Earlier this week, a home solar shopper took to Reddit looking for a home solar panel + home backu battery system that could intelligently manage solar and grid power, auto switch in a power outage, and accept ICE generator input in a prolonged grid power failure. I reached out to some home energy experts to get them an answer.
Originally posted by a Redditor going by MickFlaherty on r/solar, the post seemed relatively complex, with MickFlaherty apparently looking for advice about a theoretical home energy system that could handle every potential scenario he could envision, and that ended with a deceptively simple, “sorry for length of this but just trying to figure out what’s really possible .”
If the kind of setup MickFlaherty is asking about seems familiar, it might be because you caught a post titled, “Backup power is the LEAST interesting thing your home battery can do,” from back in April, which led to an interview with FranklinWH CEO Gary Lam on Electrek‘s Quick Charge podcast a few weeks later.
I reached out to Gary about MickFlaherty’s post, and he connected me with Ronnie Pettersson, another super-smart energy guy who also happens to be FranklinWH’s Vice President of Product and Application Engineering, and who was kind enough to help me answer MickFlaherty’s questions.
“The system described in that thread exists, and it’s how FranklinWH’s aGate and aPower S are built to work together,” explained Ronnie, before adding, “The aGate is the system’s controller, and it continuously monitors the grid. When it detects a failure, it automatically switches the home to battery power.”
I’ll quote the body of Ronnie’s email that followed, below:
For homeowners who also want generator backup, the aGate manages that through the same relay-based switching that makes the automatic grid failover seamless. Any generator works, portable, standby, or even a compatible EV, as long as it’s 240V, 60Hz and sized to the home’s batteries and loads. With a standby generator, the homeowner sets upper and lower battery thresholds (20% and 80% by default), and the generator starts and stops on its own to hold the battery in that range while the system is off-grid. With a portable unit, the homeowner starts it manually and switches the system onto generator power through the FranklinWH app.
The aPower S can charge its batteries from solar and the generator simultaneously, a capability most other systems on the market lack. Charging from both sources at once gets the battery back up faster and can cut generator runtime in half depending on the home’s size.
Regarding the reserve question specifically, yes, the FranklinWH system supports exactly what’s described in the Reddit thread. During normal grid-connected operation, solar and battery power the home. Once the battery drops below a homeowner-set reserve (20% by default), the system automatically pulls from the grid to run the home while protecting that reserve. During an outage, that reserve is used to power the home. Homeowners also get an app notification as the battery approaches that threshold, so they know when to expect the grid to kick in, or when to think about starting a generator if they’re off-grid. For homeowners who’d rather not pull from the grid at all, the system can be configured at installation to run on solar charging only.
RONNIE PETTERSSON
FRANKLINWH
While I appreciate Gary and Ronnie coming to the rescue, other Redditors chimed in as well, highlighting the fact that FranklinWH wasn’t the only solution out there that would meet MickFlaherty’s needs.
“What you’re describing sounds like the basic operation of both Enphase and FranklinWH,” wrote arcnsparks98. “I’ve installed both of these systems and they operate as you have described. Using the app, you select the discharge level of the batteries so that the generator knows when to kick in. The system disconnects the solar input to allow the generator to charge the batteries to a level that you specify. It could be 100%, 80%, whatever you want.”
And, because the Reddit hive mind is typically smarter than lil’ ol’ me all by my self, I ended up learning about another option from MickFlaherty from Sol-Ark, thanks to Head_Mycologist3917, who wrote, “I have a Sol-Ark based system that does what you want. It can automatically start the generator but you don’t have to do it that way. My solar installer’s sales person didn’t think it would work without a big whole house generator but I read the manual closer than they did.”
Which, like – if that’s not a reminder to RTFM (read the fabulous manual), I don’t really know what else could be.
Electrek’s Take Disclaimer
Wrapping your head a new home energy project can be complicated and confusing, but talking to a qualified professional installer can help you understand what’s being offered and how a given deal is being structured, and help you get a better handle on all the associated specs, costs, and financing options out there.
One you have that, take the information to an accountant or financial expert you trust to make sure you understand what’s real, what’s marketing, and what actually makes sense for you. And, if there’s and money on the table in the form of local utility incentives or tax credits, make sure you don’t leave it there.
Unless, you know, you don’t actually care about money.
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Original content from Electrek.
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