Powering a Ham Radio with a Laptop Battery

I recently had some bad luck with a cheap 12V power supply with my uBitx v6. In short, the supply was extremely noisy across all the RF bands I wanted to use. I had said in that other post that I would buy a better power supply suitable for RF, but I don't believe you should do that when you can hack something together using parts you already have, especially when just starting out.

I poached the working Lithium Ion battery from the very Dell Lattitude E5540 laptop that I'm writing this on, and everything is working perfectly.

Here is how I did that.

Find a decent approximation of the Laptop's pinout

On this page I found the basic info I needed to hook up to my Laptop battery.

Crucially, I found this info that would work if my battery pinout wasn't too different from the one in the picture. Mine had 9 pins, just like the one on that site, so chances were decent the pinout was the same or similar.

The 3 most important facts were:

  1. the left and rightmost two pairs of pins need to be shorted as two pairs (one short on each side, so the four pins effectively become two wires)
  2. one of the pairs is ground (-), and the other pair is (+)
  3. one of the pins in the middle needs to be shorted to ground

Wire the battery up to a breadboard and onto the radio

I just had to figure out which pin on my battery had to be shorted to ground to turn the battery on, since I got no voltage by simple shorting the pairs of pins on the (+) and (-) sides. Finally, I realized from the above site's pin list that my pin 6 might be something called SYSPRES, probably meaning SYSTEM PRESENT, or in human terms "This battery is not being shorted accidentally in someone's purse by their earrings - it's plugged into a laptop." Once I connected pin 6 to ground, I got a little over 12V out between (+) and (-). For safety, I added a toggle switch between pin 6 and ground.

Annotated drawing of the battery wireup job I did.
The radio turned on with zero noise - no loud helicopter blade sounds.

Turn it on

My first HF station, a uBitx v6, powered by the battery power source I hacked together.
Here it is, turned on. Yes, right now my uBitx is in a cardboard box. Stay tuned for a future project where it might live in a nice wooden box.


I will keep going with this setup as long as I can. It's working, is noiseless, is free for me, and since I don't take my laptop anywhere really, is not inconvenient yet.