EF-Series Instruction Manual
Rev 2/01 1-19
1.7.5 Batteries
In solar installations, batteries provide power for the EF-Series Unit whenever the solar panels are not
generating sufficient output.
The standard battery configurations use a 12-volt, sealed, lead-acid battery (approximately 6.0 x 2.6 x
3.7 inches). These configurations can provide 7, 14, 21, or 28 amp-hour capacities. Recommended 7
amp-hour battery types (up to four batteries) for EF-Series Units are listed below. If other batteries are
used, Fisher Controls recommends rechargeable, sealed, gel-cell, lead-acid batteries.
♦
Powersonic PS-1270 7.0 Amp-Hour
♦
Panasonic LCR12V7.2P 7.2 Amp-Hour
♦
Yuasa NP7-12 7.0 Amp-Hour
The batteries are connected in parallel by a supplied wiring harness to achieve the required capacity.
The amount of battery capacity required for a particular installation depends upon the power
requirements of the equipment and days of reserve (autonomy) desired. Battery requirements are
calculated based on power consumption of the EF-Series Unit and all devices that will be powered by
the batteries.
Battery reserve is the amount of time that the batteries can provide power without discharging below
20 percent of their total output capacity. For solar-powered units, a minimum reserve of five days is
recommended, with ten days of reserve preferred. Add 24 hours of reserve capacity to allow for
overnight discharge. Space limitations, cost, and solar panel output are all factors that affect the actual
amount of battery capacity available.
To determine the system capacity requirements, multiply the system current load (I
SF
) on the batteries
by the amount of reserve time required. Compute “I
SF
” as described in Section 1.7.3, Totaling Power
Requirements. The equation is as follows:
System Requirement = I
SF
amps × Reserve hrs = _____ amp-hrs
Finally, determine the number of batteries required for the calculated power consumption by rounding
up to the nearest multiple of 7 amps: 7, 14, 21, or 28 amp-hour capacity. If more than 28 amp-hours
are required, an external battery enclosure with additional batteries may be used.
To Next Page
Loading...