Question for 'Off Griders' and DC?

Discussion in 'Homesteading Questions' started by moonwolf, Aug 1, 2005.

  1. moonwolf

    moonwolf Well-Known Member

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    Those of you that are on solar or wind power and using DC lighting and/or appliances, what is your experience with it regarding wiring and costs?

    I know of propane or other appliances, but if you have a DC refrigerator or freezer, how does that compare to having an AC?
    How about DC 12 volt lighting like the lights in an RV camper? Does anyone use these as permanent instillations in their off grid house?

    Wiring? DC wiring? Is this required?
    What about plug in receptacles for AC use?
     
  2. SouthWesteader

    SouthWesteader Gardener

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    I used to have a DC mini-refrigerator, and it gave me a few years of service... It was pretty good, although they can be expensive or else very small. However, you do not have to have DC wiring in your home, even though wind and solar both produce DC. Inverters are sold that convert (or invert) DC power to AC. THese can cost anywhere from $20 to $2,000, depending on what size. If you want them on an appliance to appliance basis, it would most likely cost $20-$300, but if you are wanting to convert your whole house to AC from DC, it would cost something more like $500-2,000, but both those estimates would depend on the power usage of your house, or in the first case, said appliance. Just my 2¢

    Good luck! :D

    John
     

  3. patarini

    patarini Well-Known Member

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    If you use DC set up regular plugs for it -- most books say use a 220 plug so you dont get confused between ac and dc. I use an inverter with the new compact flourescent lights -- draw 11 watts but shine as brite as a 60 watt bulb. The 12 volt fridges I am used to are the small ones I use in the truck. Remember fuses are needed even on dc!
     
  4. WisJim

    WisJim Well-Known Member Supporter

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    The house we built in 1976-77 was totally off grid, and powered by an old windgenerator with a Delco 850 watt engine-generator for back up (used only a few hours a year.) We used a 32 volt DC system, with a 12 volt battery to run a few 12v DC items, such as a car radio and 12 volt blender. We had a very crude and inefficient motor-generator type of inverter that we seldom used. We bought a Sun Frost 12 volt DC refrigerator in 1981 or so to replace our Servel LP refridgerator, as we didn't like buying LP or having constant fumes in our super-insulated house.

    We ran regular 12-2 Romex for most of the circuits, and had some heavier ones for larger loads like table saw, grinder, etc., especially if they were farther from the batteries. I calculated voltage drop for most of the circuits and sized the wiring accordingly.

    We used regular 120v AC style plugs and recepticles because we had no AC outlets. Nowadays, some people recommend using one of the less common 220 or 250 volt plugs and receptacles for the DC circuits, so they don't get confused with AC circuits. Inverters are so much better today that you would probably want to have one for occassional use for certain tools, equipment, or appliances, even if most stuff in your home was DC.

    Jim
     
  5. mightybooboo

    mightybooboo Well-Known Member

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  6. Ramblin Wreck

    Ramblin Wreck Well-Known Member Supporter

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    Booboo,

    The fridge in your link sounds amazing. Maybe the trick to effective solar utilization is not inverting the power stream, but rather finding appliances that run on DC.

    Ramblin Wreck
     
  7. mightybooboo

    mightybooboo Well-Known Member

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    That frig works too,unless they were pulling a smoke and mirrors.We went to the showroom to see it in action.Ive also bought shelf and custom made items from them.They seem very honest far as I can tell.

    PS-I see it and the freezer are each on sale for 999.99. Mrs was drooling over that! :clap:

    Funny,she says just yesterday the refer was making a funny noise,and she thought to herself,if that thing goes out,I need to remember to tell Mr. to buy a solar one.

    BooBoo
     
  8. WisJim

    WisJim Well-Known Member Supporter

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    We are using a SunFrost RF12 refrig/freezer. It must be 23 years old or so, now, and we originally powered it (and our stereo and a few other items) with 4--30 watt PV panels. http://www.sunfrost.com/refrigerator_models.html
    Yes, it is a good idea to go with a DC refrig or freezer if you can to avoid inverter cost and reliability problems. Sorry to say, we succumbed to the house sized inverter syndrome when we moved to the existing farm house with all the regular "conveniences" such as forced-air central furnace, etc.
    Jim
     
  9. mightybooboo

    mightybooboo Well-Known Member

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    Jim,I saw a solar company has really gone after sun frost for poor quality seals and crummy cases.Also low effiency.As a real world owner,what is your real world unbiased opinion?

    Did your panels handle the load,or did you use a lot of genny power too? Im sure not trying to slam you,but can you comment on this link from someone who owns one and doesnt have an axe to grind? We solar alt. energy users and future users really need to get the best info for our investments,none of this is cheap.

    http://www.windsun.com/Misc_AE/Sunfrost.htm

    Thanks a lot!

    BooBoo
     
  10. mightybooboo

    mightybooboo Well-Known Member

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    Seriously Jim,do you REALLY regret using an inverter? Seems to have at least some uses,washer for one is pretty much a 120 volt propostion.As much as I can I would run pure 12 volt,but cant see where an inverter is all that evil for other applications too_Of course,there are efficiency losses.

    BTW,can you review your system again? I forgot all you have.

    Take care,

    BooBoo<---- Who has seen the light! :clap:
     
  11. Tango

    Tango Well-Known Member

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    I'm in a travel trailer with 2 120 watt Kyocera panels. I use the trailers 12v lights which are 6 watt incandescent bulbs. I don't use them to read at night (use my Coleman lantern instead) but I have the outside light on all night. It is not an eergy drainon the batteries. From what I've experienced, being conservative with my power usage, the two panels supply everything I need. My fridge is a 28 year old propane fridge and bless its coils, it is still keeping thinsg cold (but the freezer doesn't freeeze well). It has never had any service. Needles to say it has paid for itself a couple of times over by now but I wouldn't be able to afford another one.
    From what I've read wiring for 12v is simple. It certainly was simple to rig up my solar system. If I were to use solar in my house, I would wire for 12v. Don't know why it would cost any more to wire a house for 12 v as opposed to traditional wiring. The downside of course is resale value.
    I was going with solar for my cabin but have decided against it. It is, in the end, too expensive. 12 v appliances are 3 times what new electrical appliances cost and they are smaller. Even non-mainstream propane appliances like refrigerators are very expensive by comparison to reputable electrical appliances. I'm going with a gas stove, a gas tankless water heater, and gas heating (all affordable because they are mainstream) and energy star electric appliances. Was looking at a 20 cf Maytag fridge with the freezer on the bottom. Energy consumption was avg. at $35 per month. Cost of the fridge is $1200. I can't get anything near that size and price in solar or propane. Maytag should last 15 - 20 years - at least they used to. 15 years is a very long time in our high pace technological world. In 15 years, there will be something either more efficient or just plain better
     
  12. Gary in ohio

    Gary in ohio Well-Known Member Supporter

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    Inverters vary greatly in quality and current carrying capacity. They also differance in idle current. If your gonig to invert and power a fridge you need a high current load, load current idle inverter. Many (and most low cost) inverters will draw power when there is no load plugged into them. A fridge doesnt pull power except to power the compressor and inside light. If you put a cheap inverter on it you will be using some power 24x7. If your going to go to solar power make sure you use a low idle current inverter designed for solar power.