One of Seven’s characteristics is that Ultra Seven has no time limit in particular for activities on Earth unlike Ultraman.
We children felt a difference from Ultraman in the fact.
As it’s well known, Ultraman has 3 minute-long time limit for activities on Earth.
It is explained it’s because his solar energy is consumed rapidly on Earth.
From the very beginning, Ultraman was given time limit as it is more exciting if a hero has his weakness than Mr. Perfect.
Seven was given weakness later as well.
His energy source is also solar like Ultraman.
When Seven run out of solar energy, his Beam Lamp got to blink on and off.
Since it blinked for the first time In Episode 11, sometimes you can see Beam Lamp blink.
It is also depicted, as Nebula M-78 has no winter (as explained in the drama), Seven is extremely vulnerable to coldness and consumes much energy. (Episode 25)
It’s not that Beam Lamp blinks every time and it also has no clear time limit unlike Ultraman.
So it stopped short of giving us such a sense of urgency as in Ultraman’s case.
It is fun to see Seven fly close to the Sun and absorb solar energy through the protector (Episode 25).
Seven’s protector is not for nothing!
It’s for absorbing solar energy!!!