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Not All USB Power Is Created Equal
jfruh writes "We've reached a point in our electronic lives where most of our gadgets draw power from a USB cable, and we have lots of USB ports to choose from — some of which live on other gadgets, some of which live on adapters that plug into your wall or car. But those ports supply wildly varying amounts of power, which can result in hours of difference in how long it takes your phone to charge. The Practical Meter, the product of a successful Kickstarter campaign, can help you figure out which power sources are going to juice up your gadgets the fastest."
Like this little thing and also learn what the numbers and values mean. Got two, they work great and they're consistent with more pricier measurement options.
http://www.kickstarter.com/projects/david-toledo/the-practical-meter-know-your-power
At work I could plug my phone into the computer or... Buy a second plug, that seams a bit pointless even it if it does knock and hour of the phones charging time.
At home I do have choice, but why would I really worry as each night it gets charged and has all night. So again an hour does not really matter.
What am I missing from this?
Wow, I should not post when knackered.
Being the fastest might not be the best for your battery life.
I believe most types of battery when charged faster actually degrade faster.
Life fast die fast ;-)
New things are always on the horizon
Instead of that ugly one, you may get something that gives an exact value, like this one. A new iPhone/iPad expects 2A, the MacBook (10W) expects also 10/5 = 2A.
Slashdot, fix the reply notifications... You won't get away with it...
Samsung seems to measure the "reliability" of the supply or the cable, and limits power based on those values. Then the same supply will charge at different rates depending on the cable used.
In what way is it "good and practical" to ignore a standard, possibly damaging electronics which assume the standard by providing a variable non-guaranteed maximum current? At worst this is a fire hazard, as you'd end up delivering an unreasonably high current. If the device isn't intelligent enough to ask for the right current, it should be delivered a safe trickle - as the USB standard asks.
A USB port should react gracefully to a defective USB device - either limiting current or cutting power if draw is too high. It should not give the malfunctioning device the opportunity to catch fire by delivering it as much current as possible.
Liberal in what you accept; conservative in what you send.
It's not the job of the power supply to protect malfunctioning devices from themselves. It's the job of the devices to have fuses, regulators, etc. This has been true, forever.
Your wall outlets will provided whatever is requested. Your car's alternator and battery will do the same. 12V devices plugged into a cig plug will get whatever they want, if they were designed so poorly as to not have a dammed fuse.
Slashdot gets worse every day... Pipedot: News for nerds, without the corporate slant
This. A couple of years ago I plugged a defective DVD drive into an alienware notebook. It smoked the DVD drive, then blew up the entire USB subsystem of the notebook.
Needless to say, I don't recommend alienware to anyone anymore.
You can never know everything, and part of what you do know will always be wrong. Perhaps even the most important part.
Yeah, but the power supply should protect itself. If the damn thing is connected directly to the laptops 5V rail it's possible to make the laptops 5V drop by plugging in a defective decvice. That in turn means all kinds of weird shit might happen, including data corruption and hardware deaths.
I'm an Apple Abhorrent... I don't use any of their products, not even an Ipod. I'm an Android/Windows guy. But my daughter decided she had to have an iPhone and bought it with her own money. I have one of those little plugs you put in a cigarette lighter in the car. My car has two up front, one that is ignition keyed, the other is always on. The dongle is in the one that is always on. And I have a standard USB cable to charge phones and other devices from it. It charges all of my Android phones fine. It charges the GPS fine. It charges pads like the Galaxy Tab and the Nexus fine. It won't charge my daughter's iPhone, even with her white Apple USB cord. To this situation, my daughter tells me that the little dongle I have is a POS. I smiled and was reminded, yet again, why I won't buy Apple products.
Brawndo: It's what plants crave!
Any device that reacts badly to too much current is poorly designed or defective.
Yes, and if I own such a defective device, I certainly don't want it starting a fire. The thing about electronics is that most people could own a defective component and not know until it's caused some other problem.
Electronic devices can have latent defects: poor insulation that's barely adequate to protect the device through testing, shipping, and installation, but as you use the device and move a wire repeatedly, the gap in the insulation causes a short. Should the purchaser be satisfied simply by knowing that he can sue the manufacturer for damages caused by fires? Does it mean the purchaser should never take other precautions, such as installing fuses, or buying equipment with current limiters?
Thanks, but I want to take all the measures available to me to ensure safety.
John
No your wall outlets provide up to what the wire running to them will support past that and the breaker trips or the fuse pops (granted it's often much after but still generally safe for the wire). Newer homes have arc faults in a lot of places that protect from even more.
Same thing for your car every branch circuit has a fuse of a given rating try getting more than 15 amps through your 12v accessory outlet.
Pretty much the rule is you can not step down the permanent wire size without an over current protection device.
No sir I dont like it.
Which (blankety-blank-censored-blank) is no longer available. And since the cables are no longer made or sold and since they were notoriously prone to fail means that I've been trickle-charging my unit for about a year now.
Exactly why I avoid devices with weird custom cables whenever possible in consumer electronics. It's been my experience that unless a custom cable is so popular as to become a standard itself (like Apple's Lightning) that eventually you are going to run into a problem. Furthermore it adds to the cost of the device (custom cables = $) and it usually means that the company making the device had lazy and/or incompetent engineers. Now admittedly the USB spec is pretty flawed, particularly when it comes to power, but even so I've still seen lots of devices that could have used standard USB (or Firewire etc) had they taken the time to do so.
Now sometimes the standard needs to be updated. I think USB should be beefed up to handle up to 100 watts with all due haste.
Bear in mind that my day job is to run a company that makes custom cables. Think about that. I make a living off of custom cables, have the ability and equipment to make a copy of pretty much any cable, and I still think they are a bad idea for most consumer electronics.
One example: my Nexus 7 draws so much power, even when sleeping, that it is possible to connect it to a weakly charging USB port, come back a few hours later, and it has a lower charge level.
If you need a portable fusion reactor to power your tablet and/or phone *while it is sleeping* then there's something really wrong with your device.
(Bad hardware design, bad OS power management, or you installed too much background shit).
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