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I bought a 3 micro usb cables, a wall charger, and a car charger for cheap from monoprice.com
3529 WALL Power to USB Female CHARGER Converter - Black (500mah) 1 $1.67
3523 Car Charger (Cigarette Lighter) to USB Female Converter - Black 1 $1.16
4868 USB 2.0 A Male to Micro 5pin Male 28/28AWG Cable - 6ft 3 $3.66
Subtotal : $6.49
Shipping & Handling Cost : $2.92
GRAND TOTAL : $9.41
They are all in hand and work perfect for power and data!
Fresh50 said:
I bought a 3 micro usb cables, a wall charger, and a car charger for cheap from monoprice.com
3529 WALL Power to USB Female CHARGER Converter - Black (500mah) 1 $1.67
3523 Car Charger (Cigarette Lighter) to USB Female Converter - Black 1 $1.16
4868 USB 2.0 A Male to Micro 5pin Male 28/28AWG Cable - 6ft 3 $3.66
Subtotal : $6.49
Shipping & Handling Cost : $2.92
GRAND TOTAL : $9.41
They are all in hand and work perfect for power and data!
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Damn, those are some nice looking prices.
Monoprice is outstanding for many items. Look at the HDMI cables and wall mounts for TV's. All very good quality. Been using them for years.
slimm13 said:
Monoprice is outstanding for many items. Look at the HDMI cables and wall mounts for TV's. All very good quality. Been using them for years.
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Yeah I have a bunch of HDMIs from them too. I wish they had the mini usb to micro though.
I bought 4 micro usb (3ft, gold contacts, ferrite beads) and the car USB charger. So cheap.
Fresh50 said:
I bought a 3 micro usb cables, a wall charger, and a car charger for cheap from monoprice.com
3529 WALL Power to USB Female CHARGER Converter - Black (500mah) 1 $1.67
3523 Car Charger (Cigarette Lighter) to USB Female Converter - Black 1 $1.16
4868 USB 2.0 A Male to Micro 5pin Male 28/28AWG Cable - 6ft 3 $3.66
Subtotal : $6.49
Shipping & Handling Cost : $2.92
GRAND TOTAL : $9.41
They are all in hand and work perfect for power and data!
Click to expand...
Click to collapse
3529 charges at 500mAh, this is close to the charging rate from a USB port (480mAh), so it will charge....but slowly. $1.16
3523 charges at 1000mAH, thats almost the same as the provided wall adapter (980mAh). $1.28
Shop4Tech has a car charget for $2.95 shipped but dont mention the charging current. I'll post back when they reply to my email.
just ordered 2 micro USB cables 3 feet from them for 4 bux! i love monoprice
britoso said:
3529 charges at 500mAh, this is close to the charging rate from a USB port (480mAh), so it will charge....but slowly. $1.16
3523 charges at 1000mAH, thats almost the same as the provided wall adapter (980mAh). $1.28
Shop4Tech has a car charget for $2.95 shipped but dont mention the charging current. I'll post back when they reply to my email.
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With it being only 20mAH over, could that hurt the battery at all?
Bought 2 micro USB cables , and a Micro HDMI cable for varying items.
Total cost with shipping from best buy was close to 65$.
Radio shack 54$
Monoprice with shipping.
9.70
Why on planet earth would anyone look elsewhere.
Slimgym20 said:
With it being only 20mAH over, could that hurt the battery at all?
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The wall charger that came with my N1 lists the output as 1A (1000 milliamps) so it's identical.
Slimgym20 said:
With it being only 20mAH over, could that hurt the battery at all?
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It shouldn't. The quoted current rating (it should actually be mA, not mAH, which is a unit of electric charge or battery capacity) is the max amount of current it's able to supply. If the device on the other end doesn't draw more than that, which our N1s shouldn't, then it's fine. If the N1s WERE to draw more current, the power supply would probably break before the phone.
There's nothing wrong with having a more capacious power supply, and in this case, the car charger would charge our phones faster than the wall charger the OP bought.
Monoprice offers a 1000ma wall charger here, I just went with the 500ma to be safe. I will be using it at work while streaming music so a slower charger is a non issue.
I love monoprice.com The micro USB cables I bought from there look very high quality, very thick, and even has ferrite cores.
Monoprice is my favorite store to buy anything cables. Also the fact that they have thier warehouse 30 mins away from me, means i can pick things up same day. But all it not perfect, thier 3.5mm male to male cables are terrible. At least they have been since the last time i bought 4...
Thanks for making this post... I just picked up two 3ft micro usb cables, car charger, wall charger, S video cable, and 3.5mm to RCA cable... including shipping it came out to under $15!
Thank you so much for this site. I never knew about it till now.
A note about chargers and mAh ratings. My source is the Battery University:
http://www.batteryuniversity.com/partone-12.htm
They recommend for small batteries like cell phone batteries to charge them at less than "1C" (for the Nexus One that would be less than 1.4Amps or 1400mAmps) so these chargers should all be fine.
They mention that charging at higher currents can cause the battery to get hotter. Heat shortens the eventual lifespan of a Lithium Ion battery so "bigger" is not necessarily "better" in terms of chargers. A lighter charge can be gentler on the battery than a beefy charger.
They also mention that higher currents do not shorten the charge cycle by much. At higher currents the battery electronics typically kick the charge cycle into the "topping charge" state earlier and since the topping charge is very slow, it takes longer to get to 100% charge. A lighter charger may take longer to reach the end of the initial regular charge cycle, but it will turn over into the topping charge state much closer to full. Thus, a stronger charger will get you to the topping charge state (i.e. mostly full) quicker, but take almost the same amount of time to get to the really 100% full state.
I typically use a Blackberry charger on my phones - they tend to charge at lower amperage and so induce less heat. I also charge them overnight so even if the charge was slower it wouldn't really matter because 6-8 hours is plenty for any charger to get these phones to 100%, but likely the lighter charging isn't really taking much longer anyway. If I desperately needed to get my phone charged up very quickly during the day then I would definitely use the stock charger or a charger that was stronger, but still under the 1.4Amp maximum recommended current - but if you charge overnight, try using a lower amperage charger for long term battery health...
Charge rate is controlled within the phone. A 1400mA wall charger is capable of supplying *up to* 1400mA. There's no danger with using a higher rated wall charger.
flarbear said:
A note about chargers and mAh ratings. My source is the Battery University:
http://www.batteryuniversity.com/partone-12.htm
They recommend for small batteries like cell phone batteries to charge them at less than "1C" (for the Nexus One that would be less than 1.4Amps or 1400mAmps) so these chargers should all be fine.
They mention that charging at higher currents can cause the battery to get hotter. Heat shortens the eventual lifespan of a Lithium Ion battery so "bigger" is not necessarily "better" in terms of chargers. A lighter charge can be gentler on the battery than a beefy charger.
They also mention that higher currents do not shorten the charge cycle by much. At higher currents the battery electronics typically kick the charge cycle into the "topping charge" state earlier and since the topping charge is very slow, it takes longer to get to 100% charge. A lighter charger may take longer to reach the end of the initial regular charge cycle, but it will turn over into the topping charge state much closer to full. Thus, a stronger charger will get you to the topping charge state (i.e. mostly full) quicker, but take almost the same amount of time to get to the really 100% full state.
I typically use a Blackberry charger on my phones - they tend to charge at lower amperage and so induce less heat. I also charge them overnight so even if the charge was slower it wouldn't really matter because 6-8 hours is plenty for any charger to get these phones to 100%, but likely the lighter charging isn't really taking much longer anyway. If I desperately needed to get my phone charged up very quickly during the day then I would definitely use the stock charger or a charger that was stronger, but still under the 1.4Amp maximum recommended current - but if you charge overnight, try using a lower amperage charger for long term battery health...
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lessthanjoey said:
Charge rate is controlled within the phone. A 1400mA wall charger is capable of supplying *up to* 1400mA. There's no danger with using a higher rated wall charger.
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True, but this is neither here nor there with respect to the points in my post.
First, the chargers that people are finding in this thread are lower power than that anyway so they can't provide enough to hurt the battery - whether or not the phone has the protections you mention. Perhaps the phone does protect itself, but the question does not matter unless you are talking about chargers that supply more than 1400mA which they are not.
My other point was that a lower power charger can charge the phone with less overall heat and extend the battery life. The phone will protect itself from damage, but charging close to 1C - while safe - doesn't help the battery last the longest it can.
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.
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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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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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.
I have an HTC Explorer, which came with a USB cable and an adapter to allow me to charge via mains as well. (Something like this: http://i.expansys.com/i/g/g232723.jpg - that's not the exact same one, but you get the idea). This charger says on it that it has an output of 5V and 1A. I also have a Blackberry Playbook, which came with a charger with a micro USB connector. However, this charger says on it that it has an output of 5V and 2A.
I have tested the HTC charger with my playbook, and it worked, but the question I want to ask is this: would it be dangerous to try the playbook charger on my HTC phone? (2A output from Playbook charger versus the presumably expected 1A input on the phone) I would like to be able to only carry one charger when travelling and the playbook charger has interchangeable adapters for international plugs, so it would be better to take, but obviously I don't want to overload the phone and have it burst into flames or whatever.
Any advice on the matter would be great, thanks.
It's not recommended by the manufacturer. It can void your warranty, though I don't know how they'd ever find out you were doing so. There can also be issues when using the cable to transfer data and such.
I did watch a video about that Blackberry charger.
Supposedly because of that 2A output, it charges your phone twice as a fast.
Sent from my Ainol Novo7 Elf using xda premium
I don't think there would be considerable damages but..I'd just use them both, even if it's less comfortable
I looked around and I think it should be safe. From what I've read online, the phone will only take a certain amount of current, regardless of the current being made available by the charger. Because the voltage is the same (5V), and the resistance of the phone circuitry is constant, by Ohm's law, I = V/R, so I will always be the same as long as V is the same. Presumably it'll drop with a lower input current, but the max I will always be the same, and that'll be limited to a safe level.
It might take a slightly higher current (say if the max the phone can take is 1.2A or something, the 1A charger can only give 1A but the 2A would give the full 1.2A), but no higher than the circuits in the phone will allow. After reading this, I realised that it made a lot of sense, and I think it's right. I also read that if it does charge the phone faster (which it will if the phone is taking a higher current e.g. 1.2A) it'll reduce the number of charging cycles that you get out of the battery. But the consensus seems to be that doing it every now and again when travelling etc. should be fine.
Thanks for all your responses.
EDIT: I think at worst, I might damage the battery, and they're not overly expensive to replace I don't think.
I agree, the rating on the charger is what it's MAX output, not that it will push that much current to your device. If you have an extra USB cable (that you dont mind cutting apart) and a mulit-meter, you can check to see how much current your phone is pulling from the BB Playbook charger. connect your mult-meter in-line with the red wire in the usb cable (just connect all others together)
Just make sure your mult-meter is rated for at least 2A.
Hope this helps.
Devices with lithium batteries usually have a charger circuit that limit the peak current that is sent to the battery. They also utilize temperature compensation so if you are charging the battery too fast, it starts limiting the charge current.
Where you might have a problem is when it's plugged in and you are using it, especially if the battery is low. You get high charge currents, combined with the operating current.
So I'm looking to purchase a slew of new chargers for myself and my wife for at home, office in the car, etc... She has a Galaxy S4 and Ipad3; I have Galaxy S3 and Galaxy Note 10.1 2014. I'm at least somewhat aware of the charger requirements and plan to supply at least 2 amps to each device in general.
My real confusion is in the USB cable length. It seems most stock cables are roughly 3ft long and from what I can tell, going with a longer cable increases resistance, causes a voltage drop and lowers the current/charge rate. Of course a higher gauge cable will help decrease this resistance, but I'm already planning ot go with 24AWG cables.
So my question is, how long of a USB cable can I use before it has a noticable effect on my charge rate? If anything over 3ft significantly slows it down, then I'll probably just use AC extension cables instead of longer USB cables when necessary. What cable length vs charge rate do you find acceptable?
Thanks in advance!
I have a 10 foot cord that I got from mobstub and I noticed a significant increase in the time it takes to charge. I'm not sure how much degraded it is but if there's an app or something that can show me that I'll tell you the stats.
Sent from my SPH-L720 using xda premium
low voltage / low current
I don't have any empirical data to back it up, but at 5VDC & 2A or less (typically), I would not expect much of a drop in charge voltage/current due to length (10 ft or less). That's just a gut feel from building lots of cables & electronic assemblies for the fun of it !!
Good luck & have fun !!
Mark J Culross
KD5RXT
mjculross said:
I don't have any empirical data to back it up, but at 5VDC & 2A or less (typically), I would not expect much of a drop in charge voltage/current due to length (10 ft or less). That's just a gut feel from building lots of cables & electronic assemblies for the fun of it !!
KD5RXT
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If your cables are thin - don't even expect to deliver 2000mA on them. The thickness is the key here.
bmather9 said:
So I'm looking to purchase a slew of new chargers for myself and my wife for at home, office in the car, etc... She has a Galaxy S4 and Ipad3; I have Galaxy S3 and Galaxy Note 10.1 2014. I'm at least somewhat aware of the charger requirements and plan to supply at least 2 amps to each device in general.
My real confusion is in the USB cable length. It seems most stock cables are roughly 3ft long and from what I can tell, going with a longer cable increases resistance, causes a voltage drop and lowers the current/charge rate. Of course a higher gauge cable will help decrease this resistance, but I'm already planning ot go with 24AWG cables.
So my question is, how long of a USB cable can I use before it has a noticable effect on my charge rate? If anything over 3ft significantly slows it down, then I'll probably just use AC extension cables instead of longer USB cables when necessary. What cable length vs charge rate do you find acceptable?
Thanks in advance!
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At the voltages, gauges, and distances we are talking here, you are way over thinking this. It will certainly be fine at least up until the USB data transmission cable limit of 5 meters.
http://forum.xda-developers.com/showthread.php?t=2545497
According to the results from this other thread the wire length really seems to make a drastic difference.
I've heard quite a few people say that voltage drop will be minimal, but also heard of people being unable to charge their ipad 3 with a 10 ft cable.
I'd really like to use longer cables since they are generally more convenient to use the phone while plugged in, but the charge rate is also very important. So I'd like to get a feel as to what I'd be sacrificing by using longer cables.
I'm certainly overthinking this; I'm an engineer...that's what I do
Regardless, I'm planning to purchase quite a few cables and figured I should do so with some intelligence.
So with 2 votes so far for "1.5 ft or less" does that mean that people are really using even shorter cables to get better charge rates?
wire size vs voltage drop
OK, in place of my "gut feel" in my earlier post, here's just one website that allows you enter the parameters of your cable (size in AWG gauge, voltage, length & current) & then calculates the theoretical voltage drop through your cable: http://www.powerstream.com/Wire_Size.htm (scroll down to the bottom to find the calculator). For example, according to their calculations, a three foot cable using 24 gauge wires carrying 2A current would impart a little over a 0.3VDC drop. If your charger is supplying 5VDC at the source, then only 4.7VDC would make it to your phone for use in charging at the full 2A rate. Contrast this with a ten foot cable of the same size under the same conditions which suffers a little more than a 1VDC drop, resulting in only 4VDC being available at your phone at the full 2A rate for charging.
However, I would not expect the phone to continue to try to draw 2A of current under these conditions (particularly the 10 foot cable), else charging may not take place at all if/when the voltage is too low. Instead, I would expect that the charging circuit on the phone would diminish its current draw (to something LESS than 2A) in an attempt to keep the voltage closer to the desired 5VDC (or whatever the spec'd minimum is to charge the specific battery, assuming that the charger itself is putting out a nearly constant amount of power, somewhere near to its rated number of watts).
It's very likely because of this reduction in current that your overall charging rate is reduced (or to put it another way, your overall charging time is increased) on lesser size cables, etc.
YMMV . . .
Good luck & have fun !!
Mark J Culross
KD5RXT
mjculross said:
OK, in place of my "gut feel" in my earlier post, here's just one website that allows you enter the parameters of your cable (size in AWG gauge, voltage, length & current) & then calculates the theoretical voltage drop through your cable: (scroll down to the bottom to find the calculator). For example, according to their calculations, a three foot cable using 24 gauge wires carrying 2A current would impart a little over a 0.3VDC drop. If your charger is supplying 5VDC at the source, then only 4.7VDC would make it to your phone for use in charging at the full 2A rate. Contrast this with a ten foot cable of the same size under the same conditions which suffers a little more than a 1VDC drop, resulting in only 4VDC being available at your phone at the full 2A rate for charging.
However, I would not expect the phone to continue to try to draw 2A of current under these conditions (particularly the 10 foot cable), else charging may not take place at all if/when the voltage is too low. Instead, I would expect that the charging circuit on the phone would diminish its current draw (to something LESS than 2A) in an attempt to keep the voltage closer to the desired 5VDC (or whatever the spec'd minimum is to charge the specific battery, assuming that the charger itself is putting out a nearly constant amount of power, somewhere near to its rated number of watts).
It's very likely because of this reduction in current that your overall charging rate is reduced (or to put it another way, your overall charging time is increased) on lesser size cables, etc.
YMMV . . .
Good luck & have fun !!
Mark J Culross
KD5RXT
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Thanks for that explanation. It seems that even a 6 ft USB cable will significantly slow charging, and that a 10 ft even more so to the point that it may not even charge sometimes. So its looking like 3ft USB cables with AC extensions where necessary is the way to go. Maybe I'll try some 1.5 ft as well, but not sure how practical they will be for using the devices while plugged in, even with the AC extension.
If anyone has another opinion please voice it.