Page 28 - PS Battery Guide May 18

Battery guide For PowerSpout

provide large currents to meet the high power demands of starting an engine. As
the duration of engine starting is very short the total amount of energy is not that
great. However, automotive batteries suffer when significantly discharged. The
thin plates are quickly damaged and may even disintegrate. The plates also have
a high resistance, so lose energy, making a car type battery less efficient as an
energy storage device. They can be employed in some hydro situations where
there is plenty of power to meet the base load of the home, with the battery
merely providing storage for short-duration peak loads.

A deep cycle battery designed for standby energy systems has heavy plates that
are much more robust against deep discharges. However, a deep cycle battery
has limited surface area and cannot convert stored energy as quickly. Thus deep
cycle batteries must not be subjected to heavy currents or there will be damage
to the battery.

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 fully
charge for FLA type) 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
FLA 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 or loss of power to the home. Two battery strings provide
more redundancy. Generally it is regarded as good practice not to have more
than three parallel banks.

Battery recombination vents/caps
Recombination caps can reduce the watering interval from every 3 months to
once a year, they are well worth the extra cost.

© 2018 EcoInnovation Ltd (NZ) Page 28
Last reviewed 19/6/18