Part of my mod actually has unused items of various kinds including rechargeable items.

I'll share exactly what my code is, I really don't think its the cleanest in any way but it works.

Code:

//=============================================================================
// RechargeableFlashlight.
//=============================================================================
class RechargeableFlashlight expands Flashlight;

var() int bRechargeAmount; //Amount to recharge every bRechargeTimer.
var() float bRechargeTimer;
var() bool bDestroySimilar; //If TRUE, destroys similar objects in the inventory that are useless when having a rechargeable version.
var() int bTimeBeforeRecharge; //This is actually counted by the amount of time it goes in the TIMER. So if bRechargeTimer is at 1.5 and this is at 3, then it will take 3 time 1.5, so 4.5 seconds.

var int bRechargeTime;

state Activated
{
	function endstate()
	{
		bRechargeTime = bTimeBeforeRecharge;
			s.Destroy();
		bActive = false;
	}

	function Tick( float DeltaTime )
	{
		TimeChange += DeltaTime*10;
		if (TimeChange > 1)
		{
			if ( s == None )
			{
				UsedUp();
				return;
			}
			Charge -= int(TimeChange);
			TimeChange = TimeChange - int(TimeChange);
		}

		if (s == None) Return;

		if ( Pawn(Owner) == None )
		{
			s.Destroy();
			UsedUp();
			return;
		}
		if (Charge<-0)
		{
			s.Destroy();
			Activate();
			return;
		}

		if (Charge<1) s.LightBrightness=byte(Charge*0.6+10);

		GetAxes(Pawn(Owner).ViewRotation,X,Y,Z);
		EndTrace = Pawn(Owner).Location + 10000* Vector(Pawn(Owner).ViewRotation);
		Trace(HitLocation,HitNormal,EndTrace,Pawn(Owner).Location, True);
		s.SetLocation(HitLocation-vector(Pawn(Owner).ViewRotation)*64);
//		s.LightRadius = fmin(Vsize(HitLocation-Pawn(Owner).Location)/200,14) + 2.0;
	}

	function BeginState()
	{
		bActive = true;
		TimeChange = 0;
		Owner.PlaySound(ActivateSound);
		GetAxes(Pawn(Owner).ViewRotation,X,Y,Z);
		EndTrace = Pawn(Owner).Location + 10000* Vector(Pawn(Owner).ViewRotation);
		Trace(HitLocation,HitNormal,EndTrace,Pawn(Owner).Location+Y*17);
		s = Spawn(class'FlashLightBeam',Owner, '', HitLocation+HitNormal*40);
		s.LightHue = LightHue;
		s.LightRadius = LightRadius;
		if (Charge<1) s.LightBrightness=byte(Charge*0.6+10);
		if (s==None) GoToState('DeActivated');
	}

Begin:
}


state DeActivated
{
	function Timer()
	{
	local inventory I;

	if ( bDestroySimilar )
	{
	for ( I = Owner.Inventory; I != None; I = I.Inventory )
		if ( I.IsA('RechargeableFlashlight') )
		{
		}
		else if ( I.IsA('SearchLight') )
		{
		}
		else if ( I.IsA('Flashlight') )
			I.Destroy();
	}

		if( Charge<Default.Charge && bRechargeTime <= 0 )
			Charge+=bRechargeAmount;
		else if ( bRechargeTime >= 1 )
			bRechargeTime--;
	}
Begin:
	bActive = False;
	SetTimer(bRechargeTimer,true);
	Owner.PlaySound(DeActivateSound);
}

defaultproperties
{
	bRechargeAmount=40
	bRechargeTimer=0.500000
	bDestroySimilar=True
	bTimeBeforeRecharge=2
	PickupMessage="You picked up the rechargeable flashlight"
	Charge=2000
}
 

Most of it is easy to configure. You can have a delay before it starts recharging, you can edit the recharging speed, you can make it delete redundant, normal Flashlights from your inventory (will keep SearchLights).

Do with this as you wish.