Originally Posted by
the rc guy
cap pack has nothing to do with battery IR.
Sure it does....With most ESC's the capacitor is acting as a filter to filter out the high frequency ripple on the power lines with the result the battery and ESC will stay cooler.
But when the capacitor is acting as a power buffer other aspects need to be looked at. If the IR of the capacitor is higher than that of the battery then still the battery wil provide the most current and determs the voltage drop because the higher IR of the capacitor will not help to keep the voltage on level. Current Lipo batteries have an amazing low IR and can handle high currents, more than such a cap pack can handle.
I can imagine they can help with that first push but I wonder if it is really needed with current good batteries, that it is still a thing still used from the past with NiMh batteries.