Amazon PowerFast chargerAny geek household, like mine, is bound to have a slew of 5-volt USB chargers hanging around these days. Plus, a couple of days ago I picked up a Chinese no-brand USB charger claiming to offer high power with 2 amps, for just $1.75. But Amazon insists that the best charger for a Kindle Fire is the Amazon Kindle PowerFast adapter. Amazon also warns you to “charge your Fire tablet with the power adapter and USB cable that came with your device. Using another power adapter or USB cable, or charging from the USB port on your computer, will increase charging time.” But does it make that much difference? And how do various chargers perform with the Fire?

Fortunately, with my Kindle Fire hacked to use the Google Play Store, I can access the full range of battery and charge monitoring apps. For this test, I used Braintrapp’s Ampere, one of the most popular. And I tried a range of USB chargers. With the Fire about 90 percent charged, the no-brand Chinese 2-amp charger gave a starting amperage of 970 microamperes, falling away within a few minutes to a much lower amperage (around 490 microamperes). However, so did the Fire’s own charger. So too did the Asus 2-amp charger from my old Nexus 7 2012 – a notoriously picky model for chargers. So did the good-quality 1-amp charger from my Lenovo A7-10 tablet. In fact, the only difference I found with this basic 970 mA starting level was when I plugged the device into a 2-amp 2-socket charger. With that, the amperage dropped to 470 mA.

I won’t swear that the software or testing process was flawless. I did test with various cables, and got the same results. Ampere may not be the best software to test this on a Fire, but I haven’t found a better app. And I’d be interested to get feedback from anyone with a more informed position. So far, though, my strong suspicion is that, within reasonable parameters (a.k.a. a good quality 5-volt charger rated at 1 amp or above), pretty much any charger will charge your Fire well enough, at around the same rate. The Amazon PowerFast charger is rated at 9 watts instead of the usual 5, which may indeed speed things up. But so far I don’t see any compelling need to switch from my current gaggle of chargers.

There is always the safety issue, though. News reports frequently refer to no-brand chargers bursting into flame, so that is one risk to watch for. But the compatibility issue in itself seems to be a non-issue, based on my findings. So charge away.


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