USB cables

[T2urtle]

Do lengths matter much?

I'm asking for my Samsung s4. I have a 2.0A wall charger with about a 3.5-4 foot cable. The phone charges from below 40% to 100% in under 2 hours. Now when I use my 10ft USB cable running off the same wall outlet charger it takes more then 5 hours.

Is this just simple physics are am I just making crap up. My old 10ft cable didn't have this issue but that microusb port broke.

 

[Insert_Nickname]

I'm going out on a limb here, but it sounds like the charger can't push enough amps through the cable. Some older USB cables have difficulty handling more then 500mA. It could just be that...

 

[corkyg]

That has to do with the wire gauge used in the cable. USB transmits both data and power. Some have 28/24 gauge wire. (The lower number is thicker!) Some have 28/28, and power can't get through as fast.

 

[T2urtle]

hm... this is a Flat USB cable. But very thin (enough for me to say WTF) so that could be exactly my issue.

Looking at a battery voltage app on my phone, it seems to be roughly 650 w/e amps VS my OEM cable which is 1950 w/e amps.

So how much does length of USB cable how to do with things?

 

[Mushkins]

Length matters for USB, but only when you start pushing the 25-30 foot range. If you're having charging issues with a cable that short, it's either the USB port you're connected to has a voltage problem, the cable is junk, or theres a problem with the phone itself.

Swap the cable, it's probably the issue.

 

[Ganiy]

I also think that it is a problem of USB port you try to connect to or with the gadget itself.

 

[corkyg]

I also think that it is a problem of USB port you try to connect to or with the gadget itself.

Also true. Especially with laptops when on battery. A powered USB hub is best for reliability of power. Also, micro-USB connectors (at the phone end) are not very robust and are easily damaged. Always grasp them at the connector and pull straight out when removing.

As was said above - change cables.

 

[Throckmorton]

Could the phone just not realize it's on a 2a charger because of the cable? How exactly does a phone/tablet know how much power it can draw? If I plug my Samsung Tab into a 1a phone charger, it charges at 1a instead of its max 2a. Is it trying to draw 2a or does it realize the charger can only put out 1a safely and limit itself to that amperage?

 

[Insert_Nickname]

How exactly does a phone/tablet know how much power it can draw?

Its pretty simple. On a dedicated charging port the D+ and D- are shorted. Some chargers indicate the power available by putting a voltage on those. The device can then tell the power available by the difference in voltages between them.

 

[Juddog]

That has to do with the wire gauge used in the cable. USB transmits both data and power. Some have 28/24 gauge wire. (The lower number is thicker!) Some have 28/28, and power can't get through as fast.

^^ This - the rating of the cable really does matter.