Would I damage anything running 12 V on a 24 V cartridge heater? I know it wont reach a max temperature 300 °C? I am using the E3D hotend set up.
Applying 12 V to a 24 V heater cartridge won't damage anything, but you may have severe issues reaching and maintaining your target temp. A standard E3D heater cartridge is 40 W. When you run a 24 V cartridge on 12 V, you only get 10 W of heater power. Here are some rough estimates on where your hot block heat goes:
- Uninsulated hot block air losses: ~20 W depending on airflow
- Insulated hot block air losses: ~5w depending on airflow
- Filament melt power at typical print speeds: 0.3-3 W depending on filament and print speed
- Heat conducted up the heat break: 1-3 W maybe, hard to quantify
I've never heard of anyone using less than about 16 W to print. (Two 8 W power resistors.) 20 W is the lowest vaguely normal hot end power. I think you'll struggle to print.