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Topic: Arduino power usage 160mA, any way to reduce this? (Read 1 time) previous topic - next topic

Rutger

Hi,
I am making a small RGB LED light, controlled by Arduino. I have it connected to a 5-8 V powersupply. I noticed that, when the light is turned off, it still uses 3-4 W. I therefore measured the current through the Arduino which was 160 mA, even when I disconnected all buttons, mosfets, etc. Then I though that the sketch might perhaps use to much current, but when I upload the most simplest of all sketched (blink, without led usage), it still uses 160mA.

Is this the standard consumption of the Arduino? I haven't come across any reference to this and it appeard to me quite a bit. Any suggestions to lower the power consumption by the Arduino?

Rutger

westfw

That sounds quite high.  I just measured by Arduino Uno, and it only measured about 50mA (which is about what I'd expect.  There are graphs in the AVR datasheets that show they should be around 20mA when running at 16MHz, and there are two of them, plus some other relatively low-current devices.)

James C4S

Capacitor Expert By Day, Enginerd by night.  ||  Personal Blog: www.baldengineer.com  || Electronics Tutorials for Beginners:  www.addohms.com

Rutger

Thanks for the reply,

I have an Arduino Duemilanove with the ATmega328p processor. When I attach a stabilised 5V to the 5V pin, it draws 132 mA. When I connect 5V to the Vin pin, it draws 108mA. Increasing the voltage to the Vin results in the following current±

5V       108 mA
6V       140 mA
6.5V    153 mA
7V       161 mA
8.4V    161 mA

I need to use the 8.4V, since my RGB LED draws a lot of current, resulting in a voltage drop. Lower voltage would be to low for the Arduino.

James C4S

The 5V, 6V and 6.5V measurement on Vin is irrelevant since you are operating below the required voltage for the regulator.

The rest do seem to be high, even for a Duemilanove.  What do you measure if you remove the ATmega328 from the board?
Capacitor Expert By Day, Enginerd by night.  ||  Personal Blog: www.baldengineer.com  || Electronics Tutorials for Beginners:  www.addohms.com

Rutger

When I removed the ATmega328 , the current was only 9 mA (at 5V on 5V pin and 7 and 8.4V on Vin pin). Therefore I placed two other ATmega328's I have laying around. Both measure around 26 mA at the three voltages.

Clearly it is the ATmega328, but do you have any idea how come it differs from the others??

James C4S

There are any number of reasons that chip is bad.  One of the most likely is that an I/O Pin Driver is shorted to ground (or nearly shorted to ground) and is causing the high current draw.

I'd suggested throwing the chip away--clearly something is wrong with it.  :)
Capacitor Expert By Day, Enginerd by night.  ||  Personal Blog: www.baldengineer.com  || Electronics Tutorials for Beginners:  www.addohms.com

Rutger

I will
Thanks a lot for the quick and clear help :)

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