Not all charging methods created equal? - Epic 4G Accessories

I am really frustrated with charging my phone.
From the wall, using the stock 700mA Samsung charger, I get 5% every 10 min.
From a USB cigarette lighter charger modified to source 750mA, I get 3% every 10 min.
From a USB cigarette lighter charger that can source 3A, I get hardly anything.
I assume from these findings that one or more of the following is true:
1. The phone knows when it is plugged into a stock charger.
2. The phone has a current limiter that prevents overcharging.
Does anyone have a charger, other than stock, that they recommend?
I'm half tempted to hook my stock charger up to a cigarette lighter inverter and power it that way.
(I'm also half-tempted to grab a current probe tomorrow and measure what the device is pulling.)

i havent really used my oem samsung wall charger much, but i know when i try to charge from my computers usb it takes 4EVER, thats why i jumped on this ebay deal

IBNobody said:
(I'm also half-tempted to grab a current probe tomorrow and measure what the device is pulling.)
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I'd probe the chargers and see how accurate their ratings are as well....

does anyone know if using a 1mA charger would be okay? i have one left over from my evo.

The phone won't draw more than 500mA from a charger unless the USB data pins are connected.
Be careful, though... 99.9% of the chargers from China that claim to be 700mA (the nominal value of Samsung's) or 1A will overheat and die (or worse) if you try to actually draw that much current for any sustained length of time. I'd almost go so far as to say that it's SO EASY for a manufacturer to support high-power mode, I'd be automatically suspicious of any allegedly high power charger that doesn't ship with the pins shorted together.
Manufacturers know that most consumers don't know the difference (hell, most users HERE don't know the difference, and XDA is the upper crust elite of the Android phone universe), so they omit the shorting bridge and ship a charger with quoted power capacity that it MIGHT be able to sustain for a couple of minutes if you operated it in a walk-in freezer, knowing that most phones will never draw more than 500mA and it'll work fine for them. It lets them sell the charger for 99 cents AND pretend to be better than the others on the rack because it has a bigger "max power" value.
It's "RMS-vs-Peak" all over again.

Yeah I'm one of those that don't know much about the charging. I did figure there was a different charge rate when plugged into the wall and when plugged into usb or a usb converter like powerjolt.
I also found that one of the usb to micro's that I bought for using with my car powerjolt coverter won't let me connect via debugging/adb shell. was a little surprised at this... is it just a bad cord?

bitbang3r said:
The phone won't draw more than 500mA from a charger unless the USB data pins are connected.
Be careful, though... 99.9% of the chargers from China that claim to be 700mA (the nominal value of Samsung's) or 1A will overheat and die (or worse) if you try to actually draw that much current for any sustained length of time. I'd almost go so far as to say that it's SO EASY for a manufacturer to support high-power mode, I'd be automatically suspicious of any allegedly high power charger that doesn't ship with the pins shorted together.
Manufacturers know that most consumers don't know the difference (hell, most users HERE don't know the difference, and XDA is the upper crust elite of the Android phone universe), so they omit the shorting bridge and ship a charger with quoted power capacity that it MIGHT be able to sustain for a couple of minutes if you operated it in a walk-in freezer, knowing that most phones will never draw more than 500mA and it'll work fine for them. It lets them sell the charger for 99 cents AND pretend to be better than the others on the rack because it has a bigger "max power" value.
It's "RMS-vs-Peak" all over again.
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Click to collapse
D+ to D- must be shorted to get the high power mode? Maybe that was why my 3A supply was not handling it.

The Epic pulls 380mA when charging from a USB port from a Dell T3400 workstation. The result was steady at 40% and 80%.
I'll try out my other charging methods later and find out everything.
Stay tuned!
EDIT 1:
380mA is the magic number. It draws 380mA from all USB sources, including my two car chargers.
It draws 600mA from the wall adapter.
The wall adapter does indeed have D+ and D- shorted. My other chargers did not.
Here is the pinout for a USB port: http://pinouts.ru/Slots/USB_pinout.shtml
Here is the "beefy" USB charger I've been using:
http://www.wagan.com/index.php?page...ategory_id=22&option=com_virtuemart&Itemid=98
This charger is rather nice because the step-down supply (AX3002) has a large heatsink soldered to the ground tab.
It currently pulls up/down the D+/- lines via resistors. Each port is pulled down separately.
What I plan on doing next is to remove the pull resistors from one of the ports and short D+/- together.

Well, this explains a lot. This was really getting frustrating. I bought a "high-curent" charger for my car and the phone blows through the battery when I'm driving around with Maps running.

Im always on the road and for me an inverter in cigarette lighter with stock wall charger works best.the slowest charge is using stock usb cable since theres a slot for it on the inverter.2nd was radio shack car lighter in inverter.the inverter was from radio shack as well
Sent from my SPH-D700 using XDA App

IBNobody said:
Here is the pinout for a USB port: http://pinouts.ru/Slots/USB_pinout.shtml.
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Click to collapse
that is the official spec but there are actually not just four but six connectors on usb micro, which is how samsung can create a whole mess of pinut jumps for various amperage draws as well as data, entrainment dock and car dock.

Related

Charger Compatibility - 550mA vs. 700mA

I have older chargers for that output 5.0v / 550mA and have noticed that the Captivate outputs 5.0v / 700mA.
1. Can I safely use the older, 550mA chargers with the Captivate and what will the effect be?
2. Can I safely use the Captivate's 700mA charger with the older phones and what will the effect be?
Thanks.
1. Yes, you can use it. But it will charge slower.
2. Yes, you can use it. I believe that just because the charger output is higher amperage doesn't mean that it will affect the phone adversely. Think of it this way: A lamp is plugged into the wall outlet at your house. That outlet is rated at 120v 15A. The bulb isn't using all 15 amps, so no problem. But if you were to turn the voltage up or down, the lamp will get brighter or dimmer respectively.
The Captivate can take up to a 1A (1000 mA) charger.
Truceda said:
1. Yes, you can use it. But it will charge slower.
2. Yes, you can use it. I believe that just because the charger output is higher amperage doesn't mean that it will affect the phone adversely. Think of it this way: A lamp is plugged into the wall outlet at your house. That outlet is rated at 120v 15A. The bulb isn't using all 15 amps, so no problem. But if you were to turn the voltage up or down, the lamp will get brighter or dimmer respectively.
The Captivate can take up to a 1A (1000 mA) charger.
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Another question. You sound smart on this so how about using the nexus one car charger on this? Fits perfect and I don't see why not, but still Leary. .. what do you think?
As long as it puts out 5v, (which is USB standard), you are fine. The amperage is only relevant if the device REQUIRES it. For instance if the device draws 1A and your charger could only handle 550mA your device will charge very slowly.
On the other hand if your charger can handle 1.2A and your device only draws 700mA, then your charger will only output 700mA.
The important thing is the voltage, it needs to be 5v +/- 3% ...
I actually use a generic car charger I bought at walmart with 2 USB ports on it, and it works well for every USB powered device I own ... ZUNE, iPOD, phones etc.
OK. Thanks for the reply. I had read that a phone requiring 700mA that uses a 550mA charger could damage the charger and possibly the phone. That's what made me wonder. And that's what led to the question.
Let's make this a bit more interesting. There's a local, highly-reputable cell phone repair store that has stopped selling car chargers because, they say, the rapid charge is not good for the phone's battery. Their recommendation is to use an inverter (no, they don't sell them) so that you can then plug a standard wall charger into it or a USB cable if the inverter is so equipped. The AC current that results from utilizing the inverter is more consistent than the current flowing from a car charger. So...I purchased an inverter for less than $20 and use it to charge the Captivate in my car.
OK ... not sure we need to get this far down in the weeds on this but here goes ....
The USB2 standard for power distribution is 5v and the thresholds are 4.4-5.25V.
Power is supplied in units of 5v power ... 1 unit is 5v at 100mA, no device can draw more than 5 units from any one port. If you have ever seen a portable hard drive with 2 USB connectors it is because it requires more than 500mA to operate and by using 2 ports the device can draw up to 1A. For dedicated chargers the 4.4-5.25v still applies but shorting the D+/- and disabling the data connection allows the device to detect that it is connected to a dedicated charging port and draw a maximum of 1.8A.
In keeping with the above guidelines, when connected to your computer the Captivate can draw no more than 1 unit of power which is [email protected], when connected to a dedicated charger the phone can draw [email protected] and stay within the standard. (yes, it caps itself at 1A, I know).
OK ... the next bit is going to be hard to digest because there are plenty of examples to the contrary ... there is a standard for mobile USB chargers, and it requires wiring them as dedicated charging ports. What this means to us is that, in theory anyway, a mobile USB charger should allow a device to draw up to 1.8A from it (highly unlikely ... but that's the standard as written).
Here is the problem, if the device is plugged into a dedicated charging port and tries to draw it's maximum rated current, that amount of current may not always be available or it may fluctuate. This fluctuation is what causes problems. Have you ever turned you car stereo up real loud and seen your headlights dim in beat with the music? Same thing, the power system is being drawn down. There are a couple of ways to stabalize your power system ... install a large capacitor (mine is 2 Farad) to provide "conditioning", or go the transformer route.A tansformer provides conditioning, but only on its own outputs... while a large cap will condition the entire power system if installed correctly.
So yes, using a quick charger on your phone can cause issues if your car has a ****ty power system or a large stereo system which is not set up properly (again, ****ty power system). Make sure your charging device is within the standard, and you should be fine wether it is USB via a cigarette lighter port or a 110V transformer.
I appreciate your detailed, helpful reply.
Other than the important 5v parameter, what I've taken away from your information is that a car charger can be used in a vehicle with a power supply that is known to be stable, and that either a whole-car conditioning system or an inverter should be used on one with a, shall we say, "less than stable" power supply (PG version ).
Jack45 said:
I appreciate your detailed, helpful reply.
Other than the important 5v parameter, what I've taken away from your information is that a car charger can be used in a vehicle with a power supply that is known to be stable, and that either a whole-car conditioning system or an inverter should be used on one with a, shall we say, "less than stable" power supply (PG version ).
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Pretty much ...
There's more than one way to skin a cat, and that Transformer will cost you a whole lot less than a 2 Farad capacitor. I hate cats, but they serve a purpose.
@Battlehymn - one more question for you
I have converted from iPhone to the captivate (no haters please) - finally found a physical form factor with specs i like and the captivate rocks.
Anyway, I have some extra external batteries I used with my iphone that i want to use with my Captivate. I just bought a Female iPod connector and I am planning to connect it to a micro USB connector - the pinout is straight forward, but here is my question:
Should I connect the D+/- (short them together)? That is my plan. My batteries are 1900 or 1000 mAH - I assume that even if the phone tries to the draw 1.8A, the batteries have a circuit to only discharge so fast.

[Q] Are all USB Charges the Same?

I have about 5 Micro USB wall charger laying around, so when I got my Captivate I was happy to see that it used a Micro USB.
My question is.... Is all of the Micro USB power supplies the same? the ones i have are from different Motorola phones.
Thanks,
Coldheat1906 said:
I have about 5 Micro USB wall charger laying around, so when I got my Captivate I was happy to see that it used a Micro USB.
My question is.... Is all of the Micro USB power supplies the same? the ones i have are from different Motorola phones.
Thanks,
Click to expand...
Click to collapse
I assume you mean the wall charger. The charger and the cable are actually separate. You can plug any USB cable into this that has a female USB end. The other end could be mini, micro, ipod, or something else.
They are not all the same - the Moto charger delivers more Amps then the Captivate. Some charger deliver less. The phone will only draw what it is set to, so you can use just about all of them.
cool thanks
The short answer: It's probably fine
The long answer:
USB is a specification, so anything using usb should be designed to run at (for USB 2.0) 4.4-5.25 V. It *should* be fine for charging any microUSB device (the "U" is for "Universal") but I guess it's possible (though unlikely) that the company that made the charger did something funky/proprietary with the voltage/amperage, which would make it not USB even though it uses a USB port. See if the charger says the operating voltage/current on it. It should say around 5V and somewhere in the range of 150-900 mA. If it does, you're golden, if it doesn't say you're still probably fine.
The phone is actually quite picky about chargers. It can recognize a USB charger in either (1) AC wall charger or (2) USB charger. If your paritular charger can be recognized as AC charger, it can be charged in a faster rate if your wall charger can deliver. The Captivate comes with a 700ma wall charger. Some can deliver 1000ma or even higher but Captivate internally limits to 1000ma max from what I read. The higher the amprage, the faster it can charge the battery.
On the other hand, if your charger is recognized as USB charger, not only you will be prompted to select USB mode (if you configured to do so) as if you connect it to a PC, you will also be limited to maximum of 500ma of charging current per USB standard. It will be slower than the stock charger (which is slow already).
foxbat121 said:
The phone is actually quite picky about chargers. It can recognize a USB charger in either (1) AC wall charger or (2) USB charger. If your paritular charger can be recognized as AC charger, it can be charged in a faster rate if your wall charger can deliver. The Captivate comes with a 700ma wall charger. Some can deliver 1000ma or even higher but Captivate internally limits to 1000ma max from what I read. The higher the amprage, the faster it can charge the battery.
On the other hand, if your charger is recognized as USB charger, not only you will be prompted to select USB mode (if you configured to do so) as if you connect it to a PC, you will also be limited to maximum of 500ma of charging current per USB standard. It will be slower than the stock charger (which is slow already).
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It is not "picky" it follows the USB specifications. For instance I have a 4 port USB wall charger that is capable of supplying 5 volts at 2000 mA to one port or 5v @ 500 mA to 4 ports. Unfortunately the charger is not complex enough to know how many devices are plugged in at once and therefore always signals to all devices to only use a maximum of 500 mA. So if those devices follow the specs they will only draw 500 mA max since it is seen as a high current device (low current devices only should draw 100 mA max).
I DO NOT RECOMMEND ANYONE OPEN UP ANY ELECTRICS EVER ESPECIALLY ONES WHEN CONNECTED TO THE AC LINES IN YOUR HOMES. IT IS A FIRE AND ELECTROCUTION RISK AND I NOR ANYONE ELSE TAKE RESPONSIBILITY FOR YOUR OWN STUPIDITY.
However I hacked it by adding a resistor of proper value between the data pins so that the phone if it wanted to could use the full 2000 mA. Know whenever plugged into that USB port the phone goes into AC mode and from some rough testing during the bulk charging phase the phone charges at a rate of 40% per hour instead of the USB modes 20% per hour. With this hack it takes roughly 3 hours to fully charge since the final charging stage of lithium batteries requires the current to slowly be dialed back. Thats a lot better than the USB modes 5 hours.
icedfire101 said:
It is not "picky" it follows the USB specifications.
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I say it is picky because without hacking it will only use USB mode for most wall chargers and car chargers out there. It probably won't be any problem for a slow wall charger. But for car charger, 500ma is simply not enough if you also run GPS navigation. The phone uses more than 500ma of juice in that mode. I've to hack my car charger (a 700ma USB charger designed for iPod etc) couple times to let it reliably recognize as AC charger.
foxbat121 said:
I say it is picky because without hacking it will only use USB mode for most wall chargers and car chargers out there. It probably won't be any problem for a slow wall charger. But for car charger, 500ma is simply not enough if you also run GPS navigation. The phone uses more than 500ma of juice in that mode. I've to hack my car charger (a 700ma USB charger designed for iPod etc) couple times to let it reliably recognize as AC charger.
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Click to collapse
Again that is not "picky" it is doing what it is suppose to. What we really need are companies that will follow the USB standards and make Dedicated Charging Ports on there chargers. Most companies cheap out and only make 500 mA and 700 mA products (which that is why charging is so slow). Then they sell it to consumers that don't know any better. Especially with the 700 mA chargers since consumers will think that it is better because of the bigger number but devices that properly follow the USB spec will still only draw 500 mA. (I don't know what specifications Apple follows with their device but since a lot of those that I see with 700 mA are geared toward apples device they may be able to make use of them.) I know of no open specification for a USB device to pull 700 mA.
As to why the Samsung stock charger that came with the phone is 700 mA, I m guessing it is because of cost again. I can tell you though that it doesn't short the data lines with the proper X ohm resister for a Dedicated Charging Port. So I m thinking they made their own proprietary standard there just so they could save a few bucks on each charger but still give the consumer something to feel good about for buying there overpriced stuff.
I DO NOT RECOMMEND ANYONE OPENING UP ANY ELECTRONICS, EVER. ESPECIALLY ONES CONNECTED TO THE AC LINES IN YOUR HOMES. IT IS A FIRE AND ELECTROCUTION RISK AND I NOR ANYONE ELSE TAKE RESPONSIBILITY FOR YOUR OWN STUPIDITY.
Dedicated Charging Ports are required to supply 1800 mA. That means if you try and hack a device that is only rated at 700 mA to be a Dedicated Charging Port the device will possibly overheat and die or cause a fire if any device actually tries to pull the 1800 mA.
As far as car chargers: It is very simple to make a Dedicated Charging Port for a car charger provided you have an old USB one you can mod. Just get a DC-to-DC converter that will convert 11-14 volts (your car battery's voltage range) to 5 volts and throw a X ohm resistor on the USB data pins. Put it all in the empty shell of the donor and your done.

[FAQ][10/11/10] Samsung Epic USB/Wall/Charger FAQ

This message is a summary of my previous messages. I hope that it will be useful. I wrote this to document what I found out about the Epic. I'm cheap, and I didn't want to buy ANOTHER charger for my car. I had a 3A, 2-port USB charger, and I was mad that my Epic was charging slowly. I managed to modify my charger to get it to perform just like the wall charger that came with my phone.
---
Q: How much current does the Epic draw from a normal (bus-powered) USB port when charging?
A: 380mA.
Q: How much current does the Epic draw from the OEM 700mA wall charger when charging?
A: 600mA
Q: How much current does the Epic draw from a car charger or an aftermarket wall charger?
A: It depends...
If the charger has the two data pins (D+ and D-) shorted, the Epic will attempt to draw 600mA. Otherwise, it will draw 380mA.
Q: How can I tell if my phone is charging at 380mA or 600mA?
A: Turn off USB debugging (Home Screen\Settings\Applications\Development\USB debugging).
If you plug into a 380mA source (D+ and D- not shorted), you get a "Charging/Mass Storage/Tethered Mode" popup when you unlock your phone.
If you plug into a 600mA source (D+ and D- shorted), you do not get a popup.
Q: I have a 1A micro USB charger from another phone. Can I use it to charge the Epic?
A: Yes, but you won't get it to charge any faster than the 700mA OEM wall charger. The phone will only draw 600mA at most, regardless of how many amps the charger can supply. (And that assumes that D+ and D- are shorted.)
Q: I have a Palm Pre wall charger. I've heard that it charges the phone faster than the Epic wall charger. Is this true?
A: No. The Palm Pre wall charger does not charge the phone any faster than normal. With my phone hooked up, I measured 590mA (600mA with cable loss). I also saw that the charger had D+ and D- shorted. It behaves exactly like the Epic's charger.
Q: Will these 1A chargers damage my phone?
A: As long as the charger is able to supply the necessary current without overheating, chargers from other phones will not damage the Epic. A charger may be rated for 3A, but the Epic controls how much current it draws.
If you buy a cheap charger, you run the risk of having the charger's chip burn up. Among other things, this could short the charger's input voltage (12V from a car) to the USB V+ line and fry your phone.
Q: I have a USB charger that seems to charge my phone slooooowly. What can I do?
A: Your charger is probably supplying 380mA (or worse). You have a few options:
NOTE: Before doing any of this, make sure that your charger is rated at 700mA or greater. If you have an unmarked charger, chances are that it will not be able to supply 700mA out of the box. Many car charger (such as those for the Nintendo DS) have built-in current limiters that prevent the device from drawing too much current.
1. Modify Your Charger: Open up the charger and look to see if D+ and D- are shorted. (They are the two middle pins on the standard size USB plug.) Modify your charger so that it shorts D+ and D-, and remove any pull-up or pull-down resistors that connect D+ and/or D- to power or ground.
2. Modify A Cable: Slice open a spare micro USB cable (or the cable from your charger), being careful not to damage the red or black wires. Cut the green and white wires (D+ and D-). Strip off a little bit of the insulation from the green and white wires that lead to the micro USB connector. Twist these wires together and wrap in electrical tape.
NOTE: This will prevent the cable from being used as a USB data transfer cable.
3. Buy a USB Charging Cable: Look for a special USB charging cable that already has D+ and D- shorted.
Q: If I buy or make a charging cable, can I get 600mA from a normal (bus-powered) USB port?
A: It depends. The USB spec says that a port can only supply 500mA max. There is usually an overcurrent monitor built into the port that will prevent an overcurrent condition. The OS will pop up a message telling you that you've exceeded the current sourcing capacity of the port.
There are some laptops, however that have ports that allow you to violate the USB spec and draw up to 1A from a port.
Use caution when experimenting.
Q: Can you tell how much current the device draws from the device?
A: No. You CAN, however, get a battery graphing app like Battery Graph.
http://www.appbrain.com/app/battery-...odroid.battery
If you set the monitoring interval to 1 minute and start charging your phone (which should be low on charge) with the wall charger, you'll see a battery curve. You can then repeat this process with your alternate charging method. If you compare the slopes of the charging curves, you'll be able to tell if your alternate charging method is performing the same as your wall charger.
It's not as quick as using a DMM, but it works. It's how I initially saw I was having a problem.
Q: How can you tell if your USB cable has D+/D- shorted?
A: 99% of all cables will not have the lines shorted. You have to buy a "charging cable". But if you are in doubt as to what cable is what, plug it into a PC's USB port. Either the PC will detect the device (not shorted), or you'll trip the USB port's overcurrent mode (shorted).
Or... You can buy a DMM and check the resistance between D+ and D-.
- N
Is there a way to display on the Epic how much current it is drawing? Or some other way to tell if the cable being used is D+/D- shorted?
Thank you. Very helpful.
jasonsf said:
Is there a way to display on the Epic how much current it is drawing? Or some other way to tell if the cable being used is D+/D- shorted?
Click to expand...
Click to collapse
Good questions!
Q: Can you tell how much current the device draws from the device?
A: No. You CAN, however, get a battery graphing app like Battery Graph.
http://www.appbrain.com/app/battery-graph/com.modroid.battery
If you set the monitoring interval to 1 minute and start charging your phone (which should be low on charge) with the wall charger, you'll see a battery curve. You can then repeat this process with your alternate charging method. If you compare the slopes of the charging curves, you'll be able to tell if your alternate charging method is performing the same as your wall charger.
It's not as quick as using a DMM, but it works. It's how I initially saw I was having a problem.
Q: How can you tell if your USB cable has D+/D- shorted?
A: 99% of all cables will not have the lines shorted. You have to buy a "charging cable". But if you are in doubt as to what cable is what, plug it into a PC's USB port. Either the PC will detect the device (not shorted), or you'll trip the USB port's overcurrent mode (shorted).
Or... You can buy a DMM and check the resistance between D+ and D-.
Awesome! Thanks for the info!
Oh, one more thing. Are you saying that the wall charger shorts D+ and D- at the plug? So any cable is essentially shorted when using the wall charger?
Sent from my SPH-D700 using XDA App
jasonsf said:
Awesome! Thanks for the info!
Oh, one more thing. Are you saying that the wall charger shorts D+ and D- at the plug? So any cable is essentially shorted when using the wall charger?
Sent from my SPH-D700 using XDA App
Click to expand...
Click to collapse
You are correct.
For the Epic, the wall charger shorts D+ and D- together.
For wall or car chargers that have a non-removable cable, 99% of the time the short will be inside the charger and NOT in the cable.
Every computer I've used gladly lets me draw 1A without complaints. My old TP was hacked to draw 1A and nothing complained. Didn't even damage the cheapest of the cheap ebay chargers.
Firon said:
Every computer I've used gladly lets me draw 1A without complaints. My old TP was hacked to draw 1A and nothing complained. Didn't even damage the cheapest of the cheap ebay chargers.
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Click to collapse
YMMV. My netbook prevents me from drawing more than 500mA per port.
It all depends on how the USB port circuit is laid out. In the designs I've seen, there's usually a power distribution switch (PDS) in-line with the port that provides overcurrent protection. When that switch trips, it sends a bit to the hub chip that tells the hub that the port is in overcurrent state. (The PDS's secondary function is short-circuit protection. If you stick a car key in your USB port, your computer won't blow up.)
PDS's come in different current cutoff steps, so it is up to the PC manufacturer to choose the right one.
If your PC can't supply the 600mA on a single port to charge the phone, buy one of those USB power splitter cables that lets you draw from 2 ports at once.
I have found that if you plug in the phone and the options for charging, mass storage and tethering pop up, then you are only charging at 380mA. If nothing pops up then you are most likely charging at 600mA.
muyoso said:
I have found that if you plug in the phone and the options for charging, mass storage and tethering pop up, then you are only charging at 380mA. If nothing pops up then you are most likely charging at 600mA.
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Ding! You are correct. I never noticed because you don't get prompted AT ALL if you have USB debugging turned on.
This is a little off topic. Does the usb cable initiate Dock Mode? I know some other phones use magnets in the dock, but I think I read that the Galaxy S phones detect the car or home dock via the USB cable. Did you discover a mechanism for this in your usb research?
jasonsf said:
This is a little off topic. Does the usb cable initiate Dock Mode? I know some other phones use magnets in the dock, but I think I read that the Galaxy S phones detect the car or home dock via the USB cable. Did you discover a mechanism for this in your usb research?
Click to expand...
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No... I didn't find anything. Maybe I'll "rent" a dock from the Sprint store and find out.
Very nice write up. Answered all the questions I had about the slow charging of this phone. Thanks again.
Sent from my SPH-D700 using XDA App
I am getting substantially faster charges with a 1amp charger than the oem 700, it looks like it is using close to the 1000 ma on some chargers.
aero1 said:
I am getting substantially faster charges with a 1amp charger than the oem 700, it looks like it is using close to the 1000 ma on some chargers.
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Click to collapse
I'll have to pay attention to mine. I started using the 1 amp charger that came with my Touch Pro. I charge it overnight so I don't pay attention to how fast it is charging, but I'll see if I can notice tonight.
aero1 said:
I am getting substantially faster charges with a 1amp charger than the oem 700, it looks like it is using close to the 1000 ma on some chargers.
Click to expand...
Click to collapse
Which chargers? I'll be happy to try any charger that you recommend.
I haven't tested charging by timing the charges, but I have installed a widget that tells me an approximate charge rate called currentwidget, and it gives me the EXACT same values for a 700 ma charger or a 1000 ma charger. Unless this widget is just straight up lying, the phone won't charge any faster than a 700 ma charger no matter how large of a charger you throw at it.
IBNobody said:
2. Modify A Cable: Slice open a spare micro USB cable (or the cable from your charger), being careful not to damage the red or black wires. Cut the green and white wires (D+ and D-). Strip off a little bit of the insulation from the green and white wires that lead to the micro USB connector. Twist these wires together and wrap in electrical tape.
Click to expand...
Click to collapse
I was going to suggest just taping over the data pins in the USB connector (obviously, the regular, non-micro end), but I just tried it and it still popped up the Charging/Mass Storage/Tether, though selecting Mass Storage doesn't work -- the device is not detected by the computer for obvious reasons. I've been using this trick for a while for my mp3 player and my Hero at work and was surprised that it didn't work.
reauxgg said:
I was going to suggest just taping over the data pins in the USB connector (obviously, the regular, non-micro end), but I just tried it and it still popped up the Charging/Mass Storage/Tether, though selecting Mass Storage doesn't work -- the device is not detected by the computer for obvious reasons. I've been using this trick for a while for my mp3 player and my Hero at work and was surprised that it didn't work.
Click to expand...
Click to collapse
No, you need to short those pins together. If you leave them open, it won't go into high-current charge mode.
Those other devices may have had D+ and D- connected across a termination resistor. Putting tape on the pins would have worked then.
IBNobody- I was wondering if you could explain this one- when I plug my epic into the usb port of the cheap charger that came with 2 batteries off of ebay (see here) my epic seems to freeze and the touch screen becomes unresponsive- the charger states it puts out 5.2V 800ma
Could it be that the phone is trying to figure out if its being plugged into a computer vs a simple charger?

1 Amp Apple wall charger

Are all of Apple's OEM iPhone wall chargers (the white little square looking one's) rated at 1 amp? They're cheap on eBay and I like their small form factor and want to pick one up for my Captivate. Thx
I use one and they work fine.
^If you have your charger on hand, would you mind checking to see if it outputs 1Amp?
On your phone, go to Settings->About Phone->Status->Battery Status. If it says "Charging (AC)", it is charging at the max amperage the charger can offer (up to 1A). If it says "Charging (USB)", it is only charging at 500mA, the max a PC USB can offer. I'm pretty sure for iPhone/iPod chargers, it will show later case on our phone because it is not wired according to Samsung's AC charging requirement. I knew this because I had a 3rd party Car charger that was designed for iPhone/iPod and it won't let my Captivate to charge in AC charger mode. I have to open the charger and make a few mod myself to let Captivate to recognize this is an AC charger, not PC USB.
On the other hand, my 1A charger from Kodak Zi8 flash cam works w/o problem with Captivate.
foxbat121 said:
On your phone, go to Settings->About Phone->Status->Battery Status. If it says "Charging (AC)", it is charging at the max amperage the charger can offer (up to 1A). If it says "Charging (USB)", it is only charging at 500mA, the max a PC USB can offer. I'm pretty sure for iPhone/iPod chargers, it will show later case on our phone because it is not wired according to Samsung's AC charging requirement.
Click to expand...
Click to collapse
ty for the reply. I modded a usb retractable cable by shorting the middle connectors and when I go into settings it shows it's "Charging AC". This is with a generic 700mA usb wall charger I got with a cheap connector kit for my old iPhone.
Anyway, I recently got my Captivate and I find myself constantly playing with it, but it kills my battery doing so. I just want to charge my phone as quickly as possible so I can continue playing with it some more (in a good way).
I like Apple's wall charger because it's small.
From what I have read they are rated at 650 mv so fox is right that they will show as a usb connection. I have never really paid attention and am making a relatively uneducated, yet randomly tested, through my own purely subjective method of simply plugging my phone into anything that will allow my usb cord access, guess that anything with a female usb connection is fine.
Li-ion batteries are kinda dangerous so I am pretty sure there is some sort of idiot proofing built into the charging circuitry in the phone as well.
I'm pretty sure the Captivate will only draw the amps it needs so there should be no danger whether the wall charger is 1 or 2 Amps or more.
The difference is simply the charge time. The phone needs about 3 to 4 hours to get a full charge on the stock 700mA charger. When using generic USB chargers, it will be limited to 500mA max regardless what the charger is capable of and the full charge time will be proportionally longer. The bigger problem is that when your battery is really really low, 500mA may not be enough to even start the charging. That's why you need always keep the OEM charger handy for emergency.
BTW, for a car charger, 500mA won't keep your bettery from draining if you run navigation app that needs to power GPS chip, keep the screen on and download map from 3G connection at the same time. It requires 700mA or more. That is why it is very critical for a car charger be recognized by the phone as AC charger to draw more juice.
Ok, as I stated in my previous post I modded a USB cable by shorting the two middle data connectors, which tricks the Captivate into thinking it's charging with AC through my generic 700mA wall charger. It also says in settings it's "AC Charging" when I looked.
I just wanted to know if the iPhone's wall charger is rated at 1A or was it 650mA?? as newter55 stated.
thx for everyone's help.
Edit: My mistake, I thought I posted this in the Q&A section.
For some new PC motherboard with USB3.0,
they can output 900mA~1000mA(1A) in one single USB port.
You may check this out http://goo.gl/TUaef
If your PC is already 2 years old or older, the usb will only output 500mA in the max.
And, most Li-ion charger are smart enough.
In fact Li-ion charger circuit need to be well design in current control and over current/charge control.
The circuit will not pump full current to the battery in the beginning,
and it will not draw too much, so no need to worry about burn it up.
However if the current is too high let's say 10A.... it may possibly burn the circuit.
Maybe it is a bit difficult to measure current, you need to cut the wire and plug it to ampmeter....
Here is some reference.
500mA - full charge need over 3hrs
700mA - around 2hrs
1A - ~1.5 hr
johan8 said:
For some new PC motherboard with USB3.0,
they can output 900mA~1000mA(1A) in one single USB port.
You may check this out http://goo.gl/TUaef
If your PC is already 2 years old or older, the usb will only output 500mA in the max.
Click to expand...
Click to collapse
It is not about USB port side. The phone itself also detects and determines how much current it will draw. If it detects it is a PC USB, it will only draw 500mA max as Captivate is designed following USB 2.0 spec.
Ok, thanks for everyone's help. I was able to find out on my own after scouring the internet and talking to someone who has the Apple wall charger and it is indeed 1Amps. I believe all wall chargers that come with the iPhone 3g and all iPhone models after are 1Amps. Not sure about the original iPhone 2g.
Also, for curiosities sake, the iPad USB wall charger is 2Amps.
foxbat121 said:
It is not about USB port side. The phone itself also detects and determines how much current it will draw. If it detects it is a PC USB, it will only draw 500mA max as Captivate is designed following USB 2.0 spec.
Click to expand...
Click to collapse
Maybe.
I don't know the control circuit inside GalaxyS.
But USB2.0 doesn't means it is just 500mA.
iphone is just usb2.0, but it is the only thing can draw 1A from USB ?
http://goo.gl/GVqKl
(with designated m/b)
johan8 said:
Maybe.
I don't know the control circuit inside GalaxyS.
But USB2.0 doesn't means it is just 500mA.
iphone is just usb2.0, but it is the only thing can draw 1A from USB ?
http://goo.gl/GVqKl
(with designated m/b)
Click to expand...
Click to collapse
You're missing the point. The charge port on the phone can draw more than 500mA but only if it detects it is connected to a AC charger. Like mentioned above, you have to short the data PINs on the USB port or cable to let the Captivate think it is connected to AC charger. For iPhone, the data pins need to be connected to certain specific voltages in order to let iPhone know it is connected to an Apple AC charger.
When the phone can not detect AC charger characteristics, it falls back to PC USB 2.0 spec which is 500mA max.
I use one to charge my Zune. Haven't had a problem.
foxbat121 said:
You're missing the point. The charge port on the phone can draw more than 500mA but only if it detects it is connected to a AC charger. Like mentioned above, you have to short the data PINs on the USB port or cable to let the Captivate think it is connected to AC charger. For iPhone, the data pins need to be connected to certain specific voltages in order to let iPhone know it is connected to an Apple AC charger.
When the phone can not detect AC charger characteristics, it falls back to PC USB 2.0 spec which is 500mA max.
Click to expand...
Click to collapse
I fully understand what you're saying.
In iphone3, it can only draw 700mA from USB,
IP4 can draw nearly 1A from "computer" USB.
While iphone are just USB2.0 !
GalaxyS can draw 1A in max.
But does it like iphone4 can draw 1A from PC USB ? I don't know.
Or just like IP3 can draw only 500~700mA ?
I don't have new m/b and ampmeter so can't testing on it.

Findings on Galaxy S4 charging current

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?

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