What is internal resistance | How to Measure the Internal Resistance of a Battery? | Wow Electric

INTERNAL RESISTANCE ::
All batteries and also all individual cells have a "secret, hidden" value of resistance inside each cell due to the resistance of the chemicals.
This resistance is very small when the cell is new but it increases as the cell gets older.
It is very easy to measure this value. Simply put an ammeter directly across the cell and measure the current. Use Ohm's law to work out the resistance.

But this not always a wise thing to do as some cells will deliver 10 amps and some will deliver 100 amps and damage the meter.

The diagram shows a large internal resistance for the weak cell and a small internal resistance for the good cell.

If a cell did not have any INTERNAL RESISTANCE it would deliver thousands
of amps. It's the Internal Resistance that limits the current.

In most cases we neglect (do not consider) the value of internal resistance when making tests and when using a battery in a project.
But when a battery gets old, it cannot deliver a high current and the internal resistance gets so high that the output voltage drops from say 9v to 7v, even when the battery is not connected to a circuit.

This is the result of the INTERNAL RESISTANCE of the chemicals increasing to a point where they become noticeable and what we call "poisoning" of the chemicals due to the cell "aging" and new chemicals being produced in the cell that have a high resistance. Some of the terms we use are: "drying out and sulphating.
Some cells produce spikes or needles that completely short-circuit the cell and make it totally useless.

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[SaqibAli-kutu]

thanks alot .... bg music keeps focused

[jeremyspillerYT]

Please, why the awful music? It would have been a great vid without the music and genuinely doesn't need it.

[rippinscreamingmetal]

not all viewers like bubble gum music thumbs down!