Can I turn a servo off?

The project is a solar tracker. Functioning well but in order to conserve the solar charged battery power I would like to completely shut the servo off. Right now I can hear it functioning (no movement, just a light vibrating noise) even though, in the sketch, it’s not instructed to move unless the monitored photocells are below a value (it’s dark, don’t move). Can this be done in the sketch or would I need to incorporate a motor driver to shut off power to the servo? - Scotty

#include <Servo.h> // include Servo library 
Servo horizontal; // horizontal servo
int servoh = 90; // stand horizontal servo

// LDR pin connections
// name = analogpin;
int ldr_lower_right_pin = A4; //LDR top left
int ldr_upper_right_pin = A1; //LDR top right
int ldr_lower_left_pin = A3; //LDR down left
int ldr_upper_left_pin = A2; //LDR down right
int lower_right_ldr = 0;
int upper_right_ldr = 0;
int lower_left_ldr = 0;
int upper_left_ldr = 0;
int avl = 0;
int avr = 0;
int current_position = 0;
boolean dark;
//boolean limit;
int buffer = 50;


void setup()
{
  Serial.begin(9600);
  // servo connections
  // name.attacht(pin);
  horizontal.attach(8); 
  horizontal.write(90); // set initial position as 90 deg
}

int Debug_Sensors(){
  Serial.print("A1 (upper left)= ");
  Serial.print(upper_left_ldr);
  Serial.print("     A3 (lower left)= ");
  Serial.print(lower_left_ldr);
  Serial.print("     Average left = ");
  Serial. println(avl);
  Serial.print("A4 (upper right)= ");
  Serial.print(upper_right_ldr);
  Serial.print("     A2 (lower right)= ");
  Serial.print(lower_right_ldr);
  Serial.print("     Average right = ");
  Serial.println(avr);
  Serial.print("     Dark = ");
  Serial.println(dark);
  //Serial.println();
  Serial.print("     Limit = ");
  Serial.println(limit);
  Serial.println();
  Serial.print("     Current Position = ");
  Serial.println(current_position);
  Serial.println();
  //delay(000);
}

int Read_Sensors(){
  lower_right_ldr = analogRead(ldr_lower_right_pin); // top left
  upper_right_ldr = analogRead(ldr_upper_right_pin); // top right
  lower_left_ldr = analogRead(ldr_lower_left_pin); // down left
  upper_left_ldr = analogRead(ldr_upper_left_pin); // down right
  avr = (lower_right_ldr + upper_right_ldr)/2; // average value left
  avl = (lower_left_ldr + upper_left_ldr)/2; // average value right
  if(current_position <10 || current_position >170)
  {
    limit = true;//limits rotation of servo to prevent damage
  }
  else
  {
    limit = false;
  }
  if(avl >900 || avr >900)
  {
    dark = true; // is it dark? variable
  }
  else
  {
    dark = false;
  }
}

int Move_Panel(){
  current_position = horizontal.read(); //takes reading from current servo position


  // this portion is to control horizontal position
  if(avl > avr+buffer &&!dark && current_position > 10) // if left LDR pair has more light than right pair & limit is not reached & it is not dark
  {
    horizontal.write(current_position -1); //increase position of servo1 by 1 (0 is left, 90 is center, 180 is right)
    delay(10); // this delay is needed to prevent servo from going 0-180 without stopping
  }

  else if(avr > avl+buffer && !dark && current_position < 170) //if right LDR pair has more light than leftt pair & limit is not reached & it is not dark
  {
    horizontal.write(current_position +1); // decrease position of servo1 by 1 (0 is left, 90 is center, 180 is right)
    delay(10);
  }

  else
  {
    horizontal.write(current_position); // if neither condition is met, this means the panel is centre. Do not move panel
  }
}

void loop() 
{
  Read_Sensors();
  Debug_Sensors();
  Move_Panel();
  delay(50);
}

You should be able to make a conditional detach of the servo something like below.

    if (n < 500) {
      myservo.detach(); 
    }
    else {
       myservo.attach(7);
       myservo.writeMicroseconds(n); //convert readString to number for servo
    }

This topic is about that, http://arduino.cc/forum/index.php/topic,98057.0.html I think you have to do some tests. The signal line should be low, I don't know of the Arduino pin is low after the detach. Some servos can made idle with a write to position 0.

If you need to switch the servos after all, perhaps a single normal relay of a power mosfet could do.