Inverters

Discussion in 'Energy & Electricity' started by UncleJoe, Nov 26, 2009.

  1. UncleJoe

    UncleJoe Well-Known Member

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    I know a number of you have solar systems in varying degrees. I am starting to seriously research what is involved. I'm not looking to power the entire house just yet, just some lights, a desktop computer, a TV, and/or the well pump. My question is; what type of inverter do you use? Pure sine wave or modified? I've been reading that you can get a lot of "noise" from a modified. On the other hand, a lot of articles say that it isn't that big of a problem. :confused: So I'm reaching out to you people that live with solar on a daily basis. Thanks for any insight you can provide.
     
  2. allen_idaho

    allen_idaho Well-Known Member

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    I would suggest a pure sine wave inverter, mainly because some things will only run on pure sine like a digital clock or a variable motor. You will also get great performance out of the inverter as opposed to a modified sine inverter. A modified sine inverter was designed more for being mobile. It is designed for voltage fluctuation like you would find if it were hooked up to your car.

    What you should focus on, however, is the wattage output provided by the inverter. You should take a look at everything you plan to hook up to your system. On each of them there should be a tag which lists the power consumption rating. This will give you the wattage needed to run each item. From there, I would select the appropriate inverter.

    And when looking for an inverter, be sure to go by the continuous wattage rating and not the peak.

    If you wanted something to charge your phone or some batteries, I'd probably go with a 150 watt inverter. Anything that you would plug into a cigarette lighter.

    For the rest, it all depends. Like just a TV, some lights, and a computer, you could probably use a 400 watt inverter. Anything else and you are going to need to go larger. Like a Microwave, Refrigerator, Oven, or Washing Machine.
     

  3. bunkerbob

    bunkerbob Supporting Member

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    Good morning, funny you should ask. Yesterday one of my neighbors called me to relay a message to the rest of the neighborhood, that the power was out. He knew first of all I was home, retired, and could alert other neighbors that were not at home. Being off-grid we didn't know it was out.:sssh:
    We have two Trace/Xantrex pure sine wave inverters, SW4024s, they produce about 4000watts each and are connected via a serial port so they can 'talk' to each other, so when they produce 220vac their sine waves are compatible. We have a bank of 28 T-105 batteries to balance the system. You get what you pay for, and if you are going to eventually go off-grid why not start with a good inverter. That's how we started years ago in our last home. Start small, then add to it as money or opportunity arises. Thats the beauty of renewable sources, we added some panels first with a wind turbine, the turbine system had a control panel that allowed up to 30amps of solar in addition. Had a few batteries for emergency back-up even though we were grid-tied at the time. My website has some info...bunkerbob.
    The two inverters produce enough 220vac for my 1 1/2 hp well pump.
    Also try this website Home Power Magazine: Solar | Wind | Water | Design | Build, I've had a subscription for years, every issue a plethory of knowledge for all renewable energy sources.
     
  4. Tex

    Tex Pincushion

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    Sine wave inverters will cost more. Are you looking at a 12V model or something that runs on higher DC voltage?
     
  5. NaeKid

    NaeKid YourAdministrator, eh?

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    Have you considered not running an inverter as part of your plan? Inverters "drain" power out of the system even when nothing is plugged into them - that is why many of the higher-powered inverters for vehicles (RV, car, truck, etc) have both manual switch to turn it off and an "auto-switch" that when the vehicle is off, it is also off.

    A standard desktop computer uses around 600watt of power to run, that doesn't count printer, monitor or any external devices. A better choice would be a laptop that runs uses an SSD (Solid State Drive) instead of a standard "spinning" harddrive. Those kinds of computers use close to a 1/4 of the power and can run directly off of the solar-system, or, use the solar-system to keep the internal battery charged.

    Basic home lighting on 110v wastes alot of power by providing the light (good) and heat (bad). By moving over to 12-volt automotive-grade LED lighting, you get the light (good) and no heat (good). It is easy to run LED strip-lighting down a hallway for a nice "glow" in the area and then use white LED lighting as "spot-lights" to highlight a specific area (a picture, into a closet, etc). By using concave reflectors will spread the spot-light even further / wider.

    As for your well-pump - an RV-grade pump would work well - or - why rely on electricity for that? Hand-pump (ok, it sucks, but, works well) or a wind-powered pump (old-skule, but, you can't beat its simplicity) would also work very well to a gravity-based water system.

    I don't live with solar on a daily basis (just the majority of the summer) and base my posting on what I have learned through solar-use in an RV-environment.
     
  6. bunkerbob

    bunkerbob Supporting Member

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    First of all not all inverters draw power all the time, the ones I use have standby/sleep mode feature, and will come on in millisec when a load is applied, so fast you never see a perceivable delay.
    I use 110vac LED bulbs in my home, went from a 13watt draw with CFL bulbs down to 1.7watts, same lumen's, and matter of fact give a whiter type light and last much longer and have very little heat.
    DC type pumps for deep well work ok but draw more power than a comparable AC pump, I run my pump only 1 1/2 hours a day to maintain 2-5000 gal tanks. Most DC pumps are designed to run as long as the sun is up, low flow but steady. I do however use a 24vdc jet pump from my tanks to provide household pressure, this is so I don't have to turn on the inverters at all.
    RV type equipment years ago were the only ones available for off-grid use, today the market has expanded tremendously and give the consumer a multitude of choices.
    I have a 12vdc circuit wired into my house that provides power for my HAM radio equipment, cell phone chargers and power to my CCTV system.
    All power cubes(transformers), appliances that have instant on and such are on on/off switches.
     
  7. allen_idaho

    allen_idaho Well-Known Member

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    I don't have an inverter with a standby mode. Personally, I use a Wagan solar controller to keep my batteries from being overcharged and to keep my system from losing power when not in use. It basically serves the same purpose as a standby mode. I haven't had it for very long but it seems to be working well. Although, I'm only using a 400 watt inverter for some smaller items.
     
  8. NaeKid

    NaeKid YourAdministrator, eh?

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    True - that is why I had put into my first paragraph that there is an "auto-switch" that will automatically power-down the unit. But, even in the sleep-mode, there is a slight power-draw to run the internal circuits. The only way to make sure that there is zero power-draw is to use a full disconnect (switch or pull the plug).

    Thanks for letting me know that there is a 110v based LED lighting system. I will see if I can locate some locally (or, if you have a place on the 'net that you know of that I can purchase, it would be very appreciated).
     
  9. bunkerbob

    bunkerbob Supporting Member

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    I bought mine at Sams club, watch out on the net, they are way over priced.
     
  10. UncleJoe

    UncleJoe Well-Known Member

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    WOW!!! :eek: Where to start.

    allenI understand the difference between continuous and peak. I have started a list with the ratings of the things I would like to power although start up power requirements aren't always listed. This shouldn't be too much of a problem since the chance of everything starting up at one time is pretty slim.

    Tex My initial thought was 12v mainly because I don't know what the pros and cons are of a higher volt system and as bunkerbob said, starting small and adding on as money allows, is always an option. I've also discovered that pure sine is about 3x the money for the same output. But from what I'm hearing, it's the better way to go if I plan to work my way up to solar as a full time energy source.

    Naekid Yes I have been looking at 12v lighting. This appears to be a very viable option and no matter what I do, I am going to use this approach to light the barn. I'm just now looking into what other 12v appliances are available. As far as the well pump goes, I just picked up an old hand pump at an auction 2 weeks ago. I took it apart to paint it and replace the leather. I'll have that installed in the next couple weeks. I still need to get 20' of pipe to run down to the water.

    I can see from this thread that I have a lot to learn and it's not something I will just jump right into, except for the barn lights. I really appreciate everyone's input and as I progress I'm sure I'll come back to you "experts".

    As it turns out, since I posted this, I found a 7500w portable diesel generator at an auction tomorrow. If I can get it for $1000 or less I will put the solar on hold again as this would take half of the funds I have set aside for solar. Since I already have 500 gal. of fuel here for my other diesel equipment, this will give me instant access to all the power I need for the next outage while avoiding the learning curve. :eek:
     
  11. NaeKid

    NaeKid YourAdministrator, eh?

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    Expert??? Naa, just slightly experienced with different products and scenarios. I have experimented with automotive / RV grade systems (solar, inverters, converters, etc).

    As for products, I have found many RV stores and even places like Walmart have things like 12-volt blenders, toasters, ovens, coolers (heating and cooling), slow-cookers, etc. Many of the "convenience" tools are now running cross-platform - 12-volt and 110-volt systems. I also found lots of lighting choices at PrincessAuto (a Canadian version of Harbor Freight) as well as many 12-volt tools.
     
  12. WildMist

    WildMist Active Member

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    Check this oven out. It runs on DC power.
    12-Volt Portable Oven and Pizza Maker :2thumb:

    If you look through more of that page, also have links to their slow cookers, grills and stoves.
     
    Last edited by a moderator: Nov 28, 2009
  13. UncleJoe

    UncleJoe Well-Known Member

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    Well, the generator ended up going for $1950, almost as much as a new one, so I'm back to looking at solar.
    Wildmist - Thanks for the link. I'll check it out later on tonight.
    NaeKid - I never saw 12v at Walmart or Harbor Freight but then I wasn't really looking either. I'll have a look after Christmas. I don't go near shopping centers at this time of year. :nuts: Thanks.
     
  14. NaeKid

    NaeKid YourAdministrator, eh?

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    Not a problem - the products are there when you need them. I found the 12-volt goodies in both the automotive sections (where you can find plug-in coffee cups) and in the camping area (where you can find plug-in coolers). I tried to find some of the products on their Canadian website - no luck, but, that is normal for me when I see a product in the local store, I never find it on their website.

    Here in Canada, we have PrincessAuto which is very similar to Harbor Freight and I have purchased many 12-volt products from PrincessAuto. I took a quick peak through the Harbor Freight site and saw lots of the same kinds of stuff, so, I am going to assume (ya, I know what assume means) that Harbor Freight will have the 12-volt goodies too.