Solar Battery Terms Explained
Solar Battery capacity term
Solar battery capacity refers to the amount of energy that the battery can hold and be used for your electrical appliances. Battery capacity is calculated by voltages, amps per hour and the rate of the battery discharging.
Solar Battery bank term
This is multiple batteries connected together to work in your configuration and with the inverter. Solar battery banks are configured to perform at a specific voltage which is usually 6V, 12V, 24V and 48V. Battery banks are also calculated by their Amps per hour ratings, for example, 300Ah.
Battery voltage term
Voltage is the unit used for rating batteries. Lead-Acid batteries are commonly rated by 12 Volts, 6 Volts and 24 Volts. Batteries are usually connected with wires in a series which increases the overall voltage to the correct levels. In most cases, small solar or backup battery installations makes use of 12v batteries. On the other hand, larger installations will use 6V or 2V batteries in parallel to achieve increased Amp hours instead.
Amp hours term
Batteries are rated by the Ah ratings. Amp-hours, what exactly does it mean? Ah, or Amp-hours is used to calculate the amount of current a battery can output over a specific time period. Lead-Acid batteries can be easily analyzed according to their capacity depending on how quick or slow the discharge is. However, lithium-ion batteries usually only provide one Ah rating. The graphic shows that a battery being discharged for 15 hours a day, has a capacity of 402Ah.
Kilowatt an hour
Kilowatt per hour or kWh is how Eskom is billing you on the number of kilowatts or 1000watts you consume in an hour, billed per month. This makes it easy to determine your total energy consumption to calculate your total battery capacity for a battery bank.
We use voltage and Amp hours to calculate the total capacity.
Voltage x Amp-hour = Capacity in Watt-hours.
If we use a 12V battery it will be like this:
12V x 75Ah = 900Wh.
A 12 Volt battery running for 75 Amp-hours produces 900-watt hours or 0.9kWh of energy.
Battery cycle term
A battery cycle is when a battery is discharged and charged again, therefore, it is one battery cycle. You can’t always depend on the warranty of a battery to determine how long the battery would last. The best way to measure a battery’s life is to calculate the battery using its life cycle rating. You determine how many times a battery can cycle or can charge and discharge before it will go bad.
Solar Battery DOD
Battery depth of discharge is the volume of energy that is produced out of the battery during each charge or discharge cycle the battery goes through. Running a battery at a 65% discharge, actually means that 65% of the battery’s energy will be used before a charge will occur. Understanding the DOD or depth of discharge of batteries will be incredibly useful when you want to calculate the lifespan of the battery. For example, discharging a lead-acid battery too deeply may shorten its lifespan drastically compared to when you discharge it shallowly.
Solar battery efficiency
No battery is 100% efficient because a part of the power transmitted gets lost in the process of charging and discharging. Lead-Acid batteries are 80 to 85 percent efficient, while lithium-ion batteries are up to 98% efficient. For example, if PV panels produce 1kWh hours of power, Lead-Acid batteries, lead-acid batteries can only store 800Wh due to the power losses in the cycle processes. On the other hand, using lithium-ion batteries, you can have 950Wh of power available.