Choosing a hybrid inverter — recommendations?
Aug. 25, 2025
Choosing a hybrid inverter — recommendations?
I’m new here, and I see a few other threads with people looking for advice on their specific situations, I hope it’s not out of line for me to do the same. I don’t see a recent thread with a matching list of requirements and considerations.
I have a house with 200A service, 5.1kW grid-tie solar PV (with sell back) on roof, and an 8.5kW standby generator. Primary and secondary panels, with almost everything on the secondary. Automatic transfer switch that kicks on the generator when the grid goes out. The typical draw is less than 2kW, and have never overloaded the generator, but there are three loads that are on the main panel which I’d like to be able to selectively choose to run during an outage. They aren’t on the main panel because they would likely be too much for the generator, and the secondary panel is full!
So my current issues and wish list are:
But, what happens if you do export past the limit? The utility can curtail your power output through frequency shifting and that started going into effect in the U.S. back in , so all grid-tied inverters support it now. Canada probably has something similar, so I'm not sure why they want you to regulate it.
GXMnow reports the export limit is pretty big in California, your Canadian utility might have similar high amounts and if so it might be something you never have to worry about. Might be worth checking your exports per month, and if you never come close it's something you safely can ignore. Even if you do, if it's a $5 fine and you do it once every July might not be worth it. ; -)
If throttling export at a limit isn't a standard feature yet, an inverter with an API would let you setup a program to monitor your export and turn export off/on. Even if you can't set it, it you're handy at programming you could set a watchdog program to monitor exports and alert you to manually change it if you coming close to the limit.
You're the second person I've seen asking about it, so any manufacturers that don't have it are probably working on it. Any manufacturer that already support zero-export would see this as a software upgrade.
I know you're looking for a new inverter recommendation, but what's you're existing grid-tied inverter? For example if you have Enphase microinverters and their 200 amp Enpower switch then it might be least expensive/trouble to buy their battery. I know Enphase can zero-out for net metering, but I'm not sure if they can set a monthly export limit.
If you have an EV (or been thinking about getting one) you might want to look into a bidirectional charger that uses the car as a battery for the house. Just did a post on that here that might get you started. They're new and expensive right now, prices are offset by incentive programs here (30%-50% off depending on local incentives, not sure what it'll be tomorrow when Trump takes office ; -), not sure if Canada has any similar programs.
Out of curiosity, when the grid goes out and the generator comes on, how do you prevent the solar PV from back-feeding the generator? A generator relay to disconnect the PV? Yes, sell back may well increase in the future, especially since our power utility seems to be starting to wake up to the reality that distributed generation is good for them. Nonetheless, I want to ensure whatever solution I go with can limit it. The ones I listed seem to be able to. I’ve got APC systems microinverters. They don’t have an appealing solution that meets my requirements.
Pretty sure the grid can’t frequency shift though.
I do have an EV, but drawing from its battery and reducing my mobility has never made sense to me.
The solar is currently on the main panel while the generator supplies the secondary panel via the transfer switch, so they are never electrically connected. An inverter based system like the three I listed would disconnect the AC coupled PV before connecting the generator to avoid back feeding the generator. It’s a bit unfortunate to not be able to run both at the same time, but I haven’t seen a system that can use them both while keeping them isolated. In practice though I expect the generator would run after the sun has passed out of view of the panels, if not completely gone down. The majority of outages occur when the days are relatively short, and running the generator in the evening to charge the batteries to make it through the night is entirely reasonable. 3-4 hours of runtime would put 15+ kWh into the battery, which should last until morning without difficulty as the house is quite efficient and well insulated. If I do add more PV, it would be dc coupled and able to supply power to the inverter while the generator is running… although this reminds me to add “generator support” functionality (ie supplement the generator output based on current load) to my list of requirements.
For me, I typically drive less than 40 miles a day and I charge at home so the battery is generally always near full. You can set the maximum depth of discharge to ensure you always have enough power to drive somewhere. Same thing about using an EV to export power to the grid (VPP) for area like Massachusetts where utilities would rather buy power from consumers for less$ than pay big$ to fire up peaker plants, it's good money for battery owners (better than net-metering, people have reported earnings > $/yr), and good for other consumers (See connected solutions).
I think of it like this. A model S has a ~400 mile range and ~100 kWh battery. If a house consumes 20 kWh/d, than you could power the house for 3 days, and still drive 160 miles to a charging station (assuming all the local ones are down), to fill up, and drive back. Or, at 40 miles to/from work I'd get 3 days of driving and powering the house and hopefully they have the power up by then (if not, I can still hit a recharger on the way home). If your business is closed due to the storm impact, then the car's recharging via excess solar is stretching out the number of days it can provide power.
Plus I'm cheap. Buying a stand alone battery is expensive. Reusing the EV's battery? That's frugal! ; -)
No clue if it'll work with your setup. Good luck!
What I would really like to do is have about 4-5 DPDT contactors which either connect their loads to the primary panel, or to a secondary panel. They would default to the primary but software could choose to switch them over if the power was out or perhaps some other reason to want it directly connected to the inverter. Other than that I guess it would just be replacing a couple of wiring runs with longer ones, and adding a bypass connection that skips the inverter and falls back to the generator transfer switch. I would probably need direct control over the generator as well so I could program it as I see fit.
I think I need to draw out my scheme.
But many inverters have "Wifi dongles" connected to RS485, CANbus, etc, so there is an opportunity to intercept whatever control the inverter native app does and use that yourself. So it could be a bit of reverse engineering. That also doesn't assure the level of control you want is exposed even to the dongle.
My suggestion is to try and find an inverter which has the adjustments you want in its native app, and has great Solar Assistant support. That means the ability to control it remotely is there, and someone has figured it out mostly. You may need to snoop on those communications to figure out how it works.
There are some automations that SA can do which could help. For example, on my inverter, I have SA reducing battery charge current to 1 amp (basically zero, but zero is not an option) when SoC is 97% or higher. This keeps my battery from constantly being pushed to high voltage per cell, which should increase its life. SA handles this for me:
So maybe SA does enough, or maybe yo have to reverse engineer the protocol and do it yourself, but open and documented API out of the box seems rare, perhaps non existent for these types of devices.
Mike C.
I have a house with 200A service, 5.1kW grid-tie solar PV (with sell back) on roof, and an 8.5kW standby generator. Primary and secondary panels, with almost everything on the secondary. Automatic transfer switch that kicks on the generator when the grid goes out. The typical draw is less than 2kW, and have never overloaded the generator, but there are three loads that are on the main panel which I’d like to be able to selectively choose to run during an outage. They aren’t on the main panel because they would likely be too much for the generator, and the secondary panel is full!
So my current issues and wish list are:
- Generator is much too noisy at night
- Generator burns too much propane when lightly loaded (peak efficiency is at about 8kW)
- Want instant switch to backup for a few reasons — the 10 seconds for the generator to start is really disruptive
- Don’t get benefit of solar when grid is down
- Would like to be able to run three of the heavier loads and have some sort of load shedding scheme
- Provide generator support functionality (ie supplement generator output based on current load)
- This would just leave two 240v breakers on the main panel which definitely don’t need to be backed up, so would ideally like to replace the big empty main panel with something more space effective
- Want potential to add more PV, but can’t increase the amount of sell back I am currently allowed
- Power company just introduced time of use billing option, so want to use a battery to leverage this
- Strong surge and imbalance capability because a power reset event would be a serious marital issue
- Control interface with which I can programmatically control the system, preferably Ethernet
- Schneider 6.8kW XW pro — when I started looking into this over a year ago, this looked like the device to beat. Capacity a bit on the low side, but really strong surge & imbalance capacity. Looks like it is at or near end of life now though? And the firmware is less than ideal. But very robust hardware.
- Midnite Solar 10kW AIO — looks like a really strong contender. Has a couple of smart loads, but not enough and they wouldn’t work if inverter fails.
- EG4 GridBoss/Flexboss21 — has become my leading candidate since I became aware of it. Only system that directly solves the main panel issue and the smart loads. GridBoss looks like it’ll keep working even if inverter fails, plus it has a bypass that will power most from the grid although I think we lose generator if GB itself is put into bypass. Looks like some approvals still pending, but I’m at least six months away yet. This one looks like the simplest wiring job.
Want potential to add more PV, but can’t increase the amount of sell back I am currently allowedI'm not current enough to know what manufacturers allow you to limit exports to a specific value.
But, what happens if you do export past the limit? The utility can curtail your power output through frequency shifting and that started going into effect in the U.S. back in , so all grid-tied inverters support it now. Canada probably has something similar, so I'm not sure why they want you to regulate it.
GXMnow reports the export limit is pretty big in California, your Canadian utility might have similar high amounts and if so it might be something you never have to worry about. Might be worth checking your exports per month, and if you never come close it's something you safely can ignore. Even if you do, if it's a $5 fine and you do it once every July might not be worth it. ; -)
If throttling export at a limit isn't a standard feature yet, an inverter with an API would let you setup a program to monitor your export and turn export off/on. Even if you can't set it, it you're handy at programming you could set a watchdog program to monitor exports and alert you to manually change it if you coming close to the limit.
You're the second person I've seen asking about it, so any manufacturers that don't have it are probably working on it. Any manufacturer that already support zero-export would see this as a software upgrade.
...my current issues and wish list are...Sounds like you want a battery sized to meet your wallet that reduces generator run time by having the generator only come on if the grid is down and battery is low?
I know you're looking for a new inverter recommendation, but what's you're existing grid-tied inverter? For example if you have Enphase microinverters and their 200 amp Enpower switch then it might be least expensive/trouble to buy their battery. I know Enphase can zero-out for net metering, but I'm not sure if they can set a monthly export limit.
If you have an EV (or been thinking about getting one) you might want to look into a bidirectional charger that uses the car as a battery for the house. Just did a post on that here that might get you started. They're new and expensive right now, prices are offset by incentive programs here (30%-50% off depending on local incentives, not sure what it'll be tomorrow when Trump takes office ; -), not sure if Canada has any similar programs.
Out of curiosity, when the grid goes out and the generator comes on, how do you prevent the solar PV from back-feeding the generator? A generator relay to disconnect the PV? Yes, sell back may well increase in the future, especially since our power utility seems to be starting to wake up to the reality that distributed generation is good for them. Nonetheless, I want to ensure whatever solution I go with can limit it. The ones I listed seem to be able to. I’ve got APC systems microinverters. They don’t have an appealing solution that meets my requirements.
Pretty sure the grid can’t frequency shift though.
I do have an EV, but drawing from its battery and reducing my mobility has never made sense to me.
The solar is currently on the main panel while the generator supplies the secondary panel via the transfer switch, so they are never electrically connected. An inverter based system like the three I listed would disconnect the AC coupled PV before connecting the generator to avoid back feeding the generator. It’s a bit unfortunate to not be able to run both at the same time, but I haven’t seen a system that can use them both while keeping them isolated. In practice though I expect the generator would run after the sun has passed out of view of the panels, if not completely gone down. The majority of outages occur when the days are relatively short, and running the generator in the evening to charge the batteries to make it through the night is entirely reasonable. 3-4 hours of runtime would put 15+ kWh into the battery, which should last until morning without difficulty as the house is quite efficient and well insulated. If I do add more PV, it would be dc coupled and able to supply power to the inverter while the generator is running… although this reminds me to add “generator support” functionality (ie supplement the generator output based on current load) to my list of requirements.
I do have an EV, but drawing from its battery and reducing my mobility has never made sense to me.For a lot of people it doesn't make sense.
For me, I typically drive less than 40 miles a day and I charge at home so the battery is generally always near full. You can set the maximum depth of discharge to ensure you always have enough power to drive somewhere. Same thing about using an EV to export power to the grid (VPP) for area like Massachusetts where utilities would rather buy power from consumers for less$ than pay big$ to fire up peaker plants, it's good money for battery owners (better than net-metering, people have reported earnings > $/yr), and good for other consumers (See connected solutions).
I think of it like this. A model S has a ~400 mile range and ~100 kWh battery. If a house consumes 20 kWh/d, than you could power the house for 3 days, and still drive 160 miles to a charging station (assuming all the local ones are down), to fill up, and drive back. Or, at 40 miles to/from work I'd get 3 days of driving and powering the house and hopefully they have the power up by then (if not, I can still hit a recharger on the way home). If your business is closed due to the storm impact, then the car's recharging via excess solar is stretching out the number of days it can provide power.
Plus I'm cheap. Buying a stand alone battery is expensive. Reusing the EV's battery? That's frugal! ; -)
The solar is currently on the main panel while the generator supplies the secondary panel via the transfer switch, so they are never electrically connected.Nice! A simple elegant solution.
It’s a bit unfortunate to not be able to run both at the same time, but I haven’t seen a system that can use them both while keeping them isolated.Enphase's can, they make use of their high efficiency neutral-forming transformer built into the Enpower. But I suspect they still want either a very big generator, or an inverter based generator. I haven't tried my generator on it, I've got a crappy gas generator with shoddy power (But I can theoretically blackstart my system with it, so never upgraded. I'm ditching that noisy piece of junk as soon as Enphase's bidirectional chargers are out ; -).
I’ve got APC systems microinverters. They don’t have an appealing solution that meets my requirements.I've heard they're good units, didn't I hear something about them having a storage solution... let's see... here it is: https://usa.apsystems.com/apstorage
No clue if it'll work with your setup. Good luck!
The GB doesn't do anything that couldn't be replicated with multiple discrete boxes like transfer switches, smart relays, etc. The innovation is not in function but in integration into a convenient package.Agreed, but space and convenience are significant factors. Still, that might be a reason to *not* go GB and instead use a more conventional wiring setup. I already have a setup that has a bunch of load control relays, and I could extend that approach.
Mike C.
What I would really like to do is have about 4-5 DPDT contactors which either connect their loads to the primary panel, or to a secondary panel. They would default to the primary but software could choose to switch them over if the power was out or perhaps some other reason to want it directly connected to the inverter. Other than that I guess it would just be replacing a couple of wiring runs with longer ones, and adding a bypass connection that skips the inverter and falls back to the generator transfer switch. I would probably need direct control over the generator as well so I could program it as I see fit.
I think I need to draw out my scheme.
The more I read and plan a potential system, the more convinced I am that (for me) the killer feature of any inverter is it having a software control interface.Fully documented and open interface? Good luck with that.
But many inverters have "Wifi dongles" connected to RS485, CANbus, etc, so there is an opportunity to intercept whatever control the inverter native app does and use that yourself. So it could be a bit of reverse engineering. That also doesn't assure the level of control you want is exposed even to the dongle.
My suggestion is to try and find an inverter which has the adjustments you want in its native app, and has great Solar Assistant support. That means the ability to control it remotely is there, and someone has figured it out mostly. You may need to snoop on those communications to figure out how it works.
There are some automations that SA can do which could help. For example, on my inverter, I have SA reducing battery charge current to 1 amp (basically zero, but zero is not an option) when SoC is 97% or higher. This keeps my battery from constantly being pushed to high voltage per cell, which should increase its life. SA handles this for me:
So maybe SA does enough, or maybe yo have to reverse engineer the protocol and do it yourself, but open and documented API out of the box seems rare, perhaps non existent for these types of devices.
Mike C.
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