Advice for 800sf full time off grid home

[scottmag]

Can you advise?

I’m building an 800sf steel building house far from the grid in north central Florida. I’ll have gas for water heater, stove, etc.

I need to power a 24k BTU split air system and all the normal things. Four kids and one adult (me) and some small farm stuff like lights and gates. No well pump or heat system yet.

i was looking at Ecoflow but many say it’s overpriced for what you get.

I’m trying to do this myself to save on setup costs. I’m estimating, based on my current 1150sf apartment electricity bill that I will need about 8kw system, but open to advice on that.

 

[400bird]

What are your constraints?
Is price your highest consideration? Reliability?
Do you have the skills to do the wiring?
Do you have a budget?

When the weather is uncooperative, how many days of autonomy do you want? I guess I should ask, will there be a generator it supplement when there isn't enough sun? How often are you ok with running the gen? If you never want to run the gen you'll need a significantly larger battery than if you're ok running the gen if the sun is gone for 2-3 days. An even smaller battery might work if your ok running the gen on a single cloudy day, but my understanding is the fuel for that situation adds up quickly.

 

[JCSchwarb]

Hi Scottmag,

I would recommend adding 25% buffer for growth and energy losses. That would put you at a 10kW solar array size. Ensure this represents your worst month (this would indicate 50k per day or 1500 kWh / month). Really need your worst monthly kWh/30 to derive panel size.

Then your battery will be calculated somewhere around 1/2 to 3/4 that size for that area of FL (30kWh). Note, you will need to ensure no shade on the panels anytime of the year, right now, for example the angle is slightly better than 38 degrees, which causes lots of shade in the Forrest, while June is 85 degrees sun angle. You will have days with no or little power. Each inverter consumes about 1% even in idle and other household minimal draws on top of that.

We are in the same general area and have lost about 2.5 days in the past month. We are grid tied on emergency so it switches without having to worry about it. You could get by with very low loads on those days. It takes a while for the family to consider light levels before doing heavy demands. If you wanted more assurance through gray days, you could go to 15kW and double your battery bank.

Hope this gives you some design ideas. I used a porch trellis PV array to keep the roof from becoming a maintenance issue.

-Jay

 

[scottmag]

What are your constraints?
Is price your highest consideration? Reliability?
Do you have the skills to do the wiring?
Do you have a budget?

When the weather is uncooperative, how many days of autonomy do you want? I guess I should ask, will there be a generator it supplement when there isn't enough sun? How often are you ok with running the gen? If you never want to run the gen you'll need a significantly larger battery than if you're ok running the gen if the sun is gone for 2-3 days. An even smaller battery might work if your ok running the gen on a single cloudy day, but my understanding is the fuel for that situation adds up quickly.

Budget is $10k, but reliability is higher concern. I'm fine with a generator backup, but prefer to use that only for extended cloudy periods. Would like to stretch to 5 days of autonomy if possible.

I can do some wiring. I lived on a boat for years and maintained it myself with 400w of solar, but this is a bigger scenario.

 

[JCSchwarb]

Budget is $10k, but reliability is higher concern. I'm fine with a generator backup, but prefer to use that only for extended cloudy periods. Would like to stretch to 5 days of autonomy if possible.

I can do some wiring. I lived on a boat for years and maintained it myself with 400w of solar, but this is a bigger scenario.

$10K will be a challenge for sure to right size your system. My 20kW was over $40K with 50 kWh LFP rack batteries.

 

[Murphyslaww]

From our gridtie system and central texas, a 4.5 sun hour area, we are at about 36% of our 1400sqft home use on a 5.4kw system, after 9 months. I think we’ll settle at around 40% at a year. We had a Mistang Mach E for most of that time, so I think we’d have been close to 50% minus the EV. Just giving you some comperable numbers and more data, so you can possibly interpolate from there. On the smaller end, and batttery use, our solar shed studio is about 150 sq ft. And 1200 watts of panels, poorly placed, producing about 4kw per day, has 5150watt hours of lifepo4 batteries, at about $1300 and is only good for 4-5 hours of cooling in the summer, and about the same for heating when needed below 40 degrees F, in the winter. The batteries, if you want ones that are low maintenance with long lives, are what kills you. You’ll get to $10k in batteries pretty quickly, and need them. I’m not sure people emphasize enough how much batteries cost. Our Ford lightning starts to look like a bit of a bargain when/if used for battery backup.

 

[scottmag]

Clearly my budget is too small. I can spend more, will have to reduce costs elsewhere in the house build. No big deal.

I think I could build this. https://signaturesolar.com/complete...70-watts-of-solar-pv-kit-e0002-free-shipping/

Good setup for me?

 

[12VoltInstalls]

Budget is $10k

$10K will be a challenge

And totally eliminates this:

Ecoflow but many say it’s overpriced for what you get.

The SigSol will work, but I’d want to cost out everything with post-market sourced panels and consider the equipment before I committed $15k.

trying to do this myself to save on setup costs. I’m estimating, based on my current 1150sf apartment electricity bill that I will need about 8kw system, but open to advice on tha

That’s a reasonable plan imho.
I’d aim for just under two days (40hrs) of battery and a propane generator to shave some cost there. And price up used panels.
My goal would be to lessen the upfront financials enough to have backup components on hand in case something quits and you need a quick solution. Especially if you plan on ‘bugout in place’ dependability. Walmart ain’t gonna carry a 48V AIO for use in a pinch. Though batteries will be the most expensive part, you can save enough on 5kW of panels to buy one battery. I’m thinking $10k budget is possible.

That’s how I would approach it.