U.S. CitiesCity-Data Forum Index
Go Back   City-Data Forum > General Forums > Science and Technology > Cell Phones and Smartphones
 [Register]
Please register to participate in our discussions with 2 million other members - it's free and quick! Some forums can only be seen by registered members. After you create your account, you'll be able to customize options and access all our 15,000 new posts/day with fewer ads.
View detailed profile (Advanced) or search
site with Google Custom Search

Search Forums  (Advanced)
 
Old Yesterday, 12:26 AM
 
770 posts, read 765,427 times
Reputation: 556

Advertisements

I have several different USB cords, different lengths, it seems to me the longer the cord the slower the change. Is it just me, could be my phone, my outlets, or has everybody notice the same thing with their phones?
Reply With Quote Quick reply to this message

 
Old Yesterday, 03:06 AM
 
40,571 posts, read 41,994,289 times
Reputation: 16950
Wire has resistance, the longer it is the less power delivered. If you ever grabbed a plug and it's warm that's because of the resistance, the power transformed to heat and never made it to what you are powering. This is why copper is used, it's resistance is low. You have to be careful with this when using long or multiple extension cords, if you were using it for something like a power tool you could end up burning the motor up because there isn't enough power. There are different grades of extension cords.

A USB cord is going to have some pretty thin wire, the thinner the wire the more resistance it has. The length of the wire will affect your charge times, whether it's enough to make noticeable difference I don't know. The issue with the power tools mentioned above doesn't apply because the charging mechanism in the phone can operate under different loads. No idea if they offer USB cords with different wire gauges.

Last edited by thecoalman; Yesterday at 03:15 AM..
Reply With Quote Quick reply to this message
 
Old Yesterday, 10:24 AM
 
Location: Raleigh, NC
2,311 posts, read 3,506,618 times
Reputation: 3023
Quote:
Originally Posted by thecoalman View Post
Wire has resistance . . . . No idea if they offer USB cords with different wire gauges.
+1 about the above. The more resistance, the lower the voltage seen by your phone, the slower the charge.
I have a lot of gadgets, and therefore a wide range of wires, and use an app that shows the charging rate. This helped me discover that some wires do far better than others.

I've gotten long USB cables with very thin wires that charge very slowly, and some that are almost twice as thick in multiple length that all seem to go very fast.
Unfortunately, wire gauge isn't something that is usually provided with the USB cable online sales info.

I'd use as a rule-of-thumb, try the shortest, thickest wire at first.

Another concern. I got a set of USB cables that had 90-degree end connectors. Useful for one of my connection situations.
. . . The Bad News: the wire was thin, and after about a year, the charging rate went way down.
. . . The Good New, a bad comment on my Amazon purchase page generated a manufacturer's response that the cables had a lifetime guarantee and I got them replaced for free.
Reply With Quote Quick reply to this message
 
Old Yesterday, 11:47 AM
 
6,307 posts, read 2,852,981 times
Reputation: 17836
Problem is that you can't always tell the wire gauge by the OD of the cable. Some cables have thick insulation and some have thin. For power cords the vast majority are stamped on the outside with the wire gauge, but I've not seen a USB cable so marked.


Obviously you can cut the cables in half and compare them, but the people at the store kind of frown on that.
Reply With Quote Quick reply to this message
 
Old Today, 08:16 AM
 
Location: Cleveland, Ohio
11,897 posts, read 14,024,645 times
Reputation: 8102
WTF... at some of these replies.

Answer: NO. Unless you have a 50+ foot cable.
A 3 foot cable is going to charge every bit as well as a 10 foot cable.
Reply With Quote Quick reply to this message
 
Old Today, 08:47 AM
 
1,187 posts, read 430,384 times
Reputation: 3679
Quote:
Originally Posted by Peregrine View Post
WTF... at some of these replies.

Answer: NO. Unless you have a 50+ foot cable.
A 3 foot cable is going to charge every bit as well as a 10 foot cable.
Yup.
Reply With Quote Quick reply to this message
 
Old Today, 09:01 AM
 
40,571 posts, read 41,994,289 times
Reputation: 16950
Quote:
Originally Posted by Peregrine View Post
WTF... at some of these replies.

Answer: NO. Unless you have a 50+ foot cable.
A 3 foot cable is going to charge every bit as well as a 10 foot cable.

Google is telling me otherwise. They also mention the charger and the port on the phone being a factor. USB3 can carry more power than USB2.
Reply With Quote Quick reply to this message
 
Old Today, 12:50 PM
 
Location: Cleveland, Ohio
11,897 posts, read 14,024,645 times
Reputation: 8102
Stuff I learned in school tells me otherwise. It's got to be a lot longer then your average cable to effect the charging quality.
Reply With Quote Quick reply to this message
 
Old Today, 01:24 PM
 
6,307 posts, read 2,852,981 times
Reputation: 17836
Well, the question has a couple parts to it, in order to answer it accurately.


1) What's the actual current passing through the cable when charging, and what is the resulting voltage drop?
2) What is the relationship between the charging voltage being applied to the battery, and the voltage at the end of the cable?
3) What is the relationship between charging voltage being applied to the battery and its time to reach full charge?


If there's a DC-DC converter between the end of the cable and the battery, then the output voltage of that will be insensitive to anything other than the most drastic voltages drop at the input of the DC-DC converter.


Assuming Li-ion batteries, the actual profile of charging voltage and current is complex and depends on the state of charge, the details of the battery design, and the degree of s$ophi$tication of the charging circuit.


The point is that we're not talking about a simple resisitive circuit here; the intuitive idea that faster charging results from applying more voltage is not accurate.
Reply With Quote Quick reply to this message
Please register to post and access all features of our very popular forum. It is free and quick. Over $68,000 in prizes has already been given out to active posters on our forum. Additional giveaways are planned.

Detailed information about all U.S. cities, counties, and zip codes on our site: City-data.com.


Reply

Quick Reply
Message:


Over $104,000 in prizes was already given out to active posters on our forum and additional giveaways are planned!

Go Back   City-Data Forum > General Forums > Science and Technology > Cell Phones and Smartphones
Follow City-Data.com founder on our Forum or

All times are GMT -6.

© 2005-2019, Advameg, Inc. · Please obey Forum Rules · Terms of Use and Privacy Policy · Bug Bounty

City-Data.com - Archive 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35 - Top