# Promini Power consumption?

What is the power consumption of a Promini that is just giving signals to a servo once every 20 seconds? I need to know to estimate how long the Promini will run using batteries. Thanks

Not enough information. We need to know what current the servo signal input takes and what is the pulse on time in order to calculate it correctly.

However, the servo itself will take current and that will be vast compared to what the processor will take. Calculating the running time on batteries is just a guess based on an assumption, it is not a precise thing anyway. Best if you just regard the arduino to take 30mA and then add the servo current.

Many thanks - the servos are supplied with a separate source - so the batteries drive only the Promini - 3 servosmotors are driven usually one at a time periodically only by the internal clock, no other input - they are made to rotate 120 degrees each 20 seconds or so. Does that help?

Does that help?

Not really. You haven't answered any of my questions. I suspect this is an impossible thing to calculate because you don't know any of the numbers.

that is just giving signals to a servo once every 20 seconds?

Servos need a constant pulse train to keep it stationary so that makes no sense. Lets guess. Say the servo controller takes a signal of 10mA from the arduino. It matters not if it a stationary pulse train or a varying one. Add that to 30mA and you get a total current drain of 40mA for the processor and its signal drive.

Make sure the black servo (-) wire is also connected to the arduino ground.