How to buy the best (Micro USB) car phone charger for less

Frustrated that your phone’s battery level doesn’t increase quickly enough (or even falls) while charging in your car? The problem may be that your phone thinks it’s connected via USB instead of to an AC source*, and so isn’t pulling enough power. After much hairpulling and forum reading**, I came up with a solution that’s worked for me thus far by enabling “fast” charging (the common term for AC charging) in my car.

You’ll need:

  1. A USB car charger adapter with the highest amperage available. Currently these max out at 2.1A. I recommend either of PNY’s units.
  2. A USB-A to Micro USB charge only cable. The “charge only” part is important: the cable has been modified to supply full power to Micro USB devices. A conventional Micro USB cable will not fast charge your phone when paired with a conventional USB car adapter***. I recommend this PureGear cable****.

And that’s it. All you have to do is plug Item 1 above into your cigarette lighter, connect Item 2 to the phone and Item 1 and you’re good to go. Total cost of the above for me: a whopping $10.25. That’s 46% less than the minimum $19.99 most brick and mortar stores list chargers at.


*To check this on an Android device, go to Settings -> Battery while connected to a power source. You should see something like “AC” or “USB” somewhere on the screen (usually at the top).

**I’m not sure why this very useful information is so difficult to find. Much of it is buried in Forumese, the elite language spoken by tech forum dwellers who assume everyone has a clue what their vague references mean despite the lack of links or any real explanation. A commonly posted – and alternative solution – is to use a normal USB-A to Micro USB cable with DIY solder-modified charger. You know, as if the average person has a soldering iron and wants to take a charger apart themselves. I wrote this post because literally canNOT find any other coherent writeup about this problem anywhere else.

***Conventional Micro USB cables will, however, fast charge when connected to AC USB adapters. Go figure.

****I still have not seen any well written technical explanation as to why most Android devices require special cables for fast car charging or, alternatively, why just about every USB car adapter ships without the modification that would enable the same with conventional Micro USB data cables.

Author: jdrch

ISTJ, Rice Owl, UF Gator, mechanical engineer. STEM, sports, music, movies, humor. Account mine only & unaffiliated.


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