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I read somewhere that the voltage stays the same(it will be equal to the voltage of one of the batteries) but the output capacity increases. What does this mean? Will the current in the resistor increase?

Applying superposition theorem I see short circuits and therefore almost zero current going through the resistor. Am I right? So where's the increase and again what is output capacity?

We have something like this with a resistor across AB:

enter image description here

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  • \$\begingroup\$ Can you include a schematic of the wiring arrangement you are describing? Or describe it better, i.e. are both batteries in parallel also? \$\endgroup\$
    – AngeloQ
    Commented Mar 18, 2017 at 21:12
  • \$\begingroup\$ if the batteries are truly identical, then the voltage of one battery is equal to the voltage of the other battery. \$\endgroup\$ Commented Mar 18, 2017 at 21:13
  • \$\begingroup\$ Oh you mean a resistor in series between the positive terminals of two batteries, right? \$\endgroup\$
    – AngeloQ
    Commented Mar 18, 2017 at 21:15
  • \$\begingroup\$ @AngeloQ I added a picture. \$\endgroup\$ Commented Mar 18, 2017 at 21:23
  • \$\begingroup\$ Thanks, see it. No the current doesn't increase because the voltage hasn't increased. I = V/R Output capacity does increase though (Ahr rating is doubled). \$\endgroup\$
    – AngeloQ
    Commented Mar 18, 2017 at 21:23

2 Answers 2

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The capacity of a battery is a measurement of its ability to output energy, i.e. current during a certain amount of time. It is usually measured in A.h.

If the current through the resistor is such that a single battery gets discharged in one hour, adding an additional battery with the same characteristics as the first one will make a discharge time of two hours (i.e. capacity of two batteries is doubled compared to single battery).

The current through the resistor doesn't change since the applied voltage remains the same.

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This is ohms law and a simple as it gets. Identical batteries will have the same voltage at the terminals. If the batteries are not identical then the current from the higher voltage battery will flow into the lower voltage and the current will be limited by the combined internal resistance of the batteries with the terminal voltage determined by the resistance of the voltage divider comprising the internal resistance . The current thru the resistor is E/r

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