Tesla Powerwall 2


For more than a year now we've been working on a 300sq ft prototype tinyhouse for off-grid living.  This is designed from the ground up to be 100% electric and 100% off-grid.  This includes heating, air conditioning, well pump, hot water heating, kitchen, lighting and general electrical needs.  It anticipates using cellular internet, a laptop, and a large screen tv with gaming system.  No propane or wood burning or pellet stove is needed as heat/ac is provided via a high efficency mini-split heat pump system.  The idea is to have zero carbon footprint but live a fully modern lifestyle.

This is designed to be viable in the Arizona desert or the Pennsylvania woods or anywhere in between.


The reason we've doing this is because we have had a large number of customers ask for a solar system that can provide long term backup power if the grid fails or want to operate fully off-grid.  We've experimented with a number of the traditional off-grid manufacturers equipment and batteries and have not found anything simple enough for a homeower to install or cost effective enough to recommend.

The advanced capabilities of the Tesla Powerwall, combined with it's large 13.5 kwk capacity and it's full 10 yr warranty is a game changer and points to where this marker will go in the future. 

What is the Powerwall?

Tesla recently introduced the Powerwall 2.  This AC battery / inverter system allows you to store excess solar power generated during the day to use at night or to meet your needs when your solar system isn't producing as much power as your house is demanding. It connects to your main circuit panel using a simple 30amp split phase breaker and is not directly connected to the solar panels.  It connects in exactly the same way our solar kits connect to your house.

This system can store 13.5kwh of electricity which is enough to run a small house, including heating and AC using a high efficency mini-split.  If this is not enough you can install multiple Powerwalls of 13.5kw each and they work together.

What is can do for you


It can store power and then provide it when needed for people who want to optimize their solar but where net metering is not supported or new Net Metering 2.0 is being implemented.  Some parts of the US have reached a point where there is so much solar installed that it exceeds the utility needs at peak times.  Some of the Hawaiian Islands are an example and California is approaching that point.  So utilities are either not providing full net metering credits or not allowing connection of new solar systems unless that have a battery storage system to absorb the excess generation.

Backup power

While doing the above it can also provide indefinite backup power, recharging the lithium ion batteries in it from your solar panels.  The fact is that the Powerwall can be cost competative with whole house backup generators and are maintenance free with a 10 yr warranty.  It also means you don't need to worry about running out of fuel in the case of a long power outage.  In the future the Powerwall will also be able to be recharged with a portable generator if needed.

Off-Grid living

It can also provide long term power in a fully off-grid configuration.  Conceptually this works the same as when in Backup Power mode but essentially forever.  This isn't "officially" supported by Tesla right now but the unit contains all the hardware to do this currently and it is their stated goal.

We think this is where the Powerwall really shines.  We have designed out micro-inverter systems to be fully compatible and cooperative with the Powerwall 2 so that you are future proof should you decide to go this way now or in the future.

Our customers have been asking for this capability for 6 years and we can finally provide a cost effective and maintenance free solution that provides meaningful levels of power at a reasonable price. 

Buying it

We cannot sell this to you!  However, we believe in it's superiority to all other Off-Grid systems to such a degree that we're sending you to Tesla to buy their Powerwall.  The alternative would be to sell you an inferior product and we're not interested in doing that.

You can only buy the Powerwall 2 directly from Tesla through this web site:  Tesla Powerwall Web Site


The cost of a Powerwall 2 is $5500.  There is an additional cost of about $1500 for additional equipment needed and professional installation by Tesla.  That brings the final cost to about $7000 but it will vary some depending on Tesla's analysis of your house and what will be required for the installation.

Cost Effectiveness

Gaining the capability to operate independently in a power outage or long term off-grid means you need a sophisticated inverter, power management system and large scale battery storage.  Neither of these things are free nor cheap.  However, if you want this capability then it can most cost effectively be provided with the Tesla Powerwall.  

As an example, we have a 15kw Generac whole house generator with automatic transfer switch for our office.  The cost of this unit from Lowes is currently $3800.  Installation of the unit involved installation of the automatic transfer switch in line with the utility power and then running of a natural gas line and wiring the generator into the transfer switch.  Installation of the electrical components and gas would cost about $4500.  This is NOT a DIY install.  We did do it ourselves as we have the necessary knowledge and frankly it would have been appealing to pay someone to do it because it is difficult, complex and potentially dangerious.

So our installed cost is $8300 for the generator.  Annually the generator needs turnups, filters, oil changes, battery changes and other maintenance.  We have had to replace the starting battery several times and had a number of problems with the battery charge maintainer and transfer switch issues.  The projected lifespan of the generator is 10 yrs before it needs an overhaul or replacement. 

Out generator can supply 12kwh reliabily but we don't need that much power.  We needed to size it large enough to provide for maximum demand and have excess capacity to provide clean power for electronics. 

The Powerwall 2 at $7000 would meet our maximum power needs and with intelligent use it can meet all our emergency power needs.  If we wanted to go off-grid we would probably install a second Powerwall to provide 2 x 13.5 = 27 kwh of available power.  The second Powerwall is simpler to install so it would only cost $5500 for the second or third one.


The Powerwall 2 has a full 10 yr warranty. This means you can charge it 100% every single day and drain it completely overnight and it will still provide the rated power for the full 10 years.  Tesla is able to offer this warranty because they put extra battery capacity in the unit so it is never really 100% changed or 100% discharged but still provides 13.5kw of power.  The extensive engineering experience they gained with cars is being applied to stationairy storage.

If I'm buying the Powerwall from Tesla why not buy their solar system too?

Tesla solar systems are very very expensive.

Our systems use the highest quality tier-1 components but are less than half the price because we make it simple enough for you to install. Alternatively you can hire an electrical or roofing contractor to install our simple system at a reasonable price.  Our plug and play systems install in a snap, watch our videos!