Every solar panel is attached to a battery to store energy. Battery enables the generated electricity to be stored during the day and used at night. A battery storage system connects to a house in two main ways- Direct Current (DC) and Alternating Current (AC). A DC – coupled system is used consolidated into solar system. These systems have an inverter which converts Direct current(DC) electricity to alternating current(AC). The DC current electricity is produced by solar panels and stored by batteries, while the AC current electricity is used on the grid and in the most household appliances.
A battery storage system has numerous benefits when used with an existing or new solar panel.
- It minimises reliance from the grid.
- Instead of the energy being sent to the grid, maximum energy is stored by solar panels, in the battery, for future use.
- Provides electricity during power outages.
- Saves money by using the stored energy during peak times, such as evening.
- Due to significant fall in the prices of batteries more and more Australians are able to opt in for batteries.
WHAT IS THE BATTERY CAPACITY?
The battery capacity is the amount of energy stored in the battery storage system. The battery capacity is also promoted on the basis of total capacity and depth of discharge (DOD). The depth of discharge (DOD) is the amount of energy that can be drawn from the total capacity of the battery. The DOD is expressed as a percentage of total capacity. No battery has 100% of DOD.
Lead-acid battery system typically has a DOD between 30% to 50%, however a lithium-ion battery systems have a DOD of 80% or above.
It is advisable to consider the useful amount of energy in a battery system when purchasing a battery. Ask your solar expert for more information.
HOW LONG DOES A BATTERY LAST?
Batteries often last longer than its warranty (usually 2-10 years), however steadily its capacity to store energy decreases with time. Warranties of the battery varies as every manufacturer has their own product warranties. However, your retailer will also provide warranties.
WHICH BATTERY TO PURCHASE:
The three most common ways to purchase a battery storage system are:
- Fully-customised system: The installer makes the battery storage system from individual battery cells. It has customisable energy and power limits.
- Semi-customised system: Some components need to be collected to an off-the-shelf battery system to make a battery storage system.
- Off-the-shelf system: It is a typically all-in-one system which covers little customisation.
TYPES OF BATTERIES:
Ultra Battery is a hybrid with a single common electrolyte. It is a long-life lead-acid energy storage device. Its stores energy from renewables for later use.
Lead-Acid batteries are based on the technology used in car batteries. These batteries are generally used in rural areas, where connections to the grid are expensive. These batteries are relatively economical, easy to acquire and readily recyclable. However, a limitation with lead-acid batteries is that they require regular checks and maintenance, have a little depth of discharge and require external venting.
Lithium-ion batteries are based on lithium-ion technology, which has been earlier used in devices such as mobile phones and laptops. It is becoming the most prominent choice with house hold solar panels and has the capability to become the main technology in future. It has higher capacity and storage, lighter weight and higher voltage. It occupies less space, has reduced maintenance due to inbuilt battery and has a longer cycle life with a greater depth of discharge. However, it is a little expensive, has limited recycling programs in Australia and is a lesser known technology.
Flow battery, which is a type of rechargeable battery. Though these batteries are instantly recharged by replacing electrolyte liquid still they have low energy and power density as compared to lithium-ion and lead-acid batteries.
Saltwater batteries are the eco-friendly batteries, which have low maintenance, but they are a little more expensive than lead-acid batteries in terms of up-front cost.
It is important to keep an eye on how the battery storage system is operating. Different manufacturers adopt different ways of doing this: Some systems have a display on the battery along with indicators, some have remote displays inside the house, some have a system to access it on their mobile phones, laptops and computers via internet.
(Source: Battery Pocket Guide: www.ecogeneration.com.au)
Solar Power Batteries FAQ
- What does battery capacity mean?
The battery capacity is the amount of energy stored in the battery storage system. The battery capacity is also promoted on the basis of total capacity and depth of discharge(DOD). The depth of discharge (DOD) is the amount of energy that can be drawn from the total capacity of the battery. The DOD is expressed as a percentage of total capacity. No battery has 100% of DOD.
- How long does a battery Last?
Warranties of the battery varies as every manufacturer has their own product warranties. Batteries often last longer than its warranty (usually 2-10 years), however steadily its capacity to store energy decreases with time.
3.Where can a battery system be installed?
Battery storages can be wall mounted or floor standing, and could also be installed indoors or outdoors but, it really depends on the type of battery and manufacturer specifications. Large size batteries like Lead acid batteries are best suited to be installed outside as they vent hydrogen when charged. On the other hand Lithium batteries are designed to be wall mounted inside a utility room that helps control the temperature of the battery.
- Will battery work in a blackout?
Some batteries will work in blackout and others won’t. If you want the batteries to work in an event of a blackout speak to your solar designer to choose a product to suit your needs.
- Is it important to have monitoring?
It is important to keep an eye on how the battery storage system is operating. Different manufacturers adopt different ways of doing this: some systems have a display on the battery along with indicators, some have remote displays inside the house, some can be accessed through mobile phones, laptops and computers via internet.