Wednesday, April 2, 2014

Why is my phone charging so slow?!?!

Most electronics these days are designed to charge of standard USB ports, which makes it convenient as you don’t have to buy and carry around endless chargers. However, even though USB ports all look the same, the electronics that power them are not, and this can lead to some weirdness.

Many of us are used to think about chargers in terms of the physical properties of the plug, and the more savvy are aware of the voltage as well (as in, if a device requires 12 volts, you can’t charge it off a 5 volts charger even if the plug fits). There are, however, additional properties for electric current which impact this as well. The one that affects charging a lot, as it happens, is the Ampere (often referred to simply as “Amps”).

Ampere is a way to describe the amount of electric charge (passing a point in an electric circuit) in a certain time. You can read more about it here, but let’s forget formulas and science-studies for now and focus on the realities…

When something (like a charger) provides power, it would always have a certain voltage, wattage and ampere rating, which designate what it can “give” out. A high-quality one will have a clear label listing those, though most chargers will only list the voltage and ampere, because those matter most. Also, there’s a direct relationship between the three, so if you know two, you can calculate the third, if you want. The bottom line here is that the properties of a charger determine not only whether it CAN charge your device, but also how FAST it will do so.

Some electronic devices come with a wall charger that hooks directly into the device and to the wall socket. Other electronics, like the iPhone and iPad come with a wall-USB charger and a separate USB cable. This modular approach is nice, because instead of having two cables, you can hook the phone to the computer or the wall using the same cable. Naturally, you can also go on the road and charge multiple devices using the same charger (and sometimes sync with the same cable). If you look at the charger that came with your device, it should list the Ampere rating it supports. For example, here is a standard Apple iPhone USB charger:


In the photo above, you can see that this charger is rated at 1A, or 1 ampere. Most chargers out there are rated at 1 Ampere too, so this is pretty common. However, if you go and buy another one and not pay attention, you might find yourself with a weaker charger, like this:


Supporting only 0.7 Ampere, this charger would charge your device 30% slower than others, which could be bad news. On the other hand, if you DO pay attention, you can easily find chargers that support a higher rating – some as much as 2.6A. For example, this charger by Anker has 2 ports, each supporting 2.4A (for a total of 4.8A):


This charger will charge your iPhone about 2.4 times faster than the charger that comes with the phone (and it doesn’t cost too much either!)

Naturally, having a higher Ampere rating is something manufacturers want to do, but not all of them actually bother with being clear about it. For example, you might be lured into buying this car charger, thinking it’s more than 3 times faster than the standard Apple charger:


However, the 3.1 Amps rating here actually refers to the COMBINED output of both ports. In reality, the top port provides 1 Ampere, and the bottom one 2.1 ampere. This is why the bottom port is labeled “for iPad”, because if you attempt to charge an iPad on the 1A port, it will take a LOT of time. In fact, if the iPad is on at the time, its power usage will probably out-pace the power produced by the charger.

Another note on this topic is that even though the higher Amp rating doesn’t necessarily increase the cost of the device, buying these at many stores can easily cost an arm and a leg. Radio shack, for example, has a 2.4 Ampere charger, but it will set you back over $30. In online shopping sites like Amazon and eBay, you can easily find a comparable device for as low as $6 (in addition to the one by Anker I listed above).

Last note about this is that even though saving money is good, I wouldn’t advocate going too far on this. Reducing costs often requires reducing the quality of parts or performing little to no QA (Quality Assurance) by the manufacturer. This could lead to various malfunctions which could include:

1. Underperforming (lower voltage or lower current which could slow down or stop charging)

2. Over performing (higher voltage, which could damage the device you are charging or cause it’s battery to explode)

3. Overheating, which could lead to melting, shorts or even explosions

In addition, lower-end chargers might actually be falsifying their labels and sell you a 1A charger with 2A on the label…and testing it is quite difficult. In other words…shop around, but try to aim for products with good reviews, or least a brand-name you can trust.


  1. Charge your mobile devices on the go This sleek device fits neatly in your pocket and is a great backup tool in case of a 21st-century emergency Eubi Emergency .

  2. People should really be wary about the kind of charger they'd get. But it really helps to be able to distinguish between them in terms of power capacity. While that's pretty much basic for cellphone maintenance and ownership, it certainly helps to be reminded for our own sake. No one wants a faulty phone, much less a suddenly inoperable one.

    Cordia Remsen @ RBSMN