Using Solar Power for home when power company grid is off

[Mike90250]

There is also the Schneider XW series of hybrid inverters. There is not even a blink when the grid goes down, and when there is surplus solar, it can feed the grid and unwind your power meter.

[DaveC_Napa]

[QUOTE=Salts;n405752]
The answer to your problem is AC Coupling into a battery bank. At the moment, there are some really good deals to be had with SMA Sunny Island inverters, or you can just get an Outback Radian inverter.

{QUOTE]

Perhaps you did not read the first sentence of my post. My system is less than a year old. I certainly do not want to be replacing the inverter so soon. I want 20 years of use out of it.

I will most likely just go with a small generator as has been suggested. Power failures are not common where I live, but they may becore more common in the future thanks to global warming and increased fire danger.

[Salts]

Perhaps you did not read the first sentence of my post. My system is less than a year old. I certainly do not want to be replacing the inverter so soon. I want 20 years of use out of it.

The normal grid tied inverter that is currently on your solar system stays right where it is.. Nothing changes with that and it will continue to work as it has.

With AC coupling, you just ADD an additional "off grid battery inverter" that works WITH your normal grid tied inverter when the grid goes down. You're not replacing or removing anything, you're adding extra components. Your normal grid-tie inverter is required to keep doing the job its doing now, only it will do it off-grid.

[J.P.M.]

You are correct. I changed the term. There are probably a lot of terms that could describe what an inverter does. I am not sure how the discussion is better informed by distinguishing between the simple phrase "generating power' or the verbose, "deliver conditioned power at their output and while doing so, rather than generating power, lose some power from input to output". I do not disagree with what you said, and that is most likely how you learned it. I believe the important issue on a discussion forum is not what you have learned, it is what the Original Poster would like to learn.

Have you anything else to add to the topic that the Original Poster asked, which is, "Using Solar Power for home when power company grid is off".

Thank you for acknowledging your error. The conversation is better informed by the accuracy. I assume you agree or you would not have acknowledged the error by fixing it.

As for verbosity, opinions vary. IMO, getting it right counts.

FWIW, my observation is that the perception of verbosity often starts with the reader. The risk of losing the reader is often a tradeoff between being correct and as complete as possible but losing the reader (with the onus on the reader in such cases), or imparting ideas in ways that do not effectively convey the intended meaning(s) (onus on me). Some things take a few more words to describe than others.

My experience has been to observe those who think I'm too wordy often have short attention spans. When I err on communication, which is often, I usually do so as the cost of attempted accuracy and completeness and take the hit of being called arrogant, wordy or perhaps having a certain characteristic of an ancient Greek king a guy by the name of Sophocles wrote a tragedy about.

All that is part of why I often write : "Take what you want of the above. Scrap the rest". Basically, don't like what I write ? Use the ignore button and don't pay any attention to it.

As for adding anything to the topic, and attempting to satisfying your curiosity it would seem, I believe I have a lot I could add, but I'll shorten it to the idea that as things stand now, it seems to me that thinking or considering PV to be a source of power when the grid is down is not usually something most of those who are truly informed and experienced about PV usually consider first.

The smart money knows the limits of PV. The solar ignorant see what they want to see, hear what they want to hear and believe what makes life easy for them, regardless of truth or accuracy.

[Ampster]

Hardly an error. I just agreed that "deliver" was a better term than "generate.........". But I clearly disagreed with the verbosity of the rest of the explanation. The previous post is self serving and a waste of server bandwidth. It is just an attempt to convince readers that someone is always right, when they have nothing else to contribute to the discussion at hand besides throwing an insult at the original poster.

[J.P.M.]

Hardly an error. I just agreed that "deliver" was a better term than "generate.........". But I clearly disagreed with the verbosity of the rest of the explanation. The previous post is self serving and a waste of server bandwidth. It is just an attempt to convince readers that someone is always right, when they have nothing else to contribute to the discussion at hand besides throwing an insult at the original poster.

Enjoy your ignorance. You have the last word. Enjoy

[DaveC_Napa]

The normal grid tied inverter that is currently on your solar system stays right where it is.. Nothing changes with that and it will continue to work as it has.

With AC coupling, you just ADD an additional "off grid battery inverter" that works WITH your normal grid tied inverter when the grid goes down. You're not replacing or removing anything, you're adding extra components. Your normal grid-tie inverter is required to keep doing the job its doing now, only it will do it off-grid.

OK, I did not understand that from your first post. I am becoming of the opinion the cheapest and easiest solution would be to buy a small generator.

[Salts]

OK, I did not understand that from your first post. I am becoming of the opinion the cheapest and easiest solution would be to buy a small generator.

There's nothing wrong with a generator, but if you get one, I have two pieces of advice for you: 1) Run it on natural gas if you have it available. You can buy kits to convert almost any gasoline generator to natural gas and they are ridiculously easy to install. (or just by a NG generator) If the generator is under 7000 watts or so, the kit will allow it to run on gasoline or natural gas. If the generator is over 7000 (or something like that) then the modification is permanent. 2) If you run a generator on gasoline, make sure you get get ETHANOL FREE fuel. Ethanol is responsible for almost all small engine problems these days.. well, that and people not changing the darn oil like they're supposed to.

You might want to look into whole house generators that are installed on permanent pads outside and have automatic start. Just be aware that if your only fuel option is propane, it can get expensive fast. Generators suck propane like crazy.

[neweclipse]

My suggestion to add is to lean heavily towards a generator that runs at only 1800 RPM rather than at the screaming 3600 RPM.

[Mike90250]

My suggestion to add is to lean heavily towards a generator that runs at only 1800 RPM rather than at the screaming 3600 RPM.

Those tend to be larger, expensive diesel generators. But they are good

[neweclipse]

Those tend to be larger, expensive diesel generators. But they are good

True, but there are 1800 rpm NG/Propane ones out there too, just not sitting on the floor in the big box store or the like.

Price can be very reasonable if bought used from a long life elsewhere for mostly used as a standby unit, and comes with a whole house ATS.

[Ampster]

.........

I will most likely just go with a small generator as has been suggested. Power failures are not common where I live, but they may becore more common in the future thanks to global warming and increased fire danger.

I dont know much about generators, but I have been following the developments in the market for solutions to the issue you posted. I think the next year or two may see some more solutions to that issue.

Generac has recently made two acquisitions that suggest they are diversifying. First, they acquired Pika a manufacturer of battery systems. Second, they acquired Neurio a maker of energy sensing devices. Neurio is used by Tesla in the gateway of their Powerwall. I use one to turn on my EV charging and HPWH when my solar production hits a predetermined level.
Tesla has sold over 50,000 Powerwalls so there is clearly a market for a device that can leverage solar when the grid is down. California is an example where changes in the market caused a lot of people to want a backup solution. My area is subject to PG&E fire risk outages and I see more people on local social media now wanting backup. I don't think they are as ignorant as someone implied. Load shifting is another application where batteries can provide a payback that a generator can't. That demand is driven by the changes in TOU time periods. Perhaps Generac is working on some sort of integrated system that might leverage a generator and a small battery pack to give them access to that space.

BTW, my apologies for the hijack that @J.P.M. and I got involved in. As an EE you probably understand the technical issues better than most.

[Ampster]

Here is an article about Generac's market move:

https://cleantechnica.com/2019/10/04/generac-pivots-from-generators-into-residential-energy-storage-solar-at-spi2019/

I will be curious to see how this space develops over the next few years.

[SunEagle]

Here is an article about Generac's market move:

https://cleantechnica.com/2019/10/04/generac-pivots-from-generators-into-residential-energy-storage-solar-at-spi2019/

I will be curious to see how this space develops over the next few years.

It should be interesting to see where they go since most if not all TV advertisements concerning emergency power generation are made by Generac

[TKB4]

The issue the OP is bringing up is exactly why I am looking at getting a hybrid inverter for a planned system. I am now leaning toward the Sol-Ark 12 and rigging my Golf cart batteries up as the battery backup for now.

To address his issue: I have used both inverter and non-inverter generators at different times including yamaha EU1000is and 2400is, honda EU1000, EU2000 and EU3000 Powerhouse 5500 and Generac 15,000 watt generators at different times and locations and purposes. Although the 1000 s will generally operate lights TV small microwave or efficient refrigerator/freezer you really have to watch load management . The 2000 s size are much more forgiving. The 240 volt 5500 will run some smaller central units maybe hot water heater or oven etc but still have to do load management using any two high demand items (read 240v) at same time. The 15,000 runs everything but large HVAC with very little load management mostly just on startups of heavy loads like HVAC.
Drawbacks of the Honda EU3000 : Heavy not really portable at 134 lbs plus fuel, electric start only so need to run say once a month to keep battery charged or jump to start by removing front panel, and still only 120v that most houses don't need that much 120v unless have a small 120v AC that this unit might power that smaller 120v may not. So, unless you get a large 240v generator it still isn't a whole house generator for HVAC etc and the 15,000 watt unit will use about a gallon an hour if there is much load at all that is a lot of fuel to buy and haul. All the mentioned inverters are very quiet and fuel efficient . the 2000 uses about 2 gallons a day at half load. Just get a cap for about $20 and fuel line and either 6 gallon marine tank for extended use or put weight on end of fuel line and drop in any gasoline container to run more than a day at a time (hopefully non-ethanol fuel or run carb dry). All these generators are mechanical and may not run when needed and require maintenance.
Currently I have Honda EU2000 and Honda EU 3000 and am probably going to sell the EU3000.

I use an interlock breaker on my service panel and manually cut off all other 240 breakers when grid goes down . This eliminates extension cords etc.

I have also used a couple of 6 volt golf cart batteries or a spare 12 volt car battery and an inverter which can be hooked up to interlock also. If outage lasts long start car up and recharge batteries with jumper cables. This actually works pretty well for shorter duration outages. Idling a car about same or less fuel than large generator and most vehicle alternators can put out about 1000 watts.