what is the meaning of deliver and power in here
The big problem is that the batteries that power electric cars weigh a lot relative to the amount of power they deliver.

what does weigh a lot power means?
what does deliver power means?

Question

what is the meaning of deliver and power in here
The big problem is that the batteries that power electric cars weigh a lot relative to the amount of power they deliver.

what does weigh a lot power means?
what does deliver power means?

Answer

Weigh a lot means that something is very heavy.  Large batteries are very heavy.  
Deliver power means the amount of power or electricity they can produce.  These batteries, even though they are very heavy, do not give very much electricity to the electric motor of the car.