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Solar Battery Storage Comparison Table

Last updated: February 2017

Hit 'Expand' for fullscreen. Scroll within the table to see all the rows and columns.  See notes below the table.  Any corrections, additions or feedback? Email us.

 

 

We plan to update this table frequently as more products become available, and specs of existing products change.

Please note that pricing is our best estimate of retail pricing incl GST, unless specifically noted otherwise. But it is only an estimate. 

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Please read this if you are not 100% certain what a kWh is, or the difference between a kW and a kWh: What does kWh stand for?

Usable Storage Capacity (kWh)

The energy stored in a battery that can actually be used. In most cases this is less than the nominal storage capacity.

For example, the Enphase AC battery has a total capacity of 1.2kWh. But as only 95% of that stored energy can be discharged (aka a 95% DoD) its usable capacity is really 1.1kWh.

Power (kW)

A battery's power is how fast it can be charged or discharged.

For example, an Enphase AC battery is a low power battery (also known as an 'energy' battery) because it takes 4 hours and 23 minutes to discharge all its usable energy, while the BMZ ESS is a high power battery because it can discharge all its usable energy in under 40 minutes.

A high power battery isn't necessarily more desirable than a low power battery - your household's unique energy usage needs will determine how much power you will require from a battery.

Cycle Life & Depth Of Discharge (DoD)

Besides storage capacity, this is one of the most important numbers to look at when comparing battery storage. It is expressed in a format like this: 6,000 cycles at 90% DoD (depth of discharge).

What that means is - the battery should be able to discharge 90% of its capacity then recharge 6,000 times before it reaches the end of its life.

Most batteries (Redflow's Zcell is a notable exception) will have a degradation in their depth-of-discharge over time. This is usually buried in the warranty documents for the batteries.

Reposit Ready

If a battery storage product is listed on this table as "Reposit Ready", this means that it is compatible with Reposit Power's "GridCredits" software/hardware.

You can read more about Reposit Power here. 

All In One unit

This means the system includes batteries, a battery management system, and an inverter. The Sunverge SIS is one example.

If a battery management system and/or inverter have to be purchased separately this will add to the total cost of the system.

Warranty Document Supplied?

Links to a warranty document if it is available.  Don't buy a battery until you have read the latest release of the warranty document direct from the supplier. They change often and we can't guarantee the linked version is the latest.

Total warranted kWh (max 2 cycles per day)

All manufacturers were asked for a warranty document. If we got one and it explicity gives a 'total warranted kWh' figure, then this is it. 

If we couldn't get a warranty document, or the warranty document doesn't specify cycles or warranted kWh explicitly, then this number is an implied figure, calculated by us from the cycle life/DoD combined with the battery capacity. 

Be careful using implied numbers - as our experience shows that the final, documented warranted kWh figure will almost always be lower.

Also be aware that 'battery only' products will require a battery inverters cost added to the final installed price, which will increase the overall cost per warranted kWh.

Cost per warranted kWh (max 2 cycles per day)

Here we divide the battery price by 'Total warranted kWh (max 2 cycles per day)'.

This is a 'best case' cost which assumes you'll work the battery for all it's worth, discharging it multiple times per day up to its maximum amount of cycles before the warranty period expires.

The '@ cycles per day' is how many cycles per day you'd need to fully discharge the battery to get this cost per kWh before the warranty expired.

The consensus in the industry is that >95% of houses with a battery would rarely, if ever, cycle it more than twice per day.

This is why we use a maximum of 2 cycles per day in our calculations.

Use your judgement to decide if this number is relevant to your application.

Total warranted kWh (1 cycle per day)

If you only discharge the battery once per day (most likely for larger batteries in residential situations) then the warranty period may expire well before the warranted kWh are all used up.  

The number of kWh the battery can discharge per day is multiplied by the number of days in the warranty period to get the figures for this row.

Cost per warranted kWh (1 cycle per day)

This is the price of the battery divided by 'Warranted kWh (1 cycle per day)'. If you discharge the battery approximately once per day this number indicates which system may be the most cost effective.

A note on warranties

Some products in the table have different warranties for parts within the unit. For example, some "All in one" units warrant the batteries for 10 years but the internal inverter for only 5 years.

We use the 'weakest link' warranted figure (so in the above example, 5 years instead of 10 years) when calculating the cost per warranted kWh.

Disclaimer: We are only human. Although we try really hard to keep this table up to date and accurate, mistakes could have been made and figures can go out of date quickly. Check with the manufacturers before making any decisions based on this table.

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