5V battery usb battery to 12V screen

[grelc]

Hi all,

I am trying to connect my 5v external battery to my 12v 3.5" TFT LCD Screen. I have the following:

1 x 5v external battery
1 x male to male usb cable
1 x 12v to 5v car charger
1 x 3.5" LCD TFT screen

There seems to be one connection coming out from the end of the car charger, how can I connect this to the LCD power connector? I have uploaded a image
https://dl.dropboxusercontent.com/u/47274064/Photo Apr 11, 22 47 33.jpg

At the moment I am using the mains 12v adaptor to power the screen, however I want to connect it from the 5v battery pack to the lcd screen (red connector shown) via the 5v to 12v car charger (as shown on the right of the image)

I would really appreciate some input on this, thanks.

 

[(*steve*)]

The 12V to 5V charger cannot work as a 5V to 12V adapter.

You need a boost DC-DC converter.

Be aware that the current from your 5V source will be around three times the current available at the 12V output.

 

[BobK]

If you have 12V available why do you want to convert it to 5V then back to 12V?

Bob