Here's a useful factoid that you don't hear about very often:
1 volt means 1 Joule per Coulomb.
When 1 coulomb of charge falls or gets lifted through 1 volt potential difference, it gains or loses 1 Joule of energy.
If you want to lift 5 coulombs to a height of 1 volt, you have to give it 5 joules.
If you actually give those 5 coulombs 7.5 joules instead, they'll rise up to 1.5 volts above the potential where they started. The flowed through a potential DIFFERENCE of 1.5 volts.
(If they started at a point that's connected to the Earth, like a water pipe or a metal flagpole, then their new potential is 1.5 volts, because we define zero as the potential of the ground.)
