N Scale Controllers

[ezdays]

Thanks! My lowest ones have 15VDC, so I might be on the lookout for new controllers.

I wouldn't, you should be able to use what you have. At 20 volts, your engine should be flying off the track. I run N scale and use a Tech 4, and I can set my throttle range to whatever I want. The Tech II doesn't have that feature, so you can pick the highest voltage you want to run at and either mark that spot or keep the knob from going past that spot. 

Rather than measuring the voltage, what I'd do is run a train with some cars to load the engine, then slowly move your throttle until it reaches the maximum speed you want, then mark that spot. Be aware that most controller open circuit (no load) output voltages will drop with a load. I have a couple of old MRC controllers, on one I can set my max output, but when set to max (26 volts), it will drop to 20 volts when I load it. I also have a dual throttle N scale controller that is pre-set for a maximum of 12VDC out, however, open circuit, one output reads 26.3 VDC and the other 25.4 VDC. They need a load for an accurate reading, and will drop closer to 12 VDC with a load. I also have a couple of 3-12 VDC, 5 amp variable supplies that I bought on Amazon recently that have a stable output regardless of the load. I'm using those for lighting.

I have to admit, I don't run trains that often, I like the building aspect of model railroading, but I think my advice should help you.