This is the transcript for webinar Power Anytime: Using Battery Backup with a Microinverter PV System.
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Kathie:
Hi, everybody. I’m Kathie Zipp, managing editor of Solar Power World Magazine here. I would like to welcome you to today’s webinar, Power Anytime: Using Battery Backup with a Micro Inverter PV System.
Before we start, here’s just a few quick housecleaning items. Our new webinar platform allows more flexibility, so you can move the boxes around and change your sizes as you’d like. I’d like to mention that this webinar will be available after the presentation on solarpowerworldonline.com, and will also be mailed to all registrants. People always ask that. You will be able to view it again at your convenience. You’re also able to find webinar slides in the resource box on your right, which you can download at any time. There will be a question and answer session at the end of the presentation, and we encourage you to participate. You can do so by submitting your questions, whenever they come to mind, at any time. Just type them into the Q&A box on the left of your screen. Lastly, we encourage everyone to engage in this webinar conversation on Twitter with the Twitter hashtag #SolarWebinar.
Now I’ll introduce our presenter, Alan Santos-Buch. He is Renewable Energy Product Specialist with Sensata Technologies. Alan is an expert in solar and renewable applications. He has 10 years of experience in technical sales, application support, and product training and seminars. He is a certified NABSa educator, with in-depth experience in battery-based backup, AC coupled, and off-grid applications. Alan’s going to give about a 25-minute presentation or so, and then we’ll do a Q&A, but you can submit your questions through the whole presentation. Alan, go ahead whenever you’re ready.
Alan:
All right. Thanks for having me, Solar Power World and Kathie. Appreciate the introduction. As most of my audience might know already, we don’t make the blender or the microwave or laptop you see on this first slide. We make the electronic devices that can power them any time of the day, with or without utility grid. My job, part of my job is to help installers, integrators, and end-users alike, decide, select the correct magnum energy components for their renewable energy applications. Today, the discussion will focus on key parts and methods used to provide backup power to essential loads while using grid-interactive PV micro inverters connected to a battery based inverter charger. The result is power any time to the home’s essential load panel during a grid outage or interruptions, while still using the valuable, and expensive PV resource on your roof.
Moving to the next slide. The agenda and learning objectives I’ll introduce first. Sensata Technologies is the parent company, I think it’s important to understand, and how fortunate we are to have their support. Another objective is to educate you on the subject of AC coupling. With this understanding, you can expand your business within your current client base, and expand into new installations with a complete cost-effective and efficient solution to achieve power any time in a grid interactive renewable energy application.
Next, I’m excited to introduce our new grid-side micro inverter product that will enable you to design and integrate for new customers a complete Magnum Energy AC coupled solution, without using a blackout relay or diversion load controls. The MicroGT-500 is optimized to communicate with and work with our battery based MSPAE Series inverter charger. I’ll show you also the benefits of this solution, using specific line diagrams and scenarios. I’ll also talk about the timing of this new product launch, our support mechanisms and the warranty. Lastly I’ll summarize the key points in my discussion and then take your questions. I appreciate you joining today, all 500,000 of you.
Sensata Technologies is a New York Stock Exchange listed company. It’s been around for many years. In fact, this year we’re celebrating their centennial anniversary. Formerly known as Texas Instruments, the focus is on safety. They’re the world’s leading supplier of sensing, electrical protection, control, and power management solutions, and they have business centers in over 11 countries. They’re key players in automotive, appliance, aircraft, industrial, military, air condition, ventilation, data, telecommunications, etc. They’re devices, our devices I should say, improve the safety, efficiency, and comfort for millions of people every day. We are very pleased to have them as our parent company. What it tells you, really, is that we’re not going away. We have the support and resources from a major, multi-billion dollar company, and we will continue our research and development, and continue to put out there quality reliable renewable energy products.
Magnum Energy today is a product brand of Sensata Technologies. Over 12, 13 years ago it was founded. Their partners had a vision to provide reliable battery-based solutions, inverter chargers, for the mobile and renewable energy markets. They built an exceptional brand and reputation in the industry, many people are aware of. We cater to a very large segment of the RV and over-the-road vehicle market, and we are now aggressively moving strongly into the renewable energy space with grid-tied micro inverter the introduction today.
Many of our products, some of you might know. These are battery based. These might look familiar, if you can see the slide. But we made reliable products that are working off the batteries. Virtually any type of battery chemistry we can charge. We have a solar charge controller for DC coupled applications, and we have gear sine wave and modified sine wave inverter chargers. But today, for this discussion, we’re going to focus on our new micro inverter coupled with the MSPA Series inverter charger.
It’s very important to understand what AC coupling is, because that’s how we achieve this power anytime scenario. Many folks who have PV installed on their roof come to realize after a power outage event or weather event that the valuable resource, the expensive resource on the roof, is being wasted. The output no longer can be used to power the home, the home essential loads especially. AC coupling is achieved when the AC outputs of the battery-based inverter, that is the MS-PAE Series inverter, the Magnum inverter, and micro inverter land on the same output bus in the essential load sub panel. Magnum battery-based inverters can be installed in a way to utilize that power from those expensive PV modules that is being wasted during a power outage. The MS-PAE Series inverter charger can synchronize and work with virtually all grid interactive string and micro inverters. But I’m going to show you in this presentation the benefits of using our new MicroGT-500 inverter.
AC coupling allows the use of the utility interactive inverters that are required to disconnect when the power goes down. So with a battery-based bilateral-directional 4-quadrant PAE inverter, you can achieve this kind of system and have power any time. But when the utility is lost, the ac outputs of both the micro inverter and battery based inverter, coupled together in the essential loads panel. AC coupling allows the homeowner to utilize this array to power the essential loads and charge the batteries during a power outage.
However, the biggest challenge, the greatest challenge in AC coupled design is regulating the charge to the battery bank. We believe the micro inverters offer the greatest value proposition, uncompromised safety built in the box and out of the box, and flexibility in every AC coupled application.
The advantages of installing the micro inverters with battery backup using our PAE inverter charger, it’s much easier to install. It’s simpler to program. It’s flexible. As I pointed out, the micro inverter has and meets the NEC requirements for arc falls protection and detection and shutdown, and rapid shutdown.
There’s higher efficiency during cell back mode. In normal conditions, when the grid is up, and the Magnum-PAE battery based inverter charger is keeping the batteries full, it’s a bilateral-directional 4-quadrant transformer that’s always putting out 240 and 60 Hertz to reference for the micro inverter. In the case of an outage, our transfer switch opens. I prevents any power from getting back to the grid or islanding, and powers the essential load panel. In the essential load panel, the micro inverter’s output, AC output, references the 60 Hz 240 from our battery based inverter and connects. All in all, this is a lower-cost design than a DC coupled or a separate system in having a DC coupled charge controller to the battery bank separately. This is a very cost-effective way to utilize the expensive panels on your roof during a power outage.
It can be configured in higher voltages, and lower balance of system cost. The conductors are smaller. You AC is coming off the roof instead of fed at high EC voltage levels to a string inverter. As I pointed out earlier, rapid shutdown and AFCI built in were compliant with the NEC Article 690.11 and 690.12. No additional costs associated for the first responder protections. Thus the overall system cost is much lower.
Magnum inverter, and here I’m referencing the Magnum battery based inverter, are UL1741 stand alone. They’re not grid interactive. They do not sell back. However, the considerations you should still have in your design is to make sure that the Magnum PAE inverter, the battery based inverter, its output is 10% larger than the continuous output of the array. You must size the Magnum inverter a little bit larger than the array output. This would prevent any damage to the transformer when it goes into AC coupled mode.
Some brands of grid-tied inverters today are more sensitive than others. But we do AC couple with most brands out there. Our technology is basically agnostic to the brands that are out there. It’s our inverter that’s providing that reference for the string inverter to connect to. With our new micro inverter, the connection is literally flawless in the essential loads panel.
Magnum inverters do utilize frequent shift to prevent battery over-charging. That is the biggest challenge, is preventing the batteries from being over-charged. During AC couple mode, the batteries can be over-charged. The current flowing from the solar array, if it’s not used by the essential loads, the excess harvest has to go somewhere. So it goes backwards through our autoformer, it’s rectified back to DC, and it charges the batteries at full bulk. We use frequent shift as a fail safe feature to prevent the batteries from being over-charged. But with our new micro inverter, which is now optimized to communicate with the Magnum network, we can taper down that charge, or the PV source output can be tapered down to prevent battery over-charge. As IEEE standards do require, when the grid is lost, both inverters disconnect, and they will resynchronize in the sub panel referencing the battery based inverters 240 V 60 Hz output.
The new MicroGT-500 is a dual MPPT micro inverter. They’re 2 inverters in 1, so 2 modules are basically hooked up per inverter. This allows for less insulation time, lower your costs. It’s the daisy chain connection. No trunk cable required. So the time to install this system is literally cut in half. It’s optimized to regulate the Magnum battery based inverters when in the AC coupled mode by tapering the charge based on the state of charge of the battery bank. It’s looking at the control board of the battery based inverter. It knows the battery’s state of charge, and it utilizes the frequent shift that the Magnum inverter provides, which lowers the PV source output to the batteries. It works in stages from 60 Hz down to 59.2 Hz, where it will turn off the micro inverter should there be too much harvest going to the battery bank.
Frequent works, as I pointed out, by shifting the frequent up or down, which will knock out a string of micro inverter. In our case, the micro inverter, the MicroGT, is communicating with our PAE. It’s enabled when the remote control, which is required with this application, advanced remote control, the battery type is set to custom, and it activates when the voltage condition of the battery bank being charged is pushed 2 volts above the custom absorb set-point for a 48 volt system, and 1 volt for a 24 volt battery bank above the absorb set point. That’s when it starts to taper down the output of the micro inverter. The PAE is constantly targeting that absorb set point, and when the voltage exceeds that custom absorb set point, the frequent shift works in stages to prevent battery over-charge. What you have achieved is power any time to your central loads panel in the event of a grid outage.
Our remote controls are exceptionally easy to program. As you can see, there’s a rotary select knob that moves you to the different menus. You have menu buttons right on the front face, a 2-line LCD screen that provides you the current condition in real time with what’s happening with your system. The inverter charger on/off buttons. You have LED lights. If there’s a false condition they will illuminate, but if they’re green, you know the system’s good to go.
Setting up frequent shift is very easy also. You go to the setup menu. You select battery type to custom. You set your absorb voltage set point, and then you also want to set the AC in Control, which is the control button, to auto. You always want the inverter to connect automatically to the grid. You turn off the search watts feature as well.
The parts customers will need for this kind of application from Magnum Energy is of course the MicroGT-500. It comes with, and it should be purchased with to operate exceptionally, the MagWeb-GT. This is an energy communication unit that provides module level performance monitoring from every micro inverter on the roof, and it also provides you a picture in the dashboard of the Magnum battery based inverter charger and its parameters, state of charge of the battery bank, etc. Everything is there on 1 dashboard.
You’ll also need the Mini Magnum Panel and breaker enclosure, the advanced remote control, and a battery monitor kit is strongly suggested. This is the fuel gauge to your battery bank. The shunt is included in the Mini Magnum Panel, so the system complete is about $3,800 MSRP.
The other parts you would source are PV modules and racking, of course, a junction box, AC conductors that run outside our enclosure, an essential loads panel, DC cables and batteries, of course, and a certified installer and electrician is highly recommended. This is not a do-it-yourself application. This is a little complicated.
The MS-PAE inverter charger, the battery based inverter charger, has an autoformer built in. So from 1 box you get 120/240 split phase output always. We can stack these up to 4 times to have 17.6 kilowatts of power continuously. In this first phase in release of the MicroGT, we’re using 1 PAE inverter for the solution. Next phase we will be able to expand the size of the backup solution up to 15 kilowatts. Initially, the first phase will be up to a 4 kilowatt backup system.
This is the Magnum Mini Panel with the Magnum PAE inverter installed on top, remote control in the center, with your bypass 30-amp dot bypass breaker, DC disconnect, and additional space for other load breakers. That panel there retails for about $3,800-$3,900. The back plate is assembled onto the wall first with 16-inch centers, and bolts right onto your studs. All the bolt locations are pemnuts, so once you start the bolts, you can simply slide on the keyholed enclosure that slips right on to the back plate. You tighten down these bolts, and then you’re ready to set the 60-pound inverter on top One person can put this together very simply in this fashion. You would install now the DC cables, the AC and DC cables to and from the inverter charger.
The DC side as bus bars, so they simply slide onto the DC terminals and they use flange nuts to tighten down there. But all the wires are pre-cut in strips for you, and the instructions are excellent. Our manuals are, I think, the best written technical manuals in the business.
Four, finally, install the hood on top to prevent anything from falling into the inverter. Install the remote. You can install it away from this enclosure, or right on the enclosure. It has a 50-foot connection cable. You mount the front cover, and you stand back and admire your great work. Your system gear, your balance of system, the battery based portion of it, is ready to go.
I’d like to talk a little bit more technical about the line diagram here. We have in this line diagram the micro inverters, 4 of them in this example, connecting to an essential loads panel. It’s important to understand, the Magnum PAE inverter charger, the battery based inverter charger, has an internal transfer switch, AC transfer switch. In normal conditions, it is closed, and current is flowing right through it to the central loads panel from the main. If there’s excess harvest from the PV array, it flows backward to our inverter, and back onto the main, and essentially net metered to the grid. The batteries are kept at full state of charge. There’s very little efficiency lost, because we’re not converting. Only once at the panel it’s converted from the micro inverters to your essential loads.
The efficiency rating of this system is approximately 95%. If the batteries need any kind of charge, it’ll be a trickle charge in this kind of condition. Remember, this is a backup situation. Your battery bank doesn’t have to be ginormous. This is not an off-grid application where every load is going to count, and every amp hour is very important. Here you can have between a 200 and 400 amp power battery capacity depending on the loads in that essential load panel, and the duration of the power outages. That’s what we’re attempting to do here, is provide power any time the grid goes down.
You can also, what’s unique here with this new Magnum MicroGT, is install the system without the Magnum battery based inverter, if it’s not within your budget. You can prepare to add a Magnum PAE Series inverter in the future in this kind of installation. What I advise doing, however, is if you’re going to get the solar panels and the micro inverters on the roof, or into your backyard, if it’s a ground mount, that you take out the essential loads from the main AC panel and put them in essential loads panel. This way, it’s much easier when you add the PAE system, the battery based inverter, it fits right in between the AC main panel and the sub panel.
I mention it has a Mag Web GT. This is an energy communication unit. We’ve partnered with the second-largest manufacturer of micro inverters on the planet, and that is AP Systems. They’ve got a great reputation and a great product, and they are working with us very closely to optimize this system. We have, in effect, a proprietary dashboard for Magnum that provides all the information that the Magnum control board has stored in real time. It also gives you the module level electronics performance and monitoring of every micro inverter on the rooftop. It is WiFi accessible, and the second phase will be loaded up to the cloud, so you can monitor your system from anywhere with any device anywhere.
To summarize, this system is safe. It meets all the NEC requirements out of the box. It protects the first responders, firefighters, and so forth, and homeowners alike. It’s economical, among the lowest cost per watt offerings for sustainable energy today. It’s simple to install, 2 PV modules per inverter, no truck cable. It daisy chains together. There’s no diversion controller required, or load bank required for the diversion. The MicroGT is optimized to taper the charge using frequent shift from our PAE inverter charger.
Module level performance are among the most efficient in shading and cloud cover scenarios. If you have shading on 1 module, or partially covered with cloud, the entire string is not affected, as you would have with string inverter applications. You can purchase this as storage ready and combine the MS-PAE platform to back up later if this is not in your current budget. I feel we have among the best and finest aftermarket customer support and warranty in the industry. Speaking of which, the MicroGT-500 will have a 25-year warranty. The Magnum system, the battery based components, the PAE with the Magnum panel has a 5-year warranty attached to it. We give you uncompromised protection, support, with American made product in the Magnum PAE system. Our great partner, AP Systems have provided for us an optimized MicroGT for Magnum energy.
Thank you so much for listening. At this time I will open up for questions. Thank you, Kathie.
Kathie:
All right. Awesome. Thank you so much, Alan. Great presentation. I’m just pulling up the questions here now. We have lots coming in. We’ll go to the first 1 here. All right. Coming in quickly here. All right. Okay. Sorry, there’s a lot of them coming in here. All right.
Does your micro inverter work with other hybrid storage inverters on the market, like AC coupled, or is this set to only work with your Magnum Series hybrid inverters.
Alan:
That’s a good question. It is going to work with virtually any it can connect to. It is possible to connect if it’s referencing any other inverter charger’s output. However, the MicroGT is going to be optimized to work only with Magnum energy inverter chargers at this time. I would suggest that a person who’s interested in a different system, or a different inverter charger he has connected, or she, that they contact AP Systems. They have solutions in their CY500, which is a similar product. Ours is optimized for our use, for our network. It will work in other systems. But the ideal combination here is having the Magnum PAE connected with the MicroGT-500. I don’t know if that answers the question.
Kathie:
Got it. Thanks. Yeah, Thank you very much. Someone else is asking, “Do the balance of system components that you mentioned in your presentation communicate using Sunspec communication protocol?”
Alan:
Can you elaborate please? Are you talking about the ECU or the Mag Web GT, the communication unit? It’s very similar–
Kathie:
Perhaps so. They didn’t specify.
Alan:
Right. With micro inverters you module level performance monitoring. This communication unit is constantly looking at the array, and providing this information on a user interface. It is accessible in your home through local WiFi. This is the first phase. In the second phase, we’re going to push it up to the cloud, so it can be accessed anywhere in the world with any device. Within your home you can access the performance monitoring of this system initially. Later we’ll be upgrading and installing the firmware via the internet to optimize them, these communication units, the Mag Web GT, to enable anywhere in the world monitoring. It provides all the information there in real time on the Magnum PAE performance, including state of charge, what model the inverter is, what status it’s in, if it’s inverting or charging. It’ll give you the state of charge of the battery bank. There’s a battery monitor kit installed. It provides all of that critical information on 1 dashboard for you, including the micro inverters on the roof.
Kathie:
Excellent. Someone else was wondering how long the system will be down when it goes from grid tied to battery backup, or is it instantaneous?
Alan:
That’s a good question. IEEE standards call for, require, very tight frequency and voltage levels. It’s required to shut down if grid power is lost. The MicroGT will shut down when it loses that reference. However, the Magnum PAE inverter within 16 and 20 milliseconds will start inverting and powering that essential loads panel. You essential loads may not notice any drop off of the grid, but the micro inverter will likely drop out, unless it is a very fast transfer. Sometimes they do stay connected. But it’s there in the central loads panel within 5 minutes that the micro inverter will reconnected and repower the system. You might be down for 5 minutes maximum when the event occurs. If you shut off the main AC supply, you can test and see how the system works after your install and conditioning. But it will be required to shut down as IEEE standards require, and then reconnect after that 5-minute shut down.
Kathie:
Great. What about–
Alan:
Now, I mentioned–
Kathie:
Go ahead.
Alan:
I was going to point out that the system today, today’s system with PAE’s, our battery based inverters, require that you set frequent shift in the remote control as a fail safe feature, to prevent over-charging of the battery. With this MicroGT inverter, we don’t need to have diversion loads, but you still have to enable frequent shift in the same way. But our frequency shift algorithm is a little different. I don’t want to give away our secret sauce here, but we don’t’ do it as the traditional way. The new PAE inverter control board tapers down the PV source output from the MicroGT in stages, in 4 stages. That said, you have better regulation of the battery bank. It’s not an abrupt on/off of the system, so it’s less taxing on the system and will provide a longer life of the equipment.
I also pointed out that the maximum size of the array in the first phase of this launch is 4 kilowatts. That’s nameplate. Of course, these micro inverters are 500 watts output each. Two modules are connected to each inverter. You can have 4 and up to 8, or two strings of 4 in series micro inverters to provide that 4 kilowatts of array. If the array is larger than 4 kilowatts, then just land the 4 kilowatts in the essential loads panel and the balance of the array can go straight to the main panel. Now in the event of a utility outage, you will lose the balance that goes to the AC main, but at least you will have a full 4 kilowatts of power to the essential loads panel.
By the way, we’ve looked at the numbers. The incidence of outage in most residences don’t require much more than 4 kilowatts of backup power for their essential loads. We’re addressing, I think a very large market initially, and we’re going to be able to expand up to 15 kilowatts of backup power with these systems in the second phase. With that greater array size hooked up to 4 Magnum PAE, you can have literally a micro grid situation with outbuildings.
Thanks, Kathie.
Kathie:
Thank you, Alan. Very good explanation.
Someone else is asking if the system is available, or the solution is available for 3-phase projects.
Alan:
Good question. No. Magnum PAE inverters currently are not to be used in 3-phase applications. That is something in our next generation product that we are developing. But the short answer is no. However, the AP Systems YC500, this inverter is optimized to work with 2OA 3-phase. But we will be utilizing this. Obviously with our PAE we’re not going to advise applying 3-phase connections to this system because of our battery based inverter is not able to handle that.
Kathie:
When will the MicroGT go to market and be available?
Alan:
Thanks for asking that. I thought I missed something. Yes, we are launching the MicroGT inverter this summer. Our goal is to have it launch before InterSolar. So we’re looking at the June/July time frame for the launch of the MicroGT. Right now we’re working very hard with the engineers at AP Systems to finalize the firmware and the communication unit to make sure it’s trouble-free and working just right. The dashboard that I showed you in the last slide will be much different. It’ll be more comprehensive, and it will look more like a Magnum Mag Web application. It will be optimized and improved before launch. But this is happening right now, as we speak. We are working hard to get this MicroGT on the market, to distribution, by the June time frame.
Thank you.
Kathie:
Wonderful. Sorry, my phone blanks out once in a while there, so I have to open it again to get to un-mute it. What is the maximum PV wattage recommended for the MicroGT?
Alan:
It has a 500 watt continuous output, but you can hook up the new 72 cell modules today that are north of 250 watts. It has a maximum output, peak output of 600 watts. But AP Systems is not sitting on their laurels. They’re developing new products and next generation micro inverters that of course will address the much larger modules that are coming down the pike.
But as far as questions relating to what’s the maximum power. You can build very large systems with micro inverters. But where is the cutoff point? We’re addressing the residential market. We’re going to be looking at between 2 and 15 kilowatt systems that are backed up with Magnum battery based PAE inverters. That is our focus. We have been focused on battery based power conversion devices since our founding, and we’ll continue to do so. Optimizing this solution and having a solution quickly, with a reputable and reliable partner, made a lot of sense to us.
Kathie:
Excellent. We have time for a few more questions here. Someone was wondering, if an installation has an odd number of panels, can 1 module be hooked up to the twin inverter, it says here?
Alan:
Yes. Yes. They have end caps and terminators and so forth. You can have an odd number. I understand you have to substantiate this, but you can even mix and match the panels. It is unique with micro inverters. There are a lot of great benefits to using a micro inverter. I wouldn’t use it in a utility scale application, but for homeowners and smaller applications, small commercial, they make a lot of sense to me, as they’re very flexible. They’re a NEMA 6 rated container. They’re virtually submersible for a period of time. There’s less components on the roof when you’re having 2 modules hooked up to 1 inverter. You have the module level performance monitoring, which provides you precise location of any faults in the system, and easy to rectify and fix.
By the way, we have an excellent technical support staff here at Magnum answering the phones 8:00 to 5:00 Monday through Friday. We will take the calls with this product as it’s launched and provide the support you need.
Kathie:
Great. Someone else was wondering, is the MicroGT covered under the same 5-year warranty as the [crosstalk 00:40:30], and if not, what type of warranty does it have, and does the warranty change if MicroGT isn’t connected to the inverter and other systems?
Alan:
Those are great questions. Yes. Well, the Magnum component, the Magnum battery based component, has a 5-year warranty for all parts if it’s installed on the Mini Magnum Panel. The breaker enclosure I showed you, that retails for roughly $3,900, that system comes with a back plate, the breaker enclosure, the inverter charger, the hood and the remote, and the battery monitor kit. Now you can order these parts separately, but there are just 5 parts. But together it is a 5-year warranty. The MicroGT, and Sensata, our parent company, provides for a reserve, for any warranties. Of course, with their resources we’re able to offer a substantial warranty on the MicroGT of 25 years. You’ve got many years of protection, unlike a string inverter. The Magnum battery based side of the system is a 5-year warranty.
Kathie:
Thank you for the–
Alan:
Also to address, sorry, Kathie. I didn’t address the second part of that question. Yes, you can install the MicroGT without the Magnum PAE battery based inverter. That can be done, if it’s not in the budget, later. With that instance, it’s the same. We will provide the same warranty support of 25 years on the micro inverter.
Kathie:
[inaudible 00:42:26] Sorry.
Alan:
Kathie, that part number is MicroGT-500.
Kathie:
If a customer wants to install a system in stages [inaudible 00:42:37] then a unit backup, how does the cost of the MicroGT setup compare with other micro inverters on the market?
Alan:
That’s great. Well, I mentioned it’s among the lowest cost per watt solutions. We’ve crunched the numbers. We decided to partner and go this way because it made economical sense, not only technically, but just made a lot of sense on cost. Reviewing the competition and looking at the MSRP, the cost per watt is, in our analysis, the lowest out there so far. The cost per inverter, while not official yet, the MSRP will be just north of $500 each MicroGT. Remember now, it’s a dual NPPT controller inverter, so it has 2 panels connected to it, as you know.
Kathie:
Okay, I think we have time for 2 more here. Someone is wondering, you’re doing the conversion with a DC to AC and AC to DC. How does that affect the efficiency?
Alan:
As I pointed out, it is more efficient in this kind of solution, because what’s happening in normal conditions, you have the high efficiency of a string or micro inverter, which is typically north of 95% passing through, straight through our battery based inverter to the main panel. If there’s a trickle charge needed for the battery during the harvest, yeah, you’ve lost a little efficiency. There’s a little bit of a current going back to the battery to keep them full. Once that stage is complete, then again you’re at a very high efficient level. So there isn’t conversion except at the roof from the panel in the micro inverter. It comes off the roof at low voltage AC. There’s grater safety here, meeting all the requirements and shut down, rapid shut down and arc fault. It’s a safer solution and more efficient in that we’re not converting from a DC controller back to AC and then to DC again. It’s just 1 conversion at the rooftop right at the micro inverter, and that’s 95% efficiency.
Thank you.
Kathie:
All right. I think that’s all the questions we have time for. I know there’s more. If we didn’t get to your question, or you have additional ones, you can feel free to contact Alan on your own. This webinar will be emailed to all registrants, and a few people have asked that, so you’ll be able to view it again at your convenience.
Alan, thank you again for the great information, and to everyone in that audience. We do invite you to join us for more Solar Power World webinars. We have quite a few coming up, including we have Four Strategies Solar Installers Can Use to Reduce Box Costs coming up on April 28th, next week; Making Solar More Accessible Through Innovative Scrutinize on May 10th; and Best Practices for Managing Commercial and Industrial Rooftops and Solar on May 12. Be sure and register for those, and I’ll meet you back here.
Thank you so much, again, Alan.
Alan:
Yeah, thank you Solar Power World, Kathie, and my audience. Thanks for listening. I appreciate it. Hope to see you next time. Take care.
Kathie:
All right, thanks, everyone.