We're interested in the drawdown from the Furrion 12 volt refrigerator when used "off-grid". The Furrion manual describes the power use in "off-grid mode" as 5.3 Ah (Amp-hours) when the external temperature is 77 degrees F. That would suggest a battery budget of 127.2 Ah (5.3 x 24) per day. The question is: Does the refrigerator use that much? For instance, the manual suggests that there is an "Off-Grid Vacation mode" which they suggest helps to conserve power usage when disconnected from the grid. But they're not clear if the lower draw is the 5.3 Ah or some other amount. And is the 5.3 Ah an average figure accounting for the time the refrigerator compressor is not working or is it the draw when the compressor is on? This is important in deciding on the size of our battery bank. A lot of our camping is done off the grid. And while we will have solar to recharge the batteries, many of the campgrounds we like the best are heavily wooded minimizing the amount of solar we will get.

So how to size the battery bank? If we assume 127.2 Ah per day, then to go for an off-grid excursion of five days without any recharge from the sun would take 636 Ah of battery (for reference the battery that comes with the 260RD is 100 Ah but since it is a lead-acid battery it should not be discharged more than 50% leaving an effective budget of 50 Ah, not even enough to run the refrigerator for 12 hours leaving out any other draws on the battery.) Currently, we're planning on 3 200 Ah LifePO4 batteries but are considering adding a 4th. Lithium batteries theoretically can be discharged to 0%, but in practice, they last longer when discharge to no more than 30%. So the 3 batteries we have now would give a battery budget of 3 x 200 Ah x 70% (100% - 30%) or 420 Ah. That might be enough for a little over three days assuming the 127 Ah draw is correct and we don't run too much else off the battery.

Have any of you done any real-world observations on what the Furrion refrigerator actually uses? Any suggestions on how to size the battery bank? I'm already leaning towards a 4th battery. While we will get some solar recharge even from the shadiest of sites (I'm going to deploy two 100 W portable arrays that can be moved around to be in the sun, plus a 100 W panel in addition to the 160 W panel already on the roof), right now I'm planning on worst-case numbers. We also have a generator (rather not use it due to the noise) and will be employing a 40 A DC to DC charger to allow the TV to charge the batteries when driving.