phase test internal resistance of a battery

[doyle]

hi guys

im stuck on a end of year phase test, the question relates to

EXPLAIN INTERNAL RESISTANCE OF A LEAD ACID BATTERY,

i know that some charge and discharge is lost though heat, but what makes the internal resistance ect and where can i get a diagram showing it. this is not in my hilliers 5th edition but is in 6th edition


thanks
terry

 

[Mursal]

As you probably know an ideal battery (or first approximation of a battery) has the usual symbol with the voltage usually printed alongside. This will supply a steady voltage at the set rate indefinitely regardless of current flow to the load connected to it.

In reality this will not happen.

So, we need a more detailed model (second approximation) which can be drawn as an ideal battery with a resistor in series with it.
http://bit.ly/ZCL9MB (first diagram top left)
This is to simulate the internal resistance of the battery as it charges and discharges.
Now as the load current changes the voltage across the load will also change. Because the load current will have to flow through the internal battery resistance
And internal resistance (R) multiplied the current flow (I) will give an internal voltage drop in the battery. R x I = V
Where V is the voltage drop across the internal resistance of the battery.

Good Luck with your studies

 

[doyle]

thanks mursal