The Secondary Market Nobody Talks About in Solar

Over the last year I have started noticing something happening in the solar industry that most people are not talking about. It shows up quietly on Facebook Marketplace, Craigslist, and other resale platforms, and once you start paying attention to it you begin to see the same story repeating itself.

Someone is selling dozens of microinverters or optimizers or inverters that were recently removed from a home solar system.

Sometimes the listings are vague. Other times the explanation is surprisingly straightforward. The system worked fine, but the homeowner decided to convert their solar system so they could install a Tesla battery.

The listing pictured here is a good example. The seller is offering 42 Enphase IQ8+ microinverters for sale at about $50 each. According to the description, they came from three different homes that transitioned to Tesla MCIs so the systems could be paired with Powerwall. These are not old devices that have reached the end of their life. The IQ8+ is part of Enphase’s current generation hardware and works well with many modern 400 watt class solar panels.

Seeing equipment this new being removed from functioning systems raises an interesting question about what is really happening in the residential solar market.

From a technical standpoint there is nothing wrong with these systems. Enphase and SolarEdge have played a major role in advancing residential solar over the past decade. Module level power electronics allow individual panel monitoring, improve performance on complicated roofs, and make diagnostics easier for installers servicing systems in the field.

Installers and engineers appreciate those advantages because they improve system visibility and performance.

Homeowners tend to look at things a little differently.

Most people are not thinking about system architecture in the same way someone in the industry does. They are not comparing module level power electronics against string inverters or weighing the benefits of optimizer based power conversion. What they want is a system that works, provides backup power when the grid goes down, and does not feel overly complicated.

Simplicity matters more than we sometimes realize.

Tesla has leaned heavily into that idea with the Powerwall 3 ecosystem. One of the pieces that attracts a lot of attention is the Tesla Backup Switch, which is a meter collar between the utility meter at the home’s electrical panel. Because of that design, many installations do not require a traditional transfer switch or a backup subpanel.

From a homeowner’s perspective the result feels cleaner and easier to understand. Fewer boxes on the wall. Fewer electrical modifications. A more integrated system.

That level of simplicity is extremely appealing.

When homeowners with existing solar systems begin looking into battery backup, they sometimes discover that converting their system to a DC coupled architecture can make the overall installation work more seamlessly within the Tesla ecosystem. What many people do not realize at first is how much work that conversion can involve.

Removing module level electronics from an existing solar system is not a small task.

In many cases the entire solar array has to be removed from the roof. Each panel must be disconnected and lifted so the microinverters or optimizers underneath can be taken out. If there is not enough room on the roof to stage the panels safely, they may need to be lowered to the ground and stacked temporarily while the wiring is reconfigured.

Once the module level devices are removed, the panels are rewired into strings that connect directly to the Tesla inverter architecture. The panels are then reinstalled and Tesla rapid shutdown devices are added so the system remains compliant with electrical codes.

It is a labor intensive process.

Conversions like this can easily cost $150 to $250 per panel in additional labor and materials. On a 20 panel system that can add $5,000 or more to the project before the battery installation even begins. At Renewable Innovations we typically install Powerwall 3 units on an existing solar system for around $16,900, but when homeowners decide to convert their solar architecture to DC coupled the total project cost can climb significantly.

And yet people are still choosing to do it.

That decision tells us something important about homeowner priorities. Many homeowners are willing to sacrifice module level monitoring and even spend additional money if the end result is a system that feels simpler and more integrated.

It is also worth pointing out that Tesla is not the only company working toward simpler battery integration. Enphase has introduced its own meter collar solution that allows their latest generation battery systems to connect at the service entrance in a similar way that can simplify certain installations. SolarEdge has also built a full ecosystem around solar, inverters, and battery storage that works very well when installed as a complete system from the start.

But the retrofit market does not always behave the way manufacturers expect.

Enphase batteries work well with their microinverter ecosystem, but many installers do not regularly retrofit Enphase battery systems onto homes that already have Enphase solar installed. In practice, the projects often end up favoring a battery solution that integrates more easily with the service entrance and simplifies the overall installation process.

SolarEdge faces a slightly different challenge. While their batteries are designed to work with their inverter platform, adding storage to an older SolarEdge system frequently requires replacing the existing inverter with a newer model that supports battery integration. That additional step can increase both cost and complexity during a retrofit project.

When homeowners are already facing the cost of adding a battery system, that extra layer of equipment replacement can sometimes push them toward other options.

So even though Enphase and SolarEdge both offer battery ecosystems designed to integrate with their platforms, the retrofit market does not always follow the path manufacturers might anticipate.

Homeowners are prioritizing simplicity.

And the ripple effects of those decisions are now showing up in the secondary market.

Microinverters, optimizers and inverters that once sat quietly beneath solar panels are now appearing for sale online after being removed from functioning systems. Some of them are purchased by installers who need spare parts for older systems they maintain. Others sit unsold because buyers have no easy way to confirm whether the equipment still works.

Solar electronics are not like used appliances where functionality can be quickly tested. Without proper diagnostic tools it can be difficult to verify that a microinverter, optimizer or inverter is operating correctly.

If those units do not find buyers, there is a good chance many of them will eventually end up in a landfill. That outcome is hard to ignore for an industry built around sustainability.

It also raises an interesting question for manufacturers. Companies like Enphase and SolarEdge might have an opportunity to create certified refurbishment or buyback programs for equipment like this. If manufacturers could collect, test, and certify these devices, they might be able to resell them as refurbished hardware for replacement parts or smaller systems.

Programs like that could extend the useful life of these products while preventing large volumes of electronics from becoming waste. But the larger takeaway from all of this may simply be that the residential energy market is evolving.

Homeowners are increasingly looking for systems that feel integrated, predictable, and easy to understand. Performance metrics and monitoring capabilities still matter, but they may not matter as much as simplicity and system cohesion.

The quiet emergence of this secondary market may be one of the clearest signals of that shift.

If you spend enough time looking at the equipment appearing online, the pattern becomes difficult to ignore. Newer generation hardware is being removed from operating systems so the architecture can be simplified around battery storage.

That does not mean module level electronics are disappearing from the industry. They still provide real advantages in many installations and will continue to play an important role in solar design. But it does suggest that battery storage is beginning to reshape how homeowners think about solar systems.

And sometimes the most interesting clues about where an industry is heading appear in places most people are not looking. Like a Facebook Marketplace listing for 42 microinverters that used to sit quietly beneath solar panels on someone’s roof.