I want to go offgrid....but....

bgarrettbgarrett Solar Expert Posts: 48
I bought 16 acres of trees and will move there and build a new home and workshop.
I want it to be offgrid.
I dont mind learning new things
and its ok if it takes more attention than ongrid current, but...
from reading the forums for several years, it appears that I will have to learn a LOT of information and spend a LOT of time keeping an offgrid system going.
It looks like a BIG HOBBY

I am going to have to clear the property and build the buildings myself with little or no help.
I am 58 years old and while I have built barns and garages, maintained renthouses and a fleet of cars and done everything by myself in the past, my health is declining....

I would like to hear your opinion
Is it reasonable for me to build and live offgrid?


  • BB.BB. Super Moderators, Administrators Posts: 28,142 admin
    Re: I want to go offgrid....but....

    There are desires, capabilities, abilities, and resources...

    You have the desire and the capabilities. Your abilities are declining--so once you start, can your finish? And once you have finished, will you have the resources (money and outside help) to keep it going in the future?

    There are two ways to approach off-grid living (in my humble opinion).

    One is a minimalist way... Just enough to live. Some light, some heat, and a little entertainment.

    The other is to replicate our on-grid/urban/suburban lifestyle.

    And, what happens 5, 10, 30 years from now? Will the fact you built your off-grid home help or hurt you in your future plans (good investment, bad investment, adding additional living areas for family/renter/helper?

    In our current world, living off-grid with all of the trappings of an on-grid life style is still relatively expensive (in money and labor). What are your needs and desires?

    Overlaying all of the above (and anything else I am sure I have left out) against the life you want to live--and what is your answer?

    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • icarusicarus Solar Expert Posts: 5,108 ✭✭✭✭
    Re: I want to go offgrid....but....

    If you have the grid available, consider that the grid is bargain source of energy. If you want to go solar, any given system will cost ~1/2 as much to be on gird as off for a similar sized system.

  • nielniel Solar Expert Posts: 10,311 ✭✭✭✭
    Re: I want to go offgrid....but....

    "I would like to hear your opinion
    Is it reasonable for me to build and live offgrid"

    that's a question that is difficult for us to say one way or the other. i know that stuff does happen and for me, i never fathomed that i would not be able to do many of the things that i used to do even only 5 years ago. predicting the future is not my forte even for myself.
    i am assuming that your questioning is coming from facts you know now and how that may project into the future. if that is the case you have to weigh things as to how it might happen for you and if there's anything you can do to still achieve your offgrid goals with these scenarios applied. i hate to say it and it sounds pessimistic, but realistically it isn't if something will happen to us, it's what and when something will happen to us. how well you can do this will be up to you, but i'd advise to try and get some minor help with things if you go through with it as designing things with foresight can help like having the batteries more accessible and being able to move them with the help of a hand truck. i broke down and bought a good hand truck for myself to help with some things that i can't handle as well now.
    i really hated to sound discouraging to you, but my point might be to not be as independant (not meaning electrical power) by getting people to help and just plan things out better for some of those whatifs and try to see if it's still feasable for you to do it. we can't live pessimistically or in a glass bubble and you may regret not trying to do it so i encourage you to try. if you are seeing a decline in your abilities then time may go against you in the exocution of those plans so time is your biggest concern.
    i am rambling here, but some of this are my own experiences that are shining through and if i only had a bit more hindsight and got more help with things. i don't regret my efforts, ever.
  • MangasMangas Solar Expert Posts: 547 ✭✭✭✭
    Re: I want to go offgrid....but....

    Difficult question but a good one. These are my opinions and experiences.

    If your contemplating going off grid soley to save money you probably won't. Eventually, a combination of solar hardware, storage and power consumption efficient products may make Off Grid easier to digest with paritiy to Grid Tie but probably not now.

    If you are going Off Grid to be independant and for other personal reasons (in my case land conservation, ranching and the challenge) okay, try it. What will determine your satisfaction is realistically managing your expectations in terms of lifestyle vs the Off Grid solar investment you'll make to achieve it; your time, your resources, direct/indirect costs and commitment.

    First, decide if you will you cook and heat your lifestyle with gas and power everything else with solar power (including hot water). I bear the cost of bringing in gas "way out here" to minimize the cost of Off Grid solar while restraining the system's size. Hence, a "Hybrid" system. This is fundamental.

    Second and most important, detail your dwelling's conservation investments and/or deletes. It will be your best investment.

    Third and in detail, assess your lifestyle power consumption baseline by adding up what output requirements you'll need and add 50% after conservation investments.

    Fourth, before you spend any money, retain competent and experienced people knowledgeable in OFF GRID Best Practices solar applications (meaning they have actually done it with references) to include licensed electricians to guide you with a system's plan/bill of materials that covers 80% of the investment which will give you a feel for what financial resources you'll need .

    Fifth, price the system installed turnkey with the best components you can afford i.e panels, inverters, charge controllers, wiring, generator, batteries to include civil and electrical work. Include where will you securely put the solar mechanicals? Price that in too.

    Finally, if you can balance your lifestyle's baseline with the resources you're able to commit the decision will be easier to make.

    There's some alchemy in all this and a lot of determination. I had a lot of naysayers when I built my system but had a lot of experienced people too who understood what I was trying to achieve and why.

    Hope this helps and Good Luck!
    Ranch Off Grid System & Custom Home: 2 x pair stacked Schneider XW 5548+ Plus inverters (4), 2 x Schneider MPPT 80-600 Charge Controllers, 2 Xanbus AGS Generator Start and Air Extraction System Controllers, 64 Trojan L16 REB 6v 375 AH Flooded Cel Batteries w/Water Miser Caps, 44 x 185 Sharp Solar Panels, Cummins Onan RS20 KW Propane Water Cooled Genset, ICF House Construction, all appliances, Central A/C, 2 x High Efficiency Variable Speed three ton Central A/C 220v compressors, 2 x Propane furnaces, 2 x Variable Speed Air Handlers, 2 x HD WiFi HVAC Zoned System Controllers
  • n3qikn3qik Solar Expert Posts: 741 ✭✭
    Re: I want to go offgrid....but....

    If you can, plop a RV trailer there, live there a year. It will get your feet wet about living off-grid. If it works, then look a building a house. If not, you will lose very little.
  • EcnerwalEcnerwal Solar Expert Posts: 101 ✭✭✭✭
    Re: I want to go offgrid....but....

    Where's the grid WRT your 16 acres? How much will it cost to get a grid connection?

    When you have the latter figure, THEN you can start figuring on whether it makes any fiscal sense to go off-grid. Even expensive grid power is cheap compared to most off-grid power, in total cost.

    The other big question is how poor you are or are not - because you can (quite possibly with a large "connect to grid" figure as a goad) Pay A Professional to do it for you, and have a turn-key system - hopefully with someone you can call and get to come fix it, if they don't go out of business on you (do your research before choosing a contractor). The customers for these don't show up on the forums much - the contractors sometimes do, and speak of "customer's" systems...

    Not the way I'm going at it, but it's part of the spectrum of possibilities, and a lot of people do go that way. On the other hand, if you are hurting for money, even a DIY solar system can be a big drain on the cash reserves.

    Finally, you will need to cut a BIG hole in the trees. If you want 16 cleared acres, you might see if you can swap your treed acres for some cleared ones, unless you just love logging and stumping, or that particular spot. Pro loggers are another option, though you'll need to have someone else come in and clean up after them. Contrariwise, if you like trees, you might want to go with the grid, especially if it doesn't cost too much.

    The RV suggestion is a good one, as well.
  • bgarrettbgarrett Solar Expert Posts: 48
    Re: I want to go offgrid....but....

    Thank you for the responses.

    One thing that is bothering me is that it seems I will have become an electrical wizard to learn enough to set up and maintain a system.

    I have kept my 1939 Ford pickup on the road daily for 16 years, maintained a fleet of cars on my job and maintained my 5 renthouses for years so I am not afraid to work on things and I can use tools

    I dont mind learning more, but do not want it to be all consuming.

    I dont mind setting up and maintaining a solar system but I have other things I want to do also.
    I dont want to spend a lot of time every day on this solar sytem.

    How much time do you off grid guys spend daily/weekly/monthly to keep it going?

    Some points picked out of your posts---

    "One is a minimalist way... Just enough to live. Some light, some heat.."

    I live alone and dont think I will ever find a woman willing to join me. If I do, she will have to accept what I am doing.

    I dont require much to live--I am 58 and have NEVER owned a TV.

    Heat and cooking will be propane, delivered by the Propane Company truck.

    I am concerned about the refrigerator.

    Propane power for the fridge sounds good except for the high cost of the fridge and some solar guys say forget that, get an Energy Star.

    Those seem to all use a minimum of 1000 watts a day!!!

    All my other household needs combined do not total that much.

    "replicate our on-grid"

    No, I am planning a home that will not need air conditioning, so a few LED lights, I DO like the radio on during the day, but I have few other needs.

    "solar, any given system will cost ~1/2 as much solar,"

    I am not poor and I am willing to accept the cost

    Yes, grid is cheap

    I dont care

    Its not the cost that concerns me

    "a RV trailer there, live there a year"

    I placed a travel trailer on the property a year ago.

    I visit, sometimes up to 3 weeks at a time but have not moved there full time yet

    Advice given suggests that I NOT start with a small system and add on because the oldest batteries will drag the newest down.

    I plan to start with 24 volts

    backwoods solar website has six examples to help guess at how to start out http://www.backwoodssolar.com/CONSERVING

    Their second example looks reasonable to me.

    Its for a small home (thats me!)

    and costs about $4000 to $9000 and produces about 1.5 TO 2.0 kilowatt hours on a sunny day

    Their suggestion runs high efficiency lighting, TV, stereo, & DC water pumping. The AC power inverter runs color TV, VCR or satellite receiver, stereo; and limited use of vacuum, sewing machine, hand held power tools, computer, blender, DC powered deep well pump.

    That seems like a lot of stuff to me

    They suggest an AC generator is used for large appliances like clothes washer, AC deep well pump, or a table saw, and it charges the battery at the same time. That sounds ok to me, possibly adding a second system later to power my workshop.

    THAT is where I spend my days.

    Again I want you to know that I appreciate each suggestion from you guys
  • BB.BB. Super Moderators, Administrators Posts: 28,142 admin
    Re: I want to go offgrid....but....


    You have given us some very useful points of reference.

    First, roughly, where is the property? Hopefully it is in the South West where there is lots of sun. You can use the PV Calculator to estimate how much power you can generate per 1kW of solar panels (use 0.52 derating for an off-grid system).

    Next--the Fridge. Highly recommend that you look at either a simple Energy Star rated Fridge. The standard AC fridge is so cheap (and reliable), that you can easily use the savings (vs DC "solar" fridge or propane powered) to buy a couple extra panels.

    Or, if you want simple and fridge only (no freezer compartment), take a walk through the chest freezer conversion thread... Some have reported using only 250 Watt*Hours (0.25 kWhrs) per day.

    You other power usage sounds pretty low--Icarus (Tony) has a small cabin on a lake in Canada--and has been very happy with his system (see his signature for equipment list).

    The better you can estimate your loads--the less over building (or under sizing) your system you will have... For an off grid system, personally, I would size the system with known loads (and average sun), then build it 2x larger (battery and panels).

    While you can do everything with 12 or 24 VDC--I would suggest an efficient 120 VAC inverter. Easier and cheaper to find appliances. Also, you can send power farther at 120 volts.

    24 VDC would be find for a small pump to presurize your water and such.

    For hot water, solar thermal would be handy too.

    And, you will want to have as much sunlight as possible--probably 9am-3pm minimum... Any shading on a solar PV panel will kill your output by a lot.

    Maintenance wise--My 3kW gird tie system has required zero work over the last three years (sometimes, I wash the dust off the panels with a hose and broom).

    For an off-grid system, battery maintenance is where the most work is required. Filling with distilled water once a month, keeping the tops and wiring clean, etc.

    Most people kill their first couple sets of batteries from under (or possibly over) charging... Having a good backup generator will be helpful (I like the Honda eu2000i, possibly eu1000i as being very quiet and fuel efficient).

    Also, besides a DVM and Hydrometer, a Battery Monitor is the missing piece for most installations. Sort of like driving your car without a fuel gauge or odometer if you don't have a battery monitor.

    Maybe after you burn through your first set of "training" batteries, take a look at AGM or better quality heavy duty batteries.

    The Heavy Duty batteries will last many years. The AGM are very clean and require no water as they are sealed.

    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • nielniel Solar Expert Posts: 10,311 ✭✭✭✭
    Re: I want to go offgrid....but....

    that may or may not work out well for your home, but powertools and large lighting systems to run them under will be a much larger system than your home will be. you could use a large generator here too for this purpose, but that depends on your time involved in there and how much you can stand running that generator and gasoline runs for it. to run powertools i would only suggest using a true sinewave inverter, which is much more expensive than the modsine they are providing
    also, don't count on the sun always being there fully everyday due to clouds and winter presents less full sun hours to be utilized. i think you will windup getting more pv for the house than they list, for you will have to run that generator more than you'd want to with 350-500w of pv. that i would consider to be some of the maintenance you wanted to minimize. you do conserve already, but you may find it is more critical to have some extra power available just in case. remember of the scenarios of health i was talking of? you may need that extra power and if you have the money for it then don't scrimp on that aspect for you have no backup except a generator. also know that long term or often use of a generator would make me recommend the higher quality generator types made for more continuous or often usage that have lowed rpms (around 1600 or less) like onan. to run other generators often will lead to failure and most likely it will fail at the worst possible time.
    i think you are of the type of personnality that i say go for it as deep down inside you would kick yourself if you didn't. consider piecing a system together on your own based on their systems to start, but if you haven't the time then let them do all or some of it for you. you can still add to or subtract from any system so if there's something you want and they aren't putting it in that particular system then you can talk to them and tell them that's what you want. a couple good examples may be a good mppt controller instead of just pwm or agm batteries(less maintenance) instead of standard lead acids.
    you won't have to be an engineer to do this, but at least know enough to be able to know what you want and basically how it's to be done. out of curiousity, where are you located in general?
  • bgarrettbgarrett Solar Expert Posts: 48
    Re: I want to go offgrid....but....

    This is for north central Arkansas, a much colder climate than I have ever lived in, but they have more sunshine.

    I am not planning to buy from backwoods solar but I do appreciate the guide provided by their 6 examples.

    I do believe that a MPPT is worthwhile and its seems like a good idea to get a true sinewave.

    I got the bulldozer guy to clear a spot, so there is NO possibility of shading the panels.

    Thanks guys
  • bgarrettbgarrett Solar Expert Posts: 48
    Re: I want to go offgrid....but....

    I looked at BBs PV Calculator.
    Its a perfect example of my statement that it looks like it will take an electrical genius to understand.
    I was totally lost, dont have a clue about anything there.
  • nielniel Solar Expert Posts: 10,311 ✭✭✭✭
    Re: I want to go offgrid....but....

    you can always have the pvs installed professionally either totally or partially with you contributing some labor in addition to a good qualified electrician's advice just for another opinion. not too many electricians are that familiar with pv installs although he can confirm some electrical requirements and aspects of the code even if he's not that familiar with this stuff.
  • BB.BB. Super Moderators, Administrators Posts: 28,142 admin
    Re: I want to go offgrid....but....
    bgarrett wrote: »
    I was totally lost, dont have a clue about anything there.

    I am not sure which parts you are confused about--but it is not that hard to use...

    I assume you made it through the map page and picked the closest place (with similar weather) to your own.

    Array Size / DC Rating: I will pick Fort Smith AR... Use 1 kW for the panel size (does not go smaller, so pick even number to "scale" to your needs--note that 1kW=1,000watts). This is the "name plate" STC rating for the panels (marketing numbers).

    The derating factor includes a whole bunch of variables that affect solar panel through Grid Tied Inverter output... From my point of view, the 0.77 derating factor is just fine for a GT system (on grid--it agrees very closely with my own system's output). For a first pass, use 0.52 as the derating factor. This accounts for the extra inverter and a flooded cell lead acid battery losses (inverter 85% eff., flooded cell lead acid ~80% efficient).

    Tracking--you can have a fixed or 1 or 2 axis tracker--for various reasons, in the US, a fixed mount with more panels is more cost efficient than fewer panels with a tracker (and more reliable). Used Fixed Mount for your system.

    Array Tilt--the default is set you your latitude which gives the most energy over the entire year (on average). Some people (especially those with significant snow) will find mount that tilts -15 degrees in the summer and near vertical in the winter helps their collection and prevents most of the snow buildup (panels have to be high enough off the ground to clear the panels of snow). Choose default for now.

    Array Azimuth: For you, pick south (180 degrees)... Some people have east/west roofs, or local conditions (shade from mountains, morning fog, or afternoon thunder storms) where facing the arrays somewhere else makes sense.

    Calculate, then the results page. The left side of the page lists your settings. The right side the estimated "sun hours" and output by month.
    Month     Solar Radiation
    (kWh/m2/day)     AC Energy
    (kWh)     Energy Value
    1      4.13          97        7.18   
    2      4.84          102        7.55   
    3      5.13          118        8.73   
    4      5.67          122        9.03   
    5      5.77          123        9.10   
    6      5.97          121        8.95   
    7      5.85          119        8.81   
    8      6.08          126        9.32   
    9      5.34          109        8.07   
    10     5.07          111        8.21   
    11     4.43           98        7.25   
    12     3.62           85        6.29   
    Year   5.16          1331      98.49
    First column is the Month (Jan thru Dec).

    The second column is the average "sun hours" (by month). Basically, this is the "magic" number for your site. If you assume that full noon sun is 1,000 Watts per sq.meter, then in December you receive the equivalent of 3.62 of noontime sun. In Summer, you get around 6 hours of noon time sun. This accounts for the sun track across the sky, the local average weather (clouds, fog, haze), and the type of collector mount (fixed for this case) used.

    The next column is the number of kWhrs per Month (in this case, based on a 1,000 watts of solar panels, and derated to 52% for off-grid system)... Monthly numbers are fine for those using Grid Tied--but not as useful for those on off grid... Take this number and divide by 30 to find kWhrs per day. I paste this into a spread sheet--or you can do it by hand.

    December = 85 kWhrs per month

    85kWhpm / 30 days per month = 2.83 kWhrs per day or 2,833 W*Hours per day

    I like to assume that you will be not using a generator for at least 9 months of the year... So I toss the lowest 3 months and we find Feburary at 102 kWhrs per month or:

    102kWhpm / 30 = 3.4 kWhrs = 3,400 Watt*Hours per day (average)

    So, if your daily usage (for non-winter time) is (picking any number) is 1,200 Watt*Hours per day, and we would suggest doubling that rating (to allow for growth, bad weather, etc.):

    1,200 WH * 2 = 2,400 Watt*Hours per day.

    Now, the size of the solar array:

    2,400 / 3,400 * 1,000 watt solar panel (reference from program) = 706 watts of panels needed

    For battery sizing, recommend 3 days of backup and no more than 50% discharge:

    2,400 Watt*Hours * 3 days * 1/50% = 14,400 Watt*Hours of batteries

    You want a 24 volt battery bank:

    14,400 WH / 24 volt bank = 600 Amp*Hours of storage (at 24 volts)

    I hope this helps... Nothing is cast in stone here--the above calculations are just a series of rules of thumb useful for initially and quickly sizing a system.

    Depending on your local needs, you can certainly make the system 1/2 the size (or even 2x bigger) and you will find it very useful for your needs. Don't try to get any more accurate number--the weather itself can add +/- 10-20% differences, or more if you have a month of bad weather.

    For example, if most of your use is during the night (water pumping, vacuum, cloths washer, electric tool use), you could double the size of the battery bank. Some people would choose this option to increase the life of the battery bank... However cost wise, it is not a clear savings in cost--If you pay 2x for batteries and get 2.2x longer battery life--it is not much different. Increasing battery bank size is also helpful if you have periods of heavy power use or long runs of bad weather and need to avoid generator use (noise, smell, cost of obtaining fuel).

    However, I would not recommend doubling the size of the solar panels with respect to the battery bank capacity--with the way I went through the calculations, the ratio of solar panels to batteries is about the maximum recommended charging current for the average lead acid battery bank. It would be a waste of money to add more panels (battery bank may not absorb any more current). Of course, if you use lots of power during the day, then more panels and fewer batteries may make sense for your installation.

    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • hillbillyhillbilly Solar Expert Posts: 334 ✭✭
    Re: I want to go offgrid....but....

    Sounds like you're being quite prudent in proceeding slowly, acquiring as much info as possible before jumping in. Given that much, and the fact that you are able to understand automobile engines (my personal nemesis), I would guess that you will have no trouble learning the basics of how to keep track and perform basic trouble shooting on your system. Regarding some of the formulas, they can be a bit intimidating when all the terms are new and foreign; just know that once you know a bit more about how things work it's really fairly simple (this coming from a man who has tried and tried to love math, but for whom math has never returned that favor). While I am certainly no electrical whiz, or solar guru, even I have been able to figure it out, and keep on top of things. So far our system has run well, with no troubles... although I continue to learn more, and thus have some periodic questions about how to better maintain the batteries... so far so good. I don't have any idea about how much time I spend, because it's sort of a labor of love... I enjoy learning, and thus feel compelled to tinker with things a bit (and spend countless hours of "research" online). There are some really good books out there that might help you to understand a bit more on the subject, and make the mathematical equations a bit less daunting. I really like the one that the Solar Energy International put out. They also offer classes too http://www.solarenergy.org/

    With respect to Bill's suggestion that there are two basic off grid strategies, we've sort of split the difference between those two extremes at our own small house in the woods. We have all the kitchen appliances (both LOVE to cook), a nice stereo system (I need music, and NPR), but we use all CFL's a propane fridge and stove, heat with a small woodstove, cool with lots of open windows and skylights (plus a cool side of the house that's shaded and misted in the afternoon). We have a modest size PV array of about 1KW, a back up generator that gets used periodically in the winter months, and once a month the rest of the year to help Equalize the batteries (and keep the generator "excercised"). We certainly have a pretty comfortable home, but consume a LOT less power than any of our friends and neighbors for sure.
    In our case, with our limited power consumption, it would have not made much sense to connect to the grid. Just the basic connection (cable, trenching, transformer and such) would have run quite a lot more than our total solar system, so in order for that "cheap" grid power to really pay off, we'd need to be using a lot more energy than we actually need. A further plus in our area is not having to deal with the frequent power outages. It's always been my feeling that there's not a really straight forward answer to weather or not it makes sense for any one household to go "grid tie" or "off grid", as there are many factors to take into account... me personally, I love the independence of having control over our own power.
    Good luck
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: I want to go offgrid....but....

    I may as well add my 2¢ worth. :)
    Like Icarus, I have a cabin on a lake ... in the Cariboo. The nearest electric grid is 17 kms away, so it has to be off-grid. My system consists of 4 175 watt panels, Outback MX60 mppt controller, 320 Ahrs battery (insufficient), and an Outback 3524 inverter.
    It runs a 16 cu.ft. 'frige/freezer, lights, satellite Internet/computer/phone set-up, 1/3 HP electric water pump, and 1 HP septic digester pump. I do not have ideal panel exposure, and the winter light is too low for anything other than keeping the batteries up.
    Cooking is by propane stove and heating is wood. Back-up power/charging is from a Honda 2000 - with a Honda1000 and a 5kW Coleman available just in case!
    Like you, I'm getting up there in years and there are days when the arthritis is just too much for doing things. The biggest problem is always the 'heavy work', but maintaining the solar set up doesn't fall into that category. I'd say setting it up wasn't difficult, but I used to work tech for Emerson Electric so the basics were already known to me.
    I worry about the same things you do. Mostly about making the hour's journey into town over logging roads if something goes wrong. But I think the actual building would be more difficult to manage than the solar power.
  • icarusicarus Solar Expert Posts: 5,108 ✭✭✭✭
    Re: I want to go offgrid....but....


    I wrote a long reply and then lost it by clicking the wrong button,, so I'll try to reconstruct what I wrote earlier.

    Since you seem committed to this process and you are willing to pay the cost, I'll give you my experience for what it is worth.

    We started as caretakers for a large remote bush camp in Northern Ontario. Our winters are long and cold. I grew up with Kerosene lamps for light for most of the winter. We evolved to solar after using a small winter generator to charge a car battery to run the radio and a couple of reading lights,,, a great advance over lamps. At -40, getting the genny started could be a travail however.

    So we started with one 55 watt solar panel , a simple controller and a pair of t-105's Over the years the system has evolved into a dual 120vac/12vdc system. We have 210 watts of panels, a 4 t-105's, controlled with a 25 amp mppt controller.

    We built ourselves a new house last year and have retired (sort of) from the caretaking. We still live there, but now we spend a bunch of time away. Our only neighbour is 2 miles down the lake, and he is off grid solar as well.

    The reason for the dual 12/120 system is that it allows us to use a bunch of stuff without having to run the inverter. For example, we have a ceiling paddle fan that is 12vdc and it can run 24/7 without needing the inverter. We also use a 12vdc car radio with an Ipod connector. The idea behind that choice is that it sounds great running through house speakers, and it only draws ~15 watts,, way less than a conventional stereo. (and it doesn't need the inverter to be on). (We are also ~150km from the fm transmitter and the receiver is much better at picking up distant broadcasts than a household unit, we can get FM stations from 200kms away). We also have some emergency 12vdc night lights that use for quick light without needing to turn the inverter on. The water pump is also 12vdc with a current booster to run it at 24vdc. The fridge ignitor/control board runs on 12vdc as well.

    The 120vac side runs the conventional lighting, the satellite modem, charges the lap tops etc. We use Propane for fridge(s) (more on that later), cook with Propane using a standing pilot gas range. Our water heat is a demand Paloma legacy series gas water heater. We heat with wood.

    Even though we are in a new house (cabin by most standards) our usage is about the same. The difference is that the new place was wired from the ground up for solar, and it was designed for winter use. In our previous house we had no running water 6 months a year, and it could get so cold that the water buckets would freeze to the floor over night. While the new place is still small,,,~600 sq ft, it is huge by comparison, and the woodstove is in a separate room from the bedroom. Sleeping in the old house in the winter was pretty interesting,,Susan's side of the bed would be 75f and my side would be 55. If we stoked the fire over night she would roast,,if we didn't we both would freeze!

    So here is what I would do differently if I were starting over. Two simple truths emerge, from these threads and from my experience. The first is that loads WILL increase with time. The second is that you can add anything later, but somethings are much harder to add,, and batteries cannot, for all intents and purposes be added to an existing string. ( A third is that you will probably kill a set of batteries prematurely learning how to use a system)

    Before I did anything, I would consider all the aspects of fridges. If you are going to be full time for years, then sizing a system for a hi-ef compressor fridge might make sense. On the other hand, Propane fridges can be made very efficient if you add insulation on the outside of the cabinet, install t-stat controlled fan on the evaporator coils, and you give it proper air. Used fridges CAN be a bit of a crap shoot, but there are several reputable rebuilders who sell used fridges with good warrantees. You can also get a good one from a wrecked RV,,especially now with the current economic meltdown. The biggest risk with used Propane fridges is when people have run them out of level. Running them out of level causes them to overheat, and eventually leak the ammonia coolant to leak out. (New cooling units are not real expensive and can be installed quite easily, if you get a dead fridge for free, or nearly free).

    Once I had the fridge issue resolved, then you could use my daily average as a bare MINIMUM for a rough estimate. We use ~4-600 watt hours/day, add a conventional fridge and you would better than double that,, say 1.2kwh.

    In my case, I would plan to double the size of my system. I would start by adding more panels and I would probably buy a bigger controller. I like the Bluesky MPPT controller, but at 25amp it doesn't give me a lot of room to grow. I would probably get a MX 60, or it's successor which would give me lots of room to grow. (You have to look at the efficiency curves to see what happens if you run a 60 amp controller with only 10 amps say.

    I would also add at least one more pair of t-105's. (My neighbor runs 6 l-16's but I have found that the price difference makes the t-105's a better value for me,,time will tell)

    As has been suggested before, read all you can, and try to figure out ALL you loads, remembering that they will be more than you expect. Once you figure out your load, you can use all kinds of fancy calculations to size your system, but in the net/net if you use a system wide efficiency of ~50% you will be pretty close. System efficiency being charge controller, battery efficiency, inverter efficiency ect). So if for example you loads are 1kh/day, you will need the capacity of at least 2kwh/day minimum, plus any reserve you decide you need.

    So for example, we use ~4-600 wh/day,,let's call it 500wh just to be simple. When all is said and done, our 200 watts of panels allows us to use that 500 wh each sunny day with some excess. 200watts X 6 hours sun=1200 wh/day gross,,, 50% efficiency is,,,,600 wh! (Our gross numbers get a little confused since we use the bulk of our loads during the day, so that we don't either draw or have to recharge the battery for those watt/hours,,, a more efficient way to use solar).

    Plan for a system that you can grow into as you budget and needs evolve and avoid, as much as possible, the Ready, Fire, Aim.

    Good luck,


    PS We do use a number of generators to run our shops and power tools, although my collection of cordless tools is growing.
  • BB.BB. Super Moderators, Administrators Posts: 28,142 admin
    Re: I want to go offgrid....but....

    Tony and others,

    I have not tried it--but if you have FireFox, there is an add-in called Lazarus:
    Ever had one of those “oh heck” moments when you've finally finished filling out a long form, and hit submit only to see an error message? And when you hit the back button, the form was blank... If so, you know you need Lazarus. And if not, you have a chance to install Lazarus before disaster strikes!

    Using Lazarus, you can recover lost forms with a single click. Lazarus automagically encrypts and saves every form as you type. If the submission fails or if you forget to send it, your computer or browser crashes, then you can return to the page and recover the form data you originally entered.

    Lazarus is a simple, secure, reliable and free add-on for Firefox, produced by the Interclue team. If you're finding it useful, check out Interclue, our advanced webpage previewer.
    Here is another forum where it was first suggested (at least, for me) and some suggestions on security.

    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • nielniel Solar Expert Posts: 10,311 ✭✭✭✭
    Re: I want to go offgrid....but....

    if i asked my wife to live like that she'd divorce me and she certainly wouldn't have married me knowing that's how she'd have to live. i could rough it, but she is one of those spoiled types who is used to flipping on as many switches and appliances that she wants and believe me she does. i solved that by giving her a base amount within reason to pay for the electric bill and if she exceeds it, she pays that excess, with many grumblings from her after she pays it i might add. kudos to your wife as few would be willing to endure what she endures. then again, it may be that those in areas like yours that they think differently than many of those of whom are quite spoiled. i shouldn't make it sound ike this either as many guys won't do what you're doing either, but guys seem to be more willing to rough it and even that is up for debate depending on what one can define roughing it to be.

    that is a nice thing to add to firefox and i am going to try it. it won't do me, or anybody else i suppose, a whole lot of good if the forum logs you out for taking too much time, as i've done that one a few times. i guess it would still save it even though one would have to log back into the forum.
  • icarusicarus Solar Expert Posts: 5,108 ✭✭✭✭
    Re: I want to go offgrid....but....

    Aside from the stove close to the bed, what's not to love? Cross country ski on the ice in the winter, down the lake to the landing in the boat in the picture,,dog included. In fact we both love it. With advent of the net we now get all the news we wish, and we can telephone out. When I was young our only communication was short wave,, the only phone was 15 km down the lake at the railway. (I'm not sure I like it any better now however!)

    As we have gotten older we do spend a fair bit of time away. It is always a huge transition to come to the "real world" and be bombarded with all that it presents.

  • BB.BB. Super Moderators, Administrators Posts: 28,142 admin
    Re: I want to go offgrid....but....


    You are getting logged out for taking too much time?

    I have never been logged out. I have the box checked (next to User/Password boxes) to remember login (or something like that).

    When posting with delays (interruption), after a long time (an hour or more?), I will get an error--something along the lines of a "token time-out", but I just go back, refresh the page, and then post--I don't think I have lost any posts that way.

    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • nielniel Solar Expert Posts: 10,311 ✭✭✭✭
    Re: I want to go offgrid....but....

    as i said, i wouldn't mind it too much except for the skiing part. i'm not into that. i wouldn't, however, be able to be too far removed from civilization for too long anymore for medical reasons and those reasons would limit my ability to rough it anymore too. i did do some roughing it here as i had my electric and gas off (bad times) and i used my fireplace for heat and ran a genny once in a while for electric. i did this in the early 90s and i didn't have much in the way of solar and no battery at the time.

    i don't type fast and if i do a long post with some research or calculations in it, it can be lost as i am not logged in to post it at that point. all info that is attempted in a post is lost and i must then relog into the forum to start over again or just chuck it altogether as i've done a few times.
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