got a kind of health(battery) pickup, that doesnt work

so i got 2 scripts one for on my gamemanger (empty object) and the other for the pick up, when i pick it up it should send a message that my curBattery = 100, but it doesnt do anything? could anybody help me.

pickup using UnityEngine; using System.Collections;

public class Pick: MonoBehaviour {

 public BatteryLife batteryLife;
 //public float maxBattery = 100.0f;
 //public float curBattery = 100.0f;
 // Use this for initialization
 void Start () {
 
 }
 
 // Update is called once per frame
 void Update () {
 
 }

 float curBattery = 100 ;
 //float maxBattery = 0;
 void OnTriggerEnter(Collider coll)
 {
     if(coll.gameObject.tag == "pickUp")
     {
         coll.gameObject.SetActive (false);
         //curBattery=maxBattery;
         batteryLife.SendMessage("Drain",curBattery,SendMessageOptions.DontRequireReceiver);
     }
 }

}

gamemanager

using UnityEngine; using System.Collections;

public class BatteryLife : MonoBehaviour { public float maxBattery = 100.0f; public float curBattery = 100.0f; public float batteryDrainSpeed = 500.0f; public string battery = "Battery: ";

 void Start () {
     
 }
 
 
 void Update () {
     //curBattery = Mathf.Clamp(curBattery - (Time.deltaTime * (1000 / batteryDrainSpeed)),0.0f,maxBattery);
     Drain ();

     if (curBattery <= 0)
     {
         Death ();
     }
 }
 
 void OnGUI() {
     GUI.Box(new Rect(140, 175, Screen.width / 10 /(maxBattery / curBattery), 25), battery + curBattery + "/" + maxBattery);

 }

 void Death(){
     if (curBattery <= 0)
     {
         Application.LoadLevel("Death");
     }

     void Drain(){
         curBattery = Mathf.Clamp(curBattery - (Time.deltaTime * (1000 / batteryDrainSpeed)),0.0f,maxBattery);
     }
         
 }

}