Charging one’s mobile phone from the electricity in the Haram

It is better for the Muslim not to do that, and to err on the
side of caution. The Prophet (peace and blessings of Allaah be upon
him) said: “Leave that which makes you doubt for that which does not make
you doubt.” Narrated by al-Tirmidhi, 2518; classed as saheeh by al-Albaani
in Saheeh al-Tirmidhi. 

Based on this, a person
should charge his mobile phone in the place where he is staying, before
going to the Haram, so that he will have no need to use the electricity of
the Haram. 

But if a Muslim needs to do that, there is the hope that
there will be no sin on him for that, in sha Allaah, if the people in charge
of the Haram do not disallow that. But he should limit it just to what he
needs and no more, so that he will not prevent any of his Muslim brothers
from also charging their mobile phones, because they may need it just as he
does, or more. 

And Allaah knows best.