For any dyno testing there are many options, but the basic principle is the same... You want to recreate on the dyno the nearest possible simulation of your actual racing situation.
For example -- if you are racing in a 4-cell class, I set my Dyno to use 5v as the input voltage level. For 6-cell classes, I set my dyno to use 7v...
Since the Bud's "dyno" does not have a built in voltage regulator, etc. you must decide what/how you want to test...
The Bud's was designed to allow you to use your batteries as the voltage source, since that way it is EXACTLY how you race (with batteries). The downside is that the voltage DOES change as you test (just as the batteries fade toward the end of a run on the track)... But this variability can make results erratic.
Before I got my TD45, I built a dyno of my own design somewhat similar to the Bud's design -- to get stable power, I found an old computer power supply (from a LARGE computer) that had fully regulated 5v power and could supply up to 80 amps...
Whatever you use for a power source, you will need one that can supply at least 30 amps at the regulated voltage. DO NOT use a 12v power supply unless you have a way of regulating and reducing the voltage down to no more than 7v!
Does that help?
"If you cannot win, make the one ahead of you break the record."
Biff Racing Team #420 (Ah... The "good old days"...)
The local indoor Offroad Track: The RC Race Barn
TLR22-3.0, TLR22T-2.0, TLR22SCT-1.0