USB 5V power from 12v battery


I’m building a mobile power unit to run LED lights for camping, charge phones/ipads or power my raspberry pi cyberdeck

Ive got a 9Ah 12V battery mounted in an ABS ‘lunchbox case’ I’ve added a merit plug socket for 12v power out and for charging

i’d like to add 2x 5V usb sockets to charge phones/ipads or my Pi, and need to step down the 12V to 5V

would this be a suitable product? or is there something else better suited?

Thanks in advance

Hi Aaron,

Thanks for making a post! Honestly, often the simplest thing to do with 12v Lead Acid batteries is it to add in a cigarette lighter socket and use an off the shelf USB adapter for a car.

If you want a neater finish, I’d suggest using something like this:

Or you could stick the Cigarette adapter inside the box, and wire it outside with a panel mount adapter like this:

Hi Aaron,

Welcome to the forum! :partying_face:

Excellent question, as long as the draw from all the parts that you’re using is below 3A total, then you should be able to use this converter after you’ve adjusted it to the appropriate 5V out before hooking it up. The LED strip should have a current rating per metre that you can use, and your iPad/Phone should also have a rated charging current that you can use to determine whether or not this would be suitable. That being said, I believe that it would be much simpler to use a 5V battery pack instead, although as the saying goes. Necessity is the mother of… :grin:

Hi Oliver,

the USB car adapter is a great idea, i not even thought of anything like that, the space inside the battery box is limited so having all the circuitry/wiring in a unit like that will be perfect

appreciate the help


All good Aaron,

Let us know if there’s anything else that you need. Have a great day!