To determine if a 120Ah deep cycle battery can power a 700W microwave oven, we need to consider the power requirements and the capacity of the battery.
Power requirements: A 700W microwave oven consumes 700 watts of power during operation.
Inverter efficiency: Inverters are not 100% efficient, so you need to take into account the efficiency of the inverter when calculating the power required from the battery. Let's assume an average inverter efficiency of 90%.
Battery capacity: The capacity of a battery is measured in ampere-hours (Ah). A 120Ah battery can theoretically supply 120 amps of current for one hour or 60 amps for two hours.
To calculate the power consumption from the battery, we can use the formula:
Power (in watts) = Voltage (in volts) x Current (in amps)
Since we know the power (700W) and the inverter efficiency (90%), we can calculate the current required:
Current (in amps) = Power (in watts) / (Voltage (in volts) x Inverter Efficiency)
Let's assume a standard voltage of 12 volts for a deep cycle battery:
Current (in amps) = 700W / (12V x 0.9) ≈ 64 amps
Considering the above calculation, a 120Ah deep cycle battery should be able to power a 700W microwave oven through a 1400W inverter. However, it's important to note that the battery's capacity will determine how long it can sustain that power.
To estimate the runtime, you would divide the battery capacity by the current required:
Runtime (in hours) = Battery Capacity (in Ah) / Current (in amps)
Using the example of a 120Ah battery:
Runtime (in hours) = 120Ah / 64 amps ≈ 1.88 hours
Keep in mind that this calculation assumes ideal conditions and doesn't account for factors like battery efficiency, voltage drop, or variations in power consumption by the microwave oven. Therefore, it's always advisable to have some additional battery capacity or a backup power source to ensure continuous power supply, especially if you plan to use the microwave oven for an extended period or at higher power levels.