Page 14 - PS Battery Guide May 18

Battery guide For PowerSpout

"Flooded" or FLA batteries
These are still the most common lead-acid battery type in use today. "Flooded"
simply means that the batteries contain dilute sulphuric acid in liquid form.
These batteries need to be checked and topped up with de-ionised water from
time to time. Water is converted to hydrogen and oxygen as a byproduct of the
charging process. Often the water consumption increases, as they get older.

FLA batteries can come in many types that are suitable for many purposes and
often you will find sealed alternatives for the same purposes. Sealed batteries are
typically more expensive (for the same performance) but will survive some
neglect, whereas FLA batteries need maintenance (topping up).

Flooded batteries have the advantage that you are able to check their condition
using a hydrometer. It is wise periodically to check every cell after they have
been on charge for some time to verify that they have all achieved an equal and
satisfactory state of charge based on the strength of the acid solution as reflected
in its specific gravity. If the gravity is low or uneven then an equalising charge
can be conducted at a higher voltage to remedy the situation. None of this is
possible with a sealed battery as you cannot access the acid, nor is it wise to
overcharge the sealed battery at higher voltage.

Engine starting batteries (car batteries)
These are lightweight in relation to the current they can delivery ("cold cranking
amps") for starting an engine. This is because their plates are thin. These
batteries do not thrive if discharged, so they are unsuitable for off-grid energy
storage applications where they will be discharged to meet high demand at
certain times of day. If you have a very good hydro site (>1kW) where the
batteries are almost always full (with surplus power going to hot water) and
batteries are only needed to meet short duration peak loads then some clients
have used these batteries with great success and life of 7-10 years.

Heavy duty batteries
Used in trucks and boats and
recreational vehicles to provide
power when the engine is not
running, can be expected to
survive a few hundred
charge/discharge cycles (unlike
car batteries).
They are competitively priced
but will not last as long as more
costly batteries and are not
suitable for daily deep cycling
over a period of years.

Industrial or "traction" batteries
These are used on forklift trucks and are also sold as "solar batteries" because
they can survive several thousand cycles to 50% depth of discharge. They are

© 2018 EcoInnovation Ltd (NZ) Page 14
Last reviewed 19/6/18