Hi Larry, Is 18mΩ a combined internal resistane reading of all 4 cells? I got readings of .006Ω cell 1, .003Ω cell 2, .002Ω cell 3 and .006Ω cell 4, on three of my batteries which is a total of 17mΩ. and .005Ω, .003Ω, .002Ω and .004Ω on my forth battery. or a total of 14mΩ for all 4 cells.