Awesome info. I'll throw in my experience too which is much more basic. I bought the Renogy 100w kit with the basic PWM controller and no digital display. I really wanted to see how much amperage was coming in so I added a cheap (real cheap) voltmeter/ammeter I found on Ebay or Amazon. With the one panel I see around 5 amps on a sunny day with low batteries. I recently doubled this setup, just adding another 100w panel for a total of 200, same PWM controller and digital voltmeter/ammeter. It immediately jumped to an average of 10 amps coming in on a sunny day, but I saw as high as 12 before I sold the van. Here are the unique things (I think) about my setup. When the batteries are mostly charged the PWM controller lets in less amps, so if I'm not using much or any power my ammeter will go down even in direct sun, which can be confusing. Also, if driving the van and the alternator is charging the batteries the amps coming in drop to near zero on the display, never more than 2-3.