Right. Higher voltage is ONLY more efficient WHEN the same power is required (ie overall speed) as the lower voltage set-ups.
A 4S set up geared for 40mph is less efficient than a 6S set-up geared for 40mph. A 4S set-up geared for 40 compared with a 6S set up geared for 60 isn't a fair comparison.
So a low KV motor paired with high voltage, geared for x, is more efficient than a high KV motor paired with low voltage, geared for x.
I ran a 5S 5500mAh Hyperion in my buggy (XB808) and it went well - the Losi conversion doesn't place the battery in the optimum location for heavier batteries - in this case a custom build would be better.
5S doesn't always give more punch - only if you don't change the gearing or motor from the lower voltage. It's possible to have a faster low voltage car than the high voltage - it's not all down to the voltage - the motor and gearing also play a big factor.
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