[Q] volt and amp tolerances for phone and tablet charging - Android Q&A, Help & Troubleshooting

I googled around for this and was surprised to not find any similar questions.
I have a lot of different microusb chargers (and microusb cables that can plug into usb wall chargers), coming from a lot of different sources. They have varying wattage and amp outputs as well.
Do phones and tablets have a maximum power that can be safely plugged into their microusb ports? I've never encountered any problems, but it's better to be sure. I've always gone off the assumption that if it comes with a microusb plug on the end, it's safe for my Android devices. But that may not be the case.

As long as the carger is about 5V and can push over 100mA (depends on phone requirements) it'll be fine. Even if you had a charger that could give 10 amps out, the phone won't take that much current. I measured my Samsung ATIV S taking about 460mA while charging and friend's Nokia Lumia 920 took 420mA while charging.

Custom kernel with charging settings and no data cable will give you best results
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220v charger? (220v - mini usb)

I would like an additional charger as supplied in the box: from a wall socket 220v to mini usb. I see many usb charge cables but does anyone know where I can get a wall charger?
I heard usb charging is a lot slower and a usb-pc is not always available to plug into....
Not sure what country you are from...
http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=5841022471&category=67832
It says its for the iPOD but it's got the same 5.5v output required - as with all USB devices.
Just do a search for USB Wall Chargers on the net and you'll get loads.
thanks Looks good. Does anyone know if charging this way actuallu IS faster then charging from pc?
Depends on the power output of a given charger...
USB charging is done at 5 volts and 0.5 amps (more or less - I seem to recall that the wall charger for the Blue Angel delivered about 0.7 amps and a bit below 6v, possibly 5.5).
Differences in speed of charging may be achieved if the supply current is higher (logically, since power = volts * amps) although I would be very surprised if the device did not have current limiting hardware in place, which may reduce or remove any advantage.
This means that it should be possible to charge the device faster (assuming it is not precisely self regulating) with a higher power output wall charger than a Windows managed PC. Most people selling USB wall chargers should specify the volts/amps of the charger and I would be suspicious of the seller if this were not the case! Personally, I'd recommend buying a (good - beware of cheapy!) retractable sync/charge cable and both wall and car power adapters with a USB socket as it allows you the most flexibility from the smallest physical amount of kit.
HTH

Power pack

Can anybody recommend an external power pack that works with the flyer/view? I was looking at this:
http://www.amazon.com/New-Trent-IMP...FO/ref=sr_1_20?ie=UTF8&qid=1324398340&sr=8-20
It will work with your Flyer, but it will charge much slower than the HTC power cord due to the USB connector. It may or may not keep your unit powered during normal use depending the way you use your device since the current supplied will be limited by the standard USB cable (~500ma) vs. the propriety HTC charging cable (1200 ma). I would test by powering your Flyer off a standard PC USB port and see, This should be roughly equal to what this device will supply.
Hmm, me thinks I just spotted hardware hack number 3.
globatron said:
Hmm, me thinks I just spotted hardware hack number 3.
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lol
This would be great please keep us updated
I picked up a Dreamgear iSound 8000 ma model on sale from expansys, seemed like a nice unit and was supposed to be able to push 2amp but it's no faster with the HTC cable than a regular generic microUSB cable hooked up to a usb port. The biggest drawback was the thing completely died on me before the first cycle, I mean DEAD, won't charge and the flashlight doesn't even work. So much for on sale, return shipping $$.
Neil
As I posted previously in this thread it does not matter what current the source supply can provide. The cable is the magic. Standard cable, standard charge rate of 500ma which is about 30% of what the HTC charger will give you
DigitalMD, reread his post. He clearly states that using both the HTC flyer cable, as well as a standard micro USB, gives him no difference. So while your conjecture that "it does not matter what current the source supply can provide. The cable is the magic." is interesting, it is not, in fact, entirely accurate. Perhaps the cable is "the magic" in certain environments, but clearly not all.
No conjecture at all, in this case it is a fact. The Flyer cable has extra pins and conductors that are not in a standard USB cable. This tells the Flyer when a power supply is connected vs. a standard USB and the Flyer then allows for higher charging rate. Whit out that special cable, it will only charge at 500ma or aprox. 30% of the HTC power supply rate.
Actually less than that even. The htc charger runs at ~9v > 1amp. A lithium battery can rapid charge in the range of 900mA to 1.2A depending on the cell(s) in the battery.
There are two cells or two packs (can't tell which on visual inspection) in the flyer battery running in parallel. A proper htc charger running at 1A provides approximately 10W of charging power, a 5 volt source running at 500mA provides 2.5W so the USB charging will be 4 times slower.
As discussed in another thread shorting USB D+ and D- will allow the flyer to recognise a wall charger and charge at 5v 900 mA, the same could be applied to a battery pack capable of providing 900 mA sustained. It wouldn't be as quick as the wall charger but it is probably enough to provide for charging while using the device, rather than just slowing discharge.
On the question of leads, using a htc cable or standard micro USB makes no difference by default. When connected to a USB socket the flyer/view cable behaves like any other USB cable, the wiring modification is done inside the charger for a wall charger, and would most safely be done the same way for a battery pack.
The flyer internally uses a threshold voltage plus the D+ and D- pins to determine if it is charging from 5v or the dedicated higher voltage wall charger.
yes your post is a more accurate explanation, thanks
Thanks for the input. I will give that one a try and take my View cable with me. I have long road trip coming up.

Car charger question

I have a USB car charger that doesn't seem to charge as quickly as I would like it to. I say that by comparing it to previous phones and the rate at which they charged when plugged into it.
I read that you can short out the Belkin or Griffin USB charges to make it look like your phone is plugged into the wall. I'm not agains doing this because i like to tweak.
The question really is, I see that Proporta has a 4000mA (2000mA per port) dual port USB charger available. Will this allow my phone to charge like it's plugged into the wall or will it still "look like" I'm plugged into a USB prot charging?
- Cyber
Not exactly sure what you're asking, but I assume that you mean that a wall charger charges the phone faster than a car charger.
Unfortunately, I don't know if this is the case. USB is a universal standard with specific power requirements. Although there are medium and high power chargers out there, I would be reluctant to get something so extreme. I think USB calls for 500 mA standard, so I'd be careful using the charger you mention. You might want to do some more research on it, or contact the company about it.
I'm not an expert but my opinion is that usually USB-Wall charger supplies up to 1000 mAh (written on power supply transformer) while the USB-OutPC is only 500 mAh, in fact, I've noticed that the full charge of my Titan takes double the time if charged via PC.
Not sure about the amount supplied by cars USB adapter.
...my two amperes...
Some of the chargers accomplish support for things like the iPad 2 by shorting the two USB connectors. Some advertise things like 2000ma, but fail to deliver much more than 500ma. I am not sure if this is due to the choice of shorting out the data connectors to trick your phone in to thinking it is plugged in to the wall.
Back in the WM 6.5 days, you could accomplish this at the phone driver level and did not need to modify your chargers.
I would not worry about trying something rated higher as your phone would regulate the current. I personally intend to do my experimentation by shorting out the cable rather than the charger (cables are more easily replaced). Unfortunately, there is no app for WP7 that can measure the charging current, so the only way to do this scientifically is to use the battery status app and measuring the charge rate over time.
If you do the mod, post back and let us know. When I get around to the USB cable experiment, I will post back as well.

Generic USB chargers, are they the same?

I have four chargers that follow the same basic design, plug-in socket at one end, USB port at the other so you have to use the USB-data cable to charge the phone. I have one for my son's Sony Xperia Go, my ASUS Transformer Infinity tablet, my old HTC Wildfire and my even older Sony Ericsson Xperia X1i... what I'm wondering is that since they all use the USB standard, could they be interchanged without damaging the battery of the phone/tablet? Can one assume that the voltages and currents and everything (I'm no electrical guru obviously) are the same? Oh and I do actually own a SGS2 but that uses a different kind of charger anyway so it's irrelevant really...
Should be the same.
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pietpodlood said:
I have four chargers that follow the same basic design, plug-in socket at one end, USB port at the other so you have to use the USB-data cable to charge the phone. I have one for my son's Sony Xperia Go, my ASUS Transformer Infinity tablet, my old HTC Wildfire and my even older Sony Ericsson Xperia X1i... what I'm wondering is that since they all use the USB standard, could they be interchanged without damaging the battery of the phone/tablet? Can one assume that the voltages and currents and everything (I'm no electrical guru obviously) are the same? Oh and I do actually own a SGS2 but that uses a different kind of charger anyway so it's irrelevant really...
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Regarding the voltage one can assume that a charger with an USB port always will supply a voltage of 5 volts.
However the wattage of the chargers will differ. This is not really an issue as the charging current is basically controlled by the capabilities of the device to be charged (your phone) and not by the capabilities of the charger. This holds true as long as the charger is able to keep up with the current requirements of the device. This too is generally not a problem at all.
When it comes to the time it takes to charge a device, things can differ quite much.
Assuming you do not have a kernel like for example Siyah installed (and tweaked charging settings) your phone will set the charging current according to what it detects on the USB port. If it detects a standard USB port (Laptop for example) it will charge with a lower current. If it detects a dedicated charging device it will draw much more current and the charging will hence take less time. This detection (USB port or dedicated charing device) depends on the impedance between the two data lines D+ and D- of the USB cable. A dedicated charging device will have a low impedance or to put it simple: a charger should have a short between D+ and D- to be detected as such. This short is part of the charger not part of the USB cable (this allows you to charge the phone with any standard USB cable).
At any time you can use Settings > About Phone > Status to check the Battery Status. If it shows Charging (USB) then a standard USB port has been detected and charging will take more time. If however it shows Charging (AC) then a dedicated charger has been detected and charging will take less time.
Last but not least you might experience one more difference between the chargers: the amount of noise (ripple on the 5V DC) they generate. The less the better. The ripple on some chargers is that bad that the touch screen will be absolutely unresponsive during charging. The original Samsung and many other chargers are fine, but I have some low cost models here that make using the touch screen during charging impossible.
Generally I would answer your question like this: yes, chargers with USB connectors are interchangeable. However the charging result might differ quite much.

[Q] Some Questions About Charging the S4 With My Car's USB Plug.

I've previously been able to charge my phones (a droid Charge and the S3) with the USB plug in car with out any problems. It was slower than the A/C charger, but got the job done. But recently, I noticed that the S4 was taking forever to add any charge to the battery when plugged into the car's USB (Its a 2012 Ford Focus with My Ford Touch). I tested the USB line with the "Galaxy Current Charging" App and saw it was only registering 460 mAh (which is the same as when the phone is unplugged). I also tested my cigarette lighter charger which showed 860 mAh. (BTW, I tested the USB cord using my 2 Amp stock S4 A/C charger and it showed 1900 mAh, so I don't think there is anything wrong with the USB cord, itself.)
So, is there a problem with using the standard USB plug in our cars to charge the S4?
Thanks in advance,
Rich
richs10 said:
So, is there a problem with using the standard USB plug in our cars to charge the S4?
Thanks in advance,
Rich
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If you're really getting 860ma, you should be OK. The problem is that most 12v car adapters end up delivering about half that current. As you've already figured out, the S4 can accept up to about 2000ma (or 2A), but only when using a 5V/2A adapter (like the one that comes w/the device) AND only when using a compatible cable (use a non-stock cable with the AC adapter and you'll probably see more like 950ma than 1900).
You might want to try this Motorola auto charging cable http://www.amazon.com/gp/product/B000S5Q9CA/ref=wms_ohs_product?ie=UTF8&psc=1 . It's rated at about 1A, which is about half the level that the S4 can accept, but still pretty good. I haven't measured the exact output, but I can tell you that it's faster than any other car charger I've owned before.
You may also want to search online for an adapter that can achieve closer to 2A.
Andy:
I have that exact Motorola cigarette lighter charger and it works fine. My problem is trying to charge the phone in the car using the car's usb plug and a 'usb to micro usb' cord. That is where I have run into the problem with the S4. I could do this with my older phones, but the usb plug in the car only seems to supply the 460 mah with the S4. Any ideas why?
richs10 said:
Andy:
I have that exact Motorola cigarette lighter charger and it works fine. My problem is trying to charge the phone in the car using the car's usb plug and a 'usb to micro usb' cord. That is where I have run into the problem with the S4. I could do this with my older phones, but the usb plug in the car only seems to supply the 460 mah with the S4. Any ideas why?
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Because the usb spec it wasdesigned under limits it to a maximum of 500 mA. It is a given that charging will be excruciatingly slow at that low of a current draw if it even charges at all.
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richs10 said:
Andy:
I have that exact Motorola cigarette lighter charger and it works fine. My problem is trying to charge the phone in the car using the car's usb plug and a 'usb to micro usb' cord. That is where I have run into the problem with the S4. I could do this with my older phones, but the usb plug in the car only seems to supply the 460 mah with the S4. Any ideas why?
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There's a product review on Amazon, where the reviewer provides a pretty good summary that might help explain. He claims that if the device does not 'recognize' the charging source with certainty, it may default to 500ma to prevent potential damage to the charge source (which could be e.g., a PC). The recommendation seems to be to use a special charging cable that would demonstrate to the device that a low-current source is not connected.
(here's an excerpt)
"...The USB power spec is for 0.5 Amps at 5 Volts... or 2.5 Watts. This was great up until the last couple years when devices have gotten really power hungry, particularly smartphones and tablets and to a lesser extent dedicated GPS's. Some of these devices use over 2 Amps, particularly the tablets like the iPad (or in my case the HP Touchpad).
Manufacturers of these devices therefore had a dilemma. If they had their devices pull more than 0.5 Amps, they risked damaging the power source, which could be a computer, that was only prepared to source 0.5 Amps. Thus the manufacturers have used tricks to determine whether their device is connected to an unknown source, at which point they purposely only draw 0.5 Amps, or to the dedicated charger that was provided with the device, where they can draw all the power they need.
There seem to be two common tricks used. The first is to short the two data-wires together in the charger. This is what most non-Apple devices do. Since a computer or older device wouldn't have done this, the device can assume it is safe to draw all the power it needs..."
In a subsequent discussion about the review, one of the commenters went on to recommend this charging cable - note that, per above, it's a 'shorted' cable, so it can only be used for charging (not data xfer). You might want to give it a try: http://www.amazon.com/gp/product/B003VYBCAY/ref=cm_cd_asin_lnk
That will not work if the source itself is limited to 500mA. The shorted data pins on the cable only allow the PMIC to draw a higher current if the source is capable of providing it.
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