Algorithm 2. Transition procedure for four energy modes

Input:  Average predicted harvested energy: Ep(t), device consuming energy: Ec(t), residual energy level of the battery: Pt, maximum battery capacity: Pmax, luminous intensity of the sunlight: Lsun, luminous threshold: Lthreshold

Output: Working mode of the node

while True

Delay TDelay;

Acquire Ep(t), Ec(t) and Lsun;

if Ep(t) ≥ Ec(t)

if Pt < Pmax

Mode: Sufficient status (SS);

else

Mode: Redundant status (RS);

end if

else

if Lsun≥ Lthreshold

Mode: Lack status (LS);

else

Mode: Empty status (ES)

end if

end if

end while