DevTerm’s are very picky on monitors and cables - I finally found a cable and a resolution it would work with - check the specs on your monitor and make sure the cable connector is long enough to engage the micro HDMI port. (It’s slightly recessed) I have to plug my monitor in then boot. Battery life depends on the batteries - use good quality ones - there is a forum on batteries here at the forum. Can’t help you on the trackball but even when it works it is sub optimal - use an external mouse. Fan only kicks in when the CPU is HOT… Best 18650 Battery | 18650 Guide - Comparison Chart got to the 18650 battery forum group - there are 18650’s that have great capacity but the cover won’t close…not all 18650’s are created the same… Devterm’s battery bay is not generous…
Hard to tell without equipment but one of the batteries can be bad. When I first received my DevTerm I went to a local hardware store and bought some batteries, they were in a pack of 2, sealed together.
My DevTerm was dying suddenly, like from 50% to 0. As I have some battery testers, I tested them and it turned out that one of the cells was bad, it had like half the capacity of the other one, which is what was causing my instabilities.
The fan has a unit file script where the temperature is configured, it doesn´t turn on if the DevTerm doesn’t reach such temperature. You can lower the threshold to trigger it at lower temps.
When the DevTerm CM4 image was built, both devterm-thermal-printer and devterm-thermal-printer-cm4 were included. This creates a conflict for apt. This is discussed in other posts here. Basically, you need to remove the devterm-thermal-printer package (sudo apt remove devterm-thermal-printer). Others have suggested removing devterm-thermal-printer-cups, devterm-thermal-printer and devterm-thermal-printer-cm4, then installing devterm-thermal-printer-cups and devterm-thermal-printer-cm4. Either way, you should be able to run "sudo apt update: successfully. I don’t have thermal paper yet to test my printer.