USB 2.0 charging cable testing - results surprised me.

[Gadgetdude]

I have mentioned in other posts I recently picked up a cheap desktop dock that I use primarily for charging: Data Sync Dual Charger Dock Station for Samsung Galaxy Note 3 III N9000 N9005 | eBay

The one thing about it was that while it has a full size USB 3.0 port where the phone mounts (I liked that for stability), the usb port on the back was a standard usb 2.0 micro port. I had read that when using AC adapters or DC car adapters USB 2.0 vs USB 3.0 cables make no difference and that seemed to be the case when I took a standard USB 2.0 cable and charged up from the stock AC adapter. I like many of you have a lot of USB 2.0 cables around from various devices and always thought they were pretty much the same, but it seems that they can vary dramatically and so far I haven't been able to visually understand what the difference is.

As a baseline using the stock AC adapter and cable I usually always got about 8.5%-10% for every 10 minutes of charging which seemed really nice and fast as others have observed. When I got the dock I plugged it in using a one of the random USB 2.0 cable I had sitting around and noticed right away that it charged slower - about 1/2 the speed. I tested it a bunch of times and even swapped cables but it was always the same but because I planned on using it mostly for overnight charging I didn't mind it too much. I figured that because the dock charges both the phone and a spare battery, maybe something in the wiring was splitting things and that's why it was slower.

Tonight I happened to plug the phone in while driving (using some random USB 2.0 cable I had in the car) and noticed that it was charging nice and fast. On a whim I took that specific USB 2.0 cable and used it with the dock and sure enough the phone charged at full speed - what was going on here? I found this app: https://forums.androidcentral.com/e...laxychargingcurrent.free&hl=en&token=lfg6t6DR and was really surprised what I found.

All testing was done with the stock AC charger. The stock USB 3.0 cable rated 1200mA, the USB 2.0 cable from the car that seemed as fast also rated 1200mA but then I tested 4 other USB cables and got reading of two at 450mA, one 750mA, and one at 1100mA. The 450mA cables were indeed the ones that seemed to charge much slower (I also tested the ridiculous 5 inch cable that came with the dock - 1200mA but the thing is useless because it it so short!)

I haven't tested yet but I suspect that some of the USB extension cables I have might also impact the charging capability.

So - why the variation? Is it just quality, specific wiring layout, different specs for different uses? Is there a rating or a way I can make sure when I buy new 2.0 cables they will work full speed?

 

[FBA]

Yup, cables make all the difference. However, going from a high speed USB 2 cable to USB 3 cable on a high output charger won't make a difference. Car charger's a often 2MPS + and will usually charge at warp speed as well.

 

[Gadgetdude]

Yup, cables make all the difference. However, going from a high speed USB 2 cable to USB 3 cable on a high output charger won't make a difference. Car charger's a often 2MPS + and will usually charge at warp speed as well.

So it seems - I found my answers - here is a good short article that explains it and how to find good cables: How to choose a good USB data and charging cable for your mobile phone | The 8th Voyager

After reading that and examining all the cables I tested, I found my results were consistent on the power rating codes. Stock Samsung is a 24AWG*2C and the other one that worked at high speed is a 28AWG*2C. You basically want the first two digits to be "28" or lower. All the other cables that were slow are thinner and most have no codes at all. Good cable sources like Monoprice list the AWG ratings right on the product description.

 

[SpookDroid]

Yup, it's all about the Amps. And that takes two sides: the source (charger) and the transmitter (cable). Now, if you have a premium cable it won't do squat if you have a crappy charger that only outputs 500mA (OK, not crappy, just not fast enough for today's hungry hipphones). Same thing happens if you have a charger with a 2A output but using a cable with the wrong caliber wiring that won't take that much current, therefore losing a lot in the process and charging your phone much more slowly (and a potential fire hazard, too).

Same thing applies to other things, by the way. You don't want to use thin cables around your home if you'll have an stand-alone AC unit in every room, four computers, tons of lights, huge fridge, etc. sucking up power all at once, just as having thicker cables for a one-bedroom, one-commonroom home is overkill.

 

[Tyler Lietz]

Initial testing in the beginning might be good but once charge hits 92 to 95% charging speed is dramatically reduced. Everything stock with no apps running using stock charger and cable gave 2h 10min to 2h 15min charge times