I’m learning about electronics and so have been doing some little projects to test what I’ve learned.

I decided to test a car lead acid battery to see if I could work out the ir.

My questions are;

1) Did I use the correct formula?

V1-V2

V2 X R = Ohms

2) The result I got is below, is this a plausible result?

V1 12.99 V2 12.47 R 3.23

Result 0.1346 ohms

I am teaching myself in this as a hobby and also part of my work. Any assistance is much appreciated.

thanks