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Do you want your new solar system to be "battery-ready"? First you must know what this actually means...
Most of the homeowners I talk to are desperately eager to get batteries.
They want to wait a few years until the price drops significantly. When a typical battery system in 2016 has a 20-year return on investment but only has a 10-year warranty, who can blame them.
Therefore, homeowners who wish to purchase solar energy are very eager to obtain a system so that they can easily add batteries in the future.
Solar energy companies have realized this, and we are beginning to see solar systems sold without batteries, but advertised as "battery ready."
At SolarQuotes, we are receiving more and more questions about the actual meaning of "battery-ready" in these advertisements, and the best way to buy a solar system that is truly battery-ready.
The truth is that "battery ready" can mean many things. Many of the advertisements I have seen are technically correct-because you can add batteries in the future-but it may not be that easy or have the features that many people expect.
In my opinion, if you intend to claim that a particular solar system has batteries ready, then you must be more specific and explain the basis for your claim.
In this article, I will give 3 different interpretations of "battery ready"-make sure you understand which one is provided.
First let me explain the technical terminology in the title, because it is full of jargon (sorry!).
"Hybrid"-refers to a solar system that is both on the grid and has batteries. It is mixed because it is a bit semi-on/off-grid.
"Non-backup hybrid"-means that if the grid fails, your entire hybrid system will also shut down, despite the battery. You have no backup. If this sounds ridiculous, please read this article.
"AC coupling"-has nothing to do with amorous air conditioning. This means that the wire connecting the battery part of the system to the solar part of the system is 240V AC (the alternative is DC coupling, which means-well-I think you can solve it yourself).
"Battery inverter" is an additional inverter designed specifically for batteries. It must:
a) Convert the battery's DC power to 240V AC power compatible with the grid
b) Convert the 240 AC output of the solar inverter to DC to charge the battery
c) Control charging so that the battery is not damaged
d) Only use solar energy (or possibly off-peak grid power) to charge the battery
e) Discharge the battery only when the household needs it, don't discharge it back to the grid-because that makes no sense (unless you have a Reposit-but we will talk about it later).
As you can see, battery inverters must be very smart. If it knows what the electricity consumption of the house is and what the solar output is at any given time, it can only perform (d) and (e). Therefore, the battery inverter needs to communicate with a power monitor (or current transformers, which are very cheap electricity meters), which are connected to the wires that come out of the solar inverter and enter the house
Therefore, to add batteries to any solar system in this way-you just need to connect the battery inverter to a household 240V circuit. Connect the power monitor to the solar output and household input lines. Then you plug the battery into the battery inverter. Bob is your mother's brother: you have a hybrid system with no backup. 24-hour solar power generation-as long as the grid is operating normally.
It looks like this (meters are not shown for clarity):
If you want to upgrade like this, almost all grid-connected solar systems installed in Australia are "battery ready."
The key to note here is that the compatibility between the solar inverter and the battery inverter is not necessary. In other words-they do not need to talk to each other, because the output of the solar panel does not need to be throttled. Because this is a grid-connected system, solar panels can run all day long, and the excess energy just flows into the grid.
This means that your existing system can have the most inconspicuous solar inverter on the planet, and you can still call it "battery ready." This also means that if you decide you don't want the backup function and don't mind buying a battery inverter with a battery, you can buy any solar system-knowing that this type of upgrade is possible, it's safe.
Battery inverters that allow this upgrade include the super exciting SMA Sunny Boy Storage and the micro inverters in Enphase AC batteries.
SMA Sunny Boy Storage and Enphase AC batteries can be added to any solar system-as long as you don't need a backup.
But what if you want to back it up?
If you think you might need a backup when you start adding batteries, the system you need looks very similar to system #1, but it differs in two important ways. Let's play "Find the Difference".
In battery-ready scenario #2, you can run off-grid. But this means that your battery inverter and solar inverter need to communicate with each other.
The obvious difference is the off-grid switch. This allows you to maintain power in the event of a grid failure, instead of feeding energy into the grid. Because this may kill the linemen who are trying to repair it.
Another more subtle difference is that the battery inverter needs to communicate with the solar inverter. The battery inverter needs a way to require the solar inverter to limit its output. It needs to do this because when it is running without a grid and the battery is full, the excess solar energy has nowhere to go, only to smoke in a pile of toxic molten wires.
This is of great significance when you buy a "battery ready" solar system. You need to make sure that your solar inverter can communicate with the battery inverter. Electronic devices can communicate with each other in countless ways, but the standard that most well-known inverter manufacturers seem to adopt is called MODBUS. If your inverter can communicate with MODBUS, then you should be fine.
You should also know that battery inverters that can be off-grid are much more expensive than battery inverters that are shut down with the grid. They need to disconnect from the grid and control power supply and demand. They usually also need some rewiring in your home to place your base load on a separate circuit from non-essential equipment.
Good off-grid battery inverters using MODBUS include Selectronic SP PRO all over Australia and the old and faithful SMA Sunny Island
SMA Sunny Island and Selectronic SP pro are battery inverters that communicate with MODBUS and can provide backup
Now I must admit. I am not 100% real. You can actually operate the system in the picture above without the need for a communication link between inverters. Instead of asking the solar inverter to throttle its output, you can go to BANG! And cut off the power of the solar inverter. Then, when you are ready to receive more solar energy, you can turn on the solar inverter again.
You can disable the solar inverter by cutting off the power using a switch controlled by the battery inverter, or you can let the battery inverter change the frequency of the alternating current so that the solar inverter crashes on its own when it trips at low or high frequencies. Back to my era of control engineering, we used to call this kind of control "Bang Bang". Because you knock it up first, and then knock it out.
This is a terrible way to control everything-it will severely shorten the life of the solar inverter. It may also cause serious damage to many of your 240V appliances. It will actually invalidate the warranty of many solar inverters. So I do not plan to recommend this control method. In my unprofessional point of view, this is just garbage engineering.
I suspect this is what most people mean by "battery ready". They believe that when batteries become affordable, they will be able to buy battery boxes and get sparks to quickly connect them to several terminals on the solar system inverter. Voila-a fully functional hybrid system.
If you want a system with this "battery ready" level, then you need to get a system with a hybrid solar inverter compatible with your favorite battery brand. Hybrid solar inverters can convert the DC power of solar panels and batteries to AC at the same time, and handle all battery control and switching functions. As you can imagine-these hybrid inverters are much more advanced than standard solar inverters and therefore more expensive. Compared with solar inverters, hybrid inverters are expected to cost between US$1,500 and US$2,500.
In many people's expectations, a true "battery-ready" system means you only need to add batteries when appropriate. This requires a hybrid inverter.
Hybrid inverters include the popular Sungrow SH5K and the Redback intelligent hybrid system from Brisbane, which can do anything you can think of (including trading electricity with neighbors-although according to Australian electricity rules, this is technically Unlawful).
Both Sungrow SH5K and Redback are hybrid inverters, you only need to insert the battery.
If you do specify a hybrid inverter, please pay attention to these issues (make sure they are in the contract you signed so that there will be no surprises on the day you add the battery):
1. Specify whether the backup function is required. Not all hybrid inverters allow you to operate when the grid is down.
2. Whether a "real UPS" is required. UPS means uninterruptible power supply. Many hybrid inverters will power off 240V AC for 10-30 seconds when switching from Grid Connect to standalone mode. If seamless switching is important to you, then select "True UPS".
3. Make sure to connect consumption monitoring during initial installation. In order to control battery charging, the hybrid inverter needs to understand the consumption of your house. It does this with its own meters. This provides you with very useful information even before you have the battery, so you can find opportunities to shift the load to the day and make energy efficiency improvements, when you see exactly how much energy you use and when, This information will make your eyes shine. You need to specify this because many installers will assume that you don't want to monitor unless you have a battery.
4. Check the maximum amount of kWh that the hybrid inverter will handle and which batteries it can communicate with. If you have confidence in Powerwall in the future, then make sure that the hybrid inverter can communicate with it (then sit down and decide if you *really* want a Powerwall because there are better batteries!).
5. If you want to participate in the wholesale market and get better export power prices during peak hours, please check whether the hybrid inverter is compatible with Reposit Power. I will contact Reposit and ask. If the inverter is compatible, you will need to pay an additional $800 for the Reposit controller and software when purchasing the battery.
6. Check whether the inverter has an energy management relay. These switches can be used to turn on loads when there is excess solar energy (such as hot water heating) and turn off when the solar power drops. If deployed intelligently, this "heat storage control" can reduce the energy output to the grid. This may mean you need to buy fewer batteries.
7. When purchasing batteries, check whether you need to pay for an additional "battery inverter" card. Some hybrid inverters don't actually have a battery inverter—there is only room to slide the battery inverter module into it—you have to buy it.
8. Please note that choosing a hybrid inverter now will lock you to use a battery compatible with the inverter in the future. The battery's battery management system (BMS) must be able to communicate with the hybrid inverter. So you limit your options for batteries in the future.
If I were to buy a solar system today, I would be satisfied with Option 1. I really don't worry about grid backups. My local power grid is shut down for approximately 2 hours every 2 years. I can live with this. And I am a picky guy. I like to freely choose any solar inverter I like.
If I want to back up, I will choose option #2. I would buy Fronius, SMA or ABB inverters because I know they use MODBUS (the language used by battery inverters).
What I will not do is option #3. I think it is unwise to buy a hybrid inverter and hope to buy a battery within a few years. I don't think the battery makes economic sense in 3-5 years. By then the hybrid inverter you choose may be out of date, or worse, the manufacturer may go bankrupt. In 3-5 years, battery inverters will become so cheap that buying battery inverters and batteries and connecting them to non-hybrid inverters will almost certainly be cheaper than buying expensive hybrid inverters now.
I am a chartered electrical engineer, solar energy and energy efficiency expert, father and founder of SolarQuotes.com.au. My last "real job" was in the renewable energy department of CSIRO.
Hi Finn, what a great message. You have done a lot of homework, and I think your 3 to 5 year battery plan is correct. When kilowatt hours increase and the grid connection is restricted by the utility company, what will people do in the meantime, such as useless 3 kilowatts. It's 20:33, and when I write this article in Silkwood and Grid, Ergon is closed. I'm not the only person in this neighborhood who uses solar energy, but all the others are sitting in the dark because they don't have batteries. I have an independent system, but I can get electricity for my air conditioner from a separate circuit on the grid. There is no air conditioning tonight because my 36 kWh battery pack does not provide enough power for night use. In the past 12 months, my standalone system has worked well. There are more than 12 different wiring diagrams and many variations on my garage system circuit board. A simple and inexpensive way to use your anticipated photovoltaic system to get off the grid might look like this: I can say that as the bat becomes cheaper and your needs increase, you can expand the system. This system is suitable for both string system and micro inverter system. For a string system, you may have two strings to power the string inverter. With a micro-inverter system, you can have as many strings as micro-inverters, but there may actually be only two. Therefore, you will need 2 40 Amp SSRs and 1 DP DT miniature relay with a 12 volt coil. A relay driver that may have 4 ports. I use Morningstar relay driver. You will need a charger, 240V AC input, 48V DC output, 120 amps. You can use an 8 kW inverter/charger, but disconnect the inverter side. If you can find anything that can be charged without an inverter, please let me know. You need a battery pack. Technically, you can use 4 front trash dumper batteries, but you will be sitting in the dark most of the time. You will need a non-charging inverter. You can buy a cheap 3.5 kilowatt unit for 350 US dollars. I haven’t summarized it yet, but I think the charger is $600, the inverter is about $350, the relay driver is about $250, and the other part is about $50. The idea is to have as much as possible without output to the grid. More photovoltaic power. The micro switch is either on the grid or independent. Two SSRs are used for grid-connected and stand-alone. The charger supplies power to the battery from the grid or inverter, but it must never be obtained from both. If you use a large inverter that also has a charging function, use power diodes to eliminate feedback to the battery. The inverter supplies power to the load and also supplies power to the charger. With a relay driver, you have 4 ports: one will enter the micro relay and drive any SSR based on the voltage you programmed into the relay driver. When the voltage climbs too high, other ports can be used to turn off one of your strings. It can also be used to transfer electricity to water heaters or air conditioners. I use it to turn on the two air conditioners during the day when the battery is full. I think large inverters/chargers are not suitable because they will fluctuate the load of the battery, which I think is unhealthy. I see that all these systems have a lot of communication from the inverter to the load, and I am confused when things are so simple and cheap. It's 21:11, I have to finish, the others are still in the dark. The works of Finn, John Nielsen, and Silkwood are all great.
Hi John, I would love to understand your system better. Can you publish or email single-line diagrams or electrical wiring diagrams showing the main components?
Please give me your email address. Send to: [email protection]
I am also interested in understanding your system better. If available, it would be nice to show one-line diagrams or schematics of the main components.
Finn, thank you for another great article. What about automotive (EV) batteries used for battery storage in residential photovoltaic systems? I understand that Tesla and Solar City are researching or have created a system that allows your EV car battery to store energy from the solar system. Are there any EV charging systems that allow electricity to be drawn from the connected EV battery when needed for use at home?
If you just put the car charger on the home circuit, then it will use solar energy when it is available. Then you can be more fancy and put in a shunt box (or use the relay output on the inverter such as Redback or Fronius) to enable the charger only when there is enough solar energy. This is quite simple. As electric vehicles become commonplace, I hope they will all use electric vehicle integration as a standard.
Tesla used their original Roadster to achieve vehicle-to-grid (V2G), but decided not to continue.
Nissan seems to be the only electric vehicle manufacturer to provide V2G solutions for its LEAF.
http://www.theguardian.com/enel-partner-zone/2015/jul/30/batteries-on-wheels-how-vehicle-to-grid-technology-will-allow-electric-cars-to-store- Energy for everyone
It seems that V2G is in great demand, and Nissan should provide this service for cars sold in Japan. I hope the same goes for the cars they sell in the United States.
Finn, what about secondary-use electric car batteries for stationary storage? Are these all ready for prime time? http://www.greentechmedia.com/articles/read/nissan-green-charge-networks-turn-second-life-ev-batteries-into-grid-storag
Finn, thank you very much. Two years ago, I purchased a standard 3KW system with a Growatt inverter and 12 panels at a net cost, after I earned a rebate of US$2,999. I am very satisfied with it, and I calculated that it saves me $600-800 per year, depending on what happens to my bill as my electricity bill rises. Judging from what you wrote, I can assume that I currently have option 1, "Battery Ready #1: Prepare for'no backup hybrid' by using AC coupling, battery inverter and battery"? So if I decide to buy a battery in the future, do I need that and a battery inverter? In addition, you mentioned SMA Sunny Boy Storage. I went to the link and did not mention the price. Can you roughly talk about this (as an example) and the cost of the battery inverter? I think I need to increase the installation cost to connect everything to my existing system.
Yes-Sunny Boy storage will be released in a few weeks-I don't know how much it will cost-but my guess is about $1,000 (warning: complete guess). We will know soon.
The installation should take a few hours. Unless you get a Powerwall, it takes a lot of time to install mechanical and electrical.
I have taken a different path in solar energy. With the advent of LED lighting, I used 3, 5, and 10 watt LED downlights to connect 12V DC to my house. I can run the entire house's lighting on a 250W solar and 100Ah battery installation. It has been in operation for more than two years and has not lost lighting even during grid failures and multiple power outages on my input power supply. When other places nearby are in the dark, it is a great feeling that I have safe and effective light!
Yes-this is a good idea. As the only house with lights on during a power outage, it must feel cool.
Does this mean that powerful portable/semi-portable solar is becoming a reality closer to the lessor? It would be great to have a personally available stand-alone system that can be used anywhere I rent, and the safety of the power supply can make up for the shortcomings.
Hi Finn, once again, what a great forum this is. I learned a lot from this forum, and I believe many others have also. I want to comment on your scene #2. Where will power go? It seems to me that, as you said, smoking is not getting up. All inverters I know have a minimum and maximum voltage threshold. When the power supply exceeds this threshold, it simply turns off. I have read many blogs from the United States about the question of "Where does the power supply go?" I am confused about this. I don't believe I'm right, but I know some string inverters, they also have a threshold and shut down outside of this limit, that's why I asked this question for your wisdom. My Enphase micro-inverters do not smoke when the power generated exceeds the load demand, they just turn off. That's why I have 3 strings so that they don't all fall off and make me lose motivation. Each string is controlled by a relay driver, which closes and opens according to the threshold voltage I programmed. The micro specifications are as follows: overvoltage limit is 270 V, undervoltage limit is 200 V, over frequency limit is 54.0 Hz, and the lower limit frequency is 46.0 Hz. Trip time (voltage and Hz) 1 second, reconnect 60 seconds. Finn, I will thank you for your explanation of "smoke" and your comments. John Nelson, Silkwood
Yes-"smoke" is an exaggeration. They should trip due to voltage first. But my point is-although you can turn the solar inverter on and off to make it work, this is not a good way. Relying on safe trips to control anything is bad practice and is usually dangerous-and will void the warranty of many inverters, generate a truly variable voltage for your equipment, kill the entire array, you only need a little less power. It is an explosive solution, not a variable output solution. The microinverter is not a big problem, but it is still not ideal.
In my opinion, option 2 and option 3 are just the difference in the number of boxes. I think their functional "integration" is more related to engineering. Modbus can integrate two independent inverters well, right?
A few years ago (Keynes), we added a 3.5 kW system to the original 1.5 kW system, instead of installing a solar water heating system, 2 systems-2 SMA inverters. (Total expenditure of 7000 US dollars) There are two adults in the family, and two adults living in the bungalow means that all the white goods have been copied. Use low-wattage components and timers to preheat a 250-liter hot water tank in the middle of the day. If necessary, fill up the second 250-liter water tank. Tariff 33 (change to Tariff 31)-the bill for the hot water part of the electricity is reduced At $60 per quarter, the overall quarterly bill is about $350—until recently, the air conditioner has been working hard, and the average temperature for several consecutive months was much higher than average. My question is that we have reached the limit of Ergons. Is it feasible that we can add more panels with battery storage on a standalone system running some directly connected projects. If we move on, can we take it with us? We also have large generator backups that allow us to shut down the grid.
Thanks 4 imfo I will definitely pay attention to it when I buy
Finn, I recently had a conversation with a company that designs microgrids. There are many island communities in my area, where electricity comes from one source and then distributed to the entire community. If every household has a smart meter that can track current in either direction, how feasible is it to make a central battery storage facility serve the community? Many households have solar energy, but some households only work part-time and end up providing too much electricity to the utility company. The central battery bank will be a way to store surplus electricity and share it in the community. We also want to obtain TOU rates so that the excess energy generated during the day can be stored locally and used during prime time without paying for prime time utilities.
Hi Finn, I am curious what is the inherent technology that restricts ordinary string inverters from working as hybrids? Can't we have a $200 cheap box connected to a string inverter that can also hold batteries? Why can't we even do this with off-grid inverters? I know it needs some kind of AC sine wave to imitate? But why is it so expensive?
PS-I don't have any electrical background, I only have rough electrical knowledge. But according to my understanding, it only needs some capacitors and transistors to complete these tasks.
Hi Ronak, Ronald is here. Batteries need a way to charge with low-voltage direct current. They need a way to convert the low-voltage direct current they provide into high-voltage direct current that the inverter can handle or directly invert to alternating current. Traditional inverters cannot handle this task.
There are some boxes that can be used to make homes use traditional inverters to retrofit batteries. One method is to use a battery inverter to obtain alternating current from the inverter, convert it to the battery's direct current, and convert it to alternating current when the battery is discharged. An example is Sunny Boy Storage:
http://www.solarquotes.com.au/blog/sma-sunny-boy-storage/
Another method is to use a DC converter. The converter obtains a higher voltage DC power source from the panel, provides a lower voltage DC power to the battery, and then converts the lower voltage DC power from the battery to the inverter. Higher voltage direct current. An example is Goodwe GW2500-BP:
http://www.solarquotes.com.au/blog/goodwe-bp/
Unfortunately, both methods cost more than a few hundred dollars, but I do expect prices to drop and people will have more choices in the near future.
The only real reason against waiting is to lose opportunities. The calculation can be as complicated or simple as you like, because one size is not suitable for everyone.
I mentioned this before, and this is the result of many elderly people whose pensions will be affected by changes in asset valuation methods.
Solar energy is not only related to how much money you can save, but also how much money pensioners of a particular asset class can save. We are not talking about the amount of chicken shit.
Think about it, with the reduction of pension rights, energy costs continue to rise.
It has been 14 months since the beginning of this article, and the electricity price has increased by 45% due to the shutdown of the generator, and you can repay the battery in 6 to 8 years. I say mixed people are happy
Regarding your article "The truth about battery-ready solar systems" I recently added a new Enphase solar system with a micro inverter, but I have an existing old system on another roof. This older system uses an older (Sunny Roo) inverter. I have been thinking about adding batteries-currently I tend to use the AC version of Telsa Powerwall 2, which I believe has a built-in DC-AC inverter. I think it would be simple to add it to the Enphase system-but I want to know how such a battery can be integrated with the old system with Sunny Roo inverters. This is in contrast to your article "The truth about battery-ready solar systems-or a different solution? Can I plug it into the 240v main circuit?-What communication is required between the Enphase system and the Sunny Roo inverter and battery (if any if)?
You need a qualified installer to check all the details of installation and wiring, as well as local DNSP (your local electronic network) rules-but AC-coupled batteries can be connected to any grid-connected solar system on the switchboard-including Enphase system.
So DNSP allows you to add a PW2 should be no problem. The disadvantage of AC coupling is that any backup function will be limited. That is, once the grid is disconnected, you will not be able to charge the battery with solar energy until the grid is restored.
Finally, someone explained that this battery-ready battery is compatible with fluff balls. thank you. All inverters are ready, they only need a battery inverter when they buy batteries in 2020. It's that simple... isn't it? ? ? ? ? ? ? I keep getting quotes from salesmen, wow, this is a minefield, trying to decide who will sell you anything and who just wants to give you what you need. I want to use 12 sunpower 327 and a fronius primo 3kw. $5900 My transformer only has 10 kva, so I can only use the 3kva system. Thanks Finn for the clarification.
Hi Finn, I have read the above information and want to know if you have found a hybrid house on the hybrid energy website (www.hybrid.energy). Maybe you can do some research and comment on the applicability of the system as a hybrid system or an independent system. It is reasonably priced and it is recommended to use batteries up to 60% dod. They also have a modbus card, which seems to cover most aspects of a hybrid system that people might need, with reasonable storage space and can be expanded as needed. Thanks john
Hello John, this is Ronald. A few weeks ago, I had a brief conversation with Hybrid. They have completed some large-scale installations. I'm afraid I don't have the figures needed in terms of cost and reliability to write. But now that you have mentioned it, I might get them sometime.
I know this is an old article-as usual, technical information is in stock. However, for three reasons, I disagree with Finn's conclusion about the hybrid inverter. 1. The hybrid inverter will not magically become obsolete. Power electronics and conversion are well understood. They have achieved an efficiency of up to 97%. They will not get better so as to make the current one obsolete. If it is legal to connect to the grid today, it is unlikely to change. 2. For exactly the same reasons, a high-quality, high-power battery inverter/charger is unlikely to suddenly become cheaper. First of all, most systems will not go this way. They will be hybrid inverters or AC coupled because it is easier, cheaper and simpler. Of course, China may prove me wrong, but I don’t think they will become high-demand goods. In fact, my bold prediction-more expensive-is a special project. 3. I agree that buying from high-quality manufacturers does not guarantee that they will still exist within 3-5 years, and in any case, most warranty periods are up to 5 years. This is a valid point of view, but it should not be a deal breaker. This is why buying a hybrid inverter now allows you to install the battery when it makes sense to you, without additional installation costs other than commissioning. It will cost more than inverters, but not as much as panels and inverters compatible with battery inverters/chargers. This is actually a more expensive option and less flexible.
The cheapest option may be AC coupling because they are the easiest way to install and the battery comes with a built-in inverter/charger. For example, PW2 can be retrofitted to most existing systems. If you think this is the way to go, then a hybrid inverter is not the right choice, because PW2 will not use a DC charger and secondary inverter.
If you are considering DIY or DC batteries (which is strange to say-blame Enphase and Tesla), then a hybrid inverter makes the most sense.
About PW2 with AC coupling. This is a #1 system, there is no opportunity to use photovoltaic power when the grid is off, right?
I'm working on a photovoltaic system with a micro-inverter that outputs AC power "directly", and I will add a PW2 (or other) later. However, I want to build the photovoltaic system as a #2 type system (hybrid grid-connected system with backup batteries when installing batteries).
So I should make sure that there is one: * In addition to the photovoltaic inverter, there is an additional inverter that can communicate with the grid (and disconnect from it when the grid is off) and a battery? * Consumption monitoring * MODBUS * Will not invalidate the PV warranty * Wait?
"About PW2 with AC coupling. This is the number one system. It is impossible to be powered by photovoltaics when the grid is off, right?"
I think this is incorrect-PW2 has an automatic transfer switch (I think it will be used in most installations), so when the grid fails, it will continue to provide power and continue to charge through the photovoltaic system. I think this may not be available in the first release.
"So I should make sure that there is one: * In addition to the photovoltaic inverter, there is an additional inverter that can communicate with the grid (and disconnect from it when the grid is off) and the battery? * Consumption monitor * MODBUS * Will not invalidate the PV warranty* Wait?"
If you want to use micro-inverters, then you'd better follow the system recommendations-this is because micro-inverters usually don't communicate with MODBUS-but feed them to the (hopefully) controller box. Enphase is the most famous, they have their own battery system (I don't particularly like it, but I am not an installer)-I'm not sure how well they integrate with other solutions, or how many you have to skip basketball.
Another solution to the shading problem is a power optimizer like SolarEdge. They feed DC power to a traditional but proprietary inverter/controller.
thanks for the reply. Therefore, PW2 may have or include grid disconnect switching. If Tesla or some installers would say so, it would be comforting. It seems that almost no one knows what happened in this detail.
For micro inverters with SP Equinox system, I don't have many choices. I am getting this system at a favorable price/watt and service life (better than "SC"), which is why I would object to most general recommendations regarding SP.
So should I let the installer include some kind of controller box as part of the initial installation, so that the PW2 add-on used for power outage backup in the future can almost be plugged in? Kind of like Sunny Boy Island?
PW2 comes standard with complete off-grid function. This can be retrofitted to any grid connection system using the "Tesla Gateway" box. I have seen it work-it works well.
https://support.solarquotes.com.au/hc/en-us/articles/115001986773
Based on your feedback, I poke my installer harder and it seems that PW2 will independently manage on-grid and off-grid charging-whenever I make a leap, PW2 or any other AC-coupled battery system.
I am worried that if there is no end-to-end "modbus" type of communication, the AC frequency shock will eventually damage something.
At the same time, Tesla really should stop beta testing their customers.
If you can, ask a few questions. I learned a lot from reading your article, but I am fully aware that there is still a lot I don't know.
I don't currently have any solar energy, but I am considering a 5kW system. Some articles indicate that the wise choice is to install hybrid inverters rather than simple inverters to make it easier to connect batteries when they become attractive. A quotation has been provided for upgrading from the Growatt 3Ph 5kW unit to the Fronius Hybrid for an additional fee of US$1,500. A related question is that Powerwall 2 seems to have the necessary intelligence and does not require a hybrid inverter. Is this "old" news? The second problem is related to our power supply. We have three connections to the switchboard (for future air conditioning units), but only use single phase. Are there any advantages to installing a three-phase inverter instead of a single-phase inverter? Thanks for any suggestions.
Household battery storage is a rapidly changing field, and I personally don't recommend doing anything now to prepare for future batteries, because the preparation work may eventually be wasted. Powerwall 2 is designed to be AC coupled, which means that it does not require a hybrid inverter and can operate regardless of which solar inverter the house has. Other battery systems can also be AC coupled.
Single-phase inverters are fine, but three-phase has some advantages, especially if you decide you want a larger solar system. Finn wrote here some advantages of the 3 stages:
https://support.solarquotes.com.au/hc/en-us/articles/115001462573-I-have-3-phase-power-Should-I-use-a-3-phase-inverter-or-a- Single phase inverter-
Thank you very much for your reply, I can now dispel this worry.
Regarding single-phase or three-phase, I have always worried that if I have a single-phase inverter, and then install a three-phase air conditioning unit, and sometimes generate excess energy and use the air conditioner, I might charge the two-phase efficiently from the network Draw in the grid. Someone told me that this is not a problem with the smart meter, because it should balance the total power of all three phases with the single-phase output of the inverter.
I hope I have received reliable notification.
If you have three-phase power and solar power, you might end up outputting solar energy on one phase and inputting solar energy on the other two phases, but as far as your meter is concerned, it will only look at the net amount used or output. So, if your solar system outputs 2 kilowatts on one phase, and your air conditioner inputs one kilowatt on each of the other two phases, as far as your meter is concerned, your house has no electricity.
No smart meter is needed to perform this operation. An ordinary, digital, three-phase import/export meter can also do this.
Regarding the comment in this blog: "If I want to back up, I will choose option #2. I will buy Fronius, SMA or ABB inverters because I know they will use MODBUS (a good battery inverter will Language used)."
I am about to install a Frontius Primo 5.01 system with MODBUS. Therefore, as an inverter that can be connected to the battery system and work off-grid during a power outage, does this meet the requirements? I can't find a clear overview on the Frontius website or specifications.
Realize that this article is now 2 years old and things may have changed.
If you want to install Fronius Primo, since it is not a hybrid (also called multimode) inverter, you will need to install an AC-coupled battery. They operate independently of your inverter, so compatibility is not an issue. The most famous AC-coupled battery system is Powerwall 2. It can provide backup power during grid failures and charge your solar panels during power outages. They are currently not available, but if you are not in a hurry, then if you are interested, I hope you can buy them next year.
However, if you are not too interested in owning a battery, but are just worried about having a backup power source, it may be more economical to use a generator.
I need to add a battery for off-grid power to the existing 10.84 kW Enphase micro system. I also have a 9000 watt portable generator, which I want to be able to use when necessary. I know that AC coupling is the only way at this time. I want to spend the least amount of money to basically keep my solar power running during grid failures. It is possible to run the generator at night, but hope that the use of solar energy will not be lost in the event of a grid failure. Any help would be greatly appreciated
I am new to all of this and I am confused when it comes to the compatibility of batteries and inverters. When installing solar lithium-ion batteries into an existing grid-connected system, what do we mean by compatibility?
Generally speaking, the battery itself needs to be paired with a compatible hybrid inverter to work. If you already have a solar system with a normal solar inverter, it will not be able to accept batteries. If you need batteries, you can get a hybrid solar inverter and compatible batteries, or you can get a battery system that can be used with any solar inverter. Tesla Powerwall 2 is an example. Please note that if you want to save money, for ordinary households, batteries are unlikely to do this, but they can provide convenient backup power.
Hi, since this article is several years old, does it still make sense? (I noticed that it is linked to in the hybrid inverter comparison table page)
I am considering buying a product like Fronius Gen24, but am not sure if the advice is still valid, ie. Choose option #2.
I want to use my battery as if I was "off the grid". More than just a backup power supply! I want my solar/inverter to run my house, charge my battery and output any excess power during the day, but then use the battery power that I stored overnight or days with low solar output. Finn, I am shocked when you say that ordinary households use 20% of the electricity they produce. Of course, they are a common/safe way to use battery power at night and charge the battery during the day instead of outputting so much power. If they are the settings that perform this operation or the switches that can be used to customize such settings, can you let us know. The 20% usage rate is a terrible number.
[…] A system with battery backup is a priority, and having a large inverter is the only way to go. (This article explains what a battery backup system is and how it differs from a battery-ready system [...]
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