Originally Posted by
Dave H
Increased voltage on the same load will drive more current, not less. A given motor will produce more power at higher voltage. Put a 3S lipo on the same motor, current and power will increase and run time will decrease, compared to a 2S pack.
The high voltage-low current concept requires a change in load/motor to work properly, to maintain a constant power comparison. Adjusting gearing on the same motor can help some, but this generally requires a motor change in practice to realize the full benefit of higher voltage.
+ on needing to consider peak loading, not just nominal dyno ratings, to size the ESC and other amp requirements. In practice the vehicle weight and gearing, even driving style, impacts this to some degree.
Higher voltage will always result in lower current (amps) for the same load.
Lower voltage will always result in higher current (amps) for the same load.
Further, if your theory with higher/lower voltage would affect your available power, what would happen with your car when the battery voltage drop from 8.4v to 7.2v, you would have less power? No, the esc/motor still have the same power rating (wattage), so to be able to keep up with the demand from the esc/motor the current from your battery has to increase. Remember that all system is rated for a certain voltage 1s, 2s, 3s....6s. So, normally you cannot just increase voltage since it will create to much heat and you will fry it. Traxxas and other RTR cars where you can swap between e.g. 2s and 3s is designed in such way that you will have max rating and efficiency with 3s. The difference in power is actually not that much. What happens is that your motor will have a higher rpm, but you will have less torque. So, yes in most cases you would have to change your gearing due to this. Your last statement is true, but that is why you typically have dedicated esc for 1/10, 1/8, SC, etc. so you do not have think about sizing your esc based on amp/voltage ratings.