Installation manual

draw more than 2.42 kW for a sustained period you should install a larger battery bank and

inverter.

7.1.6. Battery life expectancy

In practice battery life is generally around 3-12 years, with 7-8 year life typical. Batteries are

occasionally flattened accidentally and this can have a significant impact on their total life.

Keeping them in a good state of charge (near full charge) will prolong their life.

Although there are many instruments to help determine battery state of charge, the most

reliable method is a hydrometer. A hydrometer can only be used with wet cell batteries.

Check your battery state of charge weekly and keep a log book. If your state of charge is

falling, either increase generation or decrease consumption. You need to generate at least

20% more than you use to allow for system losses.

Two parallel battery strings are better than one - a loose connection in a single battery string

can expose the whole power system to overvoltage from the runaway turbine. Two battery

strings provide more redundancy. Generally it is regarded as good practice not to have

more than three parallel banks.

Connecting batteries in series increases the voltage but not the amp hour capacity.

Connecting batteries in parallel increases the amp hour capacity but not the voltage.

Energy capacity is the same for a given weight of batteries.

7.2. Battery housing

Batteries need to be understood for what they are. Here are some key points:

 Batteries operate best when kept at around 10ºC to 20ºC. Never freeze

them. Fully charged batteries are hard to freeze but flat batteries are more easily frozen.

At low temperatures battery performance is sluggish but life expectancy is good.

 Batteries are full of sulphuric acid, lead and small amounts of other chemicals which

must not leak into the environment. Lead and its compounds are persistent poisons.

 Chemicals must not fall on or into batteries as this may cause a chemical reaction. Rain

water should be avoided as it may wash other material into the cells.

 Batteries store energy in chemical form and can release this as electricity

very quickly if there is a short circuit. A short circuit can convert a steel ruler

or spanner to molten metal spray and cause significant personal injury.

Protection from falling objects is required.

 Batteries are heavy and need a solid flat supporting surface. Good access for

installation and replacement to avoid lifting injuries is required.

 Batteries give off hydrogen and oxygen gas during charging in the correct proportions

for an explosion. Ventilation is required.

 Batteries are not maintenance free. All batteries need to be checked periodically for

individual voltage and flooded batteries also need to be checked with a hydrometer.

 Batteries need to be checked for electrolyte level regularly and topped up. If this is not

done they will be ruined and the risk of explosion increases.

 It is important to plan the accommodation of the batteries so that topping up with water is

easy to do. Batteries will use more water as they age.