# Connecting to batteries together in a circuit

1. Oct 6, 2013

### B4ssHunter

what happens when we connect two batteries together in a circuit
on of them is higher than the other
say one of them is 10 and the other is 5
if they are connected such that positives meet , as far as i know a current will flow out of the negative * even though it should flow out of the positive ( conventional current direction )* of the weaker battery with voltage = 5 volt
what if they were connected postivie to negative ?
also , why is the voltage at power sources such as power companies 240 volts while it becomes 220 volts when it reaches homes ? * at my country thats the case *

2. Oct 6, 2013

### Staff: Mentor

Can you draw a sketch of the circuits?

Connecting different batteries is not a good idea. If you connect them in parallel (independent of the polarities), you get a short circuit, with bad consequences for the batteries (or even the environment, some batteries can explode).

Electric power gets transformed to higher voltages for transmission, this reduces current and therefore losses in the cables. Close to the consumers, it is transformed back to lower voltages - the value there is independent of the value somewhere at power plants.