Top 23 Tesla Powerwall questions answered (Complete 2023 Guide)
Similar to a generator, a Tesla Powerwall is an energy storage system designed to backup your home by providing it with energy stored in its lithium cells. Further, these storing systems are capable of lowering your electric bill by damping your energy consumption from the grid during peak demand hours. If you are thinking about purchasing these batteries to back-up your home, this guide will answer all of your questions.
Full Table of content:
A) Frequently asked questions:
- How many powerwalls will I need to run my whole home?
- How long does a powerwall last? What’s the power wall capacity?
- What appliances can a powerwalls backup? For how long?
- How much does Tesla Powerwalls cost?
- What’s the lifespan and warranty of a powerwall?
- Can you use Powerwalls without solar panels?
- What functionalities does the Tesla app have to control the powerwalls?
- How long does a Powerwall take to charge with solar?
B) Powerwalls safety questions:
- How safe is a powerwall?
- Can you install powerwalls under the sun?
- How do you shut down a powerwall?
- Can your powerwalls get stolen?
- Can powerwalls be installed indoors?
- Where can you not install Powerwalls?
C) Installation questions:
- How long should the installation take?
- How complex is a Powerwall installation?
- Can you choose to stack-up Powerwalls?
D) Other questions:
- Can you charge a powerwall with a generator?
- Can your Powerwalls charge your electric vehicle?
- Can your electric vehicle charge your powerwalls?
- Do you need a transfer switch for the powerwalls?
- What’s the difference between the powerwall and the powerwall +?
- When will there be a powerwall 3 available? Should you wait?
The Tesla Powerwall Guide:
A) Frequently Asked Questions:
- How many powerwalls will I need to run my whole home?
- How long can I run my home with powerwalls? How much energy does a powerwall store?
- What appliances can a powerwalls backup? For how long?
- How much does it cost?
- What’s the lifespan and warranty of a powerwall?
- Can you use Powerwalls without solar panels?
- What functionalities does the Tesla app have to control the powerwalls?
- How long does a powerwall take to charge with solar?
1) How many Tesla Powerwalls will I need to run my whole home?
The average home with one 200 amp electrical panel (standard electrical panel size) will need at least two powerwalls. If your consumption for that one panel is high, it is recommended to get three powerwalls.
2) How long can I run my home with Tesla Powerwalls? What’s the capacity of a Powerwall?
If you have a solar system along with your powerwalls you should aim to have enough energy stored in the batteries to get you through one night, which is when there is no power from the sun.
Let’s assume your monthly consumption is 1000 kwh, that means your daily usage is 1000kwh/30days=33.3kwh and that your night-only consumption is 33.3kwh/2=16.66kwh. If you have two Powerwalls which stores 27kwh (13.5kwh each), you will be able to run your home for a 12 hrs night and a bit more which would be ideal.
If your powerwalls are stand alone (with no solar system), then you may want to get more than three powerwalls such that you have power for at least one whole day.
3) What appliances can Tesla Powerwalls backup? For how long?
Two powerwalls are able to store 27kwh. For reference, a 5 ton air conditioner (enough to cool a 2,500 sqft home) may use around 20-34kwh per night. Whenever the consumption from the electrical panel you want to backup is expected to be high it is recommended to get three powerwalls per that one 200 amp electrical panel. By using three powerwalls in parallel you will be able to store around 40kwh of energy which is more than enough to run your fridge and 5 ton A/C during the night.
4) How much does Tesla Powerwalls cost?
The current cost in 2023 of a powerwall from Tesla is $9,000. However if you buy them in pairs it will be around $16,000. The cost to install them varies across both installers and geographic location but it may be anywhere around $2,500 – $3,400.
The good news is that in the USA there is a Federal Tax Credit that will refund you 30% of the cost for the Powerwall and its installation.
5) What’s the lifespan and warranty of a powerwall?
If the battery is fully discharged and recharged once a day (1 full cycle per day) by the end of 10 years (warranty expiration) it will hold 70% of its original charge and that’s when the warranty expires. However, it is not expected for you to have the powerwall set in this “full cycle” mode for 10 years, therefore Tesla claims that the actual life span may be around 20 years.
6) Can you use Tesla Powerwalls without solar panels?
Yes, powerwalls do work as stand alone systems. However as of 2022 Tesla has made it imperative for you to get either solar panels or the Tesla Solar Roof for them to be able to sell the batteries. In other words, you can technically install them by themselves but you won’t be able to purchase them if you don’t buy a solar system as well.
7) How long does a powerwall take to charge with solar?
With sunny conditions and a 11.6kw (29 solar panels) solar panel system size, a Tesla Powerwall can charge in around 1 to 1hr 30min.
8) What functionalities does the Tesla app have to control the powerwalls?
Backup Only: All the energy in your powerwalls is saved for rainy or stormy days
Self Powered: Power your home with energy stored in your Powerwalls once the sun sets
Balance Time-Based Control: Activates the powerwalls based on a timer
Cost-savings Time-Based Control: It maximizes your electric bill savings by storing energy during “off-peak” demand hours and supplying energy to your home during on-peak demand hours (when electricity costs are expensive).
B) Powerwalls safety questions:
- How safe is a powerwall?
- Can you install powerwalls under the sun?
- How do you shut down a powerwall?
- Can your powerwalls get stolen?
- Can powerwalls be installed indoors?
- Where can you not install powerwalls?
9) How safe is a Tesla Powerwall?
Powerwalls were designed for safety. The battery is covered with a metal enclosure of more than 1 mm of thickness which allows for a 2hr fire-resistance rating that is compliant with the NFPA 855 industry standards.
10) Can you install Tesla Powerwalls directly under the sun?
The answer is yes. Powerwalls have active cooling that keeps its internal temperature low. However, if you live somewhere where the sun is extreme, it is recommended to build a structure for providing shade to the powerwalls.
11) How do you shut down powerwalls?
Powerwalls can be physically shut down by either disconnecting the A/C shut down switch or by switching the button on the powerwall from the ON to the OFF position
12) Can Tesla Powerwalls get stolen?
These batteries are expensive, so yes, if you install them somewhere accessible to the public you may run the risk of someone stealing them. In addition, uninstalling them is not that complicated. However, do bear in mind that these are 251lb (114kg) which would require multiple people to carry.
13) Can Powerwalls be installed indoors?
Yes, powerwalls can be installed indoors but not in living areas (i.e not in room, living room, etc). A common place to install them is in the garage.
14) Where can you NOT install Powerwalls?
As per the building code, a Tesla powerwall should not be installed:
- Inside living spaces
- Anywhere less than 5 ft from an operable opening to a building (i.e a window)
- Anywhere too close to gas pipelines or HVAC systems
- Less than 3ft from another storage system (Consult with your local AHJ)
c) Installation questions:
- How long should the installation take?
- How complex is a powerwall installation?
- Can you choose to stack-up powerwalls?
15) How long should the installation take?
It depends on how many powerwalls and backup gateways you are getting. A simple Powerwall installation to backup one electrical panel should take one day to install. It also depends on the installer, it is important you choose the right solar contractor to avoid delays.
16) How complex is a Tesla Powerwall installation?
A powerwall installation to backup one single electrical panel is simple. The more electrical panels you want to back up the more complex the engineering becomes. In terms of electrical work, you should expect some conduit to run to your Powerwalls. If you are very concern about this, ask your solar installer for an “on-site survey” to determine how the system will look.
17) Can you choose to stack-up powerwalls?
Some building departments do allow you to install one powerwall in front of the other. This is a great way to save space.
D) Other questions:
- Can you charge a powerwall with a generator?
- Can your powerwalls charge your electric vehicle?
- Can your electric vehicle charge your powerwalls?
- Do you need a transfer switch for the powerwalls?
- What’s the difference between the powerwall and the powerwall +?
- When will there be a powerwall 3 available? Should you wait?
18) Can you charge a powerwall with a fuel generator?
No, the powerwall is not integrated to be charged through a fuel generator. If this is what you want you may want to look into the SolarEdge Energy Bank storage system.
19) Can your powerwall charge your electric vehicle?
Yes, but keep in mind that a powerwall stores 13.5kwh of energy while a tesla model 3 stores more than 50 kwh of energy which means the powerwalls may get depleted from charging your EV vehicle.
To avoid said scenario, through the Tesla app you can set a reserve amount to what you desire and let the EV car pull as much energy as established in the settings. Also, if there is a real grid outage there is a different setting which further limits how much energy the EV can pull from the battery.
20) Can your electric vehicle charge your Tesla powerwalls?
As of this writing, this is not possible to do.
21) Do you need a transfer switch for your powerwalls?
No, that’s what the “Backup gateway” is there for. During a grid outage the Powerwall system automatically switches ON. The backup gateway is what controls the interaction between your solar system, the grid and the loads.
22) What’s the difference between the Tesla Powerwall and the Tesla Powerwall +?
While the Tesla Powerwall is a stand-alone storage system, the Tesla Powerwall + is a powerwall with an integrated string inverter. This string inverter works by converting DC energy from your solar panels to AC energy to power your home from the solar panels.
23) When will the Powerwall 3 be available? Should you wait?
As per Tesla sales representatives, the Tesla Powerwall 3 should soon be available. Tesla has not given enough technical details about it. If I were to get a storage system, I would wait until they release the Powerwalls 3 which I suspect may be somewhere around 2023.
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