Phone Charging
Thread Starter
Member
Joined: Apr 2009
Posts: 175
Likes: 5
From: Virginia
2012 E350 - Cabrio; 2017 GLS 450
Phone Charging
In my 2012 E350, I can charge my phone off of a USB 12V adapter (aka cigarette lighter adapter) twice as fast as I can the USB in the arm rest console. I'm assuming it's the difference between 1.2 and 2.4v USB plugs. Not being one with electricity or how volts/amps and such work too much, is there a way to get 2.4v out of the console plug? I hate having my ash tray open with a cable and would much prefer to stick my phone in the arm rest console, close the door and charge while I listen to music. Maybe a new fuse or something? I don't know....thanks everyone!
Senior Member
Joined: Mar 2016
Posts: 430
Likes: 33
From: Sandy Eggo
2006 CLS55
So to clarify, it's actually 1.2A. The amperage is the difference. Voltage will usually be the same regulated output around 5 volts (check your wall charger to verify output).
simple math
P=I*V (power in watts = current in amps * voltage)
V=I*R (voltage = current in amps * resistance in ohms)
this can be converted to I=V/R or R=V/I
since your voltage is likely constant, if you want to increase the amps you will need to decrease the resistance.
so find your resistance by R=V/I --> R=5v/1.2A = 4.16 ohms
if you desire that 2.1A output, replace the resistor accordingly. R=5v/2.1A = 2.38 ohms
simple math
P=I*V (power in watts = current in amps * voltage)
V=I*R (voltage = current in amps * resistance in ohms)
this can be converted to I=V/R or R=V/I
since your voltage is likely constant, if you want to increase the amps you will need to decrease the resistance.
so find your resistance by R=V/I --> R=5v/1.2A = 4.16 ohms
if you desire that 2.1A output, replace the resistor accordingly. R=5v/2.1A = 2.38 ohms
Thread Starter
Member
Joined: Apr 2009
Posts: 175
Likes: 5
From: Virginia
2012 E350 - Cabrio; 2017 GLS 450
So to clarify, it's actually 1.2A. The amperage is the difference. Voltage will usually be the same regulated output around 5 volts (check your wall charger to verify output).
simple math
P=I*V (power in watts = current in amps * voltage)
V=I*R (voltage = current in amps * resistance in ohms)
this can be converted to I=V/R or R=V/I
since your voltage is likely constant, if you want to increase the amps you will need to decrease the resistance.
so find your resistance by R=V/I --> R=5v/1.2A = 4.16 ohms
if you desire that 2.1A output, replace the resistor accordingly. R=5v/2.1A = 2.38 ohms
simple math
P=I*V (power in watts = current in amps * voltage)
V=I*R (voltage = current in amps * resistance in ohms)
this can be converted to I=V/R or R=V/I
since your voltage is likely constant, if you want to increase the amps you will need to decrease the resistance.
so find your resistance by R=V/I --> R=5v/1.2A = 4.16 ohms
if you desire that 2.1A output, replace the resistor accordingly. R=5v/2.1A = 2.38 ohms
Senior Member
Joined: Mar 2016
Posts: 430
Likes: 33
From: Sandy Eggo
2006 CLS55
Yes, easiest bet is to stick with the cig adapter.
