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What are the top 5 gotchas for going totally off grid

l00semarble

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I’m building a house from the ground up in Costa Rica which will be off grid with grid back up. I’m going to do a very high-quality system with basically all Victron maybe even Victron batteries as I am Victron dealer and get good pricing.

I have every choice in front of me for how the house is built and wired, voltages used, what appliances are chosen, light fixtures etc. I’m working on a load spreadsheet ans PDR I have some data from my current home there and some other similar homes. The home will be a luxury jungle villa at 1,500 ft elevation - very open to nature w/ very little HVAC needed but some storage spaces will be
dehumidified and we will put mini splits in the 4 bedrooms just in case someone has to knock down the humidity to sleep. I’m not asking for specific system design advice but rather general pitfalls.

What are the things that people don’t think about ahead of time that come up later or those things that “if I had it to do over again” .

For example there was recently a thread about a high efficiency front load washer that had inrush spikes back and forth due to the way the motor reverses. I would never have thought to consider this type of machine a special challenge for off grid.

Cook with induction or propane?
Passive rooftop water heater or several small instant heaters?
Pool pump choice/programming?
Lighting?
Smart home stuff?
Frig/freezer choices?
 
Number one Pitfall that most Off Grid designs don't take into account is having enough Batteries or a good generator to take you though 3-4 days of bad weather.

1) Propane if possible
2) Solar Water heater for sure in Costa Rica.
3) Pool pump with Timer so it only runs in the day
4) LED lighting
5) Your choice
6) Inverter based Fridges use a lot less power.

It was the Top load washers that had the issue. Most front loaders spin one way for a minute then pause for a few seconds and then reverse direction. I have never had an issue with spikes on mine. Also the Front loaders wash clothes much better than Top loaders while using less soap and water.
 
A big one that I've seen is not sizing it large enough to begin with. A few more KW of modules today will solve so many problems down the road and in the overall picture won't add that much cost to your system. Compare that to limping along with an undersized system for years plus hassle and expense of adding more capacity in the future.

Induction is very off grid friendly. Why be reliant on propane from someone else forever when you can handle it forever by properly sizing your system up front?

Passive solar batch style water heater that has already proven to be so reliable in PR.

Look at a VFD style pool pump

Plenty of easy to find LED

Install a Emporia home energy monitoring system in your current house immediately then transfer it to your new home.

I'm not a fan of buying a fridge that isn't normally stocked around you. The difference in daily energy usage of the most efficient fridge/freezer that might require special ordering and shipping costs vs. something decent you can find locally is less than an extra 200 watts of solar PV.
 
Theft

Cycle life of batteries

Humidity (sealed enclosures or conformal coat helps)

Surge current of motors
 
Most off-grid systems i build now have two completely independent systems.

Don’t spend any extra on energy efficiency, put the money into your power system.

Size your batteries for one nights maximum use only, and use generator power as required.

That’s the main lessons i’ve learned from dozens of people coming to me after their first off-grid system let them down or didn’t meet expectations.

So much useless advice on the internet from people who have just started living off grid (less than 5 years or so), or worse yet people that have never actually lived off grid.
 
Hybrid water heater only use around 5-600w and condition the space they are in....ideal for a garage.
ICF for the house, super strong and great insulation. 50mm closed cell followed up with 100mm open cell spray foam insulation for the roof.
I am self building in Florida so we probably have the same requirements.
 
RULE 1:
It is always cheaper to Conserve & be as efficient as possible than to generate & storing Power! This is especially important during "critical events" such as extremely bad weather or other turmoil events out of your control.

As far as I know, Costa Rica is 110/240V 60Hz, therefore I suggest very strongly going with a proper 240VAC Build by default so you do not limit yourself short and provide for any standard equipment you may desire. This does not mean that you should go wild on 240V equipment but to provide only for that which is required.

- I would suggest that you seriously consider Induction Cooktop & Air Convecting Oven, this will require 240V.
- Hot Water would be ideally a 120V Plug-In Heat Pump Water Heater (Rheem & Others have them) and if you have a Solar Water Heating panel in front of that, you will see efficiencies you've never imagined.
- Soft start pool pump programmed to operate on a schedule appropriate for your usage.
- LED Lighting of course goes with the whole build. Do note that Quality Brand Lighting is important and avoid the cheap stuff!
- Fridge/Freezer: There is a huge variety of makes & models that are efficient but some (even name brands) are not as robust as they should be, so you really have to do your research on that. Look for warranty & repair issues etc.

Home Livability !
I Very Strongly recommend a Cool Roof System, especially for your climate zone. A Light coloured roof (white is best) that has a Thermal Break via an air space between the roof's physical sheathing and the exposed surface is the best option. The freeflow airspace should be no less than 6cm (2") which allows convection to move the air up and out of a roof ridge vent, this also requires screened vents through the Soffit to allow air in but not "critters". This prevents heat absorption through the roof which is subsequently passed into the house. This is most easily accomplished by having VERTICAL Battens (2x4 typical) along the rafter lines and HORIZONTAL cross-battens which create an uninterrupted set of air channels that also provide for condensation to be expelled freely. See image posted lower down.

In the same vein as the roof, a passive rain-screen siding/exterior finish also provides that essential thermal break from the outer finish and the actual structural shell. Now with walls, you will need a weatherproof membrane that breathes on the sheathing (like the roof) and a 6cm/2" free air channels running horizontally allowing for air intake from the bottom and releasing into the soffit where the convection from the roof (vacuum) will draw that air out.

These two methods WILL cut Cooling costs significantly by preventing heat from getting into the home in the first place and will also protect the core of the structure by not being directly exposed to the exterior environment.
See attached PDF's for a good example.

Solar Gear:
Victron gear properly done including Lynx Distributors, etc will give you a very well rounded system that you can manage, adjust & monitor as it is all well integrated. NOTE: do take into account that you may want/need to expand it over time so allocate space for that and use equipment that will allow for it. ALSO look at this link, as Victron Batteries are very good but at a high price & moderate capacity. https://www.victronenergy.com/live/battery_compatibility:start

Solar Panels:
IF you can get them, the Hyundai Shingled 400W+ Panels work very well in dealing with shade situations (not easy to get) but other Quality Companies also make good Shingled Panels. These can also be Roof Mounted even on a cool roof but ideally on a ground mount or covered CarPort and such. It all depends on what & how you are designing and setup on the property.

Propane/LPG:
Do try to avoid using such if at all possible. Price Volatility and dependence on such which can be difficult to obtain during severe events, turmoil or situations outside of your control is not advisable. It is far better to be independent & self sufficient which can be incorporated when starting from a Ground Up build. Having been said, having a Propane Fuelled Generator is likely the wise option for you as it will not sour & go bad over the long term and again in your climate you will not have "cold use" issues. Now I would suggest that you look at the charging capacity from AC/Genset input and determine how many days of Genset Charging capacity that you need/want for fall back emergency use. *! NOTE: also ensure you work out a Minimal Critical Supply Requirement plan, so you can operate the home on minimal power during any bad events that may occur.

I am an Offgridder & Solar Powered, living deep in North Eastern Ontario Canada in a hyper-efficient home using most of what I have described above (adjusted for Canadian Climate of course) and can run my home quite comfortably on 3kWh a day including Radiant Heating in "frugal mode". I have also learned these valuable lessons from Tropical and Desert Regions which I incorporated into my design & build from those experiences & regional knowledge.

Hope it helps, Good Luck.
Steve
 

Attachments

  • Cool Roof Design for Hot Texas Climate _ Houston Cool Metal Roofs PART-1.pdf
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  • The Cool Roof_ A Risk-Free, Tax-Free, Inflation-Proof Investment _ Houston Cool Metal Roofs.pdf
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Hybrid water heater only use around 5-600w and condition the space they are in....ideal for a garage.
ICF for the house, super strong and great insulation. 50mm closed cell followed up with 100mm open cell spray foam insulation for the roof.
I am self building in Florida so we probably have the same requirements.
Insulation is not a thing for me. In fact much of the house doesn't even have windows that close. Temps are 80s by day, 70s at night basically year round. Not having to power HVAC makes this much easier. And water is gravity feed. Biggest load is pool pump.
 
You mention pool pump. I would avoid ever having a pool. They are expensive to maintain and time consuming.
Not negotiable. You are not incorrect. They do cost money but labor is cheap here for routine maint. This is not a frugal living situation. It is a high end luxury home and the pool is an important design element. Yes want to save on expensive electricity but grid is unstable and damages crap. Can install as much PV and batteries as I need and have grid as backup.
 
.. Yes want to save on expensive electricity but grid is unstable and damages crap. ...
Does not sound like you want to save as much as you want reliable electricity to meet your needs. Different design criteria when money is no object.

So the only other "gotcha" I can think of is finding qualified architects, engineers and installers and letting them do what they do best. Not really a DIY type of thing.
 
It is a high end luxury home and the pool is an important design element. Yes want to save on expensive electricity but grid is unstable and damages crap. Can install as much PV and batteries as I need and have grid as backup.

Get a variable speed pool pump with analog control (or digital data link if you can make that work.)
Pumps are available with built-in VFD, and programmed to detect people stuck to inlet as a safety feature. But likely have no control other than pushbuttons.
I installed a 3-phase pump and separate VFD, which has pushbuttons but also analog control.

My concept is to have a circuit track battery SoC and vary pump speed to run on surplus PV generation without drawing down battery. A variable dump load.
Given lithium batteries that can take thousands of cycles, may be acceptable to switch single speed (or 2 speed) pump on and off.
Varying speed to maintain target SoC isn't exactly what you want to do because SoC responds slowly to charge current. In the case of my lead-acid, inverter/charger holds it at target charge current, then absorption or float voltage. My system uses frequency shift to control AC coupled GT PV inverters, so my pool pump VFD should be controlled to draw excess generation before generation is curtailed.
If yours doesn't have a "curtailment" signal like that, then something voltage or SoC based might be good.

One other Gotcha! is that cheap VFD (mine, and found in some mini-split or other variable speed A/C) are not "power factor corrected" and create abusive current waveforms the inverter has to tolerate. Better equipment would present a load looking like a resistor, sine wave current, rather than something choppy which is almost a square wave. European equipment may be better. Some will have "PF" Power Factor ratings. This entire topic may or may not be an issue for your inverter, but it upsets my GT PV causing production to not start up in the morning. (consider switching 2-speed pump mentioned above.)
 
Hybrid water heater only use around 5-600w and condition the space they are in....ideal for a garage.
ICF for the house, super strong and great insulation. 50mm closed cell followed up with 100mm open cell spray foam insulation for the roof.
I am self building in Florida so we probably have the same requirements.
Or just use ICF roof decking. It starts at R22 and you can build the roof as strong as you want (including a parking garage).

Where are you building in Florida? I'm toying with ICF....
 
I'm near Palm Bay Gary.
I didn't really think about icf roof as it was a bit too radical for me lol.
BTW I have an excellent contact to assist with your icf build if you want it. Contact me here via the forum.
 
Gotcha items from my experience.
1. The costs of the main equipment are easy to calculate and add up, but the 'small items' wire, junction-boxes, cable management, raceways, disconnects, breakers, fuses, connectors, ring terminals, etc add to a Lot more than (I) expected, and because of this there is a tendancy to 'go cheap' just where we should be 'going quality'. Going cheap, and later changing parts to quality costs even more than doing it right the first time.
2. Making a list of "ALL" the loads and power uses, is a moving target, as our lives change, things that we need to power also change. Make as complete a list as possible, be sure to include the PV system losses as a 'load' and then add (or design for expansion) for future items that inevitably get added down the road. Especially if an expanding family, EV is/could be part of the future loading you need to supply.
3. Relying on past grid performance/stability/price as an indicator of future grid performance/stability/price.
4. Thinking of a off-grid system as a "one-off build it and your done" is a mistake. I believe this tech will continue to rapidly change and we should consider how a few years from now, better (cells/PV,Inverters,Controllers,tech etc) will result in an opportunity to make up-grades, expand or increase efficiency. Keeping modular, expandable, up-grade-able is a desireable feature to design from the beginning.
5. Spare parts. When you need one, waiting is not an option, plan for critical spares (fuses!) and keep these organized and ready to go.
 
Absolutely agree with OffGridForGood, most especially on do not skimp on the important parts like Breakers, Fuses and the items that keep you safe & secure. Balance of System parts add up fast ! The $1000+ items get noticed fast but the $10 & $20 bits add up really fast !

Any system you build will only be as good as "the weakest link" or part which can (and assume it will) fail.
 
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