0
\$\begingroup\$

I have an illuminated 2 port usb charger that plugs into a cigarette lighter/accessory socket in a car. The face of the charger is flat and sits flush when inserted into the cigarette lighter/accessory socket. I’d like to install this “permanently” in the rear passanger area of a car so that two passangers can charger their devices. I did not want to install a second accessory socket so I’ve opened the charger and now have the internal circuitry to which I can connect my own wiring.

Since it is illuminated, and since I don’t always have passangers in the rear, like to be able to control this with a switch. Here are the specs for the devices involved:

Power supply from car: 12v, 5A or 10A max from fuse box are both available (switched power)

Switch: 5 pin (NO, NC, C, +, -), max 3A

USB charger:

• Input 10-16VDC 2.9A

• Output 5v, 2.4A max X 2 ports = 5v, 4.8A if both are used at the same time.

QUESTION: It appears the switch I have will not be able to handle current draw if both ports are being used at their max draw (2.4A x 2 = 4.8A). Is this statement correct?

If I still want to use this switch, I will need a relay that can handle up to 5A. Is this statement correct?

Lastly, is it even worth doing all this? Should I just connect the charger directly to power from my fuse box on the 5A circuit with a 5A fuse?enter image description here

\$\endgroup\$
1
\$\begingroup\$

The photo has more surroundings than the plug itself so it is hard to tell. But based on the huge inductor, most likely that is a switch mode power supply, not a linear regulator, so if it can deliver 24 Watts of power on output, it will take a bit more than 24 Watts power on input, and so it will only draw a bit more than 2A of 12V from car. (If it were linear supply, it would have to dissipate 33W so it would just melt).

\$\endgroup\$
  • \$\begingroup\$ Ok, so what does that mean for my question? What is the best way to power this safely so that I can power both outs (5v, 2.4A each)? \$\endgroup\$ – Inked_xx Dec 20 '18 at 19:09

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.