In this episode, John Maher interviews Brian Sadler, Vice President of Solaris Renewables, about the Tesla Powerwall Expansion Module. They discuss how the expansion module works as a plug-and-play solution with the Powerwall 3, adding 13.5 kWh of additional energy storage per module. Brian explains its compatibility, installation process, and cost-saving opportunities, including tax credits and virtual power plant programs. He also highlights design considerations for expansion and the comprehensive 10-year warranty provided by Tesla. The episode provides homeowners with valuable insights into maximizing energy storage and resiliency with the Tesla Powerwall system.
John Maher: Hi, I’m John Maher, and I’m here today with Brian Sadler, vice president at Solaris Renewables, a solar company in Massachusetts providing premium solar and storage technologies with exceptional customer service and designing, installing, and servicing solar systems in Massachusetts, Southern New Hampshire, and Maine. Today, our topic is the Tesla Powerwall Expansion Module. Welcome, Brian.
Brian Sadler: Hi, John. Thanks for having me on today.
About the Tesla Powerwall Expansion Module
Maher: Sure. Yeah. Brian, tell us a little bit about the Powerwall Expansion Module, what that is, and is that compatible with my existing Powerwall setup?
Sadler: Absolutely. The expansion module is technically a Powerwall 3 expansion module. I always compare it to your cell phone. You get a cell phone and has great battery life and it lasts for a day or two, and then, over two years from now, you charge it up and then it’s down 70% or 50% really quickly, and you might get a case for it that also has a battery in it and you attach it and now it gives you expanded capacity for your battery life.
The expansion module is very similar, so the Powerwall 3 has the initial unit with the full system, which requires the automatic transfer switch, all the controls, and that’s the connection to your service, for your home, your electrical service, and how that interacts with your home and the grid and potentially your solar system or other peripheral devices in your energy system. Excuse me.
Whereas the expansion module is just giving you extra capacity. That expansion module has to be with a Powerwall 3 product that can’t be used with the former Powerwall 2 or with the Powerwall 1, and it plugs right into the Powerwall 3 through a very simple plug-and-play daisy chain wire that now gives you additional capacity without all the additional installation and without using more breaker space.
It basically piggybacks off the existing system, so it’s able to leverage the controls and the inverter and all of the setup of your initial Powerwall 3 system just to give you more capacity. It’s a smart way to go about adding additional capacity to a storage system without having to get the full units or undergo maybe additional electrical work or other roadblocks that make it harder to install.
How Big is the Powerwall Expansion?
Maher: Is it roughly the same size as the Powerwall 3 or is it smaller?
Sadler: It looks identically from the front. It is slightly narrower, and it’s probably just due to… They could make the case and save a little bit on materials to get the same amount of batteries in it, but not needing to accommodate the inverters. Essentially, if you looked at them both from the front, they look identical, you couldn’t tell the difference, and from the side, if they were both sitting there, you might notice that one is slightly narrower is all, but they essentially look the same. Literally, they could be stacked on the ground or hung on the wall and stacked, or they could be side-by-side next to each other as well.
Maher: All right, so you have some different options as far as installation goes and how you set those up?
Sadler: Absolutely.
How Much Additional Capacity Does the Powerwall Expansion Provide?
Maher: Okay. What additional storage capacity does the expansion module provide?
Sadler: It provides the same capacity as the Powerwall 3, which is 13.5 kilowatt-hours, so it gives you that additional… It doubles the capacity. You can have three expansion modules per Powerwall 3 full system, full battery. It gives you a lot of, again, additional capacity, functionality, and flexibility for installation. It depends on every homeowner’s need and electrical setup on how we would recommend.
Also, if you’re bringing solar to plug into the Powerwall 3, how much solar you have. Those are all parts of the equation for us to make a recommendation on what the energy storage system would be for a homeowner. Some folks look at it and say, “I just want one,” and we say, “You can do that, but these are the limitations.” Then an expansion module might open up that functionality or they might need another full Powerwall 3 if they have a lot of solar or if they have a lot of electrical or unload need at their home.
We might say, “You can do one, but you’re not going to have all of these things. If you did two, you’re going to have all of these things.” Then, on top of that, you can add DC expansion modules on top of that as well.
How to Determine Electrical Capacity Needs
Maher: When a customer is getting the Powerwall 3 installed initially, do you look at their power usage in the event of a power outage? What appliances and lighting and electrical systems, whatever, they are likely to need or want during an outage? That gives you an idea of what capacity they need, so you might recommend, “Yeah, we think that you should install the Powerwall 3 and an expansion module at the same time,” or do you recommend that people just start with the regular Powerwall 3, see whether or not it provides them enough power, and then they can always add the expansion module later?
Sadler: Really, really great question, and I probably should have touched on this, so thank you for bringing it up. There’s two things. There’s power, which is the instantaneous need, and that’s going to be, how many appliances and how much of your home can be supported by a Powerwall 3? Then there’s capacity or longevity, how long is that going to last? That’s where the expansion modules really come in. It’s, “How long can that last?” Given what you’re doing and how long you want to do it for, those are the limitations. We have to design and install a battery system regardless of what it is and how many pieces and parts, and how big they or little they want to go. It has to be designed and installed as if there’s a power outage and there’s no solar or anything to charge it.
It’s like a fail-safe, so whenever we install a battery system, it has to be thought of the capacity and the power of that unit alone. We do absolutely need to take a really close look at customer’s main service panel, any sub panels, depending on the size of the service, and there’s a basic load calculation that we need to do based on the square footage of the house, and that’s the baseline.
Then we need to look at, really, the individual loads. For instance, a lot of folks that are electrifying across the board, that’s a big movement, and folks are putting in whole home heat pumps, they’re electrifying with your washing, drying, cooking, and domestic hot water heating. Then folks are getting EVs or plug-in EVs, and all those are resources that have a higher energy draw, electricity draw, so it has a higher power need and then depends on how long you want to use it for.
A lot of times, we need to take a close look at that and make decisions and say, “Okay, we need to remove… You can’t have your dryer and you can’t have air conditioning in an outage,” and these are common sense things as well, right? Then we want to make sure that folks have heat, they have a cooking surface, they have their fridge, they have their basic lights, outlets, WiFi.
Basically, that would give them most of their creature comforts as well. We look at those pieces and then we have to make decisions, and that’s when we make a recommendation like, “Hey, we can give you everything, it’s just not going to last very long, so you should add a expansion module,” or, “Hey, you can only have half your house, you need to have two Powerwall 3s with the full inverter, the full setup to get you everything that you need.”
That’s where those decisions are made. A lot of times, we can go with a Powerwall 3 with one battery and then you see how it goes, and then you want more capacity, we can add the expansion modules later on, because you need to have the full setup in order to get the expansion modules as it is, so you don’t have to get the expansion modules right away. In some cases, they know that they want that. You’re like, “Yeah, it’s going to last for one hour,” and they’re like, “Okay, well, that doesn’t work for me, so I’m going to add some capacity to that.” We absolutely take a close look at all of that and make recommendations.
What Determines the Capacity in the Powerwall System?
Maher: Right. Just to clarify, so the Powerwall 3 itself determines what the capacity… How many different things you can run at the same time, and then the additional expansion module just gives you more time with those devices.
Sadler: Exactly.
Maher: Yeah.
Sadler: They have a high… What’s it called? They have a high amperage threshold, the Powerwall 3s. It’s double what the previous generation of Powerwall had and what most battery systems do have, so it can support much higher loads, but then it comes down to time. Yeah, we can back up that heat pump system, but it’s only going to work for two hours, so you want to add capacity, which is where the expansion unit comes in and gives you more time with that as well.
How Much Does an Expansion Module Cost?
Maher: Right, okay. What’s the estimated cost of an expansion module including installation?
Sadler: We install them for $12,000, and that’s the same thing. That’s a fully turnkey solution that is site inspection, design, engineering. We pull all the permits through the utility application, provide a professional set of billing plans and a one-line diagram for the customer to approve all the commissioning support on the app. We set all that up on it for our customers and also manage the warranty and any service that they may need.
Again, it does qualify for the federal tax credit and it does give you the opportunity to opt into a virtual power plant or what we call here the connected solutions programs, which are available in Eversource and National Grid. These are incentives that pay you cash on an annual basis to help offset your investment of an energy storage system, or in this case, an expansion to your energy storage system. It gives you more time, which is part of the calculation for that incentive as well. You’re able to get more money and it’s paid annually for the next five years, and obviously, along, the tax credit helps offset your investment.
How Does a Tesla Powerwall Expansion Get Installed?
Maher: Okay. How does the installation process look with an expansion module, especially as compared to the original Powerwall that you’re installing? You said it’s fairly plug-and-play, where you connect it to the Powerwall 3, and then that just gives you that extra capacity.
Sadler: That’s what it says on paper, right? Anything with the cost, and we’ve learned over the years that installing these battery systems are expensive and a bit of a wild card with the new code, so we want to take that into consideration as well. In terms of the installation process, yeah, it should be plug-and-play, but if it wasn’t planned for on the original installation, which we knew right away we need to consider that, so if this customer is even thinking about expanding with expansion modules, we should provide a buffer if we need to include bollards or if we had to build a fire room or if it’s in the garage, the location. We need to make sure that we’re thinking of that on the first go-around that, if they did want to ever add it, that we can avoid the additional costs later to do so.
The installation, in theory, it’s plug-and-play. The idea is that we can come and… In reality, we need to remove the original Powerwall 3, put the expansion module against the wall or be the first stop.
Maher: Okay.
Sadler: Then the inverter version of the full Powerwall 3 needs to be on the outside, and that’s mostly for serviceability, because it has an inverter in it, whereas the expansion module is basically just battery capacity. There’s some design considerations we want to make sure we take care of upfront, so that we can mitigate any additional cost or problems with code on the backend when customers want to expand their system.
Is it Better to get the Expansion with the Powerwall 3?
Maher: Is it a little less expensive to get the expansion module put in at the same time as your Powerwall 3, or does it really not really matter and it would cost the same to add it on later?
Sadler: John, I’d say another great question. We actually do. We give the customers $1,000 credit with the expansion module if they do at the same time, because if we’re doing the full site inspection, design, engineering, all the applications, permitting, commissioning, setup, and app education, that whole piece, we’re doing it twice. Obviously, it costs us more money, which we’re going to pass on to some extent.
We try to mitigate that best we can, but it’s real money that we need to spend for additional time, efforts, staff time, truck rolls of vehicles driving around, things like that. We do give a credit back, so we discounted $1,000 if customers are doing at the same time, because it’s saving us time and money, which we want to make sure that we pass them through the customer as well.
Maher: Right, and you don’t have to end up taking that Powerwall off the wall, like you said, and putting the expansion module on and then putting the Powerwall back on. That’s a little less labor involved as well.
Sadler: Yep.
Does the Tesla Powerwall Expansion Module come with a Warranty?
Maher: Yeah. Does the expansion module come with the same warranty that the original Powerwall 3 does?
Sadler: It does. It has a 10-year warranty, it’s guaranteed to have 70% of its day-one capacity after 10 years. Then, as a premier-certified installer, we’re able to service the system for the customer and any parts that need to replace or if the entire unit need to be replaced, Tesla is going to pay us the labor, so that the homeowner needs not to pay for that. It’s a comprehensive warranty for that 10-year period with, I would say, a pretty remarkable high percentage threshold of usability after 10 years.
Information About Solaris Renewables
Maher: All right. Well, that’s really great information, Brian. Thanks again for talking to me today about the Tesla Powerwall Expansion Module.
Sadler: Thanks, John. Nice to be with you.
Maher: For more information, you can visit the Solaris Renewables’ website at solarisrenewables.com or call 781-270-6555.