F) Battery (Dc) Wiring - NewMar 12-1800IC Installation & Operation Manual

Use the following procedure to calculate the required amp-hour capacity for your battery
system:
Note: It is assumed that the batteries are a suitable deep-cycle type, that discharge will
not exceed 50%, and that batteries will be fully recharged after each cycle of inverter
use.
1) Determine the maximum amount of time in hours that the inverter will run the
loads before an external source of AC becomes available and batteries can be fully
recharged.
2) Survey all AC appliances and determine how many watt-hours will be consumed by
each during that same period. For instance, if a 100 watt TV will be powered for 3
hours, that equals 300 watt-hours. If a 1,500 watt microwave will also be run for half
an hour, then that is another 750 watt-hours (i.e., 1,500 x .5). Bear in mind that some
loads, such as refrigerators, are intermittent, so an average must be used.
3) Add up the total watt-hour consumption of all appliances, then apply this simple
rule to determine total DC (battery) amp-hours consumed:
12 Volt Inverters: Divide Watt-Hours by 10
24 Volt Inverters: Divide Watt-Hours by 20
32 Volt Inverters: Divide Watt-Hours by 27
Note: These divisors allow for standard inefficiency during voltage conversion.
4) Finally, since it is generally recommended that batteries never be discharged below
50%, the result must be multiplied by 2 to obtain the proper total battery capacity.
Example # 1: You have a 12 volt inverter. Your total consumption between recharge cycles is
2,400 watt-hours, so...
2,400 ÷ 10 = 240 (Amp-Hours Consumed)
240 x 2 = 480
So, in this example, a properly sized battery system will be rated for at least 480 amp-hours.
Example # 2: You have a 24 volt inverter. Your total consumption between recharge cycles is
3,600 watt-hours, so...
3,600 ÷ 20 = 180 (Amp-Hours Consumed)
180 x 2 = 360
In this case, you need a battery system rated for at least 360 amp-hours.

F) Battery (DC) Wiring

CAUTION: Assure that hydrogen gas does not accumulate near the battery by keeping the
area well ventilated. A substantial spark may result when connecting the final battery wiring
due to an initial charging of the internal input capacitor.
FIGURE 2 illustrates a typical battery wiring configuration (along with temperature sensor
wiring, discussed in section G, following):
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