# Why does voltage not increase when batteries are connected in paralell? [duplicate]

Having seen this question often on this platform, but never read a statisfying answer.

• It really boils down to the Kirchhoff’s 2nd law. Try drawing a simple diagram with one resistor and two batteries in parallel. Apr 9, 2021 at 22:03
• What kind of satisfaction are you looking for? Because it's the same reason that two columns of of water side by side doesn't increase their height or pressure, whereas stacking the columns will. Apr 9, 2021 at 23:00
• What questions have answers you aren't satisfied with? Maybe someone could clarify or improve an answer. If we don't know what your confusion or dissatisfaction is, we probably can't help. Don't make us guess! Apr 10, 2021 at 3:17

First of all, you should write your questions in a clear manner. It isn't clear what voltage difference you are talking about, whether there is an emf source or not etc.

But in general note that the term "parallel" in the context of electric circuits implies that the elements that are parallel have the same potential difference between their terminals. To elaborate:

Kirchoff's 2nd Law states that the voltage differences through a loop should add up to 0 meaning a charge should have the same potential energy that it started with when it comes back to its initial position. Note that this takes both energy loses through circuit elements and gains through emf sources into acount.

When you connect two capacitors in parallel and loop through them you would see that V1-V2=0.

This means when you connect another capacitor it doesn't increase the voltage but you provide "extra space" for the charges to go. Since they are less dense, the same amount of charge will create a smaller voltage across the capacitors.

Or if you connect a battery, since there is more "space", you can store more charge using an identical battery.

This "space" is the capacitance of the capacitor and it determines how much charge it will hold for a certain voltage. And when you add another capacitor, you increase this space. To be precise, the equivalent capacitance value is the sum of the capacitances of our original capacitors.