Power Consumption - Cobra CPI 480 Operating Instructions Manual

Power Consumption

Installation
Power Consumption
For each piece of equipment you will be operating from the
inverter, you must determine the battery's reserve capacity
(how long the battery can deliver a specific amount of
current — in automotive batteries, usually 25 amperes)
or ampere-hour capacity (a measure of how many amperes
a battery can deliver for a specified length of time).
Example – Reserve capacity: a battery with a reserve
capacity of 180 minutes can deliver 25 amperes for
180 minutes before it is completely discharged.
Example – Ampere-hour capacity: a battery with an
ampere-hour capacity of 100 ampere-hours can deliver 5
amperes for 20 hours before it is completely discharged.
To determine the battery ampere-hour
capacity you require:
1. Determine how many watts each piece of equipment
consumes. This can normally be found on the product
label. If only the current draw is given, multiply the
current draw by 115 to get the watt consumption.
2. Estimate the time (in hours) that each piece of equipment
will be running between battery charging cycles.
3. Calculate the total watt-hours of energy consumption
(power x operating time) using the average power
consumption and the total estimated running time
(in hours). Power x Operating Time = Watt-Hours.
Laptop
50 watts x 2 hours
= 100 watt-hours
4. Divide the watt-hours by 10 to determine how many
power supply's (12 volt) ampere-hours will be consumed.
10
TV/VCR (up to 25") Blender
115 watts x 3 hours 300 watts x 15 minutes
= 345 watt-hours = 75 watt-hours
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