Note: The information contained in this periodical weblog may be outdated. This was my personal weblog published before January 1, 2015. Since then I have been the co-owner and Principal Solar Designer at Florida Solar Design Group.


  1. Good article. However, as head of ops for a CSA certified fabrication facility for ACPV I can tell you that at least one of the brands would easily convert back to a DC module. A simple unplugging of the amphenol connections and unbolting the unit from the back. Also, I don’t see the replacement as that big of an issue. As long as the inverter manufacturer is in business the replacement module should easily interchange(currently finding an existing match for a 5 year old panel is problematic for DC based systems). Current warranties cover shipping both ways and pay a small fee to the installer for the swap.

    1. Thanks for your insight, William. That’s good news about the warranty.

      Would there be any UL listing issues using the module as a standard DC module? I’m not familiar with the specifics of UL listing for an ACPV module.

      Your right about finding DC module replacements, but I think everyone agrees that the inverter component is the more likely component to fail.

  2. Jason,
    I will reach out to our vendors and see about the UL listing. I know how “rigid”, for lack of a better word, UL can be.

  3. That would be great.

    It’s interesting how ACPV, microinverters, and traditional string inverters are now fighting for market share, and how module manufacturers are hedging their bets about what technology will emerge the winner, if any. Again, I think the ACPV is a great concept, and it makes sense that a simple “appliance” would be the wave of the future. If the few “cons” I mentioned are worked out, it may well emerge the winner. Changing out the microinverter on an ACPV module in the field, just like and appliance part, seems to be an important factor for serviceability.

    You are right about the rigidity of the UL listing. Ideally, we would be able to convert existing DC modules into an ACPV system one day. We are already seeing interest in microinverters for systems where the string inverter has failed and is out of warranty. Unfortunately, they are often comprised of lower watt or incompatible modules (i.e. Evergreen).

    I look forward to any information you can provide about the UL listing.

  4. I am convinced that acpv will eventually dominate the residential and small business markets. Troubleshooting can then in most cases be pinpointed to defective module. If inverter is at fault it should be fairly easy to match up and adapt with a comparable replacement (even if there is some adaptability issues required as long as ul and safety guidelines are meeting compliance and accepted. More important issue is long run reliability – warranty means nothing if a co. Becomes insolvent! Hopefully good news will be the low % of microinverter failures coupled by the ongoing decrease in microinverter replacement cost. ( grid integration ) Hopefully, ev vehicle power package will continue to progress and compliment pv generation with it’s ever-improving energy-storing capacity.

  5. Dan,

    You may very well be right. ACPV may eventually be the way to go once some of the issues are worked out. One thing that might tip the scales one way or the other is standardization of connectors and sizes. If microinverters or ACPV modules all had the same connectors on trunk lines and modules were all standard sizes, then that technology would become plug and play to the extent that you could replace failed or damaged components with electrically and physically compatible parts.

    With proper and standardized safety mechanisms, ACPV modules could be a step toward the dream of plug and play solar. We let people string together Christmas lights that are often rated for no more than two strings, but we know people will daisy chain three or even four strings of lights. If we could guarantee that people would not overload a branch circuit with a plug and play solar energy system, perhaps we could start a revolution. Again, standardization is the key in my opinion.

    I don’t see EV batteries as a strong contender for distributed storage for homes and businesses in the near-term, but it could happen some day. Once again, standards would need to be established.

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