# Potential difference battery

1. Feb 10, 2014

### Lee33

1. The problem statement, all variables and given/known data

How can I measure the potential difference across two batteries? For example, if I put the batteries end to end, so the negative end of one touches the positive end of the other. And lets say both batteries have 3 volts and lets denote point A to B as the point from one battery to the other.

2. Relevant equations

$\Delta V = -\int^b_a\vec{E} \dot\ \vec{dL}$

3. The attempt at a solution

So if the length of both batteries is 5 cm then do I put a point C in the middle of the two batteries and measure the potential difference separately from point A to point C then from point C to point A?

2. Feb 10, 2014

### Staff: Mentor

Physical size (length) is pretty much unrelated to the potential difference across a battery. Cell potential depends upon the chemistry, while current capability and capacity scale with the volume of the cell.

Take a look at the Wikipedia entry on battery sizes.

"Measure" implies a physical process of determining potential difference. In that case one simply takes a handy voltmeter, places its leads across the desired locations, and takes the reading.