What are the top 5 gotchas for going totally off grid

[curiouscarbon]

one way or another, 1000 watts per meter squared is the highest game any solar builder is playing.

common photovoltaics range up to about 20% efficiency

1000W * 0.20 = 200W

so 200 watts per meter squared is the best most of anyone can hope for right now, regarding electricity generation.. until the sun becomes more bright.

heat generation can be more efficient. look up Albedo.

panels that generate heat and electricity are strictly the Most Efficient Possible. there are engineering tradeoffs with weight and maintenance.

given a nearby fusion nuclear reactor broadcasting 1000 Watts per Meter Squared, which definitely varies over season and location, FOR FREE, why would anyone not want to rely on that?

regarding energy relationships, the one I have with the Sun is Pretty Darn Good. ??

bottom line? The Sun Does Not Ask For Anything Or Subject Anyone To Politics ?

 

[AHTrimble]

Adding batteries is not too difficult as you say. I will buy enough UL listed to satisfy my AHJ and then add my DIY batteries after CO.
You know I am still pondering this.
I have 43 Panasonic 330w with the solaredge optimizers and 10kw inverter unit so can 100% put those on the roof.
The pro as I see it is then panels will keep some sun/heat away from the roof, con is they are up on the roof and I am getting older.
I have plenty of space to ground mount too but not sure if we will like the look of that.
I also have another 24 panels 280W and 315W that will be added to the mix after CO and away from nosy eyes !!!

You have a really large PV set-up...way more than we need here in AZ. We are blessed with plenty of sun...no, we're not in the desert
Sorry, I didn't understand the "CO" reference.
Our 2nd Quattro just showed up today! Yea! Now we will have 10kw & 240vAC. Oh yeah!!! And the 2 x PowerIns and the Lynx shunt as well. So you know what I am going to be doing for awhile.
DIY batteries just worry me, I don't think I have the skill, time, patience, knowledge, etc. But, the batteries we are looking at will double our AH to 800...I am thinking maybe going to 1,000AH...only thing holding me up is the money. Yuck!

 

[toms]

Worst advice I've ever heard on this forum or anywhere really lol We've been off grid since the mid 1990's and energy efficiency is king.

That’s exactly my point, in 1990 energy efficiency was king. Much of the advice comes from that mindset. Now energy storage is cheaper, energy generation (PV) is virtually given away, and the gap in price between average appliances/ building techniques is larger.

I challenge you to cost out a completed house using your methods, then i’ll do the same.

 

[toms]

It depends on where you are. @toms is in Australia, so that's his experience. Mine is completely different. In other words, there is no general 'right' or 'wrong', it all depends on specific individual use cases, locations and goals.

That is very true. The most important thing is to run your own numbers.

 

[wattmatters]

Not every site has a lot of solar PV potential. Small homes/lots, trees, location etc can mean that the available energy production is limited and so reducing the consumption side is a necessary part of the balancing act.

Every case is different. Meanwhile PV in Australia is cheaper than in Nth America.

But when considering hot water, for us it just made more sense to use PV + resistive element than less PV + heat pump HW.

 

[TOU47]

I cook with primarily propane but we have a portable 2-burner electric cook top for back-up.

I'm previously owned an induction range... that we absolutely LOVED for so many reasons. I would like to make this work again.

We use a single tankless propane water heater. I will be installing an electric one (with timer for daylight hours) right after the solar system upgrade as a pre-water heater so we won't use propane unless the electric water heater isn't working.

Love this...hadn't considered it. I wonder about a surplus hot water heater or two for daytime solar dumps & utilizing in addition with a radiant heated floors?

One thing I am extremely grateful for...we didn't do roof mounted PVs!!! I kept the roof integrity intact and the PVs on our ground 2 mounts are accessible as needed.

I consider roof mount strictly on a south facing wrap-around porch... nothing high up. (Think covered pergola) But...also want to have it adjustable which could be a bit more problematic in the winter for me in Colorado. Ground makes more sense but is a bit more unsightly & space occupying.

Currently living off grid but on a temporary small scale. Still planning & replanning the big build... for this spring.

 

[TOU47]

If they are wannabe climate heroes then you might have a chance to appeal to that but else it's a brave man to take that task on. Good luck!

Too funny! ?

If the day is nice the clothesline uses both wind and solar power and costs absolutely nothing to run.

Love this! ?

That was part of our plan...until the neighbor decides to till his field for the 4th time this year...on a windy day. ?

 

[TOU47]

This might make some people upset. But I didnt go off grid to help the environment.

Not at all.

For me, things like this have to make financial sense period. If they do... without government handouts or incentives or penalties...it will drive the market.

That being said... getting away & simplifying life (in some ways, not so much in other ways.) is a huge motivating factor for me as well.

 

[toms]

Of course all of these responses are in regards to off-grid power, which in my experience is the simplest aspect of living off grid.

 

[l00semarble]

FUNNY, the OP ran off from this thread after Post #13 when everyone started the whole Pool Pump pile which is NOT THE TOPIC BTW ! Hopefully he looks and picks out what is relevant to THEIR Question and Intentions.

I'm here. I was traveling for a bit but I have been reading the thread. I'm going to make some other replies.

Pool pump is an important topic as it will be the single largest consumer in my house by far. I did intend to get one of the latest and greatest variable speed pumps with sophisticated control. My pool will also have a waterfall feature which I think it typically done by a 2nd pump. I'm going to have to figure that out too.

 

[l00semarble]

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.

Propane is available in town but I have to hump it to the house myself (or pay a Tico worker). It isn't cheap. No way to have propane delivered so no way to have a large storage tank. I'm OK humping small bottles for now buy maybe avoiding that is good long term planning for getting older etc. So I'm going back and forth on this.

I was planning roof top passive solar with tank then mini on demand heaters at each bathroom/kitchen. If water arrives hot at the mini elec heater the thermostat just doesn't turn them on. If it doesn't thermostat kicks in and user gets hot water either way regardless of weather or rate of water consumption.

 

[l00semarble]

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.

Yes we need to size it right the first time. I will make the budget available to do it once and do it right.

You make a good point about handling cooking energy once and forever rather than hauling propane bottles all the time.

Yes on water heater but will add small on-demand heaters as backup.

For frig our current kitchen design calls for a fancy counter depth "panel ready" refrigerator that gets built in like the cabinets (like Sub-zero). I have not done any research yet to figure out if these units are a power nightmare comparted to other options. I don't think refrigeration is THAT big of a consumer (~1kwh/day?).

We may import our appliances and a bunch of other stuff for the build in a shipping container. But there are dealerships for big brands in San Jose. Any way you cut it finding parts and repairs for appliances is tough in our area. Gringos often import parts from the states if/when necessary. We have a system where other gringo owners traveling back from the states will mule parts for a neighbor in need.

 

[l00semarble]

Get a variable speed pool pump with analog control (or digital data link if you can make that work.)

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.

I was thinking the same thing. Run the pool pump hard when we have excess PV which may otherwise be wasted. Scale pump back when conditions are not as favorable to preserve batteries. Easy to have the Victron system trigger a relay on SOC which could be use in other home automation stuff to control pool pump.

 

[l00semarble]

Theft

Cycle life of batteries

Humidity (sealed enclosures or conformal coat helps)

Surge current of motors

Good thoughts. Theft is a concern for everything where we are. All gear will be in hardened, humidity controlled garage/workshop space. This is where I will keep tools and toys like ATV, SxS, dirtbikes, surfboards, etc. so it will be locked up very secure with outer layers of security as well including a big ass dog which many Ticos are nervous about. I will also have a sophisticated home security system and cameras. Obviously nothing is a guaranty but I try to not be the low hanging fruit.

Cycle life of batteries does not concern me as it is measured in the thousands, right? Even 3,650 cycles gives 10 years of service with daily cycling? By then I would hope there are great upgrade options that would be tempting to buy even if my batteries didn't age out due to cycling. Or am I thinking about this wrong?

 

[OffGridForGood]

I have not done any research yet to figure out if these units are a power nightmare comparted to other options. I don't think refrigeration is THAT big of a consumer (~1kwh/day?).

A large fridge can easily use 1.5 - 2.0 kW per day (24hrs) and in hot climate, it uses more. If you are shopping, look for the typical annual consumption figures, and if you have some items already, say a chest freezer as an example, use a kil-o-watt or similar plug in meter to find out the actual consumption.
For the pool feature, I would try to incorporate the recirc pump as the waterfall feature, or if it has to be a separate pump, at least put it on separate control to only run when you want it to.

 

[l00semarble]

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.

1. You are correct. Luckily I am in the marine electrical business and will get all marine grade gear at wholesale and import it in carry on bags. Some long cable runs will require I source cable in country but all wiring at the batteries/inverters etc will be marine that I import. All those bits and bobs do add up but I have good sources.
4. True. But I think I can size it right for the house and the use case right away rather than building it up little by little.
5. Yes. I was thinking about a vary liberal spares program including maybe even an entire inverter.

 

[l00semarble]

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.

Yes my system will be 120/240v split phase same as USA. I do plan to use two inverters to make split phase. This allows for 240v loads and for a little redundancy in 120v even if one inverter goes down. I was thinking of spec'ing as many heavy loads 240v as possible to keep the system as balances as possible.

- I would suggest that you seriously consider Induction Cooktop & Air Convecting Oven, this will require 240V.

Ok. Another vote for induction.

- 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.

I was going to do solar water heater into small on-demand units at each bathroom/kitchen

Home Livability !
I Very Strongly recommend a Cool Roof System, especially for your climate zone.

Well, our house design and construction method is all about air flow through the house. There are HUGE openings on front and back which will be left wide open when house is occupied. Even when the doors/windows are closed they only have screens. Is is all about letting the air flow through, not about insulation. House is at 1,500ft elevation but the mounting goes right up to the ocean. We usually get a nice ocean breeze during the day then in the evening the air turns around and cool air flows down off the mountain. All we have to do it let the air flow and we don't need HVAC.

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

Yes I know Victron gear well. I would only consider the batteries because I get them for far less than street price. Still, I would pay more per kwh than some other options so I have to consider other options. I do like the sealed marine grade build for my environment.

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.

For panels I think I get what I get in country or I have to import my own and get murdered on import duty. Even here you never know what you can find at any given time. At this point I'm not ready to buy so I'm not trying to narrow down panel brand/model as it is ever changing.

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.

Yes. Another vote for induction cooking etc.

Having been said, having a Propane Fuelled Generator is likely the wise option for you

My backup is going to be the grid which I have at my property. I will take from grid if my batteries get too low and solar isn't enough.

I 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

3kwh per DAY? I was planning for 10x that amount. I think I need about 30kwh/day.

 

[l00semarble]

And more relevant to this build, which seems to be in some Goldilocks zone

Yes. Goldilocks. But not by chance. The land was chosen to be able to build right around 1,500ft elevation which puts the house into the Goldilocks zone in Southern Costa Rica. I can be be hot as balls down at the beach and low 80s at 1500ft. At night cool mountain air moves down the mountain. This forecast is likely for close to sea level in our town.

Consider ducted whole house vented dehumidifier. Amazing how much closer people’s temperature comfort range is with humidity managed independently from temperature.

The house is not even enclosed at all. Huge window/door openings that will be left wide open (bugs are not a problem until after dark and even then no mosquitos). Its all about air flow. We will have some dehumidified spaces (master storage closet/secure room shared air space with linen closet, pantry/storage, and workshop/electrical room.) I was planning to have individual dehumidifiers in each space. I don't think I want to get into ducting.

Also think about speed of hot water arrival at fixtures. That either means a centrally located tank, with a large loop and small, short branches to each fixture (maybe with demand recirculating in the large loop). Avoid the single large manifold design at all costs

Or it means lots of local inline electric water heaters, sized just for the fixture. That design works better for sprawling single story house designs.

Yes I was going to do passive solar water heater on roof then inline electric at each bathroom/kitchen.

 

[l00semarble]

Propane for dryer and cooktop. Pool pump Pentair Intelliflo, if I were off grid I’d probably consider an LP refrigerator too

And then another vote for propane. No consensus on this!

 

[l00semarble]

Living in a similar climate and style of house, some of the most important decisions you will make really come down to building materials. Drywall is one example; if you have temperature/humidity cycling in a naturally ventilated house you end up with tape seam cracks.

Drywall is absolutely out of the question. I mean....it wouldn't last 6 months. Concrete/stucco/tile and tropical bug resistant hardwoods are all we are using.

Likewise, you want to make sure you always manage condensation risk throughout the year. For us we get minor condensation on the wood floors (dampness vs wet), but we have a lot of natural light that drys things out quickly. A slab on grade vs raised wood platform floor is a similar example-- the slab on grade will have very different properties which may be good or bad.

Making some of the wrong material choices ends up costing extra on your energy budget.

AIr flow also helps with condensation. I have a big allowance in my energy audit for constant ceiling fan use.