Battery Storage

The energy stored in a solar battery system that can actually be used. In most cases this is less than the nominal storage capacity figure provided. For example, the Enphase AC battery has a total storage capacity of 1.2kWh. But as only 95% of that stored energy can be discharged (aka a 95% Depth Of Discharge) the battery’s usable storage capacity is really 1.1kWh.

Some solar battery storage in the table have different warranties for components within the unit. For example, some “all in one” battery storage systems warrant the batteries for 10 years but the internal inverter only has a warranty of 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.

This is only using the Electricity generated from your Solar Panels only. Typically in Self Consumption Mode you will do 1 cycle per day. Some Solar Battery Manufacturers like Alpha ESS and Tesla give you better Warranty if you only use Self Consumption Mode. Alpha Energy Storage System has a very strong Warranty. Over 10 years they still Warrant that you will get atleast 80% of the original Solar Battery capacity. This is the point that Alpha Solar Battery Storage are in big point of difference in value.

The storage throughput is the amount of energy that cycles through the storage bank in one year. Throughput is defined as the change in energy level of the storage bank, measured after charging losses and before discharging losses. This value is used to calculate the life of the storage bank.

The kilowatt hours (kWh) is the amount of stored energy that your battery can hold and use. The total warranted kWh is the number of kWhs a battery can provide per day multiplied by the amount of days given in the warranty period. To determine the cost per warranted kWh, you take the total solar battery price and divide it by the warranted kWh.

In terms of system sizing – battery sizes are expressed as kilowatt-hours, or kWh. If the average home uses 16kWh, 30% of this during the day and 70% at night, that works out to about 5kWh of daytime usage, and 11kWh of night-time usage. So, simple math would dictate that the average Aussie would need about 11kWh of solar battery storage to offset all their night usage. The Tesla Powerwall 2 has 13.5kWh capacity and costs around $15,000, including installation.

This is important when in an event of a power outage you need to consider how much power you will need to run your loads. The larger the KW rating this allows you to have more appliances turn on.

UPS – Means Uninterrupted Power Supply. When the power from the grid turns off the battery will kick in within 30ms. This is so fast that you might not even see your lights flicker.

EPS – Means Emergency Power Supply. When the power from the grid turns off the battery will take up to 1 minute to turn on.