# Why will connecting batteries in series only generate large current flow between the two batteries if one is less charged than the other?

If you connect an uncharged battery to a charged battery in series (+ to - and - to +) there will be a large current flow between the batteries and it will heat up as if it's being short circuited, but if you do this with two charged batteries it will just double the voltage that the system has. Why? It seems that the electrons would flow from the negative of one to the positive of the other for each battery if they were connected in series bringing both of them to 0 volts, but why does this not happen?

• please draw for us the circuits you describe. Include the load resistances in each case. – niels nielsen Apr 15 '18 at 18:51
• @nielsnielsen the circuit I am thinking of is just two batteries connected to each other, positive of one connected to negative of the other and vice versa. – user180969 Apr 15 '18 at 19:46

The correct way to describe the circuit is $I = V_{total}/R_{total}$, where $R_{total}$ is the sum of the internal resistances of the two batteries + the total resistance of the wires. $V_{total}$ is the sum of the voltages of the two batteries with no load—i.e. as measured by a high-impedance voltmeter while not connected to any load (this is just what we normally call voltage).