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needs, a battery bank with greater capacity may be appropriate. The
minimum battery size recommended is 50Ah.
A number of different standards are used to rate battery energy
storage capacity. Automotive and marine starting batteries are
normally rated in cranking amps. This is not a relevant rating for
continuous loads like an inverter.
Deep-cycle batteries use a more suitable rating system, either amp-
hours (Ah) or reserve capacity in minutes. Battery reserve
capacity is a measure of how long a battery can deliver a certain
amount of current - usually 25 Amps. For example, a battery with a
reserve capacity of 180 minutes can deliver 25 Amps for 180 minutes
before it is completely discharged.
Amp-hour capacity is a measure of how many amps a battery can
deliver for a specified length of time - usually 20 hours. For
example, a typical marine or RV battery rated for 100Ah can deliver
5 Amps for 20 hours (5A x 20 hours = 100Ah). This same battery
can deliver a higher or lower current for less or more time, limited
approximately by the 100Ah figure (e.g. 50A for 2 hours, or 200A for
1/2 hour), but usually the capacity figure given is only accurate at the
specified rate (20 hours).
6.2 Estimating Battery Requirements
To determine the proper battery size or battery bank, you need to
compute the number of amp-hours that will be used between
charging cycles. When the required amp-hours are known, size the
batteries at approximately twice this amount. The expected amp-hour
requirements of each product to be used should be determined and
then added together; this total multiplied by 2 is the recommended
battery size.
Start with the nameplate ratings on your electrical products. If the
wattage is marked on the product, you can use that number directly;
otherwise, multiply the marked voltage and amperage: WATTS =
VOLTS X AMPS. Once you know the AC wattage drawn from the
inverter, multiply that by the length of time the appliance will be used
to determine the energy the load will require: WATT-HOURS =
WATTS X HOURS. You can then convert this to an estimate of the
battery amp-hours that the products require:
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Содержание Portawattz 400
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