Eclipse vs regular panel
I'm trying to decide which panel to install on my Subaru. I'm using a Rover 20A charger with Optima Yellowtop AGM battery and the choice is between Eclipse RNG-100MB or the regular RNG-100D-SS. It will be mounted between the crossbars of a Prinsu roof rack.
Based on the specs, the Eclipse is slightly more efficient, but that doesn't justify the large increase for me. ($175 vs $101 on Amazon). I also prefer the shape of the regular one, longer and skinnier, as it leaves more spare room on my rack. But a friend told me the Eclipse performs significantly better in partial shade, which is a very important factor when I'm camping. They both feature two bypass diodes, so I'm not sure what the difference might be. So I bought both panels to compare. Unfortunately the results are inconclusive.
I put both panels side by side on a sunny day with no clouds. I connected each panel one at a time to the Rover and turned on all my accessory lights to put a constant load on the battery.
I used a paper booklet about 6" x 8" and placed it in various positions around the panels, doing the same on each. I measured panel voltage and charger output, waiting for the numbers to stabilize after each adjustment. With the MPPT controller, I don't think voltage really matters, but I recorded it anyway. I think it's the current that matters.
Then I tried smaller obstructions of a lotion bottle and a 750mL water bottle, and a few scraps of wood scattered randomly.
With the larger obstructions of the paper booklet, the Eclipse performs better, sometimes by a significant margin and sometimes by a very small margin. But with the other tests, the Eclipse is sometimes worse.
So based on all of this, I can't tell how much difference there will be, on average.