Need microinverter or string inverter for installation of older panels, circa 2007

I am in the process of installing six Evergreen ES-170 SL panels that I removed from my vacation home where I needed more power generation than these provided, for an off-grid system. I plan to use these at my home in a grid-tie arrangement. My location is minimally shaded, but nevertheless thought a microinverter might be the best inverter solution. It seems that models by Enphase will not work. Looking at the website for Power One Aurora microinverters, their string sizer tool lists this panel, and therefore indicate these inverters will work. My local distributor, though, feels this is not the case.

If anyone would like to view the stringsizer tool, here's the general page for the Aurora, then select stringsizer tool.
The ES-170RL appears in the selection (RL denotes European manufacture).

If a microinverter will not work, I'll go with a string inverter that can accommodate the electrical characteristics of these older panels. My distributor no longer carries an inverter to match the Evergreens. If anyone can make an inverter recommendation, or guide me toward an older inverter that I could then find on the used market, that would be much appreciated.

Electrical Characteristics of the ES-170SL

STC Power Rating Pmp (W) 170
PTC Power Rating Pmpp (W) 147.1
PTC/STC Power Ratio 86.5%
Open Circuit Voltage Voc (V) 32.4
Short Circuit Current Isc (A) 7.55
Voltage at Maximim Power Vmp (V) 25.3
Current at Maximim Power Imp (A) 6.72
Panel Efficiency 11.4%
Fill Factor 69.5%
Power Tolerance -5.00% ~ 3.70%
Maximum System Voltage Vmax (V) 1000
Maximum Series Fuse Rating (A)
Temperature Coefficients
Temperature Coefficiency of Isc 0.060 %/ºC
Temperature Coefficiency of Voc -0.34 %/ºC
Temperature Coefficiency of Pmp
Mechanical Characteristics
Cell Type Ribbon Silicon Cell
Cell Size(mm)
Cells 108
Dimensions 1571.0 × 951.0 × 41.0mm (37.4 × 61.9 × 1.6 inch)


  • BB.BB. Super Moderators, Administrators Posts: 32,800 admin
    Re: Need microinverter or string inverter for installation of older panels, circa 2007

    If you really wanted to try it--Your panels will not damage/overvolt an Enphase micro-inverter.

    If you live in a cooler climate, the Evergreens may work "OK" for you...

    The Enphase are probably optimally behind a ~280 watt panel. The 170 is on the small sized, and two in parallel would be on the large side--But it should still work (you will get clipping on clear/sunny days with two panels in parallel).

    Get an Enphase M215 and experiment... See what the Vmp-array is and how things work (cold this time of year, so you will not see how things work in summer--so you want to log the Vmp-array and working cell temperature or ambient temperature and extrapolate to your summer operating temperatures.

    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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