Update on my Leviton USB outlet. Last night I plugged my iPhone 4s into the "low power" outlet first, then plugged my iPad 3 in the high speed outlet minutes later. When I retrieved my devices this morning I was surprised to see my iPad only went from 17% to 53% in 8 hours, and my iPhone was at 100%. While it needs more testing, it appears that the Leviton will not adjust its charging speed when one device no longer 'needs' more power.
USB Charging Delemma
- Thread starter mikei-ma
- Start date
whiskeychief
New Member
Mike-ma said:
Sorry to resurrect an older thread, but while researching these I noticed that Hubbell Wiring Devices--Kellems is listing their dual USB + duplex receptacle at at total of 3.0 Amps, with
The Part # for the current model is USB15X2W.
As far as I know, most of the other manufacturers are at around 2.0-2.1 Amps on their USB wall receptacles. Cheers.
jmorris644
Active Member
The one that I purchased, which was the original one on the market for $25 works great. I have 3 of them around the house and they charge all of my iOs devices just great.
joe
joe
tmbrown97
Senior Member
Neuro - I installed this Cooper one in September - both ports will charge high-amp devices without worrying about which is the high power or low power port. It also works with my newest ipads with their own cord - which oddly the new lightning cord doesn't work with old ipad charging bricks. This replaced an outlet in my kitchen where we only ever plugged in usb receptacles anyway, so it's much cleaner. A little strange that the outlets are upside down - not sure the reason (my install is horizontal conveniently so it makes zero difference) but I'm extremely happy with it.
tmbrown97
Senior Member
Yeah - it fits any standard decora faceplate. It may stick out just a hair more than a standard outlet would but it works very well without worrying about which port to use for what, and you can use the outlets at the same time as long as long as the plug isn't too big. I need to order a few more for the bathrooms - another common charging spot.
Wow, with the number of smart people here, it is truly amazing how few of you really understand how USB charging works, or even much about electronics.
O.K. raise your hands if you thing any 2.1A USB port can charge any USB device that requires 2.0A? O.K. Look around. If you have your hand up, you are WRONG.
Here is an easier one. Lets say you plug a circular saw that uses 18A into a plug rated for 15A? It blows the fuse, correct? So what happens when you plug a tablet that draws 2.1A into a USB outlet that can only supply 0.5A? It charges at 0.5A. How can that be? If you measure the USB voltage its still 5V. But no sparks.
Well USB charging involves MUCH more than just a socket at a certain amperage. A USB devices "asks" the charger how much current it can supply, so it can adjust to that charger. A "standard" USB outlet is only guaranteed to supply 0.5A at 5V. Anything over that is optional.
Back when all USB outlets were in computer, it wasn't a problem because a computer and smartphone/tablet had no problem conducting a great conversation on maximum current allowed, but what about "dumb" cube chargers? Not much smart in there. So manufacturers came up with a method that would use the two data wires in USB to indicate their supply current capabilities of their chargers. Apple, for example, uses two different resistance values on the data+ and data- to indicate two optional charging rates; the iPhone rate of 1.0A and the iPad rate of 2.1A If its not coded at all, the device assumes 0.5A max.
Here is where it gets complex. Different manufactures at different companies use different coding schemes, and surprise, one is not compatible with another. This means in many cases (not all) a device not understanding the charging scheme it is seeing will revert to 0.5A even if the USB port can supply 10,000Amps. A low charging rate is preferable to a fire. Wouldn't you agree?
A few devices, like recent Android devices are "smart" enough to understand charging schemes from several companies but most devices CAN'T. Also, the majority of cube chargers out there, especially if they are the color white are designed for Apple devices and can charge iPhones and iPads at their correct rates. (Again, Apple ONLY has two special rates 1.0A, and 2.1A) I have a few chargers from third parties that even indicate the coding by the USB outlet, 1.0A or 2.1A.
Oh, and one more thing. Some charging cables are made with such low quality cable, that they can't even handle over an amp or two if the coding was correct.
SO, the moral of the post is, NOT every charging port rated at over 0.5A can charge EVERY devices at over 0.5A EVEN IF electronically the power supply is big enough.
So is there a solution? Partially. First, more devices are getting smarter to read several USB codings, but today most CAN'T. Second. A few chip companies, like TI, realized this problem and designed chips to "translate" and negotiate the outlet with the device. For a while you could buy these adapters on Amazon, but it seems most were poor sellers and are not available now, but if you want to search try "USB Power Converter Adapter Charger for Smart Phone" as search term. They might still be available in China. I have a bought a bunch of them and now use them when charging any USB device. They work great, and I can now charge a Nikon camera I have with ANY charger, not just the Nikon USB charger.
You would thing they just could build these into USB chargers, so chargers would be universal, but that costs extra money, and so few people really understand the problem that it never has happened that I know of.
So when you buy ANY USB charger rated at over 0.5A, its important to know WHAT company is it coded for? If its white, and labeled at 1.0A or 2.1A its most likely Apple. But as I've been saying, don't ASSUME that if the charger is rated at a rate that is as high as or higher than the device, that it will charge at this rate. Maybe it will. Maybe it won't.
O.K. raise your hands if you thing any 2.1A USB port can charge any USB device that requires 2.0A? O.K. Look around. If you have your hand up, you are WRONG.
Here is an easier one. Lets say you plug a circular saw that uses 18A into a plug rated for 15A? It blows the fuse, correct? So what happens when you plug a tablet that draws 2.1A into a USB outlet that can only supply 0.5A? It charges at 0.5A. How can that be? If you measure the USB voltage its still 5V. But no sparks.
Well USB charging involves MUCH more than just a socket at a certain amperage. A USB devices "asks" the charger how much current it can supply, so it can adjust to that charger. A "standard" USB outlet is only guaranteed to supply 0.5A at 5V. Anything over that is optional.
Back when all USB outlets were in computer, it wasn't a problem because a computer and smartphone/tablet had no problem conducting a great conversation on maximum current allowed, but what about "dumb" cube chargers? Not much smart in there. So manufacturers came up with a method that would use the two data wires in USB to indicate their supply current capabilities of their chargers. Apple, for example, uses two different resistance values on the data+ and data- to indicate two optional charging rates; the iPhone rate of 1.0A and the iPad rate of 2.1A If its not coded at all, the device assumes 0.5A max.
Here is where it gets complex. Different manufactures at different companies use different coding schemes, and surprise, one is not compatible with another. This means in many cases (not all) a device not understanding the charging scheme it is seeing will revert to 0.5A even if the USB port can supply 10,000Amps. A low charging rate is preferable to a fire. Wouldn't you agree?
A few devices, like recent Android devices are "smart" enough to understand charging schemes from several companies but most devices CAN'T. Also, the majority of cube chargers out there, especially if they are the color white are designed for Apple devices and can charge iPhones and iPads at their correct rates. (Again, Apple ONLY has two special rates 1.0A, and 2.1A) I have a few chargers from third parties that even indicate the coding by the USB outlet, 1.0A or 2.1A.
Oh, and one more thing. Some charging cables are made with such low quality cable, that they can't even handle over an amp or two if the coding was correct.
SO, the moral of the post is, NOT every charging port rated at over 0.5A can charge EVERY devices at over 0.5A EVEN IF electronically the power supply is big enough.
So is there a solution? Partially. First, more devices are getting smarter to read several USB codings, but today most CAN'T. Second. A few chip companies, like TI, realized this problem and designed chips to "translate" and negotiate the outlet with the device. For a while you could buy these adapters on Amazon, but it seems most were poor sellers and are not available now, but if you want to search try "USB Power Converter Adapter Charger for Smart Phone" as search term. They might still be available in China. I have a bought a bunch of them and now use them when charging any USB device. They work great, and I can now charge a Nikon camera I have with ANY charger, not just the Nikon USB charger.
You would thing they just could build these into USB chargers, so chargers would be universal, but that costs extra money, and so few people really understand the problem that it never has happened that I know of.
So when you buy ANY USB charger rated at over 0.5A, its important to know WHAT company is it coded for? If its white, and labeled at 1.0A or 2.1A its most likely Apple. But as I've been saying, don't ASSUME that if the charger is rated at a rate that is as high as or higher than the device, that it will charge at this rate. Maybe it will. Maybe it won't.
this thing works well if you just want a bunch of usb charging ports: http://www.amazon.com/Family-Sized-Desktop-Charger-Smartphones-USB-Powered/dp/B00DVH62J2/ref=sr_1_3?ie=UTF8&qid=1387225447&sr=8-3&keywords=anker+usb
Anker is one of the few companies that seem to "get it" and clearly explain how their USB ports are coded. I have seen a few others like this also, but what they write sometimes seems cryptic unless you understand what is going on. The sad fact is that millions of people have been plugging in their devices to 2.0A+ USB ports that only end up charging at the 0.5A rate, if that.tadr said:
tmbrown97
Senior Member
Maybe so - or manufacturers are taking care of this better. The outlet I linked above works great and is charging all my devices at comparable speeds to the factory-included high output chargers for everything I've plugged into it - which is mostly iDevices but includes others as well - things like GPS for my Nikon DSLR; a rechargeable helicopter; bluetooth headset; raspberry pi; you name it...
It's relatively common to charge a couple iPads at once or an iPad and iPhone - or even our crappy old Android tablet - and we have not had any issues with things not charging or not charging fast enough. Even the irritating special new Lightning cables that don't work with older iPad charging bricks do work on that outlet and I get no warnings about being an unapproved device or slow charge speeds - it just works.
It's relatively common to charge a couple iPads at once or an iPad and iPhone - or even our crappy old Android tablet - and we have not had any issues with things not charging or not charging fast enough. Even the irritating special new Lightning cables that don't work with older iPad charging bricks do work on that outlet and I get no warnings about being an unapproved device or slow charge speeds - it just works.
From the ones I have tried, most charging ports now-a-days are coded for Apple, either the 1A rate or 2.1A rate. Many devices like cameras never charge any faster than the 0.5A rate anyway, so they don't really matter. A few "smarter" devices, like recent Android phones are also better at decoding the UPB port. Otherwise unless you do some detailed testing, or actually measure the current the device is drawing, you'll never know the difference.
tmbrown97
Senior Member
For people who are curious about what ano describes above, this could be an easy way to test:
http://www.cyberguys.com/product-details/?productid=76178&rH=1770
Luckily Apple devices are the most widely standardized so it works for us.
http://www.cyberguys.com/product-details/?productid=76178&rH=1770
Luckily Apple devices are the most widely standardized so it works for us.
