BajaNomad - Air Conditioning off the Grid

Air Conditioning off the Grid

RFClark - 6-7-2022 at 06:51 PM

I thought a update on our adventures in off the grid AC might be of interest here (or not!)

We like to come down in the Summer but San Felipe can be hot and humid this time of year. Over the last 30 years we have tried a variety of things.

Generators to run AC units, but they are noisy and expensive.

After mini split AC units were available we could run an AC in the day off of solar and at night in one of the bedrooms.

Now with more efficient mini splits and Li Ion batteries we can cool the whole house from 7:00 to 19:00 and the bedroom all night when necessary. We could cool the whole house all night but it only takes an hour or so to cool down in the morning.

What it takes to do it.

The most important thing is to keep out the heat and humidity in the first place.

1) A white or reflective roof.
2) An as air tight as possible house
3) insulation
4) double pane windows
5) eves that shade the walls.

Having done the above we have about 3KW of solar and 300AH of 24V Li Batteries plus a 9KW propane inverter generator.

We can generate more than 20KW of power per day and keeping the 1200 sq ft house at 76F plus refrigerator and recharging the batteries requires about 16KW per day.

We have a 24K & 18K btu Heat Pump. The 24K unit is on the East side where all the windows are. That and a retractable sun shade cool in the morning. 90F outside 76F inside load 2.2KW by about 10:00 the load drops off to 1.2KW and we start the 18K unit on the West side. By 19:00 we are only running the 18K unit and the load is down to 700W.

As it gets hotter at night we probably will need to run the AC longer requiring the generator (9KW inverter) to recharge the batteries. Li Batteries charge much faster than Lead batteries. They also like the heat.

More as the weather gets hotter!

Feel free to ask questions or make suggestions!

RFClark - 6-7-2022 at 08:59 PM

The house is on the 2nd level so we depend on wide eves. We have some trees but not that tall. We water trees and plants with our gray water plus the AC generates 5-7 gal of water per day

mtgoat666 - 6-8-2022 at 12:18 AM

Quote: Originally posted by RFClark

I thought a update on our adventures in off the grid AC might be of interest here (or not!)

We like to come down in the Summer but San Felipe can be hot and humid this time of year. Over the last 30 years we have tried a variety of things.
…

More as the weather gets hotter!

Feel free to ask questions or make suggestions!

Suggestion: Leave town in hot period!

Oh, god! Summer in San Felipe! Sounds miserable. Too hot to go outside in daylight. Too hot to go outside at night. Life is confined to AC indoors, pinching Pennies to afford the electric bill

John Harper - 6-8-2022 at 05:46 AM

Any particular reason for going 24V? Less wiring expense due to lower amp load?

John

Russ - 6-8-2022 at 05:58 AM

This guy has lots of videos and covers solar really well.
https://www.youtube.com/c/WillProwse

larryC - 6-8-2022 at 06:31 AM

Quote: Originally posted by John Harper

Any particular reason for going 24V? Less wiring expense due to lower amp load?

John

You answered your own question and 48v is even better. Then there is the savings of less charge controllers. I find that everything seems to just run smoother at the higher battery voltages.

JDCanuck - 6-8-2022 at 06:56 AM

RFClark: I am surprised you get that much daily solar power from only 3kw of panels. Works out to 6.66 hours at full rating per day in winter. I would have predicted more like 5.5 hours at full rating in winter. I'm impressed to say the least! How many hours per day average does the generator run?
It appears we may have even more surplus solar available with our system than I had thought, but we are still adding in loads and want to have some excess left over for timed charging of an EV in late afternoons.

JDCanuck - 6-8-2022 at 07:12 AM

RFClark: I have another question I was pondering. Had you looked into water sourced heat pumps for hot water preheating? We find our largest single load is the hot water demand, almost all of it through electric tank water heaters, 3 in total supplying 60 gal due to the way hot water pipes are run in cement homes, with a lot of hot water lost to the supply pipes to the demand points.
Even with the shorter supply runs from the 3 hot water tanks, it takes about 1/2 minute to get hot water at sinks and showers. I hate this wasted energy and was wondering how you handled it.

RFClark - 6-8-2022 at 09:17 AM

Goat,

Let’s compare notes over the next few months!

1) Gas prices

2) Water prices

3) Electricity Prices

4) Food Prices

5) Availability of the above

It’s 81F here, the AC is running off the Solar! The cost “0”! The looks on people’s faces when they open their utility bills or fill up “Priceless”!

RFClark - 6-8-2022 at 09:33 AM

John,

The system here is old. 48V wasn’t a real choice 14 years ago.

JD,

We have 2.4KW mounted on trackers which doubles the output. Hot water is not a problem here! We have on demand hot water and our propane bill including fuel for the water truck and generator is about $350/year.

We just sold this house, the new place we’re building next door is 48V with 4K of fixed panels and point of use demand hot water. It generates 20KW/day and the solar cost less than 40% of the original system. It’s way simpler too. Should run 4 years with little maintenance!

Generally we don’t run the generator except when cloudy or when running the AC at night.

With point of use demand hot water the runs are all under 6’!

[Edited on 6-8-2022 by RFClark]

[Edited on 6-8-2022 by RFClark]

TMW - 6-8-2022 at 12:17 PM

I have a lady friend who wanted to buy an RV and wanted a solar system to run the AC in the summer. I helped her look at several RVs and my conclusion was that RV salesmen don't know crap about solar systems.

Bob and Susan - 6-8-2022 at 06:09 PM

ive been living "off the grid" for 16 yrs

i've never seen anyone air condition their house
using ONLY solar and batteries without the assist of a generator

i have a "million miles" on my diesel generator
mini splits work great

RFClark - 6-8-2022 at 08:01 PM

Come and visit us.
Humidity is our big problem. Right next to the beach the temperature runs mid 80s to 90 degrees daytime going down to 74 around 2:00 to 3:00 in the early morning currently. Humidity runs 70-90% (we collect around 8 gal of water per day)

Currently we run the AC from 7:00 to 19:30. We hold the temperature around 75F. After sunset it takes 700W to hold that temperature (1200sq ft house). That would be around 7KW of battery overnight. We have 15KW of Li Ion batteries available to use. When necessary we have a 9KW propane inverter generator that can charge the batteries at 100A (5KW) and carry the electrical load. So we can generate a nights worth of electricity in under 2 Hrs. To generate 100% of the 20KW we use a day would require running 5hrs!

mtgoat666 - 6-8-2022 at 08:21 PM

Quote: Originally posted by Bob and Susan

ive been living "off the grid" for 16 yrs

i've never seen anyone air condition their house
using ONLY solar and batteries without the assist of a generator

i have a "million miles" on my diesel generator
mini splits work great

Bobby,
Just need to build bigger, more panels, more batteries.

Also helps to build houses designed for hot environs, large eaves, shade, insulation. The typical gringo box is not good design for desert. Have you ever been to Middle East and seen pre-AC building design?

Plant some trees! Best thing for a house is shade trees! And a garden w/out trees is undesireable barren wasteland

[Edited on 6-9-2022 by mtgoat666]

pacificobob - 6-8-2022 at 08:36 PM

Trees planted today and well cared for can provide significant shade in 5 years.

RFClark - 6-8-2022 at 09:20 PM

Goat,

You’re right eaves that shade in summer and let the sun shine on the walls in winter are very important, how much your house leaks air matters too. Solar heating and humid air leaking in are the two big items on your cooling budget that you can reduce. Doing so makes a big difference in how much energy you need to cool your home.

Batteries are equally important! Most off the grid operations have run generators in the past cause lead acid batteries suck! Li batteries are a game changer.

Consider how Hyundai gets 60 mpg from a car. They use a gasoline generator operating at an efficient power level to run the car and ether charge or draw from an Li battery for the difference. The motor can be off quite a bit of the time because the car runs on electricity.

The same idea will work with off the grid systems.

pacificobob - 6-9-2022 at 07:32 AM

In our construction I included a whole house exhaust fan. It's capable of a complete air swap in 5 minutes of use. If the house is warmer than desired and the outside air temp is several degrees cooler I turn it on .

RFClark - 6-21-2022 at 10:48 AM

We have a solar whole house fan for the big house. We have a 40W exhaust fan in the small house’s garage. We run it at night after it cools down. It makes a big difference,

Notes on Solar powered AC.

After 2 weeks of warm to hot weather I notice the following:

You can have AC on Solar only.

Air leakage makes a big difference. Wind makes it (the leakage) worse.

Keeping the heat out in the first place is very important.

Tracker solar panels deliver a more constant amount of power for more of the day. 1400 - 1900 watts from 7:30 - 18:00 currently. larger Fixed Solar arrays deliver more power midday and need more batteries to average out the power as they start and stop sooner.

It takes twice as many fixed panels to equal the power output of a tracker.

Currently we’re averaging 35-40KW of solar per day. We AC the whole house from 8:00 - 20:00 and the bedroom 24 hrs. We have enough extra power to AC 600 sq ft we are building into living space in the garage from 9:00 to 17:30.

Hook - 6-21-2022 at 05:11 PM

Do you REALLY need to try and keep the house at 76F during the day?

When we used to live in San Carlos Sonora during the summer (just as humid, maybe not as hot as SF), we discovered that we were perfectly comfortable in our house by putting our mini-splits on the de-humidify setting and putting the temp at the max: 84F. This, in combination with ceiling fans, worked just fine for us.

Try it. It may take a week or so of acclimation, but you might be surprised.

The de-humidify setting seems to run the fan and the compressor much less than the true cooling setting.

It's really all about removing as much of that humidity out of the air.

Think about it. Are you ever uncomfortable in 82-84 degree DRY air in the spring or late fall?

RFClark - 6-21-2022 at 10:30 PM

We generally run around 24-26 C during the day and 25C in the bedroom at night. The humidity runs in the mid 40s. As you point out with lower humidity at night up to 28C is fine. We open the house to air it out when it’s like that.

bajapedro - 6-22-2022 at 09:35 AM

just returned from off grid casa south of San Felipe.
Ran a Sharkaire 8000btu 24VDC mini split in my bedroom all night. (500 watt draw) Insulated windows, white roof with 4" rigid foam insulation in ceiling (R-26).
Supported with 4kw solar array and 4 200ah 24v lithium-iron batteries.
No generator.
No problems with power.

RFClark - 6-22-2022 at 10:25 PM

We have a 220v 19 SEER 18K btu AC in our BR average draw is 200-300W we run it all nght!

[Edited on 6-23-2022 by RFClark]

Udo - 6-23-2022 at 02:16 PM

I have a house in San Felipe also. We are looking at spending more time there in the summer months.
We currently have 12 solar panels (450 W. each) and 16 standard golf cart batteries. I am considering using the Li batteries. Which ones are you using? What voltage are they? How much were they and where did you buy them? Thanks for your help!

Quote: Originally posted by RFClark

Come and visit us.
Humidity is our big problem. Right next to the beach the temperature runs mid 80s to 90 degrees daytime going down to 74 around 2:00 to 3:00 in the early morning currently. Humidity runs 70-90% (we collect around 8 gal of water per day)

Currently we run the AC from 7:00 to 19:30. We hold the temperature around 75F. After sunset it takes 700W to hold that temperature (1200sq ft house). That would be around 7KW of battery overnight. We have 15KW of Li Ion batteries available to use. When necessary we have a 9KW propane inverter generator that can charge the batteries at 100A (5KW) and carry the electrical load. So we can generate a nights worth of electricity in under 2 Hrs. To generate 100% of the 20KW we use a day would require running 5hrs!

RFClark - 6-23-2022 at 02:26 PM

Udo,

Are you running a 24V or 48V system? You should be! I bought my batteries on Amazon. I’m running these in 2 different systems and am very happy.

https://www.amazon.com/dp/B094NN5KWY/ref=sspa_dk_detail_0?pd...

Bob and Susan - 6-23-2022 at 02:49 PM

Quote: Originally posted by RFClark

We have a 220v 19 SEER 18K btu AC in our BR average draw is 200-300W we run it all nght!

[Edited on 6-23-2022 by RFClark]

impossible...you are reading your data wrong

Bob and Susan - 6-23-2022 at 02:51 PM

Quote: Originally posted by RFClark

Udo,

Are you running a 24V or 48V system? You should be! I bought my batteries on Amazon. I’m running these in 2 different systems and am very happy.

https://www.amazon.com/dp/B094NN5KWY/ref=sspa_dk_detail_0?pd...

its never matters what the voltage you are running

higher voltage only means you can use smaller wire

the circuit boards in an inverter all act the same... dont be fooled by hype

SFandH - 6-23-2022 at 03:40 PM

Quote: Originally posted by Bob and Susan

Quote: Originally posted by RFClark

its never matters what the voltage you are running

higher voltage only means you can use smaller wire

Hmm, two contradictory statements.

If you have long cable runs you'll spend a lot less money on wire of the proper gauge if you run at a higher voltage because your amperage will go down. Also, heat loss is a function of the current. Less current, less loss to heat generation in the wires. Double the voltage and halve the current for a given power level.

JDCanuck - 6-23-2022 at 04:19 PM

Udo: Lithium batteries have come down in price so far it seems unreasonable to use lead acid anymore. We can draw ours down 80 percent every day and still get over 6000 cycles out of them. With lead acid you would have to almost double the rated size, draw them down no more than 50% and then expect 5 years at that draw rate before you had to replace them.
We have 6 of these batteries in a rack and we have never needed more for our fully electric 2800 sq ft house. Cost including installation labour was 10000 USD, would be cheaper now.
https://www.vpsolar.com/en/product/pylontech-us3000-lithium-...

[Edited on 6-23-2022 by JDCanuck]

[Edited on 6-23-2022 by JDCanuck]

PaulW - 6-23-2022 at 07:12 PM

Now lithium price has gone up over 600% Maybe they are not as good of an investment now. Cobalt is higher as well but not a much a lithium.

JDCanuck - 6-23-2022 at 08:02 PM

Quote: Originally posted by PaulW

Now lithium price has gone up over 600% Maybe they are not as good of an investment now. Cobalt is higher as well but not a much a lithium.

I've noted all the battery types have risen very recently in price due to supply issues. Mine were purchased in early 2021, dropped since then while lead acids rose, but you are right, have risen again recently. It will take a fair while for cost declines to begin again, and by then we will see even more technology applied. I am still fascinated by how the F150 lightning packs 120kwh into a truck that cheaply. The truck itself is essentially free outside of the batteries cost.

RFClark - 6-23-2022 at 10:03 PM

B&S

Ever hear of Ohm’s Law or Inverter ACs?

The reason you run 48V inverter systems is not just because you can use smaller cables. It’s because it requires 1/4 the amps as a 12V system to do the same job actually less than 1/4 because the losses are 1/16 that of a 12V system. The losses in cables, connectors and internal in the batteries and inverters are the “R” in Watts = the Current squared times the Resistance!

Inverter vs non-inverter AC units! Old non-inverter AC turn on and off to control temperature. Most require 3 or more times their rated power to start. More Amps, more losses!

Inverter ACs soft start (much less than the full rated power) and ramp up over 20-30S, as they run and as the area cools down they decrease the amount of cooling to equal the heat load. They try not to stop but if the cooling load is less than their lowest level they stop until the temperature rises and start at much less than full power. With the reduced power levels our 18K Btu 220V BR unit uses about .3KW per Hr average over 5-6 Hrs. We produce about 700W from sunrise on a clear morning and 1.5KW by 8:15 right now (Trackers)! That’s why we can run AC off of batteries. The power requirements are greater if it’s windy and damp obviously and greater when the sun is shining. But we don’t draw down the batteries when the sun is shining either.

Our mid-day peak for both systems is about 5KW and 40KW Hrs per day!

PaulW - 6-24-2022 at 08:22 AM

True, the cycle of continued price reductions will continue once the cost of rare materials stabilize.
However new battery technology is nearby and will not use lithium or cobalt and provide significant performance improvement with predicted lower cost once the EVs start using them. Of course then the existing batteries will get even less costly.
Not a useful comment for those like you that already are set with existing batteries. Newbies will be happy when the latest batteries show up. with new or old technology based on lower cost.
=== ===

Quote: Originally posted by JDCanuck

Quote: Originally posted by PaulW

Now lithium price has gone up over 600% Maybe they are not as good of an investment now. Cobalt is higher as well but not a much a lithium.

Bob and Susan - 6-24-2022 at 04:54 PM

Quote: Originally posted by RFClark

B&S

Ever hear of Ohm’s Law or Inverter ACs?

The reason you run 48V inverter systems is not just because you can use smaller cables. It’s because it requires 1/4 the amps as a 12V system to do the same job actually less than 1/4 because the losses are 1/16 that of a 12V system. The losses in cables, connectors and internal in the batteries and inverters are the “R” in Watts = the Current squared times the Resistance!

Inverter vs non-inverter AC units! Old non-inverter AC turn on and off to control temperature. Most require 3 or more times their rated power to start. More Amps, more losses!

Inverter ACs soft start (much less than the full rated power) and ramp up over 20-30S, as they run and as the area cools down they decrease the amount of cooling to equal the heat load. They try not to stop but if the cooling load is less than their lowest level they stop until the temperature rises and start at much less than full power. With the reduced power levels our 18K Btu 220V BR unit uses about .3KW per Hr average over 5-6 Hrs. We produce about 700W from sunrise on a clear morning and 1.5KW by 8:15 right now (Trackers)! That’s why we can run AC off of batteries. The power requirements are greater if it’s windy and damp obviously and greater when the sun is shining. But we don’t draw down the batteries when the sun is shining either.

Our mid-day peak for both systems is about 5KW and 40KW Hrs per day!

OMG... having a 220v appliance saves you NO MONEY
the appliance runs cooler but you still use the same energy

RFClark - 6-24-2022 at 08:14 PM

B&S,

Politely as possible! I’ve done this for over 60 years! 220V uses 1/2 the Amps or less than 120V for the same work. 220 is a balanced load too!

1/2 the amps is 1/4 the wasted electricity be it CFE ($$$) or solar! Is there some part of less waste you’re missing? You even mention that the equipment runs cooler on 220V! Where do you think all that heat comes from and who pays for it?

[Edited on 6-25-2022 by RFClark]

4x4abc - 6-24-2022 at 08:52 PM

CFE charges you for the kW hours (kW/h) used

so, you run a 2 ton AC during the heat 24 hours and it draws 9 amps wired to 220V
24hx9Ax220V= 47,520 W/h = 47.5 kWh
you run a 2 ton AC during the heat 24 hours and it draws 18 amps wired to 110V
24hx18Ax110V= 47,520 W/h = 47.5 kWh

CFE currently charges about 0.9 Pesos per kW/h - 42.75 Pesos per day

can you please calculate the losses in 200V and 110V in the above model in Pesos?
So we can understand the savings of 220V

[Edited on 6-25-2022 by 4x4abc]

RFClark - 6-24-2022 at 10:08 PM

OK, I’ll see if I find the same AC in 120 & 220V. The losses in the inverter are real too and probably greater. Since this is about off the grid AC I’ll see if I can do an end to end estimate. The first thing that comes to mind is inverter capacity. A 120V load uses the same capacity as a 220V load (220 split phase inverter) so unless you balance your 120V loads you could run out of capacity. Balanced loads is what 220 does automatically.

JDCanuck - 6-25-2022 at 06:08 AM

Higher amps, more heat losses downstream of the meter. More heat losses, less useful work. Pretty simple explanation to me RFClark.

SFandH - 6-25-2022 at 06:15 AM

Quote: Originally posted by JDCanuck

Higher amps, more heat losses downstream of the meter. More heat losses, less useful work. Pretty simple explanation to me RFClark.

You deleted your VAR, inductance, capacitance, AC circuit engineering spiel. I thought that was pretty good.

JDCanuck - 6-25-2022 at 06:23 AM

Sorry SFandH: I decided I was opening a whole other can of worms when we are still trying to get on top of this one. This is not an Electrical Engineering site.

SFandH - 6-25-2022 at 06:25 AM

Quote: Originally posted by 4x4abc

CFE charges you for the kW hours (kW/h) used

so, you run a 2 ton AC during the heat 24 hours and it draws 9 amps wired to 220V
24hx9Ax220V= 47,520 W/h = 47.5 kWh
you run a 2 ton AC during the heat 24 hours and it draws 18 amps wired to 110V
24hx18Ax110V= 47,520 W/h = 47.5 kWh

CFE currently charges about 0.9 Pesos per kW/h - 42.75 Pesos per day

can you please calculate the losses in 200V and 110V in the above model in Pesos?
So we can understand the savings of 220V

[Edited on 6-25-2022 by 4x4abc]

I think a big part of the savings is in the cost to build the system. If you have long cable runs higher voltage allows for higher gauge (smaller diameter) wire which is significantly cheaper than low gauge wire. I'm not sure about the significance of percent savings on day-to-day operation. I suspect JD knows.

JDCanuck - 6-25-2022 at 07:06 AM

When you go off grid solar and then oversize your panels and undersize the batteries as we have, your whole paradigm changes significantly. You find a whole lot of wasted (unused) afternoon and evening supply and try to find uses for it, while at the same time trying to reduce overnight use. We have installed timers on our 3 hot water tanks to try to balance out loads, and are looking at lowering the wattage of the elements if we need further overnight reductions.

This is why we are anxious to find an EV to use some of that surplus in later daytime periods and reduce our gasoline use. One that feeds back to the system overnight would be ideal and appears to be right around the corner thanks to Ford Engineers. Imagine if that was adopted nation wide and the effect it would have on the grid demands, in addition to supplying emergency power to homes in blackouts.

Udo - 6-25-2022 at 07:49 AM

Mil gracias for the updated information, JD!
I'll check with my solar person to see how many batteries we will need for 6000 watt system. We will be adding 12 more 450-watt panels (5400 watts). These will be used exclusively to run the A/Cs (one 220V and two 110V), plus a fridge, a stand-up freezer, a wine fridge, and a small window A/C for the wine room.

Quote: Originally posted by JDCanuck

Udo: Lithium batteries have come down in price so far it seems unreasonable to use lead acid anymore. We can draw ours down 80 percent every day and still get over 6000 cycles out of them. With lead acid you would have to almost double the rated size, draw them down no more than 50% and then expect 5 years at that draw rate before you had to replace them.
We have 6 of these batteries in a rack and we have never needed more for our fully electric 2800 sq ft house. Cost including installation labour was 10000 USD, would be cheaper now.
https://www.vpsolar.com/en/product/pylontech-us3000-lithium-...

[Edited on 6-23-2022 by JDCanuck]

[Edited on 6-23-2022 by JDCanuck]

SFandH - 6-25-2022 at 07:56 AM

Quote: Originally posted by Udo

Mil gracias for the updated information, JD!
I'll check with my solar person to see how many batteries we will need for 6000 watt system. We will be adding 12 more 450-watt panels (5400 watts). These will be used exclusively to run the A/Cs (one 220V and two 110V), plus a fridge, a stand-up freezer, a wine fridge, and a small window A/C for the wine room.

Quote: Originally posted by JDCanuck

Yikes, both of you guys live large.

Small is beautiful, less is more. Conserve.

JDCanuck - 6-25-2022 at 08:03 AM

Udo: I had second thoughts after I posted that and also Paul's response. If you seldom use your solar demand..(less than half time occupancy?) and draw down your batteries less frequently, the cheapest initial option may be your best bet, as battery and storage technology is changing rapidly and much better options may open up in the near future. We undersized our batteries in our design, and less than two years later it's becoming the right choice. Performance wise, I have no complaints on those batteries tho, as they have performed flawlessly as long as we restrain our use overnight.
This reminds me of the development of personal computers in the past decades and how rapidly technology improvements made top-of-the-line obsolete.

RFClark - 6-25-2022 at 08:13 AM

Off Grid Homes are more complex if you expect the same level of performance you had when you lived on the grid.(the grid people are discovering that the grid in California is down quite often these days so this applies to them too!)

We have neighbors who still run 12V inverter systems! They run a few lights and use gravity or a 12V RV pump for water pressure. Some still have propane fringes Those people head north when it gets hot. They either use AGM batteries or pay someone to water their batteries over the hot wether! If they come down during hot weather they run a small generator at night for a window AC in the BR. They b-tch about how hot and humid it is!

The climate is getting warmer and energy costs money! Ruing a propane inverter generator to AC our house costs about $4/hr for propane and at least $1/hr for maintenance and replacement. That gets you 7KW of power peak and 3KW average. If you are carful that’s enough to run the AC, a flat screen TV, led lights and a microwave or dishwasher. ( dishwashers require water pressure so also a water pump!) 3 hours a night is average so $15/day or $450/month in the hot weather. You also need at least a 10 cubic ft fridge but cheap efficient fridges are common so that’s not a problem. We have a large propane tank and get deliveries to our house.

You still need an inverter system to run stuff the rest of the time! Over the last 30 years we have moved from running a generator to 12V, 24V and now 48V inverters. We started with lead acid RV batteries and now use Li Ion batteries!

48V inverters and Li Ion batteries replace running the generator in sunny weather. 220V appliances for AC and other large loads complete the system. The payback for the system is at least $450/month in hot weather and probably $250 the rest of the year.

StarLink is the other key component as it finally allows phone and internet service off the grid too! $110/mo seems like a lot but Viasat plus Dish TV are about double that or more!

Other people should share their experiences too!

JDCanuck - 6-25-2022 at 08:13 AM

SFandH: Yeah, we kindof overdid it when the peso plummeted and oversized what began as a simple 2-3 bedroom casa. It's the 1 foot thing you get caught up in when you design a home for a family of ten to gather in. We now have two separate living areas with a central gathering area, with two kitchens instead of the one we originally planned on. What were we thinking?

AKgringo - 6-25-2022 at 08:22 AM

Quote: Originally posted by JDCanuck

This reminds me of the development of personal computers in the past decades and how rapidly technology improvements made top-of-the-line obsolete.

I like to stay on the cutting edge of technology. That is one of the reasons I bought my 1999 Isuzu Trooper last year.

It not only has a cassette tape player, there is something called a CD player that I can use where there is no AM radio signal!

All I need now is a solar panel on top of the Trooper.

RFClark - 6-25-2022 at 08:22 AM

We have two separate houses each with its own system. We have an inter-tie and a common generator. Since we have propane we use demand point of use hot water to save propane.

[Edited on 6-25-2022 by RFClark]

JDCanuck - 6-25-2022 at 08:33 AM

RFClark: I have costed the entire off grid solar system including 13kw backup(never needed it yet) as a percentage of the entire cost to build, and it came out to 15% extra, something I can easily live with considering the added reliability of power we now enjoy as well as zero cost for grid power and some excess to reduce or possibly eliminate vehicle gasoline costs in the future. It will only get cheaper as time goes on.
Reliable water supplies i think are far more worrisome for most in the future. My daughter in Salt Lake tells me they are restricted in the rainfall they are allowed to capture by their community laws.

[Edited on 7-23-2022 by JDCanuck]

JDCanuck - 6-25-2022 at 08:41 AM

AKGringo: I have a very lightly used Beta machine if you are interested....cheap!

RFClark - 6-26-2022 at 07:41 AM

JD,

If you have electricity you can collect water from the air and recycle your used water! We already use our gray water for plants.

JDCanuck - 6-27-2022 at 05:56 AM

Quote: Originally posted by RFClark

JD,

If you have electricity you can collect water from the air and recycle your used water! We already use our gray water for plants.

Interesting concept, RFClark. I never considered running all the air conditioning drains to the septico. Humidity is exceptionally high there, do you have suggestions on how we could extract some useful water efficiently?
We do plan to recycle engineered septico as treated water for courtyard plantings irrigation, at present it pumps out to the ground through a hose that we keep repositioning and produces clumps of greenery at the discharge as we shift it around. The new bushes seem to be self supporting once established. I now regret also separating the grey water septic from the black as they do in Europe for irrigation use directly.

RFClark - 6-27-2022 at 06:32 AM

JD,

The new 4KW of panels with a 48V 6KW 220 inverter and 9KW of batteries cost about $8K installed. Our base load with is about 120W plus a programable 40W garage fan.

We collect our AC water in 5 Gal buckets to use on our Trees and plants. At this time of year we’re collecting about 10 Gal on windy day and 5 Gal on calm days. From 25 - 40 KW Hrs of Solar. If you have extra electricity you could add a dehumidifier outdoors and collect another 3-4 Gal a day from an 800W unit. Since it exhausts warm dry air you don't want it inside in the summer!

We have a filter system on our gray water mostly to remove food to keep it from plugging up the drip system.

[Edited on 6-27-2022 by RFClark]

Udo - 6-27-2022 at 08:34 AM

Of course not! :lol:

Quote: Originally posted by JDCanuck

Sorry SFandH: I decided I was opening a whole other can of worms when we are still trying to get on top of this one. This is not an Electrical Engineering site.

Udo - 6-27-2022 at 08:49 AM

This really has been an interesting and informative thread, Appreciations to everyone that has contributed so far.
It will be worth printing the entire thread when completed.

JDCanuck - 6-27-2022 at 09:30 AM

Udo: There is a whole lot of practical information out there if you can just get people to share it. I was especially impressed with Harald's place on my brief stay there and highly recommend to fellow Nomads they try to spend some time there before he sells the place. Nothing beats decades of practical experience and seeking lo cost solutions to complicated problems.
I myself tend to over complicate issues and go searching for the latest commercially engineered solutions when there's often a very simple way of dealing with it.
Based on your panels' sizing I assume you are using the newer bi-facial panels from Canadian Solar, am I right? About the same ratings as those i had installed, but mine are from a different manufacturer.

[Edited on 6-27-2022 by JDCanuck]

Gray Water filter Installed

RFClark - 6-27-2022 at 09:47 AM

The inlet is on the left side.

1st section: sand trap and bacteria digester

Center: Filters

Right: gravity output and drip system pump

0A6D2C3E-B84E-4E1A-8D7E-FD3579744FCD.jpeg - 254kB

JDCanuck - 6-27-2022 at 10:09 AM

Quote: Originally posted by RFClark

The inlet is on the left side.

1st section: sand trap and bacteria digester

Center: Filters

Right: gravity output and drip system pump

What is the source of the grey water? Laundry, tubs, showers and sinks? Or is there rainwater and runoff in there as well? In any case...looks very impressive and I may use that design in my rainwater collectors. I am wondering why you felt it necessary to be concerned about the bacteria digesting issue if you are using it for root level drip irrigation? Thanks

[Edited on 6-27-2022 by JDCanuck]

RFClark - 6-27-2022 at 10:57 AM

The source is everything except toilets, no rain water as there’s either too little or occasionally way too much. Since food washes down the drain rather than allow it to collect I added aquarium bacteria balls and course gravel to the 1st stage. Seems to work as there are no bad smells from the system after years of use. It’s built out of 1/4” ABS sheet. It required a 4’X8’ sheet. Filter pack from eBay. Pumps have been a problem. The cheap ones don't last!

RFClark - 6-27-2022 at 11:37 AM

Here’s a link to an article on average home electrical usage. Their calculations are similar to my actual results.

https://blog.ecoflow.com/en/how-much-energy-does-an-average-...

These people also make a turnkey off the grid system. They sell the components too.

JDCanuck - 7-23-2022 at 08:07 AM

Quote: Originally posted by RFClark

The source is everything except toilets, no rain water as there’s either too little or occasionally way too much. Since food washes down the drain rather than allow it to collect I added aquarium bacteria balls and course gravel to the 1st stage. Seems to work as there are no bad smells from the system after years of use. It’s built out of 1/4” ABS sheet. It required a 4’X8’ sheet. Filter pack from eBay. Pumps have been a problem. The cheap ones don't last!

Thanks for that detailed info, I will certainly be trying to copy s
something similar. We are using shots of Chlorine bleach at present in our 3,000 liter rainwater collectors here. A post indicating what make of pump you finally settled on would be helpful as we will be needing one eventually. Our septico discharge has been running trouble free for a couple years now using an Evans pump, while I have heard our neighbour's pump has failed a couple times in similar use.

RFClark - 7-23-2022 at 08:31 AM

I tried a number of cheap submersible pumps. None proved very satisfactory. I think a good (expensive) pump is probably a good investment.

I haven't decided what I’m going to do on the new house past having a in-ground plastic receiving tank for the gray water. I am thinking about an above ground pump and sand filter though.

JDCanuck - 7-23-2022 at 08:50 AM

I was looking at this one, the kits supplied by them including the sand filters are pretty expensive.
https://evans.com.mx/albercas/bombas/bomba-para-alberca-1-2-...

Udo - 7-23-2022 at 02:53 PM

My sincerest apologies, JD. I was not paying attention to further posts, until I went to print this post for hard-copy referencing. I needed to print some extra copies for other friends who are interested in the same thing.

To answer your question, my solar panels are KYOCERA 450 watts. Made in Mexico. Chinese panels will outlast my lifetime as well as half of my relative's lives.
I should have stopped at Harald's place when I was in La Paz a couple of months ago, but I was traveling with a group of friends. So far, the most sanitary solar system and A/C I have seen are at a friend's place on K-38 of Mexico 5, as well as Lynn Chenowth's place. I will aspire my next upgrade to look like their's. However, I also want to look at RF Clark's place, which is just 2 KM. south of me in San Felipe. After a lot of research, I think I will be using Lithium-Ion batteries for my next add-in solar install. That should be about a 6KW system with 14 more panels.
That battery system will be on work-bench-like storage, so everything will be waist high (like my above-ground vegetable grid in Ensenada. This compound is currently for sale, and if I can figure out how to post photos on Nomads it will be there with an ad.

Quote: Originally posted by JDCanuck

Udo: There is a whole lot of practical information out there if you can just get people to share it. I was especially impressed with Harald's place on my brief stay there and highly recommend to fellow Nomads they try to spend some time there before he sells the place. Nothing beats decades of practical experience and seeking lo cost solutions to complicated problems.
I myself tend to over complicate issues and go searching for the latest commercially engineered solutions when there's often a very simple way of dealing with it.
Based on your panels' sizing I assume you are using the newer bi-facial panels from Canadian Solar, am I right? About the same ratings as those i had installed, but mine are from a different manufacturer.

[Edited on 6-27-2022 by JDCanuck]

JDCanuck - 7-23-2022 at 02:59 PM

I'm really interested in RFClarks various systems as well, I wonder how much he charges for tours? He seems to have put a lot of thought into living with minimal impact.

Udo - 7-23-2022 at 03:02 PM

Perhaps what I installed may be of interest to you. My gray water feeds my ocotillos and palms. I used a 20" square cement tank receiver for the water. From there, I have a gravity feed 2" PVC pipe that is about 200' long. There is a tee from the pipe to each plant. The tee is plugged on the end, and there are several holes drilled on the tee'd line, just like the septic's leech lines. I think I spent about $90.00 USD on everything. The end of the drain line is about 24" deeper than the pipe's head. Digging was easy. all on sand.

Quote: Originally posted by RFClark

I tried a number of cheap submersible pumps. None proved very satisfactory. I think a good (expensive) pump is probably a good investment.

I haven't decided what I’m going to do on the new house past having a in-ground plastic receiving tank for the gray water. I am thinking about an above ground pump and sand filter though.

RFClark - 7-23-2022 at 05:23 PM

No charge for tours! We’ll be back in San Felipe 7/26 &’8/3 then in Cerritos August/Sept. We got our building permit. Easy to find located in Rancho Nuevo. About KM 72 south of Cerritos.

The place we sold had a gravity drain in addition to the pump for the drip system it feeds about 40’ of 4” drain pipe with holes in it. We had stuff planted on it. That works fine.

Don’t know about the new place yet.

We did get the first 6 540W panels installed last week. They are flat mounted. Output is about 2800W midday. The original 3 - 340W output about 900W midday.

We used a crane to set the 2X - 3 panel racks in place

[Edited on 7-24-2022 by RFClark]

JDCanuck - 7-23-2022 at 06:52 PM

RFClark: If you are in San Felipe between the 29th and 31, we will definitely try to catch you on our way by. Thanks for the invite.
Planning on more solar yet at Cerritos or is that going to be sufficient for your needs? Wondering too how many battery units, what make and what size you are installing.

RFClark - 7-23-2022 at 09:04 PM

We’ll be in the US on those dates. Then back to Cerritos.

Solar is still cheap. We’re planning on another 6 - 540W panels and a 2nd 6KW inverter. We have 48V 100AH of Li ion batteries now and plan on adding 100AH more when we go back down. We’ll add another 200AH when we install the extra panels and 2nd inverter.

Time will tell if we need more batteries. The issue with fixed panels is you get the most power midday so you need to store it for afternoon and night use. Most of the power is used for AC to dehumidify. Cerritos doesn't get too hot but the breeze dies and the humidity goes up in the afternoon.

Panel Install

RFClark - 7-23-2022 at 09:33 PM

39C26BCB-7C64-4243-AE1D-18F7AB659AC8.jpeg - 122kB

JDCanuck - 7-24-2022 at 06:04 AM

You are building out of containers? That's a pretty intense planning project.

CAD Container House RN

RFClark - 7-24-2022 at 09:14 AM

The one story part is concrete and block. The two story part is 2 - 20’ containers spaced on a 40’ X 20’ square with 2 - 40’ containers across them and a 4’ gap between to create a 20’ x 40’ second floor. The square on the roof is a deck area. The rectangle is the solar panels. This software doesn’t do windows and doors on second floors. The front of the 2nd floor is mostly glass.

The concrete single story with a roof deck goes where we are rigging the solar panels.

6F97D8F7-04A8-4455-83AD-BD514F149B55.jpeg - 165kB

Udo - 7-24-2022 at 10:09 AM

Nice!

I will try to catch up with you at a later time in September.

Quote: Originally posted by RFClark

The one story part is concrete and block. The two story part is 2 - 20’ containers spaced on a 40’ X 20’ square with 2 - 40’ containers across them and a 4’ gap between to create a 20’ x 40’ second floor. The square on the roof is a deck area. The rectangle is the solar panels. This software doesn’t do windows and doors on second floors. The front of the 2nd floor is mostly glass.

The concrete single story with a roof deck goes where we are rigging the solar panels.

JDCanuck - 7-24-2022 at 10:42 AM

RFClark: When I looked at that model, my immediate thought was you have a natural chimney effect that should draw strong breezes in through the lower story front deck. Have you added any window/vents on the rear of the upper story to accomplish this? I saw this design in an older home in La Paz we rented and it worked very well without air conditioning.

RFClark - 7-24-2022 at 03:18 PM

Yes, that’s the plan. The 20’ containers already have exhaust fans on the east sides.