Originally Posted by
oldrcr
The devices I speak of are digital, meaning they don't have as big of a tolerance issue like a purely analog device would of days past...
The same could be true of a mAh limiting device instead of the RPM limiter. It would count the number of mAh that pass from the battery to the ESC, and when the amount it is preset to is hit, it would turn off the motor much like a voltage cutoff does...
By the way, most chargers can be set to put in so many mAh into the battery, so its not a foreign technology to put that system into use for the battery output we would want to employ. Its just a discharge meter. When it hits the preset amount of mAh used, it shuts down the output to the motor.
Current is always an analog quantity until one reaches the quantum realm. It must always be measured with an analog device, which comes with all its associated tolerances and errors. Devices that display current with a digital readout must always have an Analog to Digital Converter (a.k.a. ADC or A/D) somewhere in the measurement chain.
Creating a small, light-weight device capable of measuring with good precision the very large currents we are using is not trivial.
The idea is fine, but the devil is in the details.