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Would the voltage of a power source decrease if multiple loads / more load is added to it?

I am researching battery types, and wanted to know, if I added enough load to a battery how much / would there be any voltage drop?

Example: I have a 12 V set of batteries in series. The batteries' rated current is 48 A.

I have four loads that each require 12 V and 13 A of electricity. Would there be any voltage drop, would the load have to be significantly higher to actually see a decrease, or would the voltage stay the same?

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  • \$\begingroup\$ How is this not a duplicate? \$\endgroup\$ – Peter Mortensen Aug 9 at 13:37
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Yes, the output voltage of a battery decreases (roughly) in proportion to the current drawn from it. This behavior is usually characterized as an internal resistance of the battery, although its actual physical origin may be related more to the chemical properties of the battery than to the actual resistance of any conductive part of the battery.

For the second part of your question, you'd need to consult the data sheet of the battery you are using. This has been discussed in a previous question: Internal resistance of batteries?

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It's actually the conductor dielectric interface that matters for ESR. this rises slowly with age and rapidly below 10% SoC while the conductors are constant and conductive particles in the dielectric would discharge it.

The impedance or Effective Series resistance , ESR or Rs, internal resistance is inversely related to the cell storage capacity , Ah yet not an effect measure of SOC but reduces with rising C charge rating.

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