The Pitch | AC coupling Generac generators with solar panels and PWRcell batteries

Generac ac generator

Generac debuted a dc generator to charge the battery in its dc-coupled PWRcell solar +storage system. This year, Generac is expanding the possibilities for solar + storage + generators even further thanks to a key firmware upgrade that will allow for ac coupling.

On this episode of The Pitch, we learn more about the ac coupling upgrade from Wesley Williams, product manager with Generac, and just why this is huge for the retrofit market in more ways than one. We discuss:

  • General pros and cons of ac vs dc coupled solar systems
  • Sizing an ac-coupled battery for an existing solar system
  • Are customers gravitating more to ac coupled systems?
  • How does the dc generator compare to the ac generator?
  • What to consider when designing the most resilient whole home backup system

Check out the full 10 min chat for yourself. Part of the transcript is below.

Crowell: Historically your PWRcell system has focused on dc coupling to solar and battery storage, so why the change?

Williams: I want to make it clear that dc coupling is still something that’s going to be the standard operating factor for our PWRcell. What we’re really doing is just adding some additional capabilities so that our standard PWRcell can now also be ac coupled and there’s a lot of reasons for that.

The biggest one is that ac coupling is traditionally viewed to be the easier way to go when there’s already solar on the home and a lot of people out there are in that position. DC coupling offers some great capabilities, especially when you’re off grid or when there’s a grid outage. It’s also more efficient overall, which is a reason why a lot of people go for that for new installs. But when it comes to solar already being on the home, ac coupling typically makes the most sense, and that’s something we wanted to be able to offer as a manufacturer.

Crowell: Are you seeing new solar customers going with an ac coupled configuration? I mean, it doesn’t seem like they should, but I’m curious what the market is bearing right now?

Williams: It is something we see and there’s some understandable reasons. The big thing is that solar-only installs have been the name of the game for a really long time, so a lot of the big installation companies out there maybe have a brand or a couple of brands that they’re pretty dedicated to … so they’re somewhat committed from a business point of view.

What we’re doing by allowing PWRcell to be ac coupled is allowing these installers to judge for themselves if our battery is something they like the look of, and if they determine that it is, then it’s something that’ll work with their favorite inverter brand as well.

Crowell: Are there any keys you want to throw out for correctly sizing a system and matching the existing PV?

Williams: The big thing to always keep in mind is that you need to look at the charging capabilities of the battery inverter. For PWRcell, the name plate is 7.6 kW, so at any given point, especially during an outage, you’re going to only be able to support a maximum of a 7-kW array.

Now, we are going to offer guidance for people who have a larger array than 7.6 kW, but anything beyond those 7.6 kW is going to be managed by a separate inverter so that in an outage the only thing that’s actually ac coupled to our system is something that our system can handle.

Crowell: Have there been advancements in battery and inverter technology that streamline ac coupled systems and improve in the installer portion of things? What comes to mind is the backup loads panel — are we still needing to do that?

Williams: For Generac, that backup load panel is something that we were able to get around shortly after we launched the PWRcell product. Actually we have a whole home install configuration that takes advantage of existing technology that Generac had from its generator days of smart load management, smart transfer switching and we combine that technology with our PWRcell to offer a really robust and intelligent backup solution that’s going to also work with our ac coupled feature.

Crowell: Let’s transition into the generator side of things. As mentioned, Generac is now rolling out the ability to ac couple a generator to a PV system. Last year you announced a dc generator product that would specifically be charging a battery in a PV + storage system, which is pretty cool too. Can you compare and contrast these?

Pick up the conversation right here to learn more about the next big opportunity for Generac solar installers because of this upgrade — marketing to existing Generac generator owners:


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