I'm working on a project that runs on 12V DC. The power comes via PoE, which induces a hard limit of 15 watts on the design.
The circuit is intended to drive multiple loads that are rated for ~7W each, but only sporadically and only a few seconds at a time. However, it's likely that multiple loads activate simultaneously, which can draw up to 120W. The loads can run at 12-24V ± 10%.
The solution I'm considering is adding a battery or supercapacitor in the circuit. (This is similar to this question but with a higher power disparity.)
- Would a supercapacitor or a battery (likely lead acid) be better suited for this application? I've found ~60F supercap arrays that could easily drive 120W for 10 seconds while only dropping a couple volts, but a battery would be much cheaper.
- Would a diode and power resistor in series be sufficient for limiting the PoE current draw?
- Is there another relatively simple solution that would allow faster charging, but still gracefully handle a startup with an uncharged capacitor?
