Hi guys!
I know some of you are running overland fridges and I just got mine a few weeks back (ARB Fridge Freezer). I'm wondering if there are any sort of calculation I can do to see how long the fridge will run on my aux battery with the truck off? I have a battery gauge but it would be nice to know a running time.
Any help would be much appreciated!
Richard
Here is the basic info for you from
http://www.adventuretrailers.com/12volt_solar.html:
Tips for Evaluating 12 Volt Power Requirements
In the same way that we plan our trips revolving around our MPG and miles per tank, we need to do the same for calculating our auxiliary electrical needs. It’s really quite simple: The key is Ohms law. It is a basic equation that can be read a few different ways depending upon what number you need to crunch:
Volts x Amps = Watts
Watts ÷ Amps = Volts
Watts ÷ Volts = Amps
Let’s say you want to know how many Amps an ARB 13Watt, 12V fluorescent light is going to consume per hour. Your answer is 13 Watts ÷ 12 Volts = 1.08 Amps per hour of usage.
Understanding Deep Cycle Battery Basics
The Group 31 Valve Regulated AGM Batteries that we favor in our trailers and vehicle conversions are very stout. A general rule of thumb for calculating available power from these 105 Amp hour batteries is that no more than a 50% discharge (52.5 Amps) will give you the longest battery life and the most cycles. A cycle is each full recharging occurrence. Unfortunately, often we need to discharge beyond this 50%. A deep cycle battery is considering completely discharged when it reaches about 10.5 volts. Below 10.5 volts, most 12 volt appliances stop working. This is approximately 80% (84 Amps)
105 Amp Battery
So here’s the math again. Using our 105 Amp Battery and the ARB 13 Watt, 12V Fluorescent light as an example:
(105 Amps X .80) ÷ (13 watts ÷ 12 Volts) = 77.7 Hours of burn time.
