A Deep Dive Into The Tesla Powerwall Warranty

The Tesla Powerwall is by far the most famous home battery on the market.  The major drawback is that they don’t come cheap.

Most people would probably expect such a well-known and well-reputed bit of kit to have an excellent warranty.  And as it happens, that’s a fairly accurate conclusion — at least relative to many other home battery warranties — and it should last most households a full 10 years. However, as always, there are some caveats.

In this article, I’ll deeply dive into the Tesla Powerwall warranty.  Below I’m going to…

  • Quickly review what the Powerwall can do.
  • Describe how the warranty can cover either an unlimited number of cycles OR 37,800 kilowatt-hours (kWh).
  • Explain why trying to stick to the unlimited cycles warranty condition is pointless for nearly all households.
  • Reveal how, instead of a repair or replacement, Tesla might just provide a (potentially tiny) refund.
  • Cover how the warranty will only last four years if the Powerwall isn’t registered and connected to the internet.
  • Give the good news: you are also protected by Australian Consumer Guarantees.
  • Give the bad news: Tesla has a record of being slow to meet their obligations under Australian consumer law.

What Is A Powerwall?

The Powerwall is an AC-coupled home battery with 13.5kWh of usable energy storage.  The “AC coupled” part means it works with any solar system, regardless of its inverter.  It can produce 5 kilowatts (kW) of continuous power and provide backup power with rapid changeover.

Here are some specifications taken straight from the Australian Tesla site:

Tesla Powerwall specifications

The last point is that the warranty lasts 10 years.  While that’s likely true for most households, it will depend on how it’s used.

They give its depth of discharge as 100%, but I’m 100% sure that’s not 100% true.  On the Powerwall datasheet, they give its total energy storage as 14kWh:

Powerwall capacity

With 13.5kWh of usable energy storage, it would have an actual depth of discharge of 96%.  But because you can apparently get a little more than 13.5kWh from a new Powerwall, it’s likely to be around 97%.

They also give its round trip efficiency as 90% (up from 88%).  This means for every 10kWh the Powerwall is charged with, it can provide 9kWh of useable stored energy.  That’s impressively high for an AC-coupled battery, but it’s only achieved at the beginning of its life.  I suggest using the old 88% figure to estimate lifetime round-trip efficiency.

Powerwall round trip efficiency

Warranty Length — 10 Years (Or Probably 10 Years)

There are two ways your Powerwall warranty can work, depending on how it’s used:

  1. If your Powerwall only stores energy from rooftop solar for later household or business use OR it’s used to store cheap off-peak grid electricity for use during peak times, then the warranty will last for 10 years.  The warranty says with these conditions, the Powerwall can be cycled an unlimited amount of times.  But under these conditions, it’s basically impossible to fully cycle it more than 3,650 times.
  2. When used in any other way, the warranty will last for 10 years, or until it has supplied 37,800kWh.  Whichever comes first.  This warranty condition will apply if the battery is used as part of a virtual power plant — apart from the Tesla/Energy Locals VPP1 — or if it’s used to sell electricity on the wholesale market.

In either case, the warranty promises the Powerwall will still have at least 70% of its original usable capacity at the end of its warranty.  Here’s the table from the warranty that gives the conditions:

Powerwall warranty conditions

Just to be clear, 37.8MWh is 37,800kWh.

Unlimited Cycles Isn’t Impressive

Being able to cycle your Powerwall unlimited times may sound exciting — no limits, man!

But it is actually irrelevant for most households because, under the required conditions, it’s difficult to use more than 37,800kWh of storage within 10 years.  If a Powerwall is charged with rooftop solar and the stored energy is only used to meet household demand, it’s unlikely to go over the limit because…

  • Even homes with high electricity consumption generally won’t completely drain the battery every night.
  • It won’t be possible to fully charge the Powerwall daily (due to bad weather and/or high daytime consumption).
  • Homes with large solar systems rarely need to draw battery power during the day, while homes with small solar systems frequently have trouble fully charging the battery.
  • The usable storage capacity will decline over time.  As the warranty only promises it a minimum of 70% of original capacity, it could fall as low as 9.45kWh.

If a Powerwall’s capacity falls to 75% over 10 years and a home uses an average of 80% of the available storage capacity each day, then after 10 years it will only have used around 34,500kWh.

Most homes using a Powerwall will likely use less than this over that time.  Therefore, for most homeowners, there’s no real need to get your installation to meet the warranty’s requirements for unlimited cycles.

Of course, if you don’t meet the requirements for unlimited cycles and you’re doing something unusual — such as being part of a Virtual Power Plant (VPP) that works the battery hard or selling electricity to the wholesale market and sometimes charging from the grid to do so — then you might go over the 37,800kWh warranty limit within 10 years.

What The Warranty Covers

The good news is the Powerwall warranty covers all components, including its backup Gateway Box (that looks like a mini-me version of the Powerwall).  So congrats to Tesla for meeting basic warranty decency on this and not being a battery weasel.

Powerwall Gateway box plus Minime from Austin Powers 3.

One of the above pictures shows the Powerwall and its Gateway box. For some reason, the Tesla provided picture doesn’t show the cables that normally connect the two.

Tesla says all components will be free from defects for 10 years from their installation date.

What Tesla Will Do

If there is a defect in a Powerwall or its Gateway box or associated parts, Tesla says they will choose to do one of three things:

  • Repair it.
  • Replace it with either a new or refurbished, used Powerwall.
  • Provide a refund equal to the market value of an equivalent product at the time.  It’s not clear how this will be calculated or if installation is included.

Four-Year Warranty If Not Online

To receive the full warranty, the Powerwall must be both registered and connected to the internet (to receive software updates).  If it’s not connected to the internet or loses connection for an undefined “extended period”, Tesla will only provide a four-year warranty.

I can understand that home batteries are relatively new tech and may need updates to avoid problems, but four years is only 40% the length of a typical warranty, so it’s a hefty haircut.  However, it is much better than not providing a warranty at all, which is what some manufacturers do.

What Will Void the Warranty?

There’s a range of “general exclusions” that will void the warranty if they apply.  This is not unusual, and the exclusions boil down to:

  • The Powerwall must be installed according to its manual.
  • It must be used normally, i.e. no unapproved hacking or other altering.
  • Tesla won’t cover anything outside of their control, including wars, disasters, and theft.2

The warranty also states it doesn’t cover cosmetic damage that only affects the unit’s appearance and not its performance.  Additionally, it doesn’t cover noise or vibration that is not “excessive or uncharacteristic”.  It also can’t be removed from its original location. All fairly standard stuff.

No Maintenance Required

One thing that is not required to maintain the warranty is professional maintenance, as the installation manual says none is required.  But it does say the owner must keep it clean and ensure its vents are free of obstruction.  In Australia, that will mostly mean keeping spider webs off it.  So pretty much a full-time job in Queensland.

No Compensation if the Battery Breaks

The warranty says that, “to the greatest extent permitted by law”, Tesla won’t be liable for anything.  This means no compensation for not being able to use your Powerwall if it breaks down.  But you are still protected by Australian Consumer Guarantees that say you can claim for reasonable losses that result from a faulty product.

You Can Transfer the Warranty

If you sell your home, the Powerwall warranty can be transferred to new owners. However, because the warranty is void if the Powerwall is removed from its original installation location, it can’t be uninstalled and moved or sold and retain its warranty.

You Are Protected By Consumer Guarantees

This article is about the Powerwall’s written warranty, but in this country, you are also protected by Australian Consumer Guarantees that should provide a higher level of protection than any battery warranty I’ve seen.  I’m not a lawyer, so this is just my personal opinion and not a professional one.

Unfortunately, Tesla can be slow when it comes to honouring these guarantees, as this article on a defective Tesla car part demonstrates.  Still, at least you have the option to claim under Australian Consumer Guarantees if needed.

If they continue to drag their feet, feel free to tell us so we can write about it if Tesla appears to be in the wrong.

Overall, It’s A (Relatively) Decent Warranty

All things considered, the Powerwall warranty is pretty good.  It covers components and will last a full 10 years (for most households). And while Tesla has sometimes been slow meeting its obligations under Australian Consumer Law regarding cars, they seem to be better with Powerwalls.

My main concerns are:

  • Tesla might choose to “refund you the market price of an equivalent product at the time of the warranty claim”, and it’s possible this could only cover a portion of what you paid.
  • I think Tesla could potentially go bankrupt, causing warranty support to disappear.  Call me paranoid, but apparently this is something Elon Musk and I see eye to eye on.

On the plus side, the Tesla Powerwall is one of the most reliable battery systems out there.  So if you get one — fingers crossed — you may not have any problems for over 10 years anyway.

Footnotes

  1. Tesla’s smallprint: “5 years extended warranty offer applies when you purchase a new Powerwall and connect to the Tesla Energy Plan and remain connected on the Tesla Energy Plan. If you decide to leave the Tesla Energy Plan, your additional 5-year extended warranty will be removed and revert back to the remaining manufacturers warranty.”
  2. You can tell Putin is a talented leader as he can manage all three at once.
About Ronald Brakels

Joining SolarQuotes in 2015, Ronald has a knack for reading those tediously long documents put out by solar manufacturers and translating their contents into something consumers might find interesting. Master of heavily researched deep-dive blog posts, his relentless consumer advocacy has ruffled more than a few manufacturer's feathers over the years. Read Ronald's full bio.

Comments

  1. Etyem Petyem says

    Just forget say the price.

    Most important!

  2. Nigel Perry says

    For me, one of the biggest hurdles to investing in battery storage is the initial cost and duration of payback.
    I’m certain my usage would change, as in, I’d set my ducted a/c to begin heating the home early in the morning before we rise. However, I’d probably like to move house in 5 years and I’m assuming the battery would become a fixture and can’t be installed via a wall mounted plug.
    I’ve considered building my own server rack system but how to integrate it into the home is above my pay grade. Maybe there’s some smart gateway that can manage the solar exports and charging envelopes but tbh I wouldn’t mind if it only provided power to the a/c and oven.. Like Kermit said, it ain’t easy being green.

  3. Simon Polomka says

    Had one installed Nov 21, Live in Perth area.
    Has made a significant difference to the power bill, half of the year it charges before noon so we are able to run AC to keep the house cool in the afternoon.
    The big bonus not mentioned in this article is that it works well with black-outs, kicks in quickly and we can run the whole house during the black-out. We’re not waiting on the re-connection of the power.

    • Nigel Perry says

      Yup, it’s amazing how often we get blackouts here, especially when the weather gets nasty. Do you mind me asking how much you paid all up? I assume you already had 6.6kw of solar already?

      • Simon Polomka says

        The battery was just shy of $14,000, added to the 6.6 kw of Tindo panels with Enphase micro-inverters installed the previous month.
        Panels face North West.

    • Hi Simon, how long can it provide complete backup during power outages? Thank you ?

  4. Simon Polomka says

    The battery was just shy of $14,000, added to the 6.6 kw of Tindo panels with Enphase micro-inverters installed the previous month.
    Panels face North West.

  5. Hi, thanks for the article. A question on multiple powerwalls, hopefully someone knows the answer, I can’t find it anywhere.

    If I have 2 powerwalls, does that mean I can supply up to 10kw to my home simultaneously (ie both batteries providing 5kw each)

    • Ronald Brakels says

      Hi Tim

      If you have two Powerwalls, they will be able to supply 10 kW of continuous power in total.

      But note that since installing multiple Powerwalls isn’t cheap, you may want to consider if you’d be better off installing a hybrid inverter and battery instead.

      • Awesome thanks Ronald, a simple straight forward answer, much appreciated.

        I think I’ll start with one, and see how we go. I’m planning as much solar on the roof as possible 10kw+ and ideally run the house without reliance on the grid. But slightly worried our overnight power requirements won’t be insignificant

        • Ronald Brakels says

          As you haven’t got solar yet, I recommend looking into a hybrid inverter plus batteries. But on the other hand, as Tesla lowered its price at the start of this month, multiple Powerwalls aren’t as expensive as they were. But I should point out that multiple Powerwalls can get complicated if you have 3 phase power.

          • Thanks Ronald. Single phase only so that simplifies.
            I am deep into the Tesla eco system on the automobile front, so I’m happy to go with the powerwall system so it’s all one eco system.
            The latest feature that ensures solar charge directly into the car is music to my ears. I know there are ways to achieve this with other products, but I’m kind of at an age where I just want everything to work, without me having to tinker and troubleshoot in the middle.
            Me 20 years ago would have been happy to look more broadly.
            I also really like the blackout backup from the Powerwall. Before I looked into solar I assumed this was just standard, but came to learn it’s actually quite a rare feature (to be able to use your solar and battery in the event of a blackout)

  6. I have had alot of issues with tesla even agreeing to my issues with my powerwall 2. Been on the phone with them for at least 3 long winded waits for them to acknowledge there is a problem. I’m lucky at best to get 7kwh from unit and that’s well under the 70%.
    The best response I’ve had from them is, “those figures are what you are getting on your phone app but it’s not what we are seeing on our end, have a nice day!”
    I almost lost it at him, anf other guy said I just need to keep ringing up to complain. How is a business as large as tesla have no support for its actual products.

    • Colin Martin says

      Nathan, how are you going with this Tesla issue.. I ask because I will be going through that soon because one of my Powerwall 2’s is at 79% in 3 years..

      I’m communicating with Tesla annually.

    • Colin Martin says

      Hi Nathan Any Advancement on your battery degradation,,

  7. So given that a Powerwall costs around $17k installed and the warranty runs out after a best case 37,800kWh, it would be a fair statement to say that the minimum capital cost is just shy of 45c per kWh, making it the most expensive residential energy you can buy. In addition you’d need to add to that the cost of charging it which would add a minimum of 7c (lost FIT earnings) for an all up cost of a minimum of 52c per kWh for every kWh served from the battery.

    Of course if you only half discharge the battery, that doubles these per kWh costs.

    The upshot is that you certainly don’t buy one to “save money”.

    • 45c is cheap mate. in SA we are paying 52c a kW and get a measily 5c feed in.

      unless you get it free it’s not worth having. but when will power become 60c? 80c? it’s still only half what the EU pays during peak times. it still could happen. do you remeber when gas was ‘cheap’?

  8. Simon Polomka says

    My mention of “just shy of $14,000” for a powerwall 2 installed Nov 2021 included installation and upgrade of the switchboard (mentioned by me previously). I’m not sure where the $17,000 comes from unless it’s a price variation since then by Elon, or exchange rate change.
    In WA we receive 2.5 cents per kWh before three pm.

    • “In Australia, across our network of over 150 solar installers we expect this installed cost of a Tesla Powerwall 2 to cost between $15,000 and $17,000 excluding Solar Panels and any rebates that might be available in your state.Apr 11, 2023”

      When I got a quote just less than 2 years ago it was $17k installed in NSW, in conjunction with putting 16kW on the roof.

      Prices have drifted downwards recently, the latest offer I got from Tesla was $12900 inc GST for the unit, I’d expect installation would lift it above $14k.

      Using $14k you get 37c per kWh, with the 2.5c FIT in WA you are effectively paying just shy of 40c/kWh without factoring in the cost of funds of that $14k, i.e the fact that parking it against the mortgage would save you $700 post tax dollars a year – which should be factored into the costs of making the buying decision.

  9. You won’t get anywhere. Until we get a class action there is nothing that can be done.

    They won’t accept any fault on their end

  10. We installed a Tesla Powerwall 2 in Jan 2022 at our rural weekender (future retirement home) to provide backup power as well as reducing our carbon footprint.
    We have had a few outages, of which we were there for 2 of them and found that the backup did not kick in. How do I contact Tesla for service? Or do I contact the company I bought it from (Natural Solar)

    • Finn Peacock says

      Hi Anne,

      Assuming Natural Solar promised or implied that you would have backup, they are responsible for delivering on that, so contact Natural Solar.

      If Natural Solar doesn’t come to the party, you could advise Tesla of that fact – they welcome feedback on their installation partners – and may take action.

      Finn

  11. Colin Martin says

    Hi Anne

    Your experience will help others in the AUS/NZ Tesla Powerwall FB Group.

    Quite a few have mentioned this problem because they hadn’t ensured/were ware of this problem, their Quotation/Invoice didn’t have a note saying something like, “In a blackout situation or Off-Grid the PW2 must be able to use Solar to run the house and charge the battery and after Solar hours the PW2 must run the house”.

    If you’re not a member here’s the link.

    https://www.facebook.com/groups/2411227932430251/?mibextid=c7yyfP

  12. Colin Martin says

    I now going through the rapid degradation of one of our PW2’s . It’s now at 76% since Mar’20 and now the loss has flattened out it will probably be at 70% in 2026

    I have the extra capacity with the other PW2’s, but I’m concerned about the single user PW2 owners because they aren’t getting their full use. If you assume 3%pa loss, in my case that single PW2 should still have 88% kWh available.

    I have attached today’s email from Tesla. I’m communicating with them because my installer company, last week, went into voluntary administration. The key word in the email is “below” 70%..

    Here is the email from Tesla

    “Dear Colin Martin,

    This is Andrew from the Powerwall Support team in Energy Customer Support. Thank you so much for reaching out.

    I reviewed the system and can see 1 of the 3 Powerwalls does have more degradation than the others, however it has not yet fallen below the 70% threshold to trigger a warranty claim. I would advise continuing to monitor the system and if you notice further degradation, please reach out to us for another review to see if it needs to be replaced at that time

    Please let us know if you have anymore questions or concerns.

    Warm regards,

    Andrew | Energy Customer Support
    6569 Las Vegas Blvd South, Suite 200, Las Vegas, NV 89119
    p. (877) 961-7652”

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