How to choose a charger?

IAmAndre · July 30, 2015

Hi there,

I got an Asus Transformer a couple weeks ago and I'm quite happy wih it. However, the battery life isn't that great but it's still decent. I can lose like 20% in less than one hour of heavy use (web browsing, heavy downloading and social networks). The other day I thought that the tablet died since it stopped charging as the battery was at 1%. An hour later, I found out that the charger was causing the issue : Asus provided a charger with a ridiculously short USB cable, so I replaced this cable with the one provided with my Chromecast. After using the Asus charger, everything was fine. I also noticed that the charger that came with my phone has a lower voltage than the Asus one, and when I use the USB cable that came with my Chromecast to connect a phone to a computer, the phone starts charging but won't be recognized by the computer, even though the cable works fine when it comes to power up the Chromecast.

Now I would like to know I can replace this USB cable, as it seems like only the short one is able to deliver enough power to charge it correctly. Are there any specs/numbers to look at? Also would my phone charge faster if I use a charger with a higher voltage? How can I choose a power bank that would be perfect both for my phone and my tablet?

Thanks

mattrunyon · July 30, 2015

Chargers are usually based on the amperage more than the voltage. Most handheld electronics are 5V chargers I think, but they vary in amperage (phone 1.5A or so, tablets 2.1A or so). So look on the original plug and see what the voltage and amperage are. Try to match those.

Also, Asus should probably replace the charger under warranty if it's only a few weeks old.

IAmAndre · July 31, 2015

Chargers are usually based on the amperage more than the voltage. Most handheld electronics are 5V chargers I think, but they vary in amperage (phone 1.5A or so, tablets 2.1A or so). So look on the original plug and see what the voltage and amperage are. Try to match those.

Also, Asus should probably replace the charger under warranty if it's only a few weeks old.

Thanks for your reply. You're right, the voltage is almost the same, but the amperage differs a lot : 850mA vs 1.35A. Then I guess that I should get something that maches this criteria and having something with a higher amperage wouldn't increase the charging speed (or would it?). Also, do you know what's the deal with the cables? Only the shortest cable is able to charge the tablet when the battery is critically low. Should the cable itself have some particular specs?

ShiftHitTheFan · July 31, 2015

Thanks for your reply. You're right, the voltage is almost the same, but the amperage differs a lot : 850mA vs 1.35A. Then I guess that I should get something that maches this criteria and having something with a higher amperage wouldn't increase the charging speed (or would it?). Also, do you know what's the deal with the cables? Only the shortest cable is able to charge the tablet when the battery is critically low. Should the cable itself have some particular specs?

There are also some high wattage usb charges that output 9v /12v /20v dc if requested by phone. My Zenfone 2 accepts 9v, along with some Samsung phones. Qualcomm quick chargers can output up to 20v dc!

Usually in your phone's manual, it will list the input specs. Buy a charger with at least those.

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NEVER EVER BUY CHEAP USB CHARGERS!

Cheap usb chargers use cheap components, and usually use workarounds to keep the price down. Cheap components fail quick! i personaly would never buy a usb charger under $10. Anything under that, and you risk buying crap. The only exception is if the manufacture is known to be good. My personal favorite charger brand is ANKER. Great quality, for a good price.

http://www.amazon.com/s/ref=bl_dp_s_web_2335752011?ie=UTF8&node=2335752011&field-brandtextbin=Anker

Teardown of cheap usb charger: