my S2 dosen't appear to charge my phone fully over night...
For what it's worth I'm charging with a Note 1 charger...a thick shielded cable via the S3 docking station....and getting 900mah...
will get my original cable tonight and have a go tomorrow...
interesting read, my s4 lead and charger are still in the box and I'm using my nexus 10 ones phone charged from about 30% to full in just over 2. may have to change the old HTC £2 lead I've got connected to my works pc then, maybe why it's struggling to charge when playing music. guess this is one way to get people to buy more expensive cables
Very interesting read, thanks TS.
My original charger and cable set is still in the box; I've been using my Mom's old Galaxy Note charger.
I'll try the original cable + wall mount and see how fast it is compared to my current charger.
wmccann2 said:
Using a 5a digital bench power supply, I took a normal micro USB cable, cut it in two, added in the 82k resistors and tested.
Click to expand...
Click to collapse
Can you show me your final cable with a pic? Thanks
After this thread I have stopped using my blackberry bold cable to charge s4 and of course the cheap one too.. thanks op!
Sent from my GT-I9500 using xda app-developers app
I'm not sure if shielded vs. unshielded is the difference - probably wire gauge is the difference.
For example, if you shop at Monoprice, you have two options for USB cables: 28 gauge cables, and 24/28 gauge cables.
For wire gauge, lower is larger - the 24/28 gauge cables have thicker wires for the + and GND lines. A pure 28 gauge cable is likely to drop voltage a bit at high currents, and my observations have been that most newer devices, ESPECIALLY Qualcomm-based ones, are VERY finicky when it comes to input voltage drops.
As to the charger itself:
Apple chargers are almost guaranteed not to charge at full current, as they don't conform at all to the USB battery charging standard. Some newer Android devices do have at least partial detection of Apple chargers, so they may charge at 1A if an Apple charger is detected (any Apple charge, even 2.1A ones).
It sounds like the included official charger is a tablet-compatible one. Samsung tablets expect D+ and D- to be held by the charger at 1.2 or 1.8 volts (I forget which). As a result, Samsung tablets will not charge from standard chargers (like an N7 charger), but standard devices (like an N7) will charge from Samsung tablet chargers.
Now, the question is: Does the GS4 *require* a Samsung tablet-style charger, or did Samsung just include a tablet-style charger because it's backwards-compatible with standard devices? (less part numbers to track in inventory).
A useful pair of points would be: Using the same cable, does the Samsung charger behave significantly different from a Nexus 7 charger?
wmccann2 said:
Hi,
Using a 5a digital bench power supply, I took a normal micro USB cable, cut it in two, added in the 82k resistors and tested.
Before: 450ma, after 1.73a
Then using a clamp meter I tested it with a 2amp Asus tablet charger - it varied between 1.48 and 1.61 amp.
I have since built a few more cables - one to use in my car (again 2 amp charger).
All in all, it works very effectively. Thanks for the initial research (saved me having to open my charger.)
BTW I suspect it is the charger where the resistors are, not the cable, otherwise the phone would try to pull 1.5a + from a laptop if you connected it.
Left my samsung cable at work so will test it tomorrow (if I remember)!
W.
Click to expand...
Click to collapse
I missed this post on my first read-through: What happens if you just short D+ and D- when using the bench supply?
Hi,
After my battery went from full to empty in less than two hours when using a sat nav app yesterday, I need an in-car charger for the dashboard. I have a micro USB one but the flap on the Z3 makes it annoying. So I was wondering if there were any good magnetic adapters?
I have a 2A USB charger for the lighter socket, so I only need either a USB-magnetic cable, or an adapter that will take a micro USB. Ideally one that exits at the bottom of the phone so it can be routed neatly, rather than sideways which will then need to bend round.
Anyone have any recommendations? How about some pics of how you're set up in your car? (I have an airframe+ vent mount coming today)
the X2 magnetic charger (which just clips on any usb cable) on amazon has great reviews, depending on your case or mount you might have to shave off some of the adapter
proclip / brodit (depending on where you are in the world) offers great magnetic mounts and chargers, some need to be professionally installed, however its been stated in reviews that they fit tight so they might not work with cases, especially bulky ones and they have been known to peel up tempered glass screen protectors
I am in the same boat as you, I want a magnetic charging mount for my car and I spent a few hours tuesday researching options to no joy :|
I've used brodit mounts before but I wanted something a little more discreet than a hardwired solution - which is why I went for the Kenu Airframe+
The X2 seems to get good reviews but I'm not sure if it would be frustrating that the cable would come out sideways (as the phone would most likely be in landscape mode). Although many of the satnav apps I'm trying actually work pretty well in portrait..
if you got it horizontal the cable would be out the top or bottom yeah?
I usually keep mine in portrait
you use waze?
probably would be coming out of the bottom of the phone if in landscape.
don't know what I'm using yet - I have about 8 apps installed and I'm trying them out. Some have demo routes which is helpful, but some need me to use them while I'm driving to test so it'll take a while to settle on one.
I quite like tom tom's look and feel as I'm familiar with their standalone devices, and copilot seems good too. Haven't tried waze or google maps navigation yet, they're next.
yeah waze is killer, my CO recommended it and ive been hooked since
Its 95% effective when spotting speed traps and errs on the side of caution (sometimes cops wont be there, moved along, already pulled someone over), gives reports on potholes, construction ahead, real time traffic, speed traps, stopped cars, etc. its amazing, my friends and I are blown away.
its only difficulty is when you don't give it a direct address, it can have troubles searching for a restaurant or some such but if you have the street name you're set
mgiraudjr said:
the X2 magnetic charger (which just clips on any usb cable) on amazon has great reviews, depending on your case or mount you might have to shave off some of the adapter
proclip / brodit (depending on where you are in the world) offers great magnetic mounts and chargers, some need to be professionally installed, however its been stated in reviews that they fit tight so they might not work with cases, especially bulky ones and they have been known to peel up tempered glass screen protectors
I am in the same boat as you, I want a magnetic charging mount for my car and I spent a few hours tuesday researching options to no joy :|
Click to expand...
Click to collapse
I have an X2 adapter, it's great, BUT it is not strong enough to be secure when under the device. The torque of the cable will cause it to come off when above the device too.
Using a thinner-gauge cbale might help, but then the voltage drop will be too great to keep the battery from discharging.
My personal favorite has been:
Right-angle MicroUSB (this makes a HUGE difference in convenience on the Sony devices, since the cable goes to the right instead of straight down from the mount) - http://www.amazon.com/StarTech-com-Micro-USB-Cable-UUSBHAUB3RA/dp/B001AR4NC8/
Quick charge 2.0 car charger - http://www.amazon.com/Powermod-Charge-Certified--Vehicle-Charger/dp/B00P9UILUM/ - The StarTech cables are fairly thin gauge, so drop too much voltage when charging at 5v/2A to keep the phone charged during Navigation. QC2.0 chargers supply the Z3 with 9v, so the same wattage requires less current, and hence less voltage drop through the cable. (same reason long-distance power lines run in the hundreds of kilovolts...)
Does quick charge work through the magnetic port, or you mean you use the USB Port?
rplumb said:
Does quick charge work through the magnetic port, or you mean you use the USB Port?
Click to expand...
Click to collapse
I use the USB port, the magnetic port is too unreliable for a vehicle. The thin-gauge right-angle cables make using the USB port MUCH less of a hassle, but they need QC2.0 for proper charging through such a thin cable. (too much voltage drop for high-power standard-voltage charging)
I am looking into purchasing a Magnetic USB C charger adapter like the ones in the links below.
has anyone had any exposure to using these on their honor 8 or other phones?
is it a waste of my money or a good investment to preserve the charger port?
Magnetic Charger
IMO, waste of money, especially since Type C appears to be a more robust port than it's micro predecessor was. Also the cable may not handle voltage regulation properly which would result in a fried device.
Telperion said:
IMO, waste of money, especially since Type C appears to be a more robust port than it's micro predecessor was. Also the cable may not handle voltage regulation properly which would result in a fried device.
Click to expand...
Click to collapse
Good point there on the voltage issues. I'm also a little concerned on how it will function with a case on it as well.
This device seems to be built very tough.
I've had several Samsung devices in the past few years and every one of them had charger port weakness.
There are a few cons with cable such as those
1-lower charging rate
2-might not fit case cutout
3-finicky connection-it breaks away easily which is good cuz it a safety feature but attaching it is not that easy.
My experience with wsken xmini. Currently using it for tablets only as its safer for my kids. Wsken have a new rounded design that supposedly easier to connect, but still waiting for discount b4 purchasing.
I'm using exactly the same one. I really like but it this cable isn't a data cable. But I'm satisfied with the product
How are these possibly being looked at as a waste of money? Neighbor's kid running through your house and tripping over your charging cable ripping it out of the bottom of your phone leaving your phone safely still remaining on top of the table rather than crashing to the hardwood floor sounds a lot better than your phone crashing to the floor/wall.
Our phone are light enough that they will drag before it disconnects. I use it cause my niece usually yanks the tablet while it is charging.