Costs less per kilowatt-hour compared to most other batteries in the market Features a higher power output than many competing products, allowing you to power more home devices simultaneously Has a built-in hybrid inverter for combined solar and battery installations Cons Many customers have reported long waiting times after ordering a Powerwall online, based on our analysis of reviews The Powerwall 3 is incompatible with older models and non-Tesla inverters Our team reached out to Tesla for comment on customer reviews mentioning long wait times but did not receive a response. Frequently Asked Questions About the Tesla Powerwall Did Tesla stop selling the Powerwall? Tesla still sells the Powerwall battery. However, when Tesla launched the Powerwall 3 in 2024, it stopped offering the older Powerwall 2 and Powerwall+ models online. Currently, you can only buy these two models from third-party distributors. How long can a battery with 13.5 kWh of capacity last? The duration of a fully charged Powerwall with 13.5 kWh of capacity depends on the total power consumption of the devices connected to the unit. To estimate the duration of 13.5 kWh, divide this value by the total power consumption of the connected devices. For example, if running electronic devices would use 2 kW of consumption, a 13.5 kWh battery could supply power for around six hours and 45 minutes. If running larger appliances that require 10 kW of power, the battery could supply around an hour and a half of power. How long can a Powerwall battery power a house? As discussed in the previous question, this depends on the total power consumption of the devices connected to the Powerwall. For example, an 8 kW load of electricity will deplete your Powerwall twice as fast as a 4 kW load. If you need more hours of backup power, you can connect up to four Powerwall 3 units into a 54 kWh system. Can a Tesla Powerwall run an air conditioner? Yes, the Powerwall 3 has a rated power output of 11.5 kW, which is enough to power a typical residential air conditioner. Central air conditioners typically consume less than 5 kW of electricity or even less than 3 kW if you have an energy-efficient unit. Single-room mini-splits can achieve even more hours of cooling with a Powerwall, since their typical power input is only around 1 kW. However, note that the Powerwall 2 may struggle to run an air conditioner because its continuous power output is only 5 kW. Methodology: Our System for Ranking the Best Solar Batteries Our team evaluates solar battery brands based on the value offered to solar homeowners. Our review methodology includes homeowner surveys and interviews with industry experts, complemented by in-depth research of the renewable energy market and data analysis. We then use that research to review each battery brand and determine a rating out of 5 stars. Here are more details about the factors we consider in our review: Battery options (20%): Solar battery manufacturers that offer different system sizes can meet the energy needs of a wider range of homeowners. On the other hand, if a brand only offers one battery model, its storage capacity may be too high or too low for the energy needs of certain homeowners. A battery brand must offer at least four different options to score a full 20%. Depth of discharge (25%): The depth of discharge (DoD) is a key factor when comparing batteries because it determines the storage capacity you can actually use. For example, a 10 kWh battery with 100% DoD offers its full capacity, while a battery of the same size with 50% DoD only offers 5 kWh. A battery brand must have 100% DoD to score 25%. Round-trip efficiency (25%): No battery system is 100% efficient, but a high round-trip efficiency means you will lose less energy per charging cycle. For example, if you store 10 kWh in a 70% efficient battery, you are only getting back 7 kWh per cycle. On the other hand, a 90% efficient battery will give you back 9 kWh per cycle. In this case, you are saving 2,000 kWh for every 1,000 cycles. A battery brand must have at least 96% round-trip efficiency to score 25%. Warranty length (15%): Solar batteries are expensive, but a solar warranty protects your investment. Leading battery manufacturers typically offer a 10-year warranty, but the specific terms and conditions vary by brand. A battery must have a 10-year warranty to score 15%. End of warranty capacity (15%): Batteries gradually lose their storage capacity as they accumulate more charging cycles. However, batteries that retain a higher percentage of their storage capacity can handle more kilowatt-hours of energy over time. A battery must have at least 61% of its rated capacity after 10 years to score 15%. You can also read our full solar company methodology to learn more about how we rate and review installers, including Tesla. If you have feedback or questions about this article, please email the MarketWatch Guides team at editors@marketwatchguides.