Your average daily amp-hour requirement from the last line
of the System Loads Worksheet.
________
Maximum number of consecutive days without power generation that
you need
to supply your loads (days without solar, wind, hydro, engine-generator, etc.)
________
Multiply line 1 by line 2. This is the amp-hours or storage
you need.
________
Maximum depth of battery discharge you wish to subject your
battery bank to.
Each discharge takes a certain amount of life out of the battery. The deeper
the discharge, the greater the loss of battery life. Do not exceed 80%
(0.80).
________
Divide line 3 by line 4 and write result here.
________
Select the proper temperature correction factor from the list
below for the
coldest temperature your battery bank will reach. Consider such factors as:
heat and insulation in the battery room and if the heat will be lost when you
rely on the battery storage. Keep in mind that the battery plates and
electrolyte temperatures are the important parameter here. Brief dips in air
temperature of only a few hours will not immediately cause an equal
temperature dip inside the battery cells.
________
80 F 27 C 1.00
40 F 4 C
1.30
70 F 21 C 1.04
30 F -1 C
1.40
60 F 16 C 1.11
20 F -7 C
1.59
50 F 10 C 1.19
Multiply line 5 by line 6 and show result here. This is the
TOTAL battery
capacity required in amp-hours.
________
Enter the amp-hour rating of the proposed battery cell you want
to use.
________
Divide line 7 by line 8 and round up to the next whole number.
This is the
number of battery cells wired in parallel required.
________
Divide the nominal system voltage (12, 24 or 48 V) by the battery
cell
voltage (usually 6 or 12 V). This is the number of batteries in series
required.
________
Multiply line 9 by line 10 and enter result here. This is
the TOTAL number of
battery cells needed for the bank to meet voltage and amp-hour requirements.
________
