Power Rating –
The power rating of a battery is expressed in kilowatts (kW), this indicates the maximum amount of power the battery can deliver at any given moment and determines what appliances or loads the battery can handle at once.
Battery Capacity –
The capacity of a battery is expressed in kilowatt-hours (kWh), this indicates the total amount of energy the battery can store and deliver over a period.
Depth of Discharge (DoD) –
The percentage of a battery’s total capacity that’s been used, relative to its overall capacity.
Eg: If you have a battery that holds 5kW of energy and the DoD is 80% it means you’ve used 4kW of energy.
Round Trip Efficiency –
Is a measure of how much energy you can get out of your battery compared to what you can put in. The higher the percentage the better because it means the battery is more efficient at storing and delivering energy with minimal losses.
Eg: If a battery is charged with 100kWh of energy and later delivers 90kWh of energy when discharged, the round trip efficiency is 90%
Warranty –
Always read the fine print! Don’t just look at the number of years the battery is warranted for, look at the cycles too.
Eg: A battery may have a 10yr warranty with a limit of 5000 cycles. This means you can charge and discharge your battery for a total of 5000 times only, regardless if that takes 10yrs or less.
Egress Protection Ratings (IP + 2 digits) –
An IP rating indicates the level of protection an electrical enclosure (your solar battery) has against solids and liquids.
Eg: An IP55 rating means the battery can withstand an outdoor installation where dust and rain may be present. An IP67 rating means the battery can withstand an outdoor setting where dust and heavy rainfall may be present and potential flooding; where your battery may be submerged up to 1m for 30 minutes.