Please explain the 4 step check. The car just sat for 8 days with no activity, and started like new yesterday.
do you have a multi-meter? if not go to an autozone, oriely etc and let them put the tester on it for free.
but if you are curious and have a meter....
1) with meter set to DC volts - check battery at terminals (the actual posts of the battery) with the car off, lights off etc. should get 11-12 +/- 0.5 a reading of 10.0 isn't the end of the world but I'd like to see 10.5
2) meter set to DC volts - check battery cables in the cable (IE if you can see it put the probe on the copper of the cable in the end of the clamps) - same check as above - should be 11-12 volts +/- 0.5. Specifically - should get the same reading as in test 1. if you don't the cables aren't on tight enough or there is dirt - corrosion etc between the cable and the battery - normally this is a case where you need to take off the cables - clean the posts, clean the cables - and test again.
3) meter set to DC volts - car on - A/C on - headlights on (why - load in the system) - let run for some 30 seconds or so - meter to battery cable or posts
should read 12.5-14.3 volts. why the range - new cars today have variable field alternators that vary output amps and voltage based on car need, available engine power - and battery condition as a function of internal resistance. IE the computer is balancing out the electrical loading based on factors to reduce fuel consumption if it's not needed.
so don't freak out if your 09 or newer car is only reading 12.5 volts at the battery. as opposed to rule of thumb it must be at least 13.5 at idle . . . . . . .
it's fine if it's 12.5+. it's good enough - with ac on, headlamps etc - I honestly expect it to be north of 13 - but if the battery condition is good - computer might back off.
4) meter on AC volts - low range (0-1- if that's an option for you). car on, ac on, headlamps etc - meter to battery cables. reading: 0-0.6 Vac. ideally it should read 0 - however nothing is perfect. any more than 1 Vac - indicates the rectifier pack is going bad or gone bad. car alternators actually produce AC current - like in your house - and there's an internal rectifier circuit that corrects it to DC - if you get AC leakage it will gradually kill a battery. and it's not good for the other electronic circuits but they are mostly protected.
this set of tests is similar to what those test machines do - without performing a deep cycle test on your battery