questionswhy does it take so long for my phone to charge…


I have a guess. Some usb cables don't do well when used for charging. I don't know why but I tested many usb extension cables before I found some that worked. Some cables use a bit of the power to light up and I found that they were horrible for charging. The other thing is not all usb outlets are the same, some have more amperage than others and will provide better charging current.


Any extra resistance anywhere in the charge path will lower the rate.


Dedicated chargers are designed to provide more current than the USB spec mandates for hubs and other devices.


Cheap extension cables use a substantially thicker wire core and connectors, which ultimately increases the resistance and drops the voltage. Check your adapter and confirm that it is 1amp or 1000 mA or higher. You can pick one up too on eBay or elsewhere, and if you do, get a 2amp/2000mA type and you should be fine. If you are using it with a PC or Mac USB port, the port must be charing-friendly (1amp) as the standard 500mA will not suffice with longer cables than 3'.

Hope this helps...


The teeny little electricity bits need to rest and snack along the way, just like all other teeny little creatures. The longer they have to travel without getting a chance to rest and eat, the more of them [sigh] die along the way. So the longer the extension cord, the fewer little electricity bits actually get to your phone, and they're tired and weak when they arrive. How can you possibly expect them to work at their very best under such conditions?

If I remember correctly, I learned this from one of ZeFrank's "True Facts" lessons on youtube. Hope it helps!

P.S. This one is good, too!

P.P.S Some ZeFrank stuff is NSFW


most newer smartphones or tablets, etc., need hefty power, 2A 5V. if you're using your desktop computer, change the USB port to one in the back off the motherboard, they have more juice than extensions on the front. however, a notebook computer even on AC power might not have the juice to charge some devices through its USB. better to find some AC charger rated for 2 Amps and use it. USB cables rarely cause voltage or amperage loss unless old or broken or kinked, but always try another cable just in case. also, use only one device per charger to make sure it has enough juice. also make sure the cable is the right one for the device, not all USB cables are created equal...


There can be a combination of issues. First, the longer cable may be constructed of thinner conductors, which has more resistance per unit distance than thicker wires, and being longer means more total R.

Second, the USB standard only allows for 500mA charging current unless negotiated to a larger value. Unfortunately, the manner of negotiation is not completely standardized - some, including Apple and HP, use supplies that connect a resistor network to the data pins, at each of the power supply and the matching device, and each end checks the characteristic voltage and resistance to decide how much power to supply and how much power to take. A high resistance cable could disrupt that.

Others depend on shorting the data pins together with a low resistance to negotiate a higher current, and actually use a special "charging" cable that shorts the data pins together to charge at the highest rate. If you substitute a normal cable, the charging rate defaults back to the 500mA rate.


You shouldn't notice a substantial difference as long as you plug your extension cable (by which I take it you mean a USB A male to A female cable) into the charger that came with your phone or a charger with equal or greater amperage specs and then plug the same charging cable you get such quick results with into the extension. That's what I do every night and many afternoons with my ten foot extension, and I see no noticable increase in charging time. I have a very ordinary extension cable, but if yours is very thin or long you might lose some current and voltage to heating the wire. If your setup is the same as mine, I'd try a different extension cord or see if you can exchange it.


@pinchecat: I don't know what "wut" is supposed to mean, but your post about medical malpractice lawyers was spam, nothing more, nothing less, and totally off-topic for the question and the answers in play here. I was really surprised to see it coming from you.


@craighansen has the answer. Your phone wants more than the USB standard 500mA at 5V. Either the cord that came with it is non standard and has some way of telling the charger that it is OK to give it 1000mA or whatever, or the extension cable has something strange about it which either doesn't allow for currents greater than 500mA, or messes with the signal from the phone to the charger that tells it to send the juice.

My suggestions would be either to try another extension cable, or just charge the phone more often.


@pinchecat: You or someone using your account posted an advertisement for people who'd had a particular kind of surgery and experienced problems to call a toll-free phone number. I called the number: it goes to a law firm that handles medical malpractice class action suits.

I tattled on it as being spam, and it was deleted.

Are you saying you didn't post it? If so, it's probably a good idea to talk to whoever has access to your computer and to change your password.