Charging USB devices

I bought a new tablet and the manual states that you must only use the charging cable and adapter provided lest you damage it. I was wondering if my power strip that has the usb charging ports is okay to use. I hate those gigantic adapters that take up all the space on my surge strip, especially when you have a phone, a tablet and a camera all fighting for a slot.

99.9% of the time this is just CYA by the legal department. There may be a few devices that actually require specific chargers but I don’t know of any. The charging may not be optimal speed, but it is extremely unlikely to damage anything.

I agree with Telemark that it probably wouldn’t cause damage, but it may not be sufficient to keep the device charged, especially if you’re also using it at the same time.

Try to find something that’s at least 2.5A if not 3.1A+. That’s a measure of amperage (how much power it can go out) and most embedded cheap USB ports do not have that kind of output, which is why they usually want you to use the included charger. But you can substitute the included charger with any other one that’s well-reviewed and up-to-spec.

If you’re not sure of your USB port’s output, chances are that it’s low-power. You can get USB power meters, but it’s cheaper just to get a better charger. You can get chargers with like 5+ ports, each with high power output.

Perhaps the biggest advantage of the USB standard is just that - standardization. I find it difficult to believe that anything labeled as a USB device cannot handle standard USB charging.

I agree with the others - it’s CYA by the legal department.

The issue is twofold. First of all, the older USB standards only provided a very small amount of current (I believe 500mA). Most devices wanted a lot more than that, so they started using hacky extensions that allowed the device to detect if more current is available and then draw on it. These extensions were never formally standardized, so you could wind up in situations where incompatible cables and devices would do the wrong thing. Worse, a number of cheap USB cables produced in China completely ignored the defacto standards in dangerous ways. There’s some Google engineer who had a blog devoted to dissecting this kind of dangerous junk.

The new USB-C standard has attempted to resolve the issue by standardizing high-amperage current draws over USB, but the standard is quite new and a lot of devices are still using the older mini- and micro-USB connectors instead.

It’s only a problem if you are using really cheap stuff that doesn’t implement the basic precaution of “Don’t give more current unless the device says it can handle it.” Sure, it’s possible the port won’t use the same method that your device uses, but the worst that would happen is that it will “trickle charge” rather than “fast charge.”

It’s CYA, possibly combined with what Apple does, which is try to lock you into proprietary stuff so they can overcharge for it.

Some of the cheap knockoff chargers really can damage your devices, because they do a lousy job of meeting the standard. You’ll see things like, instead of a steady DC 5 volts, a sine-wave output that oscillates between 0 and 10 volts.

But yeah, the standard is the standard, and any reputable device should be interchangeable.

Quick side-bar on this. I bought a Kia Soul for my wife a few years ago. She really wanted it, honest. Due to the nature of The Deal, it had all kinds of BlueTooth and other stuff I wasn’t interested in, but it had a Specific iPod USB connector that I was interested in. Except, the manual clearly pointed out that what should have been a universal USB connection, or even a proprietary Apple connection, could only be accessed by buying a separate proprietary KIA charging connector. Which I still don’t understand. I didn’t buy it.

Start here. Links to more comparisons. All the oscilloscope plot screen captures you could possibly want.

Thanks for the answers, although I remain unclear. I don’t even want to ask about car charging. :slight_smile:

OK, short answer: If your charger is a cheap knock-off piece of crap, then it could harm your device. If your charger is decent quality, then the worst that can happen is that it won’t charge your device as quickly as the same-brand charger could. And even that probably won’t happen.

A device that’s becoming increasingly common is the li-ion battery pack that can be used for jump-starting a car or even a truck. These are made with quality factors that seem to be all over the map, and most of them typically also have two USB charging ports, and because they have relatively big batteries in them, they are typically capable of putting out at least 2.1 amps through each USB port (the actual jump-starting is done through special large connectors that deliver hundreds of cranking amps for brief periods through jumper cables). I have the one that was recommended in this article.

I am frankly uncertain about how safe it is to use to charge various electronic devices, especially something like the Kindle that charges just fine on a tiny trickle charge from an old front USB 2.0 port. I did try it on my Samsung phone, but only long enough to determine that it did in fact start charging and didn’t seem to do any noticeable harm, but I’m not comfortable using it routinely. It’s mainly intended as an emergency jump-start device.

Thank you.