New guy from Western North Carolina needing advice

[jgonzalez8499]

Hello everyone. I am hoping to to find some good help from others that have experience in the Solar Power area. To start off let me describe the area that I will be needing a solar power system. I have a small cabin/shed I use during hunting season and just for breaks from the normal routine located in Western NC area on the mountain side with clear unobstructed views. The cabin is only about 120 square feet. According to the solar websites, my region gets roughly 4.5 usable hours per day. My goal is to be able to supply enough power to keep a mini-fridge (energy star rated - approx 220kWt/year) plugged in and occasional LED light use at night. Also the occasional recharging of an iPad/cell phone/laptop. Nothing else would require power.

I have been trying to find kits but it seems that the smallest ones I have seen are designed for small homes and provide much more than I need. Ideally I envision a panel or two, batteries, and something I can plug an extension cord or surge protector into.

Does anyone have any advice or recommendations for equipment I could use to set this kind of system up? I would greatly appreciate any help with this.

[inetdog]

Hello jgonzalez8499, and welcome to Solar Panel Talk!

I would start with the system sizing calculator in a sticky thread of the off-grid section.
Once you have an idea of what size components you need, we would be happy to make suggestions of how to put the system together.
Pre-packaged systems are usually overpriced and inflexible, so even though you do not have a lot of knowledge going in, the component route usually works best.

[jgonzalez8499]

Update on System Size

Thanks for the reply. I looked through the Off Grid section and tried to determine what kind of set up and size I will be needing. My goal is to run this whole system complete off grid. It is a system that will be a very small cabin that is used for long term camping/hunting. So far below is what I have come up with. First I will list what I am going to be powering and if from anyone's experience my numbers are off please let me know.
Energy Star Mini Fridge - 275kWh/year
Laptop Charge - 75kWh/year
Phone Charge - 5kWh/year
iPad Charge - 75kWh/year
HE/LED Light - 5kWh/year
total - 435kWh/year (approx 37kWh/month)

From running a sizing calculator it recommends:
2 - 200 watt panels

But what it does not recommend is how many batteries or size of batteries, how kind of inverter or power control I would need.
Also for calculations I am using 4.5 hours of usable sunlight per my location in Western North Carolina.

[Sunking]

Thanks for the reply. I looked through the Off Grid section and tried to determine what kind of set up and size I will be needing. My goal is to run this whole system complete off grid. It is a system that will be a very small cabin that is used for long term camping/hunting. So far below is what I have come up with. First I will list what I am going to be powering and if from anyone's experience my numbers are off please let me know.
Energy Star Mini Fridge - 275kWh/year
Laptop Charge - 75kWh/year
Phone Charge - 5kWh/year
iPad Charge - 75kWh/year
HE/LED Light - 5kWh/year
total - 435kWh/year (approx 37kWh/month)

From running a sizing calculator it recommends:
2 - 200 watt panels

But what it does not recommend is how many batteries or size of batteries, how kind of inverter or power control I would need.
Also for calculations I am using 4.5 hours of usable sunlight per my location in Western North Carolina.

First mistake is you do not use yearly average sun hours. If your average is 4.5 Sun Hours you go dark in every month with less than 4.5 Sun Hours and destroy your batteries. You use worse case, most likely you are looking at around 3 Sun Hours in December or January 37 Kwh/month means 1.2 Kwh per day. You look it up. Assuming 3 Sun Hours panel wattage = [1200 wh x 1.5] . 3 Sun Hours = 600 watts.

Battery was in the Stickies. You need 5 day autonomy. 5 x 1200 watt hours = 6000 watt hours. To find Amp Hours capacity you need to select a battery operating voltage. With 600 panel watts you could go with 12 volts, but that gets a bit expensive. when it comes to wiring, controllers, and safety. Being such a small cabin you could get away with 12 volts. But I would only recommend it if everything you use operates on 12 volts and safety/expense is of no concern. 24 volts with an Inverter is more adaptable, twice as safe, and less expensive in the long term. To find battery AH Capacity = Watt Hours / Battery Voltage. So 6000 wh / 12 volts = 500 AH or 250 AH @ 24 volts. Take your pick.

A MPPT charge controller is determined by Panel Wattage and battery voltage. Minimum Controller Current = Panel Wattage / Battery Voltage. So 600 watts / 12 volts = 50 amps, or 25 amp at 24 volt battery. Four of these batteries would be about perfect. They cost roughly $140 to $160 each.

Lastly keep your wiring losses to less than 2%. That gets real expensive at 12 volts requiring special tooling to make it safe.

One last thing. Hope my friends do not find your cabin with those bright shinny panels getting their attention from miles away.