I might be in the wrong place but I want to try and get a decently credible answer.
I have just bought a brand new 12v AGM car battery. The voltage drop in the battery when a load is applied appears to be too large. It's voltage when disconnected is 12.8V. I know my car draws very close to 1amp when a battery is first connected and my clamp meter confirmed it did again this time, but the voltage of the battery dropped to 12.7V at the posts. R=V/I, thus the internal resistance is apparently 0.1 ohms. Is this not an appropriate way to measure internal resistance, as I believe 0.1 ohms is way too high?