How do you calculate total emf in series connecte cells?

Answer 1

With cells connected in series, the total emf of the 'stack' is simply the sum of

the individual emf's of the individual cells.

-- Even if one cell is connected backwards in the string. Then its emf is considered

negative when the sum is being performed.

-- All of this is true only as long as there is no external connection between the

ends of the stack, you're measuring the emf on an 'open-circuit' basis with a

voltmeter, and the cells are not providing any current to an external circuit.

Once the series combination of cells is connected to an external circuit and begins

to produce current, the total emf at the terminals of the stack will decrease. It'll

depend on the magnitude of the current, and on the 'internal impedance' of each

cell. If the cells are not precisely identical and in identical states of charge, then

a calculation of the total emf is virtually impossible.