USB Port won't charge devices
 

I have tried two different phones and 3 cables and for whatever reason, the port isn't pushing enough power to charge the device. It has enough power for a flash drive to function properly. It worked fine for charging my phone since I purchased the car last January. They only thing I could think of is that it has been super cold in the midwest and that is causing the battery not to operate at capacity but I would have though alternator would power everything when the car is running. The only changes that I can think of that I used a ODB2 to Bluetooth adapter last week but I unplugged it after use.

You're right, the car runs on the alternator when it is on.

To trouble shoot the problem... did the USB Port ever function properly and pump out enough power to charge your phone in the first place?

AFAIK -- Car USBs charge really slow. The charging port is much more efficient.

Chances are the USB port in the car only provides the 500mA USB 2.0 standard and not the higher current that a dedicated charger would supply.

Has nothing to do with your car battery being low, but a limitation of the USB port in the car

If you use an adapter in the cig lighter (which can supply 12v at several amps) it would be up to your adapter to supply the 2.1 amps @ 5v or whatever is required to charge your phone

Yea it did up until this week. It was a super slow card but it functioned.

Phone battery might have just crossed a point where it can't charge from such a weak source.

This isn't a phone charging issue, the USB port was never meant to charge devices in the first place.

-alex

The USB port on this car originates in the stereo.

As long as the stereo is working you will not have a problem with power (its not the battery).
Most USB devices put out a certain amount of power and if the port detects that this current has been exceeded, it can shut down the +5Volts to the USB device.
For some devices they can continue to communicate (like our phones) but not get any power from the USB port.

Also - some phone pull a lot of current to charge when they get below a certain level of discharge.
My Motorola phones will not "wake up" from a complete discaharged state when plugged into ANY computer USB port.
You have to charge them with the wall wart until they arre above ~5% before you can move them back to the USB port.
Maybe your phone charge level is too low, or the battery is getting old?

Yeah that usb on the car don't even bother with it..

I have a note 4 and it needs 2+ amps to charge But it can also do 9v fast charge on the stock wall charger it comes with.. I been looking for a fast charger 9v car charger but can't seem to find any...

But this is what I have and it works great..PowerGen 2.4Amps / 12W Dual USB Car charger Designed for Apple and Android Devices - White https://www.amazon.com/dp/B00622AG6S..._Of25ub0G9864E

My OnePlus one supports quick charge 2.0 with an aftermarket kernel and I use this in my car:[ame="http://www.amazon.com/PureGear-Qualcomm-Charge-Extreme-Charger/dp/B00QQPG57K/ref=sr_1_11?s=electronics&ie=UTF8&qid=1424450548&s r=1-11&keywords=qualcomm+quick+charge+2.0"]Amazon.com: PureGear Qualcomm Quick Charge 2.0 Extreme USB 12W Car Charger, Black, Single Port: Electronics[/ame]
Also since you have the galaxy note 4 and the chipset supports quick charge 2.0 this will show that little notification pop up that adaptive charging is being used