internal resistance of a battery

Thread Starter

Hurt_it_Circuit

Joined Oct 2, 2012
53
Does the internal resistance increase as the voltage of the battery goes up? For example does a 1.5V battery have a lower internal resistance than a battery of 9V? Made from the same manafacture.
 

bertus

Joined Apr 5, 2008
22,278
Hello,

A 9 Volts battery consists of 6 AAA size batteries.
As the active area is smaller of those AAA cells, the internal resistance is higher.
The AA battery has a larger active area, so the internal resistance is lower.

Bertus
 

Austin Clark

Joined Dec 28, 2011
412
The simple answer is no. Voltage and internal resistance aren't directly related.

Generally, the bigger the battery, the lower the ESR, because as was stated before, you have a bigger active area. Of course, different types of batteries have different ESR values as well.

A D cell has the same voltage as a AA, but is much bigger, has much lower ESR, and has a greater overall capacity.
 

Thread Starter

Hurt_it_Circuit

Joined Oct 2, 2012
53
I am confused by a 9V battery has 6 AAA batteries and that the active area is smaller. I am new to circuits and I am taking my first class about them. What is active area mean? What does ESR mean?

When we conducted our lab it asked to measure the internal resistance of both batteries. When we set up our experiment we connected a 9V battery to a breadboard and a resistor (R1). We measured the current across and since the circuit is in series it does not change. We were having some difficulty with our multimeter and it began giving us odd measurements. We then plugged our values into Ohm's Law V(battery)=I*R1 + I*R(battery). We then solved for R(battery) and got like 29Ohm's for the 9V. We conducted same experiment for the 1.5V battery and got 8Ohm's. Did we set up the experiment properly?
 

t06afre

Joined May 11, 2009
5,934
This will also depend on the condition of the battery. The internal resistance will increase as the battery is discharged. So your result could be correct
 

Ron H

Joined Apr 14, 2005
7,063
Hello,

A 9 Volts battery consists of 6 AAA size batteries.
As the active area is smaller of those AAA cells, the internal resistance is higher.
The AA battery has a larger active area, so the internal resistance is lower.

Bertus
I think you meant AAAA, not AAA.




There are other ways of making a PP3 9V battery. See the Wikipedia article.
 

Ron H

Joined Apr 14, 2005
7,063
Does the internal resistance increase as the voltage of the battery goes up? For example does a 1.5V battery have a lower internal resistance than a battery of 9V? Made from the same manafacture.
In a 9V battery made up of 6 AAAA cells in series, the resistance will be 6 times that of a single AAAA.
 

peck68

Joined Nov 27, 2009
73
All cells will have a resistance to them, also called Equivalent Series Resistance, these vary with different chemistries. NiMH batteries have a generally high resistance, generally able to supply only 1 or 2 amps under short circuit. While Lead Acid batteries can supply over 20 amps because of their low resistance!

If you have one cell with resistance R, and an identical cell in series, then hopefully you should know that resistances in series add up therefore the resistance now becomes 2R

Hope that helps a bit ?

I have two 3000F capacitors with a resistance so low they can supply over 100 amps!
 
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