Cell Phone Charger Issues!

Your car is running at the time you are trying to charge? Some car's "lighter" sockets are on all the time, others only when the car is.

Have you (or they) used a multi-meter to test the voltage at the socket under the conditions where you want to use the charger?

 

Also, is OP checking while the ignition is 'Ready', not just in Accessory mode?

There will be a significant voltage difference at the 12V socket. The radios used in some events I support can only receive, but not transmit, in Accessory mode. This applies to non-hybrids as well as my Prius. Transmitting requiring non-hybrid engine running or Prius in 'Ready'.,

 

The 12volts available at both plugs is plenty to provide the 5 volts the phone needs.
I had trouble with the Chargers Sprint provided for $50 and found the $20 USB chargers from PepBoys worked so well I bought them for everyone in the office for Christmas 5 volts 1 amp
Here is a picture
As you can see it is a dual charger gives Tablet and a phone a charge in car or hotel Etc. I have a spare in armrest counsel.
I've repaired power supply's too if you have one rated to provide the 5 volts but not the 1 amp that one draws while navigating ect many over heat and just cannot keep up. FYI


iPhone ?

 

Also not all cables are created equal! If it was cheap, if it is light weight there may be enough resistance in the cable to create enough voltage drop under load that the phone will refuse to charge. Try a mobile charger that will put up at least 2A and a good, heavy cable and see if that doesn't fix the problem. I've seen this issue in multiple cars including my Prius. In the Prius a good charger and cable will work in any of the powered up states.

 

The USB (Universal Serial Bus) are all rated to meet a Universal standard up to 7.5v and 3 amps. The size / resistance of the wire used can limit the length of the cable but the standard is met. Which is why I prefer the USB cable style charger and not the others from cell carrier with red lights that glow even when there thermal fuse has popped and they aren't charging due to over heating / can't produce 1 amp continuously.
As you say two steps:
1.) a charger rated for 5 volts and 2amps or more
2.) a rated cable to exceed the above.



iPhone ?

 

The assumption here is that you are plugging in a USB adapter into the accessory (cigarette lighter) outlet(s). If so, you need one that has a 2.1 volt USB port. Some USB adapters are only 1.1 volt and would take forever to charge my iPhone.

 

I think you mean amps, not volts. All USB should be very close to 5 volts.

 

I had the same problem, my el-cheapo $10 foisted on me by Verizon USB charger just won't work in the Prius. Presumably I'll have to go out and pick up something less crappy, ah well...