Yesterday we re-visited the topic of internal resistance. To demonstrate the idea, 6 volt lantern batteries were used. The battery voltage was measured with a volt meter; then A 1 ohm 10 watt resistor was placed at the output terminals. A second voltage reading was immediately taken.
From these two readings we can determine a rough estimate of the battery's internal resistance. Can you figure out how?
Why is internal resistance important? Well- if you've ever tried to start your car on a cold day, I'll bet you were hoping your car's battery had lots of cold cranking amps! Or put another way, low internal resistance.
Here's a good link to the concept along with some info on how those fancy battery testers work:
http://batteryuniversity.com/learn/article/how_to_measure_cca_cold_cranking_amp/
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