Download Deep Cycle Batteries for Remote Off-Grid Power

Deep Cycle Batteries for Remote Off-Grid Power Systems
Batteries - An Introduction.
Batteries are used to store energy, just like a fuel tank in a car. Just like a fuel
tank, they do not produce energy. The energy taken out needs to be replaced
or the battery will eventually run out of power.
The most popular types for solar and wind applications are deep cycle lead
acid batteries. From the cost and reliability perspective, this established
technology continues to dominate. Lead acid batteries have to be treated with
care or they will need replacing very quickly.
The care they require is quite simple - they must not be over-charged or
over-discharged. In a solar or wind energy system, the charge controller takes
care of the batteries, ensuring that they give an optimal life. For gel or AGM
batteries, little or no user maintenance is required. Wet unsealed batteries
need occasional topping up with distilled water.
Heavy Duty Deep Cycle Batteries
The difference between a proper heavy duty 'deep cycle' battery and the
'starting' battery on a car is significant. A car battery is designed to produce a
short burst of power to start the engine. A deep cycle battery is designed to
provide power over a far longer period of time.
If you use a car battery on any system which discharges the battery deeply,
the car battery will fail quite quickly. The stress of a deep discharge often
permanently warps the lead plates, causing a shorted cell.
For this reason, deep cycle batteries have far heavier and stronger lead plates
inside of them. This enables them to better withstand the stress of a deep
discharge. It also makes them more expensive, as these days, lead is very
costly.
Leisure batteries and marine batteries are generally a cross between a starting
battery and a deep cycle battery. They are cheaper than true deep cycle
batteries due to the fact that they use less lead in their construction.
Long-life deep cycle industrial batteries are produced in 2v cells, which are
joined together on site to provide the correct voltage (i.e. 12 x 2v cells = 24v
battery bank). This enables the assembly of massive battery banks, which
otherwise would be virtually unmovable as a single unit.
The the amount of energy a battery can store is rated in Ah (Amp hours). It
varies depending on how quickly the power is taken out, however most
batteries are rated at the 20hr or 100hr rate. This means that a battery rated at
'100Ah @ C20', is able to produce 100Ah when discharged over 20hrs, i.e. a
constant load of 5 amps.
The life of a battery is expressed as 'design life' or 'cyclic life'. If a battery is not
cycled much, it will normally last for the design life. If a battery is cycled
regularly, its life will depend on the depth of the discharge cycle and the
number of cycles it has to do. This data is often shown plotted on a graph by
the manufacturers and is the key to a good deep cycle battery.