user33550: I have a small project with arduino UNO R3 + RTC clock DS3231, that control through a relay a electrovalve (12V). 
I would like to use the entire circuit on battery. 
The electrovalve (a small motor) has a consumption of 500mA and will be active 4 times a day for 15 second. 
I have a 7Ah battery, and I had calculated that my system will work only around 34 hours with it... is there any way to optimize circuit consumption ? 
Thanks for any suggestion !

user23644: You can turn off the entire Arduino and let it wake by your RTC. That way you can conserve a lot of power. (link)
Also you will have losses from the power regulator when powering the Arduino from 12V. You might consider using a Arduino Pro mini with 3.3V powered by two AA batteries. That should last for years.

33550: <p>I have a small project with arduino UNO R3 + RTC clock DS3231, that control through a relay a electrovalve (12V). </p>

<p>I would like to use the entire circuit on battery. </p>

<p>The electrovalve (a small motor) has a consumption of 500mA and will be active 4 times a day for 15 second. </p>

<p>I have a 7Ah battery, and I had calculated that my system will work only around 34 hours with it... is there any way to optimize circuit consumption ? </p>

<p>Thanks for any suggestion !</p>
 23644: <p>You can turn off the entire Arduino and let it wake by your RTC. That way you can conserve a lot of power. (<a href="https://playground.arduino.cc/Learning/ArduinoSleepCode" rel="nofollow noreferrer">link</a>)</p>

<p>Also you will have losses from the power regulator when powering the Arduino from 12V. You might consider using a Arduino Pro mini with 3.3V powered by two AA batteries. That should last for years.</p>
