Wednesday, November 22, 2023

Adapting Ozito battery for ham radio power

We have quite a few low cost Ozito (Bunnings) battery powered tools around here even though I've been transitioning to Makita. The battery packs put out about 20V when fully charged which is too much for nominal 12V radios. I purchased a variable buck converter that can regulate this voltage down. 

To get power from an Ozito battery I butchered a spare single battery charger with pins like this:

Internally, there's quite a bit of circuitry - a bit surprising considering the low cost. The metal pins are soldered right through the board so rather than trying to remove the board I just clipped the power input and soldered on to the back of the battery + and - pads:

A few cables later and we were up and running receiving FT8:

Regrettably, the buck converter produces noticeable noise peaks on the waterfall:

Threading the output DC cable through a toroid improved things quite a bit:

The spectrum looks much better although there is room for improvement:

Credit to VK3KR, David, for the inspiration for this project.


Grant said...

Can I ask what type of buck converter you used, this looks good as I'm looking to do this to a ryobi battery, thanks Grant VK3MSG

Peter Marks said...

Grant, it's this one from AliExpress but I don't think I'd recommend it as noise was noticeable and I don't really need the adjustment features.