[Finnster]

I don't like that C rating multiplier either, and I think it gives far too much influence to an otherwise unreliable and often distorted rating. IE, going from a 25C to 30C is a 20% increase. This is unrelatable to the difference in runtimes.

As said, adding 130g to a Truggy that weighs ~4300-4500g is only a 3% increase. I doubt you will really notice it. However if you've increased the pack size by 25%, you will most def notice the increase in runtime.

I often calc what my power consumption is for a given application, and its then freed from the voltage fo the pack. EG, your current setup, over 10 min of racing, how many mah do you consume? You can easily turn this to Wh/min. Then you determine the runtime you desire and then calc the needed Wh. Then you can determine the various capacities needed for a given voltage.

I would not assume every motor is going to pull 100A+. Its not. My 1515/2Y-8S setup never pulled that high, yet made as many watts as the low volt setup before. Additionally you do not produce as much waste heat, which is wasted runtime.
Given the same Wh of batteries, my 2Y on 10S will run longer, harder and cooler than a 1.5D on 4S as I am not wasting 100's of watts of power as heat.

The eff% should also be considered, but yeah, beyond a certain amount its not worth worrying over as there will be far more factors that have a greater influence that you can control here (such as style of driving, track layout, mud accumulation, etc etc.)