Recommend a good inverter

levsmith
levsmith Solar Expert Posts: 56 ✭✭
in Off Grid Solar & Battery Systems #1
Alright guys, I'm going to start building my first system in a couple weeks. I've found some batteries, now I need an inverter. Right now I am just planning on running the fridge and sump pump during power outages. The fridge has a surge of about 850 watts and the sump pump surge is about 1200 watts. So I think I need an inverter with around 2500 watt surge. Can anyone recommend a good inverter? I would like to stay around $100-150 range but i'm really not sure what a decent one costs. I assume a modified sine wave will be ok with those 2 things. Thanks for any help!
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  • waynefromnscanada
    waynefromnscanada Solar Expert Posts: 3,009 ✭✭✭✭
    #2
    Re: Recommend a good inverter
    levsmith wrote: »
    So I think I need an inverter with around 2500 watt surge. Can anyone recommend a good inverter for around $100? I assume a modified sine wave will be ok

    A "good" 2500 watt surge inverter for $100.? Unless you're able to come across a still operating used inverter that no one wants any more I fear you're whistling Dixie with that one.
    In general, MSW does not work well with motors and compressors. The MSW usually causes the motor/compressor to consume roughly 20% more power, run hotter and has a habit of shortening the life of fridge compressors. Beyond that, if the fridge has electronic controls, they MIGHT be damaged by MSW. Oh, and don't be surprised if the fridge start surge is greater than the mentioned 850 watts.
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  • levsmith
    levsmith Solar Expert Posts: 56 ✭✭
    #3
    Re: Recommend a good inverter
    waynefromnscanada wrote: »
    A "good" 2500 watt surge inverter for $100.? Unless you're able to come across a still operating used inverter that no one wants any more I fear you're whistling Dixie with that one.
    In general, MSW does not work well with motors and compressors. The MSW usually causes the motor/compressor to consume roughly 20% more power, run hotter and has a habit of shortening the life of fridge compressors. Beyond that, if the fridge has electronic controls, they MIGHT be damaged by MSW. Oh, and don't be surprised if the fridge start surge is greater than the mentioned 850 watts.

    Ok thats what I was wondering on the price, which is why I changed my original post. I understand that MSW is not ideal but like i said, its for emergency backup at the moment. I hate to spend the money on a PSW for something that is likely to be used only once or twice a month for a few hours. As far as the fridge surge, that was tested with my riobi equovalent of the kill-a-watt. Its a fairly small fridge and no electronic controls.
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #4
    Re: Recommend a good inverter

    Don't waste your money on an MSW inverter to run motors; they will draw more power on the improper waveform and so you'll need an even bigger inverter to supply it.

    Your price range is not at all realistic. Something like this is probably the best you can hope for: http://www.solar-electric.com/samlex-pure-sine-wave-inverter-pst-1500-12.html
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  • levsmith
    levsmith Solar Expert Posts: 56 ✭✭
    #5
    Re: Recommend a good inverter
    Cariboocoot wrote: »
    Don't waste your money on an MSW inverter to run motors; they will draw more power on the improper waveform and so you'll need an even bigger inverter to supply it.

    Your price range is not at all realistic. Something like this is probably the best you can hope for: http://www.solar-electric.com/samlex-pure-sine-wave-inverter-pst-1500-12.html

    Thanks Cariboocoot, thats what I was afraid of. I'll just have to save a little longer for the PSW. Is samlex a decent brand?
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #6
    Re: Recommend a good inverter
    levsmith wrote: »
    Thanks Cariboocoot, thats what I was afraid of. I'll just have to save a little longer for the PSW. Is samlex a decent brand?

    Not top-of-the-line. In fact they aren't recommended for surge operation because they have no real capacity for it. But one with enough running capacity may be able to start small-surge motor loads.

    Now that I think about it, the SA series may be a better choice: http://www.solar-electric.com/sa1wa12vosiw.html

    Be sure you have your surge demand correct; very few meters will actually capture it because it doesn't last long.
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  • levsmith
    levsmith Solar Expert Posts: 56 ✭✭
    #7
    Re: Recommend a good inverter
    Cariboocoot wrote: »
    Not top-of-the-line. In fact they aren't recommended for surge operation because they have no real capacity for it. But one with enough running capacity may be able to start small-surge motor loads.

    Now that I think about it, the SA series may be a better choice: http://www.solar-electric.com/sa1wa12vosiw.html

    Be sure you have your surge demand correct; very few meters will actually capture it because it doesn't last long.

    Thanks for your help. How would I make sure I have the surge demand correct?
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #8
    Re: Recommend a good inverter
    levsmith wrote: »
    Thanks for your help. How would I make sure I have the surge demand correct?

    Most sure-fire way: really expensive Fluke meter with fast capture and peak hold.

    Calculating way: take the running Amps and multiply by 5 for compressors and pumps.

    Most refrigerators, even the small ones, will clip better than 1kW on start-up. Pumps can be even worse depending on the size of the pump. A Sump pump is usually 1/4 to 1/3 HP, so it will have similar start demand. It is most unlikely both would come on at the same time so you don't have to add the two together to get inverter capacity.
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  • mtdoc
    mtdoc Solar Expert Posts: 600 ✭✭
    #9
    Re: Recommend a good inverter

    For a decent TSW inverter at an excellent price, have a look at the Xantrex Prowatt SW2000 (3000 watt surge) rating. Can be found for about $370 online (google is your friend).

    Review be a NAWs forum member HERE
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  • mike95490
    mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    #10
    Re: Recommend a good inverter

    While it's unlikely both the Fridge and Pump will start at the same time, it's quite likely one will be on when the other starts up.
    AND
    If this has been going on a while, the batteries will be soft, and the 4th time your pump starts up, 2KW of surge has to pull 166A from the batteries. Without the inverter faulting on low voltage. You need really good cables and prime batteries, not $8 from the yard that read 12.3v This will be a good trick with 4, 6V batteries wired into a 24V bank.

    But it's not my basement.
    Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
    || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

    solar: http://tinyurl.com/LMR-Solar
    gen: http://tinyurl.com/LMR-Lister ,

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  • SolarPowered
    SolarPowered Solar Expert Posts: 626 ✭✭✭
    #11
    Re: Recommend a good inverter

    SunForce - PSW inverters from Amazon if you are a prime member.
    Samlex - PSW Inverter From amazon if you are a prime member.
    Power Bright - PSW Inverter From amazon if you are a prime member, power Bright and Samlex use the same Inverter board
    Go Power - PSW Inverter From amazon if you are a prime member.
    Xantrex / Schnieder Electric- Different badging same product Amazon or Ebay.

    Stay away from Wagan, Ramsond brands. Ramsond uses the same boards as sunforce, but for some reason has massive quality control issue, so does wagan.
    Definitely, don't buy any inverter in a box written all over in chinese, chances are it won't come with an English instruction manual, chances are the sales rep can't read the box either and is actually selling you MSW inverter, not PSW inverter. Had that happen to a friend that asked me to look at his inverter. Stay away from harbor Frieght its actually not cheap equipment for what you pay for, and its all modified sine wave.

    If you really have high aspirations, Outback and Magnum are probably the best for driving large compressor equipment, and will probably last years longer than those I mentioned up top.

    Good Luck.
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