What is the cheapest and simplest way to dummy load 450w, 15V, 30A, only for a few seconds?
I would like to measure the max output capability of an MPPT charger controller, basically as a "all losses included" way of measuring actual solar panel maximum power capability.
The theoretical maximum output is 440w. In reality, the solar panels probably won't output more than 350-400w on the sunniest day.
The controller has a load-side shunt, allowing me to measure current easily.
I'm planning to use a MOSFET to short-circuit the load-side through a dummy load. The resistance needs to be very low to allow 30A to flow at 14.4V. I've considered using a ceramic heater, but they are typically dimensioned to have a resistance that restricts current to their dissipation-capability under continuous load, to prevent overheating. I could buy a heater dimensioned at 500w, but it would probably take up a lot of space. Since it only needs to operate for a few seconds, the concern is different.