Tesla published the Powerwall home battery user manual online. Here’s what we found.

by Anna Gretz
March 30, 2016
Home Battery

We searched every page of the manual to bring you the most interesting and surprising elements of the Powerwall.

Tesla’s Powerwall home battery is finally being installed in actual homes around the globe, bringing a new era of mainstream residential energy storage to life. With Tesla’s Powerwall solar battery, people can power their home with the free, clean energy provided every day by the sun. To support this new (growing) group of Powerwall owners, Tesla published the Powerwall home battery manual online. We searched every page of the manual to bring you the most interesting and surprising elements of the Powerwall that previously, only battery owners could know. Here’s what we found.

Hold on, what is the Powerwall again?

Before we get into the good stuff, let’s highlight the major parts of Tesla’s new home battery, the Powerwall, and get a quick look at the new upcoming model, the Powerwall 2.0:

The Tesla Powerwall is a lithium-ion home battery that charges using electricity generated from solar panels. Lithium, the lightest of all metals, has the greatest electrochemical potential. This means that lithium provides the highest energy density per weight, far lighter and more efficient than the popular lead acid battery. The growth of lithium-ion technology has brought along with it many advantages. In comparison to batteries that have been popularly used in the past, lithium-ion batteries are cleaner, live longer, recycle better, and require much less maintenance.

Home batteries, like Tesla’s Powerwall, are the simplest and best way to solve the solar energy glitch -- the fact that solar is an intermittent energy source, since the sun is not always shining. Experts from the fields of science, engineering, technology, and sustainability are all coming to the same conclusion: energy storage in the form of home batteries are the best way to launch residential use of renewable energy into the future.

Households with rooftop solar are taking their energy systems to the next level with home batteries. They’ll have to if they want to protect the value of the energy generated from their solar panels, according to Tesla CEO Elon Musk.

Tesla’s home battery model, the Powerwall, charges using electricity generated from solar panels. According to Musk, every home with solar panels needs a home battery.

Tesla’s Powerwall has gotten a lot of attention for sleek design, but the real headliner is its price. The 7 kWh daily cycle battery is available to installers for a mere $3K ($3.5K for the 10 kWh back-up model). The 220 lb, indoor/outdoor battery comes with a 10-year-warranty, so battery owners know that they not only have plenty of energy at night when the sun goes down, but reliable emergency back-up power as well.

What’s New About the Powerwall 2.0

At an event in Paris, Elon Musk announced that the new Powerwall (or Powerwall 2.0) will be coming out around July or August of this year, and promised a step forward in the home battery’s capabilities. Musk didn’t give many details about the new technology Powerwall 2.0 will possess, but we’ll tell you everything we know:

Though the current Powerwall has an impressive lifecycle, Elon Musk has hinted that the new Powerwall’s lifecycle will be even longer.

Here’s a little background on lithium-ion battery lifecycles: Lithium-ion has a significantly higher cycle life than lead acid in deep discharge applications. This means that lithium-ion batteries can support a higher number of complete charge/discharge cycles before their capacity falls under 80%. Recent data shows that a lead acid battery would have to be 2.5 times larger in capacity than a lithium-ion battery to get comparable cycle life.

The difference in cycle life is even greater in extreme climates. In warm climates where the temperature hovers around 90 degrees Fahrenheit, the difference in cycle life between lithium-ion batteries and lead acid models is huge. In these extreme temperatures, it takes less than 1000 charge/discharge cycles for lead acid batteries to drop below 80% in retention, while lithium-ion batteries wouldn’t see that much of a drop until at least 2000 cycles. This huge jump in battery lifetime is an exciting development for consumers who don’t want to worry about their battery capacity dropping when they need power the most.

The exact details of Elon Musk’s Powerwall 2.0’s lifecycle have not been released yet, but we’re excited to see some new advances in lithium-ion battery technology. And though all the details of Powerwall 2.0 haven’t been released, we do have access to all the exciting highlights of the first Powerwall. Let’s dig in.

The Powerwall doesn’t just store energy from solar panels… it can get power from the grid, too.

The major goal of Tesla’s Powerwall is to store energy, and make it available whenever you need it, no matter where you’re getting your energy from. The manual states, “Powerwall enables the storage of energy from solar panels during the day, or from the grid when energy rates are low.” The latter is called time-of-use shifting, or the money-saving technique of storing energy from the grid when rates are at their lowest, so you can avoid paying fees or higher rates during peak-demand hours when people in your area need electricity the most. This alone can lower your electricity bill considerably, especially now that some states (like California) are hiking electricity rates for grid-connected customers.

From what we’ve seen so far, it doesn’t look like Powerwall owners are opting to use their home batteries with a grid-only power connection. In fact, new Powerwall customers are having their home solar systems upgraded, or installed completely from scratch. Solar-connected customers do seem to be set up for the greatest benefit from Tesla’s home energy storage system, as they’ll have the opportunity to rely less on an unreliable grid.

The Powerwall operating temperature ranges from -4 to 122 degrees Fahrenheit.

All things considered, this is a really impressive range. The fact that the Powerwall can continue to operate in temperatures so far below freezing is surprising. But if Elon Musk is looking to populate the world with Powerwalls and use them to provide energy to… well… everyone (as he mentioned in his initial unveiling of the product), there are going to be some areas who are excluded from the whole “indoor/outdoor” description. Northerners, if you want the Powerwall to give you effective back-up power during the next Snowpocalypse, you’re going to want to keep your Tesla treasure inside.

(Note: The manual does state that extreme temperatures within the operating range can affect the performance of the battery, as expected.)

The maximum altitude for Powerwall operation is 9845 feet. Sorry, Brian Head, Utah.

There are admittedly few people, comparatively, who live at an altitude high enough to exclude them from having an operating Powerwall home battery… but there are some. There are at least 10 cities (each with more than 100K occupants) that are located above the Tesla Powerwall altitude ceiling. This doesn’t include smaller towns or less-populated areas higher than the 9,845 foot altitude mark. That means that over a million people are out of luck when it comes to Powerwall installation in their area.

It might not seem very significant compared to the world’s population, but in Elon Musk’s initial Powerwall pitch, he illustrated how many solar panels and batteries it would take for the world to run on battery power. When it comes to Brian Head, Utah, Musk will have to get creative… or better yet, keep developing the technology.

All of the Powerwall packaging material is completely recyclable.

This next point shouldn’t be surprising if you know anything about Tesla Motors. Sustainability and creativity have always been a part of Elon Musk’s company, down to the very last detail. The manual states that every component of the Tesla Powerwall’s packaging can be recycled. The guide tells buyers to re-pack the packing materials into the shipping box in reverse order, and return the box to a Tesla reseller. You can also simply recycle the materials yourself.

Did we mention that the Powerwall comes packaged in an awesome-looking wooden pallet? That might be our favorite part.

Click Here to check out the Powerwall manual for yourself (and get a glimpse of that cool wooden pallet). Swell is proud to be one of the first Powerwall providers, and we can’t get enough of details of Tesla’s Powerwall. To check out Swell’s other batteries, Click Here, and check back for more energy storage news.