Tesla Powerwall 2 vs BYD Battery

If you have heard the term ‘solar battery’, you probably know that the Tesla Powerwall 2 is the most popular home battery worldwide. And if you know just a tiny bit more about solar batteries, you probably also know that the BYD solar battery is Tesla’s biggest competitor from the East.

But what happens when you put both these batteries into a fighting ring? Which one wins in a head-to-head battle? Let’s do an in-depth comparison and find out.

Battery Specs

Both the Powerwall and the BYD batteries are lithium-based storage devices with smart functionality. But the similarities end there. Here’s a look at the key specs of both models and who beats whom at what.

1. Capacity

The Powerwall offers a 14 kWh energy storage capacity, of which a decent 13.5 kWh is usable. The average Kiwi home needs somewhere around 15-20 kWh every day, which means the Powerwall packs enough juice to last through an entire day, considering you are using some of your solar power during the daytime.

Among BYD’s offerings, the BYD Premium HVM is similar to the Powerwall, with a 13.8 kWh capacity. The BYD Battery Box Premium LVS is a low-voltage model with a smaller, 3.8 kWh capacity. 

That said, all the above batteries can be made to store more energy by connecting multiple units together. In Tesla’s case, you will have to add in more Powerwalls, meaning that your energy capacity can only be in multiples of 14 kWh. 

The BYDs, on the other hand, are wonderfully modular (more about this in the design section ahead). With the HVM, you can simply go on stacking battery modules till you reach a maximum capacity of 22.1 kWh. After that, you can add three such towers in parallel to make a whopping 66.2 kWh. 

With the LVS, you can keep stacking till you reach 23.1 kWh. But, if you are looking for massive energy storage for commercial needs or if you are secretly building a time machine in your basement, you can keep connecting LVS towers together until you get an incredible 245.8 kWh! In case you were wondering – no, the Tesla can’t do that.

Winner of this round: BYD 

2. Chemistry

Here’s an important one - while both batteries are lithium-based, they use different chemistries. The Tesla Powerwall 2 uses the more traditional NMC (nickel-manganese-cobalt) chemistry, while BYD uses the LiFePo4 (lithium iron phosphate) chemistry.

NMC batteries are lighter, more compact, and great for sudden power delivery. All of these are great traits for an electric car - which is one reason Tesla’s cars so great. But for a box of battery cells standing in the corner of your garage, these aren’t really necessary features. 

LFP batteries, on the other hand, have much better thermal resistance, making them safer than NMC batteries. Legend says that LFP batteries can be punctured or thrown from the fourth floor without producing any fire - just some smoke at the most. This is not the case with NMC batteries. At abnormally high temperatures, NMC batteries can catch fire, or worse, even explode. That said, the Tesla Powerwall, with its active cooling, is a remarkably safe battery.

Aside from this, LFP chemistry also has a lower rate of degradation, which means a BYD battery will have more storage capacity in it after eight or nine years than the Powerwall 2 at the same age. LFP batteries are also considered a bit more ethical, since they avoid cobalt mining, which has recently come under fire for not being sustainable. 

Winner of this round: BYD

3. AC vs DC-coupling

The Tesla Powerwall is an AC-coupled battery, while the BYD models are DC-coupled. In other words, the Powerwall can be supplied with AC power, while the BYD will charge with DC power coming directly from the panels. Both options have their pros and cons.

DC-coupled batteries have fewer current conversions in them, leading to higher efficiency. The BYD batteries have an impressive 96.5% efficiency, while the Powerwall 2 just manages 90%. However, efficiency isn’t the only thing of concern here.

AC-coupled batteries allow for flexibility and simplicity of installation. They can be integrated easily into existing solar power systems, and can also be charged using grid power. This allows you to install the Powerwall without solar panels. DC-coupled batteries are complex to install, often cost more for the labour, and offer little flexibility in terms of charging.

Another factor to consider is whether you use single or three-phase power. The BYD battery can be used for both 1 and 3-phase applications, while the Powerwall can only be used for single-phase applications (note that you can use the Powerwall for 3-phase by using one battery for each phase, which forces you to have multiple units). Check out our detailed DC vs AC-coupled battery post to learn more.

Winner of this round: Tied (depends on the type of application) 

4. Dimensions and weight

The Tesla Powerwall is 115 cm tall, 75 cm wide, and 14 cm thick. In comparison, BYD’s HVM battery is larger with its dimensions of 585 x 1461 x 298 cm. 

Speaking of weight, the BYD HVM packs a whopping 205 kg compared to Tesla’s 125 kg. As mentioned previously, BYD’s LiFePO4 chemistry adds to its weight. But once installed, you won’t be moving the battery around your home regularly, which means the added weight isn’t really a problem.

Nevertheless, if one really likes to boast about their lightweight battery, they would probably like the Powerwall more.

Winner of this round: Tesla

Take a look at our detailed comparison table for both Tesla and BYD batteries. Let us now move to other aspects of comparison.

Features

Not long ago, batteries were ugly, bulky boxes of chemical fluids and electrodes with no such thing as features. There was no Wi-Fi connectivity, no sensors, no thermal management, just dumb-looking plastic cases with stickers on them. But times have changed, and solar batteries offer more than just energy storage. Here’s a look at the key features of both batteries:

5. Thermal management

Tesla is the only home battery with a cutting-edge thermal management system that uses a liquid-cooling system, allowing it to operate in an impressive range of temperatures from -20 to +50 degrees C. 

Tesla's thermal management system

BYD, on the other hand, has a more basic ‘natural cooling system’, which is another way of saying that it uses air vents to cool the cells.

Winner of this round: Tesla

6. Smart Functionality 

The Tesla Powerwall has a smartphone app with a fabulous user interface. It allows the user to check the level of charge, charging/discharging status, and several other things.

BYD’s batteries also have Wi-Fi connectivity, and come with the ‘BE Connect 2.0’ app for checking battery status. However, BYD’s app is pretty basic and less intuitive than Tesla’s.

Tesla also offers the unique ‘Storm Watch’ feature, which allows users to prepare for a blackout in advance by fully charging the battery. You can turn the mode on manually, and the battery even communicates with meteorological departments to learn about upcoming storms and prepare for an outage. As for BYD, their engineers are probably still thinking of designing such a feature. 

Another important feature of the Powerwall is its ability to switch over to stored energy from grid energy quickly in the event of an outage. The change is so rapid that most homeowners won’t even notice that their grid power is out. In comparison, the BYD batteries can take a few seconds, sometimes even a minute, which is clearly too long!  

Winner of this round: Tesla 

7. Design

A decade or two ago, the idea of aesthetically pleasing batteries would have been ridiculous. But modern batteries have shown that design can play an important role in impressing buyers. The Tesla Powerwall was one of the first batteries to pay attention to aesthetics. The Powerwall 2 is a sleek, rectangular battery that is boxy and yet pleasing in design in a minimalistic way. It has a signature white color and a beautiful green LED strip on its side.

The BYD battery fails to match Tesla’s aesthetics. Both the HVM and LVS look like boring office filing cabinets, and are not something you’d proudly display in your lobby. But design is about more than just looks. The BYD batteries have an excellent, patented modular plug design. BYD revolutionized the stackable design, which allows you to add battery modules like connecting Lego blocks (let’s say very heavy Lego blocks) without the hassle of wiring.

Winner of this round: Tied (Tesla for aesthetics, BYD for functionality) 

8. Brand Reputation

One of the reasons the Tesla Powerwall is so popular is the fact that it is made in the U.S. The overall public perception towards products that originate in China is still not great. And this is why you may dismiss BYD as just another Chinese electronics company. 

But BYD is far from that - it is the world’s second-largest battery manufacturer, and is predicted to overtake Tesla in market shares not just for home batteries but also for electric cars. It is a multi-billion dollar company with nearly 30 years of experience and a staggering 220,000 employees. 

Obviously, Tesla is no longer just the ‘iconic start-up’ company that it was just a decade ago. As of late 2023, it is owned by the world’s richest man, and has already sold half a million Powerwalls globally.

Winner of this round: Tied

9. Price

Among the reasons for the Tesla Powerwall’s popularity is also its relatively low price. For a premium-brand battery with a ton of modern features, the Powerwall doesn’t cost a fortune. Tesla sells the battery at $11,800. Add in the Backup Gateway (the system’s brain) and installation costs and you can expect to spend around $20,000 for the battery.

BYD does not list battery prices on its website. In fact, it doesn’t even have a dedicated webpage in New Zealand for its solar batteries. BYD’s battery prices vary based on its capacity, and its highly modular nature means there can be plenty of capacity options and therefore a lot of different prices. That said, a BYD battery the size of the Powerwall will cost upwards of $20,000 with installation. 

As mentioned previously, DC-coupled batteries in general cost more to install, so you can be sure that for the same size, you would be paying more for a BYD than a Powerwall.

Winner of this round: Tesla

Which Battery Should You Buy?

Alright, so we had nine different rounds of a fierce battle, with BYD scoring some impressive points, and Tesla hitting back with other, equally impressive points. Out of the nine rounds above, Tesla won four rounds, BYD won two, and we saw a tie in three rounds.

While this may indicate that the Tesla Powerwall 2 is a better contender, it is important to note that the traits compared in some rounds may be more important to you than traits compared in some other rounds. 

For example, if modularity is more important to you or you have a 3-phase connection, you will likely opt for BYD. Similarly, if you are adding a battery to your existing PV system or if you prefer one of the best monitoring apps, then the Powerwall makes more sense.

Ultimately, both BYD and Tesla offer superb solar batteries, and you won’t have any serious regrets no matter which of the two options you choose to install.

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Other good reads:

Solar Power Battery Storage - An Introduction
Are Solar Batteries Worth The Cost In NZ?
Solar Batteries Vs. Petrol Generators In The Face Of A Cyclone