September 11, 2019

Solar Pantry Part 4: The Plan

At last we've come up with a plan! But before I jump into that, I'd like to summarize this blog series so far (for those just tuning in):

Solar Pantry Part 1: Feasibility
  • In which I count the cost of putting my pantry fridge and freezer on their own solar power system,
  • and learn that it's beyond our budget at the present time.
Solar Pantry Part 2: Analysis 
  • In which I analyze how and why I use my fridges and freezer,
  • and learn that 
    • many of the items I store in these appliances don't actually need refrigeration or freezing.
    • my pantry is simply too warm in summer for good food storage conditions.
  • In which I explore off-grid methods of keeping food without a fridge or freezer,
  • and get a couple of good ideas suitable for us. 

What I realized from these exercises is that my original goal was too narrow. We need to address not just freezing and refrigeration, also we need to improve our food storage conditions in general. In the light of that, Dan and I have come up with a three-phase plan:

Phase 1
  1. Move the freezer from the pantry to our enclosed back porch.
  2. Put the freezer only on solar power.
  3. Replace the old pantry refrigerator with a small chest freezer converted to a refrigerator. It will go on the back porch too.
Phase 2
  1. Update the pantry to make it more energy efficient:
    • better insulation in walls
    • replace old windows with energy efficient ones
  2. Work on ideas to cool the room in summer. Moving the fridge and freezer will certainly help with that. Other ideas:
    • ventilation, cool cupboard?
    • shade the window that gets afternoon sun
    • ice block "air conditioner?" (Ideas at Off Grid World.)
Phase 3
  • Make a root cellar.

Cost analysis for Phase 1 - I couldn't put both my old energy-guzzling fridge plus freezer on solar, but can I manage the freezer only? Based on the readings from my Kill-A-Watt meter, the freezer uses 1600 watts per day. If I've done my calculations correctly, here's what I've come up with. Remember, I only have $1500 for this project, but already have the solar panels.

2, 345-watt solar panels
   ✔
4, 250 AH 6-volt deep cycle batteries
$822
150-volt, 60-amp MPPT charge controller   
$431
1000-watt pure sine wave inverter    
$150  
TOTAL
$1403

Admittedly, there are still a number of other things like panel racks, wiring, connectors, fuses, battery box, etc., but it looks like we have the funds for the major components. Following are a few notes related to the above.

Solar panels. 345 watts, 57 volts each x 2 panels = 690 total watts for the solar panel array.

Wiring. Fortunately, we only have about 25 feet between the panels and battery bank. That will save both in amount and size of wire needed.

Batteries. Why 6-volt? Why not 12-volt? For a couple of reasons. Firstly, because so far I haven't been able to source 12-volt deep cycle batteries locally, and shipping for batteries is very high. Marine and RV batteries sold around here are dual purpose, listing cranking amps and low amp-hours (usually 35 to 55). They aren't cheaper and I'd need more to get more amp-hours. Plus cranking batteries won't take as many recharges as true deep cycle batteries.

The second reason is because 6-volt batteries are more heavy-duty. 6 and 12's are about the same time size. Why aren't the 6-volt smaller? Because they use heavier plates, which means more discharge cycles.

So, wiring two 250 AH 6-volt batteries in series will double the voltage to 12. Wiring the two pairs in parallel will double the amp-hours to 500. That's not quite two day's worth of energy storage, but that's more than I've got on the grid! Plus those four batteries are within my budget, although I'm still trying to shop around.

So far the only place I've been able to find 6-volt lead acid batteries is at Batteries+Bulbs, and I'm having a hard time finding other sources. I miss the days of phone books, when all local options were listed topically in the yellow pages. Search engines favor SEO (search engine optimization), paid ads, and political favoritism, which doesn't help one wanting to explore all the options. [UPDATE: I also found them at Interstate Batteries for the same price. Batteries+ is closer, however, and offers a 10% discount for ordering online.]

Charge controller.
  690 watt solar panel array (57.3 volts)
÷ 12 volt battery bank
= 57.5 amp minimum charge controller (rounded up to 60)
I'm looking at the Outback FLEXmax 60.

Inverter. This converts the DC (direct current) electricity produced by the system for my AC (alternating current) appliances. Thanks to my Kill-A-Watt meter, I know that the freezer uses about 185 watts when it starts up, then quickly drops to 100 to 102 watts and gradually decreases to 87 watts. The freezer light uses 24 watts. Recommendations for sizing inverters vary depending on the solar expert, so I finally decided on a 1000-watt inverter with a 2000-watt surge capacity.

Chest fridge. I first read about converting a chest freezer to a chest fridge in Prepper's Total Grid Failure Handbook. Several readers mentioned using them and how-tos can be found online. Two are at New Life on a Homestead and A Self-Sufficient Life. For now, the chest fridge would be plugged into the grid, until I get a better idea of exactly how much electricity it uses. As a freezer, the model I'm looking at is 5 cubic feet and has an energy rating of 219 kWh per year or roughly 0.6 per day. That translates to 600 watts per day, but surely as a fridge it should consume less(?). An experiment I plan to try is using it as an ice box. If I can freeze enough ice bottles in the freezer, it's possible that I can keep the chest fridge cold enough. We'll see.

5 cubic feet is not very big for a fridge. It will replace the fridge in the pantry, but I'll still have the fridge in the kitchen. I figure this situation will force me to change my habits and routine, plus implement more alternatives to refrigeration. The most perishable items I refrigerate are milk and meat. After that I would say leftovers and salad greens, but really, everything else could be stored elsewhere if I had cooler storage conditions. That's where a cooler pantry and root cellar will come in.

So that's the plan. The first order of business is to clear out the back porch and get ready to move the freezer. It's about due for a defrost anyway. After that we'll just take it one step at a time.

Next  → Solar Pantry Project Part 5: Back Porch Preparations

Solar Pantry Part 4: The Plan © September 2019

23 comments:

Ed said...

I've always been intrigued by putting up solar panels somewhere on our house. I have a friend in Arkansas who has lived in a solar powered house for decades and have learned a lot through their experience. But for now, it will have to wait until we get our house fixed up and then can focus funds towards it.

J.L. Murphey said...

You set out to find an alternative and you found an economically friendly solution. WTG!

Lady Locust said...

Sounds like a good plan. It will be interesting to see how much you use your ice-box/chest fridge one the root cellar comes along.

Leigh said...

Ed, I know what you mean. It's taken almost ten years of house repairs and upgrades for us to be ready for even a solar moderate project. From what I understand, it's a huge learning curve, not only in terms of lifestyle, but also care and maintenance of the system. I just read an article last night geared toward absolute beginners. The gist was, "don't spend a lot of money on your first set of batteries, because you WILL destroy them! Everybody does!" Not confidence building, lol, but confirms that keeping this project within a tight budget is a good idea to start. :)

Jo, where there's a will, there's a way!

Lady Locust, right now I'm planning to use the chest fridge for milk and dairy, because those are my essential "must keep cold" items. There should be enough room for leftovers and salad greens, and I'm glad I still have the kitchen fridge as backup. If we can get cool down the pantry and/or get the root cellar built, that should take care of the rest of my refrigeration needs. Or so I hope!

M.K. said...

The very first thing that came to my mind was the last item on your list: a cellar. When I think of the old-timers who stored and canned and utilized their huge gardens to feed their large families all year -- a big asset they had was a basement/cellar. I'm thinking of the old farmhouses I know of in W.Va., where I'm from. Underground it's a pretty steady 55 degrees, right? So you can use nature herself for storage rather than technology. We can't have cellars here -- too close to sea level. But if you have space above water line for a cellar, even a small one, it could be your best long-term answer. Just lots of digging!!!

Leigh said...

M.K. that's the problem, a lot of digging! LOL. But I agree it would be the best option. I really wish we could put it under the house, but Dan has nixed that idea for a lot of reasons. We're still looking at places for it, so it won't become a reality for quite a while yet.

Rain said...

You guys are so organized. And you're very well-learned on electricity. I think it's very smart what you're doing. I like the idea of the solar air conditioner, I checked out the link. I guess it's kind of like my "emergency" cheese cave. I ran out of room in the little bar fridge so I took one of those foam coolers and put 2 ice packs in it and it keeps about 9-13 celcius. I just have to change the ice packs before bed each day. I like the list you have with the pricing too. Were your solar panels expensive? If you don't mind that is? :) A root cellar is also something I hope to have when we get our place. I've been thinking a lot about how I can rely less on refrigeration. I don't ever want to cut it out but just use it less.

Nan said...

Hi Leigh, Thank you for such a great series of articles. I do have a question or 2 though, is your freezer the frost-free type? Have you actually used your freezer on solar power yet?

Leigh said...

Rain, the organization is only on paper, lol. I think it's always a good idea to have a backup plan! That's a good idea to use the coolers with ice as an auxiliary cheese cave. Using non-electric methods does require some monitoring, but I think it's worth it.

Do you have Craigslist in Canada? That's where we found our solar panels. They were new, just leftover from a contractor's project, so he sold them well under retail. Ours were $240 each. I notice many similar offers on Craigslist. Different size panels, but new and at discounted prices.

I think a root cellar is a must for anyone wanting to be less dependent on electricity and refrigeration. I've seen some nice ones in people's basements.

Nan, thank you! My freezer is not frost-free, it's manual defrost. I understand the frost-free models use more energy, so for us that's good. We don't have the freezer on solar yet. We're still in the preliminary calculations, but I have been cleaning out and rearranging the back porch in preparation to move the freezer. That will be the next blog post in this series.

Renee Nefe said...

Glad to see the plan coming together. :D

Several years ago I tried to talk hubby into an attic fan. My thinking is the basement is cold, suck that cool upstairs. Hubby isn't for it and really hasn't given me a reason...he is like that. oh well, it just means the electric bill is higher.
Right now he is working on hiring someone to mudjack our sinking concrete. We will see how long that takes.

Rain said...

Hi Leigh, yep we do have Craigslist here. We have another site called Kijiji which is kind of the same. Good idea to look for things on there, you just never know what people are willing to get rid of at good prices! I'd like to have a real cheese cave along side the root cellar one of these days! Mouse proof of course! :)

Leigh said...

Renee, that's a good idea. Can you find a solar model? Our attic vent fan has been fantastic, plus keeps the house more comfortable and keeps the electric bill down!

Rain, it's true about what people are often willing to let go at good prices. Especially if you can find someone with leftovers from a big project.

When will you all start looking at properties again? It's good to have a list, although I admit we ended up making quite a few compromises because of what was available. Still, the potential to make your dream come true is wonderful.

Chris said...

It's been interesting to watch this plan's evolution. I think the key lesson here, is that the common fridge is treated like a regular food pantry. We all forget it costs money, though.

We have two fridges at the moment, because we have a family of four. So chill a lot of water bottles. Especially in summer, when we need the hydration. Without air-con, it helps to cool us down by drinking chilled beverages. The extra fridge comes in handy during Christmas, with guests. As we prepare a lot of food.

When the kids leave home though, I can see use paring down to one fridge.

Ed said...

Yeah it is definitely a learning curve involved. My friends that have been totally reliant on solar energy for a coupe decades however make me realize that it is very much doable, especially in the age of LED lightbulbs. Back when they started, light was sparse in their house which takes a lot to get used to but with LED's, it isn't so much of a problem. One also has to learn to go without resistance heat like toasters, hair dryers and such but for me, that isn't hard. There is a bit of needing to be able to futz with electrical components from time to time but it should be within in the wheelhouse of most amateur electricians.

Once again, I'm excited to look over your virtual shoulder and see how your project progresses!

Nancy @ Little Homestead In Boise said...

It was just curious if you have ever thought about learning how smoke and cured meats? Make sausages, etc? Things that would not require refrigeration?

Goatldi said...

I hope this link works. I watch on occasion a show called "Restored" Brett Waterman restores very old houses and on this segment they highlighted a house that had a California Cooler in the original kitchen. They brought it back to life and this link (crossing fingers) isn't that exact one but gives you the idea of how it works.

California Cooler (cabinet) - Wikipedia
https://images.app.goo.gl/6Agmbd2hnYZwymtKA

I started thinking about the possibility of incorporating one in my cabin at some juncture. Great blog post and will look forward to the journey.

Leigh said...

Ed, anything that produces heat is a real energy guzzler, isn't it? Seems cooling is next in line! I am finding a lot of pretty good DIY information, although each one seems to focus on some things and omit others. Dan has been wishing for someone with experience to talk to. That would help a lot.

Nancy, yes, I have! What we need is a cold smoker and a root cellar! I brine cure a lot of our meat and Dan smokes it but his set up is a converted grill so it makes a lot of heat. Hence a hot smoker. Then we need someplace cooler than our house or pantry. So it's within the realm of possibilities for us, it will just take some time to get there!

Goatldi, good photo! I've seen a number of these, also modern versions called "cool cupboards." When get to the pantry, that's an option. The problem we have to solve first is the air in our crawl space. It's cooler than air temp, but it has a musty odor to it even though the crawl space is dry. If we can solve that, I'd like to do the cupboard/cabinet in our pantry.

Leigh said...

Chris, I didn't scroll up far enough in my comment box! :o Your summers are similar to ours so I get the two fridges. With producing our own milk and eggs, the need for refrigeration is a priority. Of course, if we had a big kitchen I could have gotten one of those jumbo fridges instead of having two small ones! But I think these steps will help a lot in terms of working toward alternatives.

Mike Yukon said...

It's a good plan and will work well for you!

Leigh said...

Mike, I hope so!

Rain said...

Hi Leigh :) We start looking for properties again after the winter. My pre-approved mortgage ran out so we used the down payment money to pay back some debt. We are stuck in this lease until next June 30th anyway so we're saving once again for the down payment. I'll apply for the mortgage in March or April. I've been browsing the real estate sites and it's funny that I see all the same properties I saw last year! But Alex and I decided come hell or high water, 2020 is the year we stop renting. Even if we have to "settle" for something we don't particularly want. We are living in a renter's money pit. After seeing what's out there in our price range, we also will have to make some compromises.

We just thought that if we could find a place with a large acreage, we could eventually build our off-grid paradise in the middle of the acreage and Alex could use the on-grid house for his music studio. It's all in the dream phase at the moment though! :)

Leigh said...

Rain, maybe some of those properties will have price drops! Good idea to pay off more debt. That gives you wiggle room with the mortgage. It's true that renting is a money drain. For the longest time Dan didn't want a mortgage, but we never had enough to pay cash. We finally reasoned that we'd either be paying rent or a mortgage, and at least with a mortgage there's a chance of getting it paid off. Never so with rent.

It's good to be flexible with your dream, but don't give it up. We had to "settle" and there are still things we wish we had (like a basement for a root cellar) but we've adapted and made it work for us. You will too.

Leigh said...

SHFT Plan, I was going to thank you for the information, but it seems the link is just for advertising.