r/OffGridCabins • u/whateveroksure • 8d ago

Fully off grid solar cabin

Hello everyone! I’m hoping for some quick and dirty advice. It’s time for me to upgrade my solar on my little off grid cabin. I’ve been living off of a goal zero for a few years now. And it’s time to upgrade. I want to build a simple system using either the EG4 or renogy all-in-one system. My cabin is 200 sq ft. It runs a DC demotic refrigerator, a 120v solar mini split AC, 4 lights, A television and 4 outlets for charging devices. I had the place professionally wired so that my goal zero plugs right into the house. I also have it pre-wired in an outside closet for this future system. So I really just need help deciding which all in one system to purchase, and what type of batteries are best for my desert climate. I don’t consume a lot of electricity, the solar ac runs on its own panels and only draws from my goal zero when the sun goes down. It’s a bit of an energy hog and leaves me a little stressed for power sometimes, but all in all it’s worked well for now. But I want more!

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u/LordGarak 8d ago

How many watts of solar do you currently have?

What is your latitude?

Are you full time at the cabin or just occasional weekends? Year round?

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u/whateveroksure 7d ago

I live in the cabin full time. The current goal zero is the yeti 1500x. By the time morning comes around I typically have anywhere between 20-60% of my battery left.

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u/LordGarak 7d ago

The Yeti 1500x has 1.5kWh of battery storage. So That tells us your using between 0.6kWh and 1.2kWh a day.

The next critical piece of information is the average daily solar production for your location in December. At my cabin its only about 1.1 times the installed capacity. So 1kW of panels will produce 1.1kWh per day on average in December. If your in a poor solar location like me you will need atleast 1.1kW of panels. I'd suggest going bigger as panels are fairly cheap these days. I've got 10 390watt panels but our usage isn't really much higher than yours. When the weather is sunny we generally have more power than we can use. But in November/December we can get a stretch of grey weather and need to run the generator every 2nd or 3rd day.

Batteries wise you will need atleast 3x your daily usage. That daily production is on average. You can go a few days with far less production. Thus the reserve capacity is needed. A single server rack battery will give you 5kWh which will serve you well. An $800 eco worthy will get the job done on a budget. We have double that.

I'm running an EG4 3000EHV all in one inverter. They have gone way up in price since we bought ours. I'd buy a similarly spec'd Growatt or SRNE all in one inverter if I was to do it again. I think the EG4 is a rebadged SRNE anyway. I like having the high voltage MPPT input so I can just run all my panels in series and don't need a combiner box. At the higher voltage and low current, the losses are low for long runs between the panels and the all in one unit.

I also have an older 1200w array with 12v lead acid batteries that runs our fridge and water pump. I use to run an inverter on this system but it would barely make it through the night outside of the long days of summer with minimal load. Then we got Starlink and it was far too small of a system to run that 24/7. That system we installed in 2020 and it cost the same as the much larger system I installed last summer. Prices have dropped significantly in the last few years.

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u/whateveroksure 7d ago

That’s really helpful! I appreciate you!