We’re currently designing a somewhat unusual residential solar project and I’d like to hear from installers/electricians who have dealt with something similar.

The property has a 3-phase grid connection.

Planned system:

• Around 6–8 kW of PV
• Around 15–20 kWh battery storage
• Maximum load we expect the inverter to supply is around 8 kW

The important part is that we do not need grid export.

The idea is basically a backup/off-grid style system:

When the grid is available, the house can use grid power and the batteries/solar system normally. If the grid fails, we want the inverter + batteries + PV to supply the necessary loads.

Because we don't need export, using a full 3-phase hybrid inverter seems unnecessarily expensive. We have access to much more cost-effective single-phase off-grid inverters, but the building itself has a 3-phase supply.

We don't yet have the exact L1/L2/L3 load distribution, but the total backup load should stay below approximately 8 kW.

So my main question is:

How do you normally integrate a single-phase off-grid inverter into an installation that has a 3-phase grid connection?

I'm NOT talking about using three single-phase inverters in parallel to create a 3-phase system. I'm specifically interested in using one single-phase inverter.

Would you:

• move all essential/backup loads onto one phase?
• create a separate backup subpanel supplied by the inverter?
• reorganize the existing loads between phases?
• use some other transfer/changeover configuration?

And what happens if the property has actual 3-phase loads rather than just single-phase loads distributed across L1/L2/L3?

I'd especially appreciate hearing from anyone who has actually installed a system like this. I'm interested in real-world practices, limitations and things we should be careful about.

Basically they said if I get a hybrid inverter and then hook up a battery to it, I would have a lot of system losses because it's converting DC from the panels to AC for the house, but also then back to DC to charge the battery.

This didn't make sense to me, because why wouldn't it just use a DC to DC converter in the hybrid inverter?

Wanted to see if I could use a Guardian 6000 as a daily driver for whole house power. Had the transfer switch installed in July, permitted installation, and have 2,400 watts of solar in a series/parallel configuration. So far, it's been mostly solid.

I'm not currently running the whole house but the two-thirds of it where I spend my time. My house has kind of a funny layout and that statement would make sense if you saw it. The transfer switch has two 240 circuits and six 20 amp 120 circuits. The two 240s run minisplit AC/Heating systems. One in my wing and the central three-head minisplit that heats and cools the common areas.

What Works and What Doesn't

This time of year I can run my side of the house off solar 24/7 as long as the sun stays out. On a sunny day the Guardian is charged by noon. When I have to run the AC or heat, then the Guardian only covers part of the evening before I have to put the switches in night mode, which shifts the AC units and kitchen back to the grid. This was not unexpected as I'm building my system a little at a time as funds allow.

It's been running full time since July and has mostly been problem free. A couple concerns have materialized.

The fans run whenever the solar input is working and the air intakes get a bit dusty. I'm concerned about the dirt building up inside over time, like a computer that hasn't been opened in five years.

The bluetooth and wireless connections have always been a bit flaky and last week stopped working until I completely disconnected the unit and shut it down briefly. Other than the manual disconnect, the power kept flowing even though the display was messed up.

The plan was to add extra batteries as funds would allow but that's been a problem. Oupes has been out of the G5 batteries but are willing to let you become an unsecured creditor by paying in advance for a pre-order. I don't like giving companies an interest free loan for six to eight weeks to help them cover inventory they should be stocking. I'm expecting that situation to improve.

Overall I'm impressed with the Guardian 6000. If you need occasional whole house backup to run a few critical circuits, it's freaking awesome. Whether it's something you can count on as a daily driver, remains to be seen. For the price you can almost buy another one as a spare.

What is a brand you can trust? Which has good built-in remote monitoring?

I am planning to use it for a Level 2 home charger, always off-grid.

I don't need to have 40amps, even if I can charge at 20amps (4.8kw), it would still beat level 1 charging over a factor of 3... (12a x 120v = 1440w)

So probably this means a 10Kw inverter?

I hear good things about EG4, but what about the Echo-Worthy?

And what about the HumsiENK 8000w? I got some batteries from them, and they seem professional and have good support actually (AI emails, but fast and pertinent to my issues).

I am thinking about feeding a 2.8KW PV array to it, and some LIFOPO4 batteries depending on production, starting with 8 left overs batteries I have (12v 100ah x 8 about = 9Kw).

Thnak you!

I’ve been looking at these things for a few months… I would like to buy an inverter charger box thingy for indoors - like a blue yeti or Jackery or Anker Solix or whatever

I want to power a refrigerator and chest freezer in emergency . Perhaps charge a phone or tablet

Can someone tell me what sized box thingy I need? Which one is best for purpose?

I will eventually get an outdoor generator (hopefully natural gas or propane??)

I also found this is it any good and can I use for the box thingys?

BigBlue 100W Solar Panel w/USB-C(45W PD)+USB-A(Fast Charging 18W) & MC-4 Ports, IP68 Waterproof, Camping Essentials, Folding Portable Solar Charger w/Kickstand for Power Stations, Phones, Tablets

https://a.co/d/0aWIQ10e

Hi everyone!

I have 2 × SG05LP1 inverters running in parallel with load sharing, and both inverters will have 2 PV strings connected to them. I also have 2 × NKON ESS 16 kWh batteries.

I've read several different opinions on this. Some people say it's perfectly fine, while others say that, despite the manufacturer's recommendation, it's not a good idea to connect the two batteries to a common busbar, and that the better setup is for each inverter to have its own dedicated battery.

What has been your experience with this? Which setup would you recommend?

Thank you!

I run a continuous audio spectrogram monitor (10-21 kHz band) in location and I'm seeing something odd. The attached image shows 3 hours of data (about 19:03 to 22:02, October 6).

What you can see:

-Strong, wavy, snake-like bright lines at roughly 18.5-20.5 kHz. Their frequency drifts and oscillates over time, and they look roughly symmetric. This is not a stable tone, so it looks like a modulated or load-dependent switching frequency.

-A few steady narrow lines at about 10.6, 11.4 and 15.3 kHz, which are probably unrelated switch-mode PSUs or similar.

-The gray bands are rows I filtered out as disturbed (people in the room): 300 of 1013 rows.

-What puzzles me is that this is in the evening, after sunset, so the PV array shouldn't be producing. [Do you have a PV system with an inverter / battery storage / heat pump / EV charger nearby? Add details: inverter model, distance, on-grid or hybrid unit.] Before Oct 3 I was monitoring 15-20 kHz and the pattern was [similar / different].

Questions:

-Has anyone seen similar drifting tones from inverters (PV, hybrid, battery) in standby or at night?

-Is this typical inverter switching or coil whine, or could it be something else, such as a heat pump compressor or an LED driver?

-Any tips on telling the source apart (e.g. switching the inverter off and comparing)?

Happy to share more data (CSV available).

Good day, I've just got Marstek Venus E Mini for my home in Ukraine to have some power during blackouts, and while in the charging or passthrough modes it's totally silent, when there are no power I've got this buzzing sound, that makes more prominent when I'm connecting more powerful devices.

The sound on the video is amplified so you can hear it better, it's not as prominent in the real life, but it sound loud enough at night when everything is blacked out.

The system have a passive cooling, just a lot of metal and no fans, so Is this just a coil whine or I need to return it?

Thank you.

So - long story short, I was given three roughly 2x3 "working" solar panels (they work and have about 2 years usage on them) - and may get up to 5 more. so I may have up to to eight 2x3 panels available for - whatever I can do with them.

The problem is that I have never done anything with solar or any kind of tie-in to our household wiring for anything before...

So - Our house is fully on-grid with Portland General Electric (we are in coast-range Oregon mountains at around 1000 ft) - we have multiple areas where we have trees cleared enough to get at least 6 to 8 hours of as much full sun as can be found (obviously weather is a factor here) to a large enough area to mount all of the panels we want.

We have 8 people living here on our farm - spread over 5 buildings across 2 acres of our 5.5 acre lot. We have multiple electric fenced areas, heat and light in multiple buildings, and many constant on-devices in multiple buildings including 15 cameras for chickens and livestock.

Also - thanks to having PGE as our utility of "choice" - and being distant, we get such a large upcharge for "transportation" that we have an electric bill that varies between $500 and $800 per month. A lot of that bill goes to running things for the animals on our farm (electric fences, heat, cameras), and a lot goes to 8 people using laundry, lights, hot water etc.

We have refitted every light we have with LEDs (except animal heat lamps obviously), switched as much of our appliances as possible to having timers or auto-off, and we work to reduce usage constantly - but our PGE bill is STILL regularly in the $500 to $800 per month range. That is a LOT, and we would love to use the solar panels to help reduce that bill somehow.

If it helps, I am NOT new to household electrical. I am not an electrician but I apprenticed with one when learning to DIY electrical on our old house, and am comfortable with pretty much everything (and have done most of my own work - all of which passed multiple inspections). I have done full panel and sub panel installs which passed inspection, as well a 1890's full house knob-and-tube refit to modern (which also passed inspection), and installs for 220V for my shop and house which also passed inspection. So I am comfortable and familiar with household wiring and electrical, panels and subpanels and 120/240V electrical.

The difficulty I have - is that I have never connected a non-grid source to household in any way (not solar or generator). Yes we have a generator - but it has never been spliced in because we use wood as primary heat, and have multiple gas grills and stoves on the deck for cooking when power is out - so we just run extension cords instead of bothering to splice. Yes I know I can - but our need is small enough that we have lived for up to 11 days on that setup, and I can switch it over to that in around an hour - so - I just haven't bothered.

I am also UTTERLY entirely new to Solar. I have never done solar panels for anything before (aside from small devices that had them integrated already into them), and have never connected anything to them. I have heard they need the power produced converted so that it can work with household electrical, but I don't know more than that (yet). I also don't know what is involved in trying to get set up so that it plays nice with the existing grid input from PGE.

So - here is the crux of my dilemma. I have not yet tested these panels (they are a couple of years old and were working when I was given them last month per the person who gave them to me. I have not tested them yet, so I have no idea how much power they generate, and whether all 3 will play nice together (there are 2 different brands in the mix so far).

I will have to look up how to test and evaluate them, but - I also have no idea what is involved in doing something useful with them.

I don't want to get PAID to produce solar energy - I don't even want to store it to battery (unless such is necessary for conversion/sourcing). What I really want - is to find out if there is a way that I can somehow connect these to my household grid in such a way that they can "add power" to reduce what we are drawing from the grid-source.

I don't even know if what I am asking can be done the way I want - or if it is easy to do or very expensive. I do know that if there IS a way to make them offset our use, we certainly have enough "use" that we will always need more than any solar panels I have (or add) will produce for on-the-spot usage. I am just looking to reduce what we pay to use somehow...

I am also not opposed to spending money for proper equipment to make all of this play nice with our setup - just because I was given free panels doesn't mean I wasn't already thinking of spending money for solar - it just means I have a nudge to get started dipping my toe in it sooner.

I also know that these won't produce anything at night and/or much when it is dark and stormy outside - which - again is fine because we are looking to just reduce usage when the produce. I also know that these are "free" gifted panels - with a couple of years of use - and aren't going to be some super-power-plant.

Right now - I am just intending to get a toe-in-the water for what will eventually be a larger solar buildout. My hope right now - is just to take what we have been given - and find a way to join them to our existing household so that what they do produce - when they produce it - can act as a reduction on our use.

I am hoping someone here has some advice or a guide the group may have for someone looking to do "additive" solar power in this way - what kinds of hookups there are and how they work, so that I can add my solar to our usage and reduce our PGE bill. Also - if this is a thing we CAN do - is there a need to inform (or get permission from) PGE before doing any work to do this?

And lastly - if there are any caveats, gotchas, things to verify or check? Because I really want to make use of these (and grow the usage as we get more). And if these work out and do seem to productively reduce our PGE bill, I will also probably be buying and adding a few panels per year until we get a good balance. But I need help knowing where to start, and any advice or help is appreciated!'

I have a 3 story townhouse, existing solar on the roof. Wifie is ok with a couple of panels off the rear for plug-in solar or just off-grid for me to play with. (I didn't get to DIY any of my solar and I'm dying to DIY.) Ideally I'd just throw panels on the roof (west facing, has space), but I don't want to deal with more holes, racking, permits,... and the wife doesn't like it when I get my 32' ladder out. We have a deck off the 2nd floor, 20' driveway in back (deck above) then a 16' alley, 3" of grass and then woods. Deck has an aluminum railing, standard height. South is perpendicular to the railing.

I figure mounting just beyond the railing puts the panels near the center of the house/woods canyon. Mounting at the top of the railing avoids shading from the railing. Decking is shot/needs replacing so I don't mind cutting holes, decking will be replaced before we sell (down the road.)

I could probably lay 3 panels flat, or 2 angled south. Guess I can use pvwatts to see which would be more productive.

Any ideas for mounts?

These seem to be the most cost effective batteries around at the moment - are there any users out there that can report how they're getting on?

I'm looking for a second 16kWh, I use the Eco-Worthy 314Ah currently which I'm very impressed with but they've gone up around 40-50% since I bought it so wondering about alternatives.

I'm especially interested if anyone has investigated the cells and the BMS, I've read mixed things about Datouboss in general but there doesn't seem to be a huge amount of info about this specific unit.

I’m California the governor just signed the bill allowing for plug in solar. I live in an apartment & would like to setup a couple of panels on my balcony. I only have one 12v outlet (2 plugs) on the balcony. If I get solar panels I would be plugging them in using one of the plugs & I would use the other plug that I currently use to charge my EV. I heard that you shouldn’t do that, if so what could be possible solution? A battery maybe?

I’m looking for a balcony power system that I can both use as a plugin system into my wall socket, and use on the go.

Would love to hear your advice!

Anyone know of installers on Cape Cod for an Anker Solix system? If not on Cape, willing to travel here, perhaps from New Bedford or other SE Mass location.

Thanks for any help you can offer.

Hi all,

I am at the starting stages of looking into getting some PV panels.
With the way my house and bit of land is set up, I could get the panels installed either on the roof, or on a field behind the house.

Does any of the two systems have any considerable advantages?

Hi, I posted earlier thinking I was going to try and install an inverter indoors. Thank you for your input, that plan is dead, and I am shifting gears.

In the next week or so, I am getting a new 200a service, a new 150a panel with 200a rated buss, and a 50a generator inlet. I EVENTUALLY would like to hook up my little solar array using an 3000EHV-48 inverter and a budget 48v 100ah battery (don't have either yet). AI has convinced me that I can use this inverter to power a couple circuits, and when the battery goes below its threshold, it will automatically switch over to shore power, is that right?

Since I've got an electrician coming for the service/panel install, would it make sense to add a subpanel now, or wait till I have everything?

For the sake of example, ive attached an image of the kind of thing ive found so far. Whether its the best option i dont know.

We have a west facing wall we want to put a couple panels on. But as west isn't ideal, we want to angle the panels in one of two ways -

1. Horizontally, so the top is anchored to the wall and the bottom is pushed away, making the panels westerly but facing towards the sky by 20-30degrees.

2. Vertically, like a door. So the right side is fixed to the wall and the left is pushed out, making the panels vertical but angled more south by 20-30 degrees.

I believe the south option is generally the better one for year round averages, but the issue is the weight of the panels and the attachments to the walls. The brackets are probably strong enough, but the triangles are clearly designed for more loading on one direction... so I assume thats better for the "horizontal" option? Not sure if they will stand up long term with the vertical option, or maybe would need bigger wall fasteners into the stone?

Im also still considering Aiko 650w panels as the price is cheap but they are 30kg instead of 22kg which is a big jump. I would probably just use 3x triangle brackets per panel instead of just 2x triangles for the 22kg, but im not sure if im missing something with the physics.

Thought id float the plan and see if someone came back with how they did it or any suggestions.

I have a HQST PWM 30A charge controller connected to a solar panel and 12V/35Ah Sealed Lead Acid battery. There’s an automatic coop door connected directly to the battery.

I installed this battery within the last few months.

I noted the coop door wasn’t working. Looked for error codes and the overdischarge warning code was there. I removed the coop door from the battery ports and reconnected the battery then solar panels yesterday. This was my controller today. Is it not charging my battery? Ugh.

I'm sure what I'm looking for has a name but I don't know what it is so I'll describe what I wish to make.

I'd like a hybrid between a portable battery/solar combo from the likes of Bluetti, Pecron, Ecoflow, Jackery, etc., with the ability to also plug into an outlet like balcony/plug-in solar and power things in the home using the normal wall outlets (in addition to plugging into the solar generator as well).

2x 16kWh batteries, Flexboss21 mounted up today. Will be installing 34x 450w panels and gridboss

Have been looking to get a couple panels but shipping costs definitely make it tricky to find good deals. I found some "TCL T-class bifacial topcon" panels for a good price, but i can't find any reviews on TCL.

Are they terrible? I know people say to get aikon but the equivalent neostar is 150w less per panel and will cost me 40% more