Installation Manual

29
RENEWABLE ENERGY APPLICATIONS
Most deep cycle batteries used in the Renewable Energy Industry were
originally designed and manufactured for use in Industrial applications where
consistent charge cycles are carried out from six to twelve hours until the
batteries reach a full state of charge. In Renewable Energy (RE) applications,
a lengthy charge time is not typical and in most instances a maximum of
4-6 hours of peak charge is achieved each day due to limited daylight and
varying weather conditions. To ensure the batteries received sufficient charge,
charging systems must be adequately sized or additional charge sources
added to prevent deficit charging and premature battery failure.
There are two definitive types of battery-based systems used in Renewable
Energy applications; Off-Grid and Grid-Connected. Off-Grid systems are
often used where a customer chooses not to connect or there is no available
connection to a public utility. This customer may live remotely and have
chosen to install a renewable energy system from a single or combination of
renewable sources to generate and store adequate power to run all electrical
requirements within the home.
With Grid-Connected systems, a customer typically lives in an area where they
may experience frequent or extended service interruptions from their public
utility. This may be a result of poor weather conditions, an unreliable power
grid or natural disasters. The renewable energy system is used as a backup
power supply, meant to supplement power during brief outages and/
or to reduce energy costs by selling excess power generated from the system
back to the utility.
OFF-GRID SYSTEMS
When sizing a battery bank it is important to determine the appropriate
capacity requirement to meet the load which will be supported and not
oversize for the application. A battery bank which is too large for the charging
source often leads to sulfation issues due to lack of proper charging as well
as frequent supplemental charging from another source. (ex. generator)
DEPTH OF DISCHARGE
Depth of Discharge (DOD), is used to describe how deeply the battery has
been discharged. A battery which is 100% fully charged would have a DOD of
0%. A battery which has been discharged by 20% of its capacity, maintaining
80% of its capacity, would have a DOD of 20%. If a battery has been
completely discharged with no remaining capacity, the DOD is 100%.