Thanks for your comments, Chris and nice to hear from you as I’ve been following your QMX Carrot build with interest.
You are right - the 13V 5.5Ah battery is way more than the QMX needs, but it is what I had available. I am using an LDO linear regulator to provide a steady 12V to the radio as I’m very nervous about how I power it. It’s an LM1085IT-12 in the module covered with black heatshrink, visible in the selfie photo next to the water bottle. I plan to make up a smaller battery with 18650 cells to better suit portable operation with the QMX.
The QMX is an amazing achievement - so much capability - Hans has produced a tiny marvel and is to be congratulated.
73 David VK3KR