MaxAmps Race Edition Lipos

[BrianG]

The math isn't overly complex.

For parallel resistors, there are a few methods: If all resistors are the same take the resistor value and divide by the number of resistors. So, if you have 100 X 3 ohm resistors, that would be 0.03 ohms. If using different value resistors (or can be the same), you can use "product divided by the sum" (R1*R2*R3*Rn)/(R1+R2+R3+Rn) or the "conductance" method 1/(1/R1+1/R2+1/R3+1/Rn).

For series, just add them up.

The advantage to using multiple resistors, especially in something that will generate this kind of heat, is the ability to spread out the thermal load. Also, you have much more flexibility in the actual ohmic value.

I was going to make a lipo test station a while back (which is why I have these resistors) and was going to create several 20 parallel resistor banks of 0.15 ohms. Then, just put those banks in series or parallel depending on the desired load and lipo voltage under test. Originally, I was going to use a MMM ESC in high-power brushed mode (can do ~300A for short tests) to regulate the actual amount of power to the resistors. The project never got anywhere because of a few technical details. You can read about it here if interested: http://www.rc-monster.com/forum/showthread.php?t=21478