All USB Power Adapters Created Equal?

OK, so this is a total dumb noob question that I'm embarrassed to ask on this forum. But we all have to start learning at some point, right? :shrug: So here goes...

Are all USB power adapters created equal? Can I charge any micro-USB flashlight from an AC outlet using a USB power adapter, like the little 1" white "cube" that charges my iPhone?

I ask this question because I have various devices with micro USB charging ports. Some use cords that are USB on one end, with a hard-wired "wall wart" on the other end. Others have cords that are USB on both ends. If the cord is USB on both ends, I always charge the device on my computer's USB port. I've been tempted to plug one of these USB cables into my Apple wall adapter. But I'm not sure if there are compatibility issues. I don't want to fry a device to find out.

So now I'm thinking of buying my first light with a micro USB charging port (MH20GT). Of course, I can remove the batteries and charge them in my Xtar charger. But I'd also love the convenience of just plugging the light into a wall outlet (rather than a USB port).

Will any old USB power adapter that plugs in the wall suffice to connect directly to a light? I see many USB power adapters for sale that look exactly like the one Apple makes. Are they all pretty much the same? Should I get a certain kind to charge USB lights?

Thanks in advance for any advice.

Any adapter will work. There are different charging rates from adapters though. The apple device charger you have will work fine. I believe they are 1 amp

The answer is yes and no.
Not all usb adapter can deliver the same amount of power. Using an adapter than can provide 0.5A with a device that requires 2A will not work (The other way around will).
Usb adapters contains a coding, saying how much power they can deliver, this coding varies depending on brand and not all equipment checks the code.
The most versatile adapters are the ones that can deliver 2.1 or 2.4A with automatic coding, they can power just about any type of usb equipment.

There is also the detail about quality, some cheap adapters are very bad quality and is dangerous to use.

I have tested some adapters here: http://lygte-info.dk/info/ChargerIndex UK.html

Bigburly912 said:

Any adapter will work. There are different charging rates from adapters though. The apple device charger you have will work fine. I believe they are 1 amp

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2 Amp I believe.

Just ordered this 2 amp wall plug that can charge 2 devices at the same time,ideal for my work and personal phone and my tablets.I bought it so the leads fit into the top for ease of use.

HKJ said:

There is also the detail about quality, some cheap adapters are very bad quality and is dangerous to use.

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As HKJ posted, there are some dangerous USB power plugs out there.

Ken Shirrif's blog has some teardowns from a few years ago, but illustrate the dangers in cheapie chargers when it comes to creepage and the distance between high voltage and low voltage separation. A lot of these cheap chargers ignore safety standards and have poor quality parts.

Check these out for example:


http://www.righto.com/2012/10/a-dozen-usb-chargers-in-lab-apple-is.html - his comparision of various chargers that were available a few years ago.
http://www.righto.com/2012/05/apple-iphone-charger-teardown-quality.html (Apple USB Charger) vs http://www.righto.com/2012/03/inside-cheap-phone-charger-and-why-you.html (Generic cheapie)
http://www.righto.com/2014/05/a-look-inside-ipad-chargers-pricey.html - teardown of an Apple Ipad charger compared with a cheap fake.


Also another video showing showing how dangerous cheap chargers can be http://www.youtube.com/watch?v=wi-b9k-0KfE

keithy said:

Ken Shirrif's blog has some teardowns from a few years ago, but illustrate the dangers in cheapie chargers when it comes to creepage and the distance between high voltage and low voltage separation. A lot of these cheap chargers ignore safety standards and have poor quality parts.

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The list I posted a link to is newer and contains that kind of analyses for more than 70 adapters.

I also put a heavy load on them and then look to see how much the voltage sags and how much ripple current I see with the oscilloscope. I'm also looking for any inductor or transformer whine or buzz. I also use 26 AWG cables and better, (no 28 AWG and long cables). I've seen several tenths of a voltage drop on 28 wire gauge cables when using higher current.

I've read the info on the links by HKJ and Ken Shirrif (thanks to those who posted them). It appears the Apple USB power adapter is among the best available, provided it's genuine. I'll refine one of my original questions...

Is the Apple USB power adapter a reasonably safe and universal option to charge most any USB rechargeable flashlight?

I'm uncertain what amperage the Apple adapter puts out (1Amp and 2Amp are mentioned in this thread). I'm also uncertain what amperage a typical USB rechargeable light requires. (I'm interested in a Nitecore MH20GT, but I don't see a required charging amperage listed).

So again, I just hope to determine if the Apple adapter is a good universal option for a variety of USB rechargeable lights. Again, thanks in advance for enduring my novice questions.

I'll throw in my own 2c here and maybe someone can chime in.

I made my own charging station using a 2.1a 5v power source that was once for a router. Measured 5v at the terminals, cut off the end and soldered 2 22awg cables with diy micro usb ends on them.

One cord is about 5ft long which plugs into a usb OTG tablet adapter which has 4 usb ports where I have 3x micro usb cables to charge my powerbanks and cell phones.

Also off of the main tap I've put a 15ft microusb cable so that I can use the same tablet from my bed without having to move cables around.

It's an interesting setup, mostly because I wanted a cable that was clear so that it visually disappeared.

Even with calculated voltage drop, my tablet and cell phones stay sufficiently charged.

I have no special codes, or circuits to identify the power source and it's ability to charge devices. It all seems to just work even though it's low tech.

I've torn apart cheap chinese usb power sources, and have found no special circuits that regulate anything.

Asides from not knowing how long things should take to charge, they do seem to charge.

The only issue I seem to have is that my tiny tablet seems to slowly drain to shutoff if I play a legacy PC game such as battlefield 1942, but other than that, the tablet battery seems to stay charged when plugged in except if I put the table on high brightness or am just constantly surfing, of which after 2-3 hours, the charge level of the battery will drop to 93%.

Cell phones and power banks seem to charge just fine.

For the $3 in parts I invested, it's worth it despite the shortcomings and it seems to work.

I've looked into the links on the page regarding safety, but I'm assuming that since the powersource was for a linksys router, it's 'ce' stamped, that soldering on microusb connectors on the end can't be all that bad.

Insulator Collector said:

Is the Apple USB power adapter a reasonably safe and universal option to charge most any USB rechargeable flashlight?

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I doubt any light will check the usb coding, this means they will work fine with the Apple adapter.

Insulator Collector said:

I'm uncertain what amperage the Apple adapter puts out (1Amp and 2Amp are mentioned in this thread). I'm also uncertain what amperage a typical USB rechargeable light requires. (I'm interested in a Nitecore MH20GT, but I don't see a required charging amperage listed).

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Apple has both1A and 2.4A adapters. In the table I linked I list the current.
My guess is that the light uses 1A.