Not all batteries are equal

With many households already having solar PV installations many people are now looking at energy storage systems to upgrade their home energy supply.

One of the most common questions is what battery is best for my needs. There is a lack of knowledge and a great amount of misinformation in the battery storage industry. It is critical to do your own homework and not just believe what salesman / installers are telling you as they are often restrained in their knowledge by the battery brand they are trying to sell.

In an effort to compare battery technologies a company called ITP renewables, in Canberra, set up a battery test site, to conduct longitudinal performance testing of conventional and emerging battery technologies. This is an Arena funded testing facility set up to independently test and compare different battery technologies under Australian conditions for both performance and longevity for a 3 year period. This testing centre was first set up with Phase 1 in 2016 then phase 2 started in 2017. Originally it was for lithium-ion batteries only but now includes other technologies.

The SoNick battery is included in round 3 which started in 2019 and to date showing excellent results. 10 Previous 6 monthly reports are available from the test centre and can be

This is potentially the only facility to independently test a range of battery technologies over an extended period in the world and make the results publicly available. The battery test centre provides consumers with independent information on battery performance to compare against claims made by manufacturers. As can be seen by the results those appearing at the battery test centre can be very different from those being claimed by manufacturers.

Most batteries are cycled several times a day, including rest periods, under different temperatures to try and simulate real life usage in both summer and winter. Some batteries have worked under the cycling conditions and failed under the temperature conditions. Restrictions from some batteries mean they are only cycled twice a day rather than 3 times a day. This means some batteries have completed more cycles than others while operating over a similar time period.

One issue that became immediately apparent was the difficulty in installing and commissioning some batteries. This also meant some batteries, notably Redflow’s bromide battery were replaced several times before a working battery was commissioned. The efficiency of the manufacturers response also varied widely between batteries. Experiences at the battery test centre are presumably also experienced in home battery installations.

One of the issues being experienced with batteries that have a BMS (battery monitoring system) is the difficulty in translating the SOC (state of charge) correctly from the battery to the inverter. This is why many batteries specify that they only work with one or two inverters.

From this testing it has been made clear that not all batteries are equal and that initial purchase price is not necessarily a good indicator of expected performance or longevity of a particular battery. Ease of installation, degradation or capacity fade and reliability are also important factors to take into consideration, especially as most people expect their battery systems to last more than a couple of years.

Another thing to take into account and not specifically tested at the test centre is whether a battery is required to be connected to the internet. This can make a big difference if a battery needs to operate in an off-grid capacity, either temporarily or permanently. Although connection to the internet can make remote monitoring and adjustments easier it can be problematic if it is a requirement of a warranty and you then have power outages.

As can be seen from the table below many of the batteries in phases 1 and 2 are no longer operational for varying reasons with only Sony from Phase 1 and GNB and Pylontech from Phase 2 still operational.

Time and use as well as temperature variations will affect longevity and can degrade batteries significantly. This capacity fade is one of the important features to be tested in the trial.

The 10th report has several graphs and shows capacity fade or degradation figures and when batteries reach or are expected to reach 60% capacity, both those verified in operation and those extrapolated from current observations. The results have varied widely between different batteries, however all lithium-ion batteries have had some degree of degradation meaning some very different expected life cycles for different brands. This degradation in capacity can make a big difference over time to how a battery will provide power and needs to be taken into account when original sizing of battery systems takes place.

These are just some of the questions you need to think about when installing a battery energy storage system and want to make sure the battery system is designed for your needs. If you aren’t asked these questions you need to ask if the salesman / installer is trying to find out the best system for your needs or just trying to sell you the system they want to sell you.

If you would like to know more about getting a safe, reliable and recyclable battery energy storage system for your own home, business or micro-grid to increase your energy independence visit us at We have a number of different sized systems that can cater to your budget and household needs.

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