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Sundance Power
Systems, Inc.
Phone: 828.645.2080
Fax: 828.680.9798
11 Salem Hill Road
Weaverville, NC 28787
E-mail |
The size of the Battery Bank is determined
by the Load Analysis, as well as the number of days of autonomy that are
required to reserve power in periods of inclement weather when the resource
is not available for charging.
Click here for Grid-Tied Inverter
Sizing.
Renewable Energy System Components:
-
Battery Bank
The Battery Bank is sized to store enough
energy to meet your electric loads when the charging source (for example:
sunlight in the case of PV) is not available. The Battery Bank in an
Off-Grid system is sized based upon how many days of autonomy is required
to sustain your daily load requirements with little or minimal charging,
and is also based upon the average number of charging hours from your
power source that you have available per day. In a Back-Up system the
battery bank is sized upon specified loads that are determined as "critical
loads" that you would want to maintain in the event of a power outage
from the grid.
- Charge Controller
The Charge Controller is sized based
upon the Voltage of your system and how many Amps the solar array and/or
turbine produces at maximum production. Maximum Power Point Tracking
Controllers are becoming standard which are designed to maximize the
output of your solar array.
- Inverter
Inverters are sized based upon the Average
AC Daily Load from the Load Analysis. Every Inverter has two ratings,
voltage and wattage capabilities. For example, a Xantrex SW5548 is a
48Volt Inverter with a continuous output of 5500 Watts. Some larger
systems incorporate more than one inverter.
Calculating the
Required Battery Bank Size:
Multiply “Total watt-Hrs per
Day” from the Load Worksheet and
the “Number of Days of Autonomy”.
Multiply the result by the planned “Depth
of Discharge” (either 0.50 for typical
optimum longevity or 0.80 for lead acid
deep cycle batteries).
Multiply the result by the appropriate “Derating
Multiplier” from the Table.
Divide the result by the capacity of
the batteries. This may not result in
a whole number. Round the number of batteries
to fit the system voltage, i.e. a twenty-four
volt system requires sets of 2 when using
12 volt batteries. |
| Table: Derating
for Low Temp |
| Battery Temp (F) |
Multiplier |
| 80 |
1.00 |
| 70 |
1.04 |
| 60 |
1.11 |
| 50 |
1.19 |
| 40 |
1.30 |
| 30 |
1.40 |
| 20 |
1.59 |
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