The duration a deep cycle marine battery can power a portable refrigerator/freezer depends on several factors, including the capacity of the battery, the power consumption of the refrigerator, and the efficiency of the battery and electrical system. To calculate the approximate runtime, you'll need to know the following information:
Battery capacity: Deep cycle marine batteries are rated in ampere-hours (Ah). Look for the Ah rating on your battery to determine its capacity.
Power consumption of the refrigerator: Check the user manual or specifications of your portable refrigerator to find its power consumption in watts (W) or ampere-hours (Ah) per day.
Efficiency factor: Consider an efficiency factor of around 0.85 to account for energy losses in the electrical system.
Once you have this information, you can use the following formula to estimate the runtime:
Runtime (hours) = (Battery capacity in Ah * Battery voltage) / (Power consumption of refrigerator in watts * Efficiency factor)
For example, let's say you have a deep cycle marine battery with a capacity of 100 Ah and a voltage of 12V, and your portable refrigerator consumes 50 watts per hour. Using the formula:
Runtime = (100 Ah * 12V) / (50W * 0.85) ≈ 22.35 hours
Please note that this is a simplified estimate and doesn't take into account variables like temperature, battery age, and variations in refrigerator power consumption over time. Moreover, deep cycle batteries are not designed for full discharge, as it can reduce their lifespan. It's recommended to keep the battery at a state of charge above 50% to maximize its longevity.
Additionally, if you plan to rely on a deep cycle marine battery for extended periods, you may want to consider a solar panel setup to recharge the battery during the day and extend the runtime of the refrigerator further.
Always check the manufacturer's specifications and guidelines for both the battery and the portable refrigerator to ensure you use them safely and efficiently.