Also, you asked, a 24V bulb may or may not work. I might be the perfect thing, actually I just don't know. A brake light is typically a higher wattage bulb (more current at a given voltage). A 12V bulb -especially the brake bulb would draw some power. That said, you voltages you are running at conventional are fairly low and more load is good in that it makes the output of the Z4000 lower. A 24V bulb has a higher resistance since it's rated fo double the source voltage.
So specifically, a 24V brake lamp might be just the ticket. A lesser bulb like say a turn signal or marker light or dome light rated for 24V might not be enough load at these low voltages. So again, specifically a 24V brake light, I would give it a shot. If you can get a socket and try different lamps- 12V or 24V, just see why amperage they draw at a given voltage in the ranges we are using starting at the lowest value the Z4000 puts out, and then raising it to say 16V max.
