How it works | System Components

Battery Bank

What is it?
Your battery bank is the place where all of your energy that you made during the day will be stored. At night or during extended periods of cloudy days, this energy is 'used or discharged' from the batteries to power your home.

There are many types of battery technology. Some types are extremely efficient (like the Lithium Ion batteries you might find in your digital camera) but the chemicals found in these batteries are extremely toxic and are not used for the large scale battery banks typically used in a renewable energy system. Also only some batteries are designed to cope with the daily charge and discharge needed with a home system. For these reasons, there are a limited number of battery types that are typically found in a renewable energy system.

The batteries used in a renewable energy system are called deep-cycle batteries and they often come in two types: 'flooded' or 'gel' . Both types have advantages and disadvantages depending on your needs (you can read more on these battery types below). Unless requested, we sell most of our systems with 'flooded' batteries.

How will they be installed?
The battery bank MUST be installed in a fire-safe, weather-proof, purpose built enclosure. It must ne vented to the outside and if 'flooded' batteries are used, must have easy access for maintenance (read more below). It should be kept a close distance to where the inverter will be installed.
The batteries are wired up in series to create 'banks' of certain voltages (usually 24 or 48 volts depending on your panel array wiring and your inverter input).

How long do they last?
Batteries are definitely the 'weak link' in the system. Though they are necessary for any Stand Alone or remote system, they are usually one of the first components that needs replacing. This does not mean that with good care, your batteries won't live their expected lifetimes. The problem is that batteries often get discharged too far. Each time they are brought too low, time is being taken off their life

We try to design our systems so that ideally, the batteries are only discharged to 10%. If this cycling is maintained through being aware of your system performance, conserving power during cloudy days and using a generator back-up, there is no reason why your batteries won't last.

Depending on the make of the battery, they are built for 5, 10 and even 15 year life spans. We like to supply high quality deep cycle batteries that carry a 10 year warranty.

More info...
A 'flooded' or Flooded Lead Acid battery is a large plastic box that contains lead plates and is 'flooded' with electrolyte — a type of battery acid. When they charge, some of the water in the electrolyte turns into gas. For this reason, there are openings in each battery that allow the home owner to re-fill the battery with distilled water. This typically needs to happen about once or twice a year. If the batteries are accidentally over-charged, this usually results in more gas and therefore a refill of more water (though if a battery is overcharged too much it will be damaged!).

A gel battery costs more to purchase, but it is sealed and does not require maintenance. A major drawback to gel batteries is that if they are overcharged they can be damaged for ever. This can quite expensive to replace.