So the tester I have is the old school resistant type tester (where you hold a switch on the bottom for 10 seconds and watch the gauge to see where it falls). I also used a larger group size battery for testing from my 04 Ram SRT10 and saw no difference. I don't have an ammeter, I have a volt gauge (all new wiring on this whole car. With a volt meter I get 12.8 at the battery and 12.7 up at the front. 1 wire power master 130 amp alternator and I'm seeing 13.3ish on the volt meter when driving (dial style autometer gauge plus driving so not like I'm able to check down the tenth of an amp in that situation).