BYD - Battery Reviews

About BYD

BYD stands for Build Your Dreams and one of BYD's many dreams is to be the no.1 company for solar battery storage.

This giant Chinese company entered Australia's home battery battleground in 2017 when they introduced the "B-Box".  These days they no longer shorten its name and it's called the "BYD Battery Box".  It's a stackable, modular battery that has one low voltage and two higher voltage versions.

I'll describe the Battery Box below, but first I'll give some information on BYD.

BYD Company Info

BYD was founded in 1995 and listed on the Hong Kong Stock Exchange in 2002.  They say their name stands for "Build Your Dreams" but sometimes I wonder if they just grabbed some letters that hadn't already been taken and decided what they stood for afterwards.

The company started out as a battery manufacturer.  Exploiting cheap Chinese labour allowed them to compete with producers in other countries.  By 2002 they were producing 65% of the world's rechargable NiCd batteries.  As China's labour costs rose, BYD invested heavily in automation. 

In 2022 BYD was the world's third largest producer of lithium batteries with 12% market share.  At the start of 2022 they had 135 gigawatt-hours (GWh) of battery production capacity and this was projected to rise to 445GWh by the start of 2024.  In practice, actual battery production is typically around 60% of total capacity but, because they're always rapidly expanding, in 2024 BYD may produce over 300GWh of batteries.  That's over 11 kilowatt-hours (kWh) for every person in Australia. 

BYD began making automobiles in 2002 and is now the world's 10th largest car manufacturer.  This means they took the opposite path to Tesla, which started out as an electric vehicle (EV) manufacturer and then moved into solar battery storage.  In the first six months of 2023 they sold 1.25 million EVs and plug-in hybrids.  By October 2023, Tesla and BYD were neck and neck in total sales of pure EVs, with Tesla less than 1% ahead.  BYD looks certain to become the world's largest EV manufacturer.

While not the largest electric bus manufacturer in China, BYD has made something like 200,000 of them.  Mostly in China, but others have been made under licence in a number of countries including Australia.

BYD's headquarters are located in a giant hexagon.  My guess is they looked at the United States Pentagon and decided to go one better.  It's located in Shenzhen - a city on the Chinese mainland opposite Hong Kong.

BYD EV sales have only recently started taking off in Australia, but it may not be long before our roads are chock full of them.

BYD Battery Box Appears Safe

The BYD Battery Box has cells with lithium-iron phosphate (LFP) chemistry.  While this is the safest type of lithium battery, the actual level of safety will depend on its design, the quality of components, and the care taken with its manufacture.  The good news is - so far - BYD Battery Boxes seem safe.  Given BYD has around three decades of experience with lithium batteries, I'd expect them to get this right.

Hybrid Inverter Required

Battery Boxes require a compatible hybrid inverter or battery inverter.  The list of compatible inverters includes Fronius, Goodwe, SMA, Solis, Sungrow, and GE.  Victron and Australian-made Selectronic battery inverters can also be used.

Low & Higher Voltage Versions

There are three versions of the BYD Battery Box:

• The low voltage Battery Box LVS
• The higher voltage Battery Box HVS and Battery Box HVM

Low-voltage batteries have thick and heavy cables and need to be located very close to their inverter.  Higher voltage batteries provide more flexibility with where they can be located.  This is often important due to Australia's strict fire safety standards for battery installation.  

Modular & Stackable

All Battery Boxes consist of modules that can be stacked on top of each other.  The number can vary and this gives flexibility in storage capacity.  The usable energy storage per module and the number that can be used varies between the three different Battery Boxes:  

• Battery Box LVS:  1 to 6 4kWh modules for 4-24kWh of storage
• Battery Box HVS:  2 to 5 2.56kWh modules for 5.12-12.8kWh of storage
• Battery Box HVS:  3 to 8 2.76kWh modules for 8.28-22.08kWh of storage

If more storage is desired multiple modules can be connected in parallel.

Expandable

Unlike some modular batteries, the storage capacity of BYD Battery Boxes can be increased at any time by adding additional modules, provided the maximum number isn't exceeded.  Because they plug into each other when stacked without needing additional wiring, adding extra modules is relatively easy.  Despite this, it's still a good idea to get the amount right from the start, as it will save you the installation cost of having modules added later. 

Power

The maximum power output of a BYD Battery Box is determined by either its hybrid inverter or by the number of battery modules.  If the inverter's limit is not an issue then the maximum continuous power output will depend on which version of Battery Box is used.  As a percentage of its usable storage capacity, they can provide the following amounts of continuous power in kilowatts (kW):

• Battery Box LVS - around 60% of usable storage
• Battery Box HVS - around 78% of usable storage
• Battery Box HVM - around 72% of usable storage

So a Battery Box HVM with 11kWh of usable storage when new could provide 7.9kW of continuous power. 

Because their continuous power output is better than most, they are sometimes described as "high power" batteries.  This can be useful if you don't want a lot of battery storage capacity but still want your battery to provide a reasonable amount of backup power.

Backup Power

A Battery Box's hybrid inverter - or battery inverter - determines how its backup power operates.  Most people will want their Battery Box to be able to supply backup power and to be able to charge from rooftop solar during the day when the grid is down.  If this is what you want, it's important to check with your installer that you will actually get it.

The time taken to transfer to backup power when there's a blackout also depends on the hybrid inverter.  With a Fronius Gen 24 hybrid inverter it's around 40 seconds, although Fronius says it can take a minute and a half.

Off-Grid Capable

Provided it's paired with a suitable hybrid or battery inverter, BYD Battery Boxes are suitable for use off-grid.

Installation Location

Battery Boxes will normally be located outside due to fire regulations.  They are suitable for outdoor installation but should be placed where they will be out of direct rain and sunshine.

Operating Temperature

Their given operating temperature is from -10°C to 50°C.  The upper limit means a shaded Battery Box should continue to operate under all but the most extreme heat conditions, but not that battery systems normally have their maximum power output reduced as they approach their maximum operating temperature.  The lower limit is given as -10°C but the rate at which it charges will be reduced from -10°C to 5°C.  This will rarely be an issue in Australia.

Efficiency

Roundtrip efficiency is how much energy a battery system will provide compared to how much is put in.  The lower voltage Battery Box LVS has a roundtrip efficiency of at least 95% while for the higher voltage ones it's at least 96%.  This level of efficiency isn't bad, but not uncommon for modular battery systems.

There will also be some losses from the hybrid inverter.  If a 96% efficient battery is paired with a 97.5% efficient inverter their combined roundtrip efficiency will be 93.6%. 

Battery Comparison Table

If you want to compare the three Battery Boxes to each other or other batteries, you can check out our solar battery comparison table.

Warranty

The Battery Box warranty lasts for either 10 years or until it provides an amount of stored energy it refers to as the "Minimum Throughput Energy".  This is equal to around 3,000kWh for every kWh of usable storage when new.  It's a little less for the lower voltage Battery Box and a little more for the higher voltage ones.

Most households will discharge a daily average of less than the battery's full usable capacity when new - especially if the house is not part of a VPP.  But if a higher voltage BYD Battery Box discharges an average of its usable storage capacity when new every day, then its warranty will last around 8.3 years.   

If it instead discharges a daily average of 1.5 times its usable storage when new, the warranty will only last around 5.5 years.  This means households that work their battery at high capacity could see their warranty end long before the 10 year maximum is reached. 

If you intend to work your battery hard by charging it during the day with solar for use in the evening followed by charging it with cheap grid electricity late at night for use in the morning, you may be better off choosing a different battery.  An example of one with a warranty that allows greater energy throughput is the Sungrow modular battery.

The Battery Box warranties promise they'll maintain a minimum of 60% of their original capacity for as long as the warranty lasts - which can be well under 10 years, depending on how they're used.

Warranty Claims

If an issue arises with your BYD Battery Box you should first contact your installer.  But if they are no longer around you can contact their Australian service representative, Alps Power, during NSW office hours.

• Alps Power:  (02) 8005 6688

You can also send them an email at:

• [email protected]

The SolarQuotes View

Home batteries are a new and rapidly changing technology.  This makes it difficult to be certain how batteries will perform long term.  This includes ones that have been around longer than most, such as the BYD Battery Box.  But at this time, based on feedback from installers in our network, we are able to recommend the BYD Battery Box and include it on our chart of recommended brands.

In SQ's Installers' Choice Awards 2023 for home batteries, BYD scored silver in both best battery and best value home battery brand categories, and bronze for best support.

If you have a BYD battery system, you are more than welcome to share your thoughts on it with other Australians by leaving a rating and review.