SolPad: A Game Changer for Residential Solar?

SolPad integrates PV, battery, and inverter, dramatically lowering the cost of solar.

The National Renewable Energy Laboratory has established a goal of making residential solar cost less than $1.50 per watt, installed, by the year 2020. With current prices between $3 and $5 per watt right now, I’ve been thinking that NREL’s target would be unreachable, even with the dramatic decrease in the cost of PV panels. As the NREL report states, it’s the “soft” costs – design, installation, and permitting – that represent almost half of the price of a residential PV system, and those costs have not decreased like the hardware costs have. SunCulture Solar hopes to change that with its innovative patented all-in-one unit: the SolPadTM, a panel that integrates a PV panel, battery, charge controller, and flexgridTM inverter.

SolPad Modular All-in-One Unit

SolPad Modular All-in-One Unit

Plug and Play Solar, Storage, and Energy Management

SolPad comes in two flavors: SolPad Home (shown above), for permanent installations, and SolPad Mobile (pictured below), a portable solar power station. Both units include integrated batteries and a hybrid inverter that can work in stand-alone and grid-tied designs.

SolPad Mobile

SolPad Mobile

Modular Design to Reduce Installation Costs

Installation, permitting, inspection. and interconnection represent the bulk of the soft costs associated with residential and commercial PV systems. SolPads can be easily snapped together in rows and columns, making the installation simple and foolproof, which translates into quicker inspections and user-friendly permitting. There’s no wiring between modules – they snap together like Lego blocks.

Connectors Allow Modules to Form a Row

Connectors Allow Modules to Form a Row

Connecting Multiple Rows

Connecting Multiple Rows

After watching their promotional video, I realized that this isn’t simply a solar panel – it’s a complete energy management system for the home, comprising power generation, energy storage, grid-interactivity, emergency power, home automation, and control software. I was intrigued … and loaded with questions.

I contacted SunCulture Solar CEO and Chief Product Architect Christopher Estes and asked him some questions about the SolPads. Here’s the conversation:

Is the PV module a standard monocrystalline silicon?

No. We use high-efficiency monocrystalline silicon cells for both of our SolPad Home™ and SolPad Mobile™ products.

What are the power output and efficiency of one panel?

Just to clarify, SolPad™ is not a solar panel as solar panels do not store energy and control your home. SolPad is a totally new product category.

There are two categories of SolPad:

  • SolPad Home and SolPad Mobile

  • SolPad Home has 333 watts of Solar collection for charging the 1kWh onboard battery that powers its built-in 500 watt FlexGrid™ inverter.

SolPad Mobile (portable product) uses the same technology as SolPad Home. It has 70 watts of solar collection for charging the on-board 550 Wh battery that powers it’s built-in FlexGrid inverter. SolPad Mobile’s FlexGrid inverter can output 2000 watts peak (10 seconds) and 1000 watts continuous.


What kind of batteries does it have? What’s the capacity?

We use a lithium-sulfur hybrid chemistry battery cell right now. Eventually, we will be using solid-state cells from vendors that are ramping up to make solid state batteries available, such as Dyson. The capacity is 1 kWh for SolPad Home and 550 Wh for the SolPad Mobile. These batteries are very safe (non-flammable). Airlines are now switching to these for their long life and safety.

Does the flexgrid inverter’s anti-islanding feature comply with NEC requirements?  Is it a microinverter?

Yes, but it is not a microinverter. It is a totally new class of inverter. You cannot connect a battery to a micro-inverter. It will destroy it as micro-inverters use MPPT [maximum power point tracking] to pull the maximum current from the PV panel. Thus, a totally new class of inverter had to be developed, one that automatically works standalone (no utility), standalone AC microgrid, or utility grid connected, and that scales organically.

Our FlexGrid inverter has an incredibly fast anti-islanding disconnect time of 50 milliseconds.

How does it connect to the home – through the service panel or just plug into an outlet?

Connection to the home will depend on the service territory and country. Regardless of the jurisdiction in the U.S., SolPad Home panels can be wired into the service panel and comply with NEC codes. In addition, SolControl Breaker is a smart IoT circuit breaker that is inserted into your home’s electrical panel and communicates with the SolPad Home units. Once these breakers are installed into the electric panel, they allow water heaters, dishwashers, HVAC systems, or an entire room to be integrated into and controlled by the SolPad eco-system. 

SolPad Integrated System

SolPad Integrated System

SolPad portable and rooftop products comply with UL and NEC requirements. For 240 volt outlets with verified NEC compliant breakers, SolPad Home panels can, in certain areas of the world, also be connected that way with SolPad Connect Adapter.

If it connects through an outlet, then it’s only going to power half of the home (one side of the service panel). How do you assure that it powers the whole house?

In the case of plugging SolPad Mobile into an outlet, SolPad Mobile is not intended to power your entire home but rather offset the power consumptions of specific items that you choose to power only with solar from SolPad. For example; ceiling lights, TV, computer, coffee maker, using SolControl. In this case, it does not matter which phase you are connected to as long as it is “behind” the utility meter.

Sol Control IoT Outlet

Sol Control IoT Outlet

The video mentions Sol Control’s PLM (Power Line Modem) technology.  Does it use WiFi or other wireless communication for anything?

Yes, that is Power-Line Modem technology. Sol Control uses several communication technologies, including WiFi, PLM, and Bluetooth.

SolPad Mobile – What is the power rating (watts) and storage capacity (watt-hours)?

  • For each mobile SolPad product:

  • 70 watts power

  • Battery capacity is 550 watt hours capable, which can be fully discharged without damaging the battery

  • 2kW peak power, 1kW continuous

  • 25 lbs weight  

What’s the price per module?

We are currently finalizing the selection of our manufacturing partner and supplier vendors. Once that is finalized, we will announce our pricing. However, as noted in our press kit’s economic analysis based on a Department of Energy white paper, we estimate that the projected installed cost of a SolPad Home™ 5.3kWDC SolPad system that includes a total of 12.5kWh of storage capacity and 8.0kW of output power would retail at $19,442.69.  

As noted in our economic analysis, that installed cost is about half the price of other premium solar+battery systems on the market today.

SolPad Cost Comparison

SolPad Cost Comparison

Tom’s note: that’s $3.66 per PV watt, including battery storage and installation. (The NREL goal of $1.50/watt does not include battery storage.) Most PV systems cost $3 to $5 per watt installed, not including storage, so a typical 5 kW array would cost $15k to $25k . Adding a 12.5 kWh battery bank adds another $7k to $10k. In short, a $20k SolPad system is comparable to a $30k traditional system with equivalent power and storage.) 12.5 kWh of storage should keep an average house powered for six hours or more, depending on load.

How long is the warranty?

The warranty period for a SolPad, including its FlexGrid inverter, will not be determined until we have made a final selection of our non-SolPad component vendors and a manufacturer. However, we anticipate that the warranty for our FlexGrid inverter and the warranty for our photovoltaic panel and our power electronics will be 25 years. Depending on the final battery chemistry selected, we anticipate that our battery will be warrantied for 10 to 15 years.

Rolling It Out

SunCulture is currently selecting manufacturing partners and looking for investors. The company expects the first wave of SolPads to hit the market in the second half of 2017, beginning with pilot projects in California.

I don’t use the term “game changer” casually, but I have to say that if SunCulture can pull this off and produce a system at the price reported above, it could be the wildcard that gives rooftop solar a winning hand. With its integration of solar power, distributed storage, and control software, SolPad gives homeowners an energy management system that rivals those being adopted in the commercial sector. It’s exactly the type of off-the-shelf, plug-and-play design that could bring residential solar to grid parity.

As George Harrison sang, “Here comes the sun, and I say it’s all right.”

Images and video courtesy of SunCulture Solar


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Here’s more information, copied directly from the SolPad Home Factsheet:

SolPad Home Factsheet

SolPad Home™ is the ultimate sustainable energy solution for powering an entire home with clean solar power. It offers homeowners an unprecedented level of control over their electricity generation, energy storage and usage. SolPad Home includes 96 cells connected by diodes, generating 330 Watts of solar charging. It is truly the world’s first fully integrated solar energy solution created for the modern smart home and sustainably-minded global citizen.

SolPad Home combines solar and smart home components that traditionally have always been bought and installed separately. Due to this integration and elimination of parts, SolPad’s fully integrated product design approach reduces the total cost of installed solar + energy storage by up to 50% when compared to other existing product offerings.

SolPad ‘Solar Micro Storage’

SolPad ‘Solar Micro Storage’ is built-in battery storage at the panel level. This revolutionary storage configuration uses forthcoming solid state battery technology, which is the first time such technology has ever been designed into a solar panel device. Solid-state batteries are lightweight and inherently safer than standard Lithium-ion based batteries. They have broader operating temperatures and a longer life, and the solid-state low-voltage battery design is optimized for safe roof-top operation.

SolPad has two Solar Micro Storage options, a standard 500-watt hour, and an optional one kilowatt hour. The optional one kilowatt hour battery can be fully recharged from zero by the sun or grid in approximately three hours, while the 500-watt hour standard battery can be fully recharged in a mere hour and a half.

flexgrid™ Inverter Technology

The patented flexgrid™ inverter combines intelligent bi-directional power inverter technology with efficient MPPT tracking and communications built on top of the SolControl IoT (Internet of Things) energy management platform. The flexgrid inverter is designed to seamlessly integrate with built-in solid-state ‘solar micro-storage’ and this innovative combination allows SolPad to operate with electrically optimized power efficiency.

SolPad’s flexgrid inverter can automatically detect when to charge from the sun or charge from the local utility grid, adjusting for cloudy or rainy days, as well as changing local electricity rates. During the most expensive daytime hours, SolPad Home will switch to stored battery power, then switch back to grid power when rates are low. Flexgrid will also detect when there’s a power outage or blackout and safely disconnect itself from the grid. Once off the grid, SolPad automatically forms a personal solar micro-grid that will keep delivering power to specific lights and appliances during the day or in the dark. Flexgrid technology automatically senses power voltages between 110 and 240 volts and allows any SolPad to work out of the box without any configuration, anywhere in the world.

ConnectTM System

ConnectTM allows SolPads to snap together wirelessly without complicated cabling or wiring, allowing for faster and simpler installation and significantly decreased costs. The SolPad Home Connect system is the most innovative power delivery interface to get power from your roof into your home.

SolControl Breaker

SolControl Breaker is smart IoT circuit breaker that is inserted into your home’s electrical panel and communicates with SolPad. Once installed, it allows water heaters, dishwashers, HVAC systems, or entire room to be integrated into, and controlled by, the SolPad eco-system.


SolLink is the central communication hub for SolPad and other smart devices. SolLink monitors your SolPad and home’s daily energy activities, and process the data to automatically optimize your home’s energy usage, as well as give SolPad user’s full control over the home’s lighting and appliances through a smartphone app.


SolControl is a smart plug that communicates with SolPad. When a light, appliance, computer or any AC device is plugged into a SolControl plug, SolPad’s user-friendly iPhone app is able to manage and control the solar power delivery and energy usage of the plugged-in device, either automatically or manually.

SolControl Software App

SolControl’s home automation and energy management software allows you to monitor and control your connected appliances and SolPad devices, putting cost-saving control into a gamified and easy-to-use smart phone application. The engaging and interactive UI helps you become more aware of your energy consumption and helps conserve electricity by autonomously learning usage habits and intuitively providing suggestions to further optimize power consumption. Analyzing your energy usage alongside your local rate structure, SolControl’s software draws power from the SolPad’s storage system when utility rates are highest, maximizing utility bill savings. With SolControl, anyone can manage and control the distribution and delivery of their solar power to individual appliances, individual rooms, or to the entire home, which has never been done before.