1. Solar batteries don’t have to come with eye watering price tags

People have been deterred from getting solar batteries for their solar systems for the last few years due to the large outlay cost associated with them despite their interest to install them.

Tesla are probably the most recognisable brand of solar batteries in Australia, but when people enquire into the pricing to add some to their solar systems, they are taken back by the price tag (from around $14K – $17K) and decide not to pursue a solar battery solution.

There are numerous more viable options on the market that provide much better value for money, which could reduce the overall cost by at least 30% to 40% compared to Tesla or other top tier marketing brands such as Sonnen and Fronius.

In fact, Dyness batteries utilise the same LiFePO4 prismatic cells as the latest generation Sonnen systems, but cost considerably less (around 40% less).

2. It is not cost effective to get larger capacity battery storage than you actually need

Solar batteries are generally used to store excess solar energy generated to from your solar system which would otherwise be exported to the grid.

It would not make sense to install a larger battery than the excess solar power that your solar system can generate.

Many people make the mistake of purchasing a large battery such as a Tesla Powerwall 2 which is 13.5kWh of capacity, when they may only have enough spare solar energy to partially fill it, and may never be able to fill it, meaning that a considerable amount of money would be wasted.

It is best to go with a modular battery system and start with the only the necessary storage capacity and build up capacity if and when your requirements change.

3. Not all lithium solar battery chemistries are the same

The most common chemistries are Lithium Iron Phosphate (LiFePO4) and Lithium-Ion batteries.

There are two main types of lithium-ion batteries: nickel-manganese-cobalt (NMC), and nickel cobalt aluminium oxide (NCA), and they are commonly referred to as Lithium-Ion batteries.

There are pros and cons for each
battery chemistry type:

Lithium-Ion is lighter and hence more energy dense than LiFePO4.  This makes it more popular for portable electronic devices where weight is an issue. LifePO4 is more suited for applications that are more stationary such as solar systems and RV applications.

Lithium-ion is less stable than LiFePO4 (specially at higher operating temperatures) and hence less safe as it is much more prone to thermal runaway (quick release of energy if overheated or damaged resulting in explosion). LiFePO4 remans cool under high discharge rates and has very low risk of thermal runaway, whereas high discharge rates can significantly damage Lithium-Ion batteries.

LiFePO4 is more durable and hence can withstand many more cycles than Lithium-Ion.

Cobalt used in lithium-ion batteries is a toxic material whereas LiFePO4 in non-toxic, hence LiFePO4 is much more environmentally friendly as there is no toxic materials used during the manufacturing process or end of life recycling of the batteries.

 4. Lithium solar batteries cannot be fully discharged

If they are discharged to 100% depth of discharge (DOD) for any longer than a few hours this will damage the battery cells.

For this reason, all lithium batteries have in built battery management systems (BMS) which will control all aspects of battery charging and discharging to protect the batteries.

When used with compatible solar inverters, the battery BMS will communicate with the inverter to protect the batteries.

Most inverters will only discharge batteries to around 80-90% DOD.

Most lithium batteries are warranted to around 80-90% DOD.

5. Lithium batteries cannot be charged in cold climates below 0 degrees celsius.

Most lithium batteries will start charging at around 5 degrees, but only at a very low charge rate. The charging rate will increase linearly to full charging rate at around 25 degrees.

For lithium batteries to function properly in cold climate regions, the batteries would need to be installed indoors in a location where the ambient temperature is no less than around 10 degrees.

Some batteries brands (such as Tesla) have internal heating systems, which allow the batteries to be installed in cold climates and can function normally.

Other lithium battery brands (such as Dyness and UZ Energy) are developing internal heating systems which will be implemented into their battery systems and be available in the Australian market soon.