Hi. I wanted to jump in just to give you a head’s up on your plans. Before you rush into any buying, it’s important to consider what you need at minimum. Right now, you probably will be disappointed with your purchase. Please note that I am making up all these numbers as best I can for a reasonable example. You need to get a little deeper into this before you can be sure of what you need.

Step1, Power Output: Decide what things you want to power in an emergency and figure out how much power that is, at maximum. You want to power a refrigerator which is a huge power drain. A typical side-by-side fridge is going to use 800-1000 watts. There should be a metal plate inside the fridge that will have the information. It might list the voltage and amps instead of Watts, in which cast you multiply 115v (assuming) by the number of amps to get the max Watts. Now do that with all the other things you want to power. It’s honestly good to have a spreadsheet to keep track.

You will use that maximum number against what your battery pack says is the maximum. The Delta Pro 3 says it handles up to 4000w, so that sounds great, but look into that more and makes sure “up to” means with the actual device you are getting and not only by adding extra equipment.

Step 2, Capacity: OK, now you have to figure out if you have enough storage capacity (battery power). Again, from the spreadsheet, let’s say you measured 1000W. That means that for a full day’s use, you need 24hours X 1000W = 24,000 Wh, or 24 kWh! The good news is that your fridge doesn’t run 24 hours a day. They cycle on and off. If you have a kill-a-watt (and if you don’t, honestly you should get one), connect it to your fridge and let it go for 2 or 3 days to compute an average. Keep in mind that with no AC on in your house your fridge will run harder, so add 20% or so to that number for safety’s sake. I’ll go out on a limb ad say you’ll end with an average of 150-175w/hour, or so somewhere between 3.6-4.2 kWh per day.

Now, you might see the problem. The bank you want is “only” 4kWh. That’s a lot for a portable device, but not very much if you want to run a fridge. Realistically, it will run only a fridge for less than 2 days before it’s out of power unless you have a way to recharge (see next step 3). You will likely want to run it for 2 hours and turn it off completely to save power. Depending on the quality and how often you open it that might extend things, but you see what you have here. A 4kWh system is not what you are looking for, unless you can recharge it every day.

Step 3, Generation power: 300W worth of solar panels is not a lot at all. And those 3 panels will probably only generate around 200W on a good day, and only maybe 10 hours a day in the summer if there are no clouds. That means you can probably get 2 kWh extra every day, if you are lucky. That’s about half of what you need for just your fridge. You definitely need to shore up that 300W worth of solar panels. You can literally never have too many. Also, make sure they are all compatible with each other. It’s best to buy all of the same kind at the same time because you can run into lots of problems mixing different panels. Even buying the same brand many months apart can be a problem. That technology changes a lot all the time.

*By the way, this actually matters. If you still have incandescent bulbs in your fridge, replace them with LEDs. I was once running a generator at maximum, and opening the door choked everything, because 2 40W light bulbs is a lot of extra juice to support.

**I live in Houston, and was out of power for 4 days and 6 days last season and for 6 days I had lots of gas left over from my 6 gallons runnig my 2kW Honda inverter generator. I generally have the luxury of knowing when a storm is approaching and filling up my gas cans with non-ethanol gas (since hurricanes don't really sneak up on you). Everyone is different and has different needs so I hope this works out.