One of the things I've noticed over the years is that even though a 100 watt panel delivers the same power as before, the rated amps have gone down and the rated voltage has gone up.? The solar panel I had 10 years ago had an optimal operating current rating of 5.8 amps, and it delivered that.? My current panel is rated at 5.29 amps for optimal current, and thats what it delivers in full sun.? But renogy has a new panel out now, and it has an optimal current of 4.86 amps.? So if you're using a pwm controller, you would have gotten another ~20% more power with an older panel than a newer panel.? The incentive to go to mppt is getting higher.
