14
To achieve
50% cycling you should
calculate your amp-hour consumption
between charging cycles and use a battery
bank with twice that capacity**. Each AC
appliance or tool has a rating plate on it and will
be rated in either AC amps or watts or AC VA
(volt-amps) apparent power. To calculate amp-
hour consumption, use one of the formulas to
the right to calculate the DC amp-hour draw for
a 12-volt system.
Calculate the amp hours for every AC
appliance or tool that will be operated on the
inverter. This will provide the total number of
amp hours used between recharges. Size the
battery bank using this number as a guideline.
A good rule to follow is to size the battery bank
a minimum of two times larger than the
total amp-hour load requirement. Plan on
recharging when 50% discharged.
BATTERIES
(AC amps x 10) x 1.1 x hours of
operation = DC amp hours
(watts/ DC voltage) x 1.1 x hours of
operation = DC amp hours
(AC VA/ DC voltage) x 1.1 x hours of
operation = DC amp hours
DC voltage is 12, 24 or 32 depending on
your system.
**Batteries are typically charged to 85% of full
charge when charging with alternators without three-
stage regulators.
Typical Power Consumptlon
The chart identifies typical power
consumption for common AC loads. Use it as
a guide when identifying your power
requirements.
Many electric motors have
momentary starting requirements
well above their operational rating.
Start up watts are listed where
appropriate. Individual styles and
brands of appliances may vary.
If using the same battery
bank for the inverter and other
DC loads, be sure to consider
the power consumption of the
DC loads when sizing the
battery bank.
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inverter efficiency.
AMP-HOUR CONSUMPTION FORMULAS
NOTE
Certain laser printers, breadmakers,
digital clocks and appliance/tool chargers
may not operate on modified sine wave.
