# those 5v usb chargers **URL:** \ **Category:** Factual Questions\ **Created:** [March 11, 2014, 1:54pm UTC](https://boards.straightdope.com/t/those-5v-usb-chargers/683425 "2014-03-11T13:54:51Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![bardos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bardos/32/1069_2.png) [@bardos](https://boards.straightdope.com/u/bardos)\ **Post date:** [March 11, 2014, 1:54pm UTC](https://boards.straightdope.com/t/those-5v-usb-chargers/683425/1 "2014-03-11T13:54:51Z")
It seems to me that everything functions on batteries nowadays In the past year I have seen my life upgraded: My son gave me his old IPAD and I have recently purchasesd a Sony Xperia SmartPhone. Both come with 5v chargers which have independent USB cables. Both have the same exact ratings: Input of 110v-240v output of 5vDC 1000 MiliAmps. My question is, Are these chargers really the same, are all smartphone chargers now at 5v DC? Can I use the same charger for phones and IPAD? ---
**Author:** ![UncleRojelio](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/unclerojelio/32/3160_2.png) [@UncleRojelio](https://boards.straightdope.com/u/UncleRojelio)\ **Post date:** [March 11, 2014, 1:58pm UTC](https://boards.straightdope.com/t/those-5v-usb-chargers/683425/2 "2014-03-11T13:58:42Z")
No, your iPad will need a 2 amp charger. ---
**Author:** ![Dewey\_Finn](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dewey_finn/32/4222_2.png) [@Dewey\_Finn](https://boards.straightdope.com/u/Dewey_Finn)\ **Post date:** [March 11, 2014, 2:01pm UTC](https://boards.straightdope.com/t/those-5v-usb-chargers/683425/3 "2014-03-11T14:01:44Z")
Not if it’s an iPad mini. I can charge my iPad mini with the same small charger I use with my iPhone or I can charge it via the USB port on my PC. ---
**Author:** ![bardos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bardos/32/1069_2.png) [@bardos](https://boards.straightdope.com/u/bardos)\ **Post date:** [March 11, 2014, 2:13pm UTC](https://boards.straightdope.com/t/those-5v-usb-chargers/683425/4 "2014-03-11T14:13:09Z")
The charger which came with the IPAD says 5v 1Amp. The IPAD itself measures 18.5cm X 24cm, which google says is 7.3" X 9.4". So is it a mini or a maxi? ---
**Author:** ![andrewm](https://avatars.discourse-cdn.com/v4/letter/a/c57346/32.png) [@andrewm](https://boards.straightdope.com/u/andrewm)\ **Post date:** [March 11, 2014, 2:18pm UTC](https://boards.straightdope.com/t/those-5v-usb-chargers/683425/5 "2014-03-11T14:18:57Z")
> [@UncleRojelio](#): > > No, your iPad will need a 2 amp charger. False. It will take longer to charge with a 5W adapter, but it will work. ---
**Author:** ![leahcim](https://avatars.discourse-cdn.com/v4/letter/l/b4bc9f/32.png) [@leahcim](https://boards.straightdope.com/u/leahcim)\ **Post date:** [March 11, 2014, 2:19pm UTC](https://boards.straightdope.com/t/those-5v-usb-chargers/683425/6 "2014-03-11T14:19:14Z")
An [article](http://www.extremetech.com/computing/115251-how-usb-charging-works-or-how-to-avoid-blowing-up-your-smartphone) on the topic. Basically, all USB ports can provide 5V, 500mA, but USB chargers can provide up to 2100mA. Generally, if the port fits it will work, but it might be slower normal if the charger you are using can’t provide the amperage of the “standard” charger for the device. ---
**Author:** ![Rhythmdvl](https://avatars.discourse-cdn.com/v4/letter/r/85f322/32.png) [@Rhythmdvl](https://boards.straightdope.com/u/Rhythmdvl)\ **Post date:** [March 11, 2014, 2:23pm UTC](https://boards.straightdope.com/t/those-5v-usb-chargers/683425/7 "2014-03-11T14:23:38Z")
On-topic ignorance fighting request: [ol] [li]In general, it’s the device that draws a particular amount of current, and if plugged into a mainstream USB wall charger will only pull that current, whether or not the charger is rated above that amount. A higher-rated charger will generally not push or force that amount of current down the line. If the charger is rated below the device’s draw, charging will not occur or be much slower. (ignorant/accurate)[/li] [li]In general, USB cables are fairly universal. A random, non-specialist USB cable that fits a device should be capable of carrying the requisite current irrespective of the device it was originally packaged with. (ignorant/accurate)[/li] [li]Inserting the word ‘universal’ into a set of cable standards with many sizes and shapes and only one orientation was a good practical joke. (ignorant/accurate)[/li][/ol] ETA: Reading article posted by **leahcim** while I was typing (ignorant/accurate) ---
**Author:** ![bardos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bardos/32/1069_2.png) [@bardos](https://boards.straightdope.com/u/bardos)\ **Post date:** [March 11, 2014, 2:33pm UTC](https://boards.straightdope.com/t/those-5v-usb-chargers/683425/8 "2014-03-11T14:33:08Z")
What does “(ignorant/accurate)” mean? ---
**Author:** ![Rhythmdvl](https://avatars.discourse-cdn.com/v4/letter/r/85f322/32.png) [@Rhythmdvl](https://boards.straightdope.com/u/Rhythmdvl)\ **Post date:** [March 11, 2014, 2:42pm UTC](https://boards.straightdope.com/t/those-5v-usb-chargers/683425/9 "2014-03-11T14:42:12Z")
It means you should completely darken the correct response with a number 2 pencil (I’ll be feeding the answers into a Scantron reader later today). ---
**Author:** ![leahcim](https://avatars.discourse-cdn.com/v4/letter/l/b4bc9f/32.png) [@leahcim](https://boards.straightdope.com/u/leahcim)\ **Post date:** [March 11, 2014, 2:44pm UTC](https://boards.straightdope.com/t/those-5v-usb-chargers/683425/10 "2014-03-11T14:44:47Z")
I don’t know how anyone could possible verify whether or not he was reading the article while typing. ---
**Author:** ![Rhythmdvl](https://avatars.discourse-cdn.com/v4/letter/r/85f322/32.png) [@Rhythmdvl](https://boards.straightdope.com/u/Rhythmdvl)\ **Post date:** [March 11, 2014, 3:00pm UTC](https://boards.straightdope.com/t/those-5v-usb-chargers/683425/11 "2014-03-11T15:00:24Z")
> [@leahcim](#): > > I don’t know how anyone could possible verify whether or not he was reading the article while typing. Rhythmdvl, this is sergeant Sacker. Listen to me. We’ve traced the IP … it’s coming from inside the house. Now a squad car’s coming over there right now, just get out of that house! ---
**Author:** ![Digital\_is\_the\_new\_Analog](https://avatars.discourse-cdn.com/v4/letter/d/a88e4f/32.png) [@Digital\_is\_the\_new\_Analog](https://boards.straightdope.com/u/Digital_is_the_new_Analog)\ **Post date:** [March 11, 2014, 3:54pm UTC](https://boards.straightdope.com/t/those-5v-usb-chargers/683425/12 "2014-03-11T15:54:44Z")
Since I have a cold, I specifically disclaim the accuracy or value of my answers below. > [@Rhythmdvl](#): > > On-topic ignorance fighting request: > [li]In general, it’s the device that draws a particular amount of current, and if plugged into a mainstream USB wall charger will only pull that current, whether or not the charger is rated above that amount. A higher-rated charger will generally not push or force that amount of current down the line. If the charger is rated below the device’s draw, charging will not occur or be much slower. (ignorant/accurate)[/li] This is effectively accurate. It’s possible that a charger will not provide enough current to usefully charge a device, and that the device will opt to not charge at all. But that’s a fairly rare condition these days, I believe. > [@](#): > > [li]In general, USB cables are fairly universal. A random, non-specialist USB cable that fits a device should be capable of carrying the requisite current irrespective of the device it was originally packaged with. (ignorant/accurate)[/li] I’d say this is accurate. > [@](#): > > [li]Inserting the word ‘universal’ into a set of cable standards with many sizes and shapes and only one orientation was a good practical joke. (ignorant/accurate)[/li] I’ll go with ignorant on this one…because I don’t think it was a “good” joke. 🙂 > [@](#): > > ETA: Reading article posted by **leahcim** while I was typing (ignorant/accurate) Leap of faith - accurate. I suppose it’s possible you got up and walked away, or and thus were not actually typing. ---
**Author:** ![kayaker](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/kayaker/32/441_2.png) [@kayaker](https://boards.straightdope.com/u/kayaker)\ **Post date:** [March 11, 2014, 4:43pm UTC](https://boards.straightdope.com/t/those-5v-usb-chargers/683425/13 "2014-03-11T16:43:15Z")
[I recently purchased this car charger with two slots](http://www.amazon.com/dp/B00GX5ORL4/ref=pe_385040_30332190_TE_M3T1_ST1_dp_1), one delivers 5V, 2.4 amps, the other 1 amp. Works great. [And check out this detailed review!!](http://www.amazon.com/review/R1BSQFGYMS2DCH/ref=cm_cr_dp_title?ie=UTF8&ASIN=B00GX5ORL4&nodeID=2335752011&store=wireless) ---
**Author:** ![Colophon](https://avatars.discourse-cdn.com/v4/letter/c/f05b48/32.png) [@Colophon](https://boards.straightdope.com/u/Colophon)\ **Post date:** [March 11, 2014, 5:37pm UTC](https://boards.straightdope.com/t/those-5v-usb-chargers/683425/14 "2014-03-11T17:37:59Z")
> [@Rhythmdvl](#): > > On-topic ignorance fighting request: > [ol] > [li]In general, it’s the device that draws a particular amount of current, and if plugged into a mainstream USB wall charger will only pull that current, whether or not the charger is rated above that amount. A higher-rated charger will generally not push or force that amount of current down the line. If the charger is rated below the device’s draw, charging will not occur or be much slower. (ignorant/accurate)[/li][/ol] This may be true of USB chargers, but it’s not true of standard DC adapters, as I discovered when I plugged in what I thought was my scanner power adapter but turned out to be the adapter for a power drill. Cue loud bang and puff of smoke. ---
**Author:** ![abel29a](https://avatars.discourse-cdn.com/v4/letter/a/ebca7d/32.png) [@abel29a](https://boards.straightdope.com/u/abel29a)\ **Post date:** [March 11, 2014, 5:49pm UTC](https://boards.straightdope.com/t/those-5v-usb-chargers/683425/15 "2014-03-11T17:49:52Z")
Of course not, a DC wall adapter could have any voltage rating under the sun (well, not really). However, any DC adapter marked USB must confirm to the 5V voltage rating (with a max. amp of 0,5-2,1A as noted above). Some cheaply made electronics (like your scanner, I guess), have no over-voltage protection, no reverse polarity protection and no draw-current limiters, and will fail if any DC adapter is used that doesn’t fulfill its exact requirements, but these are thankfully growing rarer… ---
**Author:** ![bardos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bardos/32/1069_2.png) [@bardos](https://boards.straightdope.com/u/bardos)\ **Post date:** [March 11, 2014, 7:55pm UTC](https://boards.straightdope.com/t/those-5v-usb-chargers/683425/16 "2014-03-11T19:55:39Z")
Please, back to my original question: Could I basically use any 5v 1 amp charger for my IPAD and phone? That is, carry only one charger on vacation, for example and use it for both apparatuses? ---
**Author:** ![Rhythmdvl](https://avatars.discourse-cdn.com/v4/letter/r/85f322/32.png) [@Rhythmdvl](https://boards.straightdope.com/u/Rhythmdvl)\ **Post date:** [March 11, 2014, 8:06pm UTC](https://boards.straightdope.com/t/those-5v-usb-chargers/683425/17 "2014-03-11T20:06:04Z")
Relevant answer from the [Apple community.](http://store.apple.com/us/question/answers/ipad/iphone-v-ipad-charger-cables-wattage/QFF2KJFJXKFFKU7KX) Using ‘ipad iphone charger interchangeable’ in Google got several confirming answers (both of the charger and the cord), but before blowing anything up I’d repeat the search to feel comfortable on your own. > [@](#): > > I must correct and update the other answer that was posted for this question. > > Apple now sells USB power adapters in 3 wattages: > > - 5W ships with iPhones > - 10W ships with old iPads > - 12W ships with the latest iPads > > It is the adapter (the block that plugs into the wall) that determines its wattage and voltage. The cables are completely interchangeable with anything that it fits. > > As new devices step up the wattage from 5, to 10, to 12, Apple has created adapters to help them charge more quickly. All of the adapters are backwards and forwards compatible (they all “work” with older and new devices). However, charging an iPad that came with a 10W adapter with a 5W charger will be very, very slow. But it works. > > Here is the correction to the previous answer: Charging an iPhone (usually a 5W device) with a 10W charger will NOT charge it any faster. It won’t harm the phone either. The charger simply steps down the wattage for the device and charges as it a 5W charger would. ---
**Author:** ![leahcim](https://avatars.discourse-cdn.com/v4/letter/l/b4bc9f/32.png) [@leahcim](https://boards.straightdope.com/u/leahcim)\ **Post date:** [March 11, 2014, 8:06pm UTC](https://boards.straightdope.com/t/those-5v-usb-chargers/683425/18 "2014-03-11T20:06:56Z")
> [@bardos](#): > > Please, back to my original question: Could I basically use any 5v 1 amp charger for my IPAD and phone? That is, carry only one charger on vacation, for example and use it for both apparatuses? I’m going to say “yes” (if the cords fit). Whether or not your device is going to blow up is determined by the voltage, not the current, and the voltage is uniformly 5V for USB chargers (but, as noted by **Colophon** not for general DC adapters). ---
**Author:** ![Rhythmdvl](https://avatars.discourse-cdn.com/v4/letter/r/85f322/32.png) [@Rhythmdvl](https://boards.straightdope.com/u/Rhythmdvl)\ **Post date:** [March 11, 2014, 8:09pm UTC](https://boards.straightdope.com/t/those-5v-usb-chargers/683425/19 "2014-03-11T20:09:30Z")
> [@leahcim](#): > > the voltage is uniformly 5V for USB chargers . Does Apple consistently respect non-Apple standards? ---
**Author:** ![Dr.Strangelove](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dr.strangelove/32/6613_2.png) [@Dr.Strangelove](https://boards.straightdope.com/u/Dr.Strangelove)\ **Post date:** [March 11, 2014, 9:50pm UTC](https://boards.straightdope.com/t/those-5v-usb-chargers/683425/20 "2014-03-11T21:50:38Z")
As others have said, baseline USB provides 500 mA and is compatible with pretty much everything, and some chargers can provide more than that. The problem is that these high current modes aren’t a part of the baseline USB specification, and so the device and charger need some way to negotiate the higher current rating. This is done via some kind of resistor network involving the data lines. There are several different standards out there: the Chinese have one; there’s another semi-official USB standard; Apple has a few of their own for different power levels; Sony has their own as well; there are probably others. It is actually possible to build a [charger that supports](http://datasheets.maximintegrated.com/en/ds/MAX14578AE-MAX14578E.pdf) all of these methods simultaneously, but in general there’s no guarantee that you will actually get high speed charging from a high-current charger unless it’s specifically designed for it. [Next page](https://boards.straightdope.com/t/those-5v-usb-chargers/683425.md?page=2)