Stall current peaks at 5Amps at 12V, but only 2.5Amps at 6V. The Shield says it has a maximum of 2A. If the voltage is lower than 12V, would it be able to operate at higher currents?
Power = Voltage * Current
Power(12V) = 24Watts
Power(6V) = 24Watts = 6V * 4A
Is this correct or what other low cost single channel motor controllers are available?
Thanks
Yes, you can run at lower voltage or lower duty cycles to deliver lower effective power to the motor, thus keep it within its safe operating limits.
I'm not sure I understand your 24W calculation. The current does not go up when the voltage goes down. It is the opposite. If you apply 12V to a 5A motor then roughly speaking you will get 2.5A flowing at 6V.
Also beware of "2A" motor drivers: we have an application note here that explains why you generally will not get that amount of current from them:
Other low cost single-channel motor driver include our Rugged Motor Driver and Basic Motor Driver. Finally, we have an application note that shows how to parallel a 2-channel motor driver to get (approximately) twice the effective current:
This should work for any similar motor driver.
--
The Ruggeduino: compatible with Arduino UNO, 24V operation, all I/O's fused and protected
The 24Watt calculation was in regard to the amount of power going through the circuit. If I am operating at 6V, will the electronics be able to operate at 4A?
No, your motor driver (just about any motor driver) is limited by current, not by power. In your mind you are trading off voltage for current while keeping the power the same. That's not the way it works, however. The reason motor drivers are rated by current (not power) is that the power mostly doesn't matter. A "2A motor driver" (assuming it really can deliver 2A) must be limited to 2A regardless of whether the input voltage is 6V or 12V.
--
The Rugged Circuits Yellowjacket: 802.11 WiFi module with ATmega328P microcontroller, only 1.6" x 1.2", bootloader