Sometimes even a well designed and assembled power supply can be dangerous because of defective components. Big Clive on Youtube does many teardowns of cheap electronics, and here's one of a USB power supply that's dangerous because of internal damage to the transformer:<p><a href="https://www.youtube.com/watch?v=3Hdn0MuCK_0" rel="nofollow">https://www.youtube.com/watch?v=3Hdn0MuCK_0</a><p>Because this is an intermittent fault it's possible that non-destructive testing would not find it.
I trust Anker's chargers more than anyone elses. (No association with them, just a happy customer.)<p>In general, chargers from big brands (Apple, Amazon, Samsung, even Ikea) are fine because they don't want to risk damage to their brand if one were to burn down a house or something.<p>If your charger has a brand you've never heard of, beware!
From what I've experienced, most power supplies are just awful and don't hold up at all to their specs, especially current in excess of 500mA.<p>I've been working with LEDs recently (APA102s), and I attempted just doing some testing with 4 meters (60 LEDs/m) and a cheap old 5VDC laptop power supply that in theory was rated for 5A+. Didn't work so well. Overheating, not providing enough current to keep the LEDs acting stable, power on spike, etc...<p>To solve my problem, I've purchased two 5V 90A Meanwell power supplies, and those seem to work pretty well. But needless to say, I cannot imagine cheap/small power adapters working well at all.<p>At my day job, we have some hardware that requires 800mA at peak to run. Even many 1A USB supplies we've found to offer nowhere near that current capacity. And if they do, they frequently fail after a while.
I think the best power supplies are those commissioned by big manufacturers to go with their hardware. The HP Touchpad's power plug being a good example. These brands don't want a poorly designed adapter killing their products.
Makes me wonder if DC wiring will ever catch on in newer homes. We don't have much need for AC anymore. The only places in a home where one needs AC is in the kitchen for large appliances, and garage/laundry room. And really that's just because of the motors. I'm not sure if those could be converted to DC motors and what powerloss that might entail. But the point stands; you could totally get away with building a new home where you drop AC to the kitchen and garage, and then 12VDC+5VDC everywhere else (12V on the wires, put a regulator to drop to 5V in the outlet for USB-C ports). The power-loss of DC in a home won't be that large. The end result is that the AC to DC transformer will be centralized to one location, where you can spend more money up front to get higher reliability, cleaner power, better safety, and better efficiency. Plus, if you have solar, you can avoid AC to DC conversation altogether, saving on a good chunk of powerloss there.<p>The caveat, of course, is that lots of devices don't natively support DC input. Phones, tablets, and modern USB-C laptops are fine. Lighting is easy; just do permanent LED installations. The LEDs will last a very long time since they won't have regulators in them. Desktops are an issue. I believe the only desktops that support DC input are HTPC builds, using those micro PSUs. Perhaps there's an HTPC PSU that's got enough beef to power a normal desktop? You'd also have to find monitors that accept DC input, which do exist but that will narrow your market significantly.<p>Rob Rhinehart is an early adopter (see: <a href="http://robrhinehart.com/?p=1331" rel="nofollow">http://robrhinehart.com/?p=1331</a>) of this type of home. Sounds crazy, but it seemed like a glimpse at a hopeful future, at least everything outside of the kitchen.
I've been searching for a good-quality usb hub. After a few years of intense competition, there are basically two options on the market: cheap chinese crap, and cheap chinese crap in an expensive designer enclosure.
This is obvious to the point of not reiterating but don't ever plug your stuff into cheap/unknown chargers. I've seen the AC jump across to the low power DC side MANY times and it insta-destroys anything designed to just take the +5vdc.<p>I work in the event industry and we supply recharging cabinets for corporate events. We use Anker.
I generally avoid anything that doesn't have legitimate safety certifications: UL, ETL, TUV, etc. ("CE" as printed on random imported crap seems to mean nothing in particular.)<p>Also, you can usually count on actual, non-counterfeit chargers from well-respected phone and tablet vendors being just fine. I've never thrown out an old USB charger from an iphone, samsung, motorola, asus, just put them in a box for possible later use :)
After reading Ken Shirriff's review a few years ago, I bought a bunch of Touchpad chargers off eBay (before the clones started appearing) and use them for tons of stuff.<p><a href="http://www.righto.com/2012/10/a-dozen-usb-chargers-in-lab-apple-is.html" rel="nofollow">http://www.righto.com/2012/10/a-dozen-usb-chargers-in-lab-ap...</a><p>Otherwise I stick with Anker/Aukey; am a huge fan of the 6-port "charger bricks" and have used one next to my bed (phone, two tablets, a couple of USB-powered devices like a sleep monitor) for 3-4 years now.
Here are some good analytical reviews of USB power hardware, including safety: <a href="http://www.lygte-info.dk/info/indexUSB%20UK.html" rel="nofollow">http://www.lygte-info.dk/info/indexUSB%20UK.html</a><p>In general I buy Anker stuff - decent pricing and solid stability/quality/safety.
There's a difference between active and passive protection systems - similar to certain Lithium-ion batteries. A lot of the cheaper manufacturers skimp out on a lot of such components (hence why you hear of e-cigs blowing up, etc).
I've been very satisfied with my charger from ChoeTech. I figure that if something is Qualcomm Quick Charge Certified, then it is probably adequate to charge my devices.