Comparison of cheap MSW Inverters

vcallaway
vcallaway Solar Expert Posts: 157 ✭✭✭✭✭
in Solar Product Reviews & Opinions #1
In setting up my backup power system for my home I've learned quite a bit about cheap inverters. Sometimes the hard way.

My goal was to build a system that would switch on inverter power to a couple of circuits in my home when the power goes out. Part of that goal is to do it cheaply and reliably. There are inverters on the market that have built in transfer switches and battery chargers. Most of those start at double what my budget was.

I picked up a couple of inverters that could be considered bargains. Providing they can do the job that is. My target size is 2000 Watts. That will run pretty much everything I can run on a MSW inverter in my home at the same time.

No load current draw and over voltage turned out to be critical for my application. The inverter sits idle most of the time. A charger keeps the batteries topped off. Absorption charge voltages can trigger an over voltage alarm with some inverters.

Now for the details:
Vector VEC054D 2000 Watt
Maximum Efficiency >87%
No load current draw <0.8A
Over Voltage Shutdown 15.5 +/- 0.5 V DC
Price: $180 from the B&D Outlet store.

Opinion: In testing the no load current was about 0.6Amps. Fans only come on when needed. My TV, computers, TiVO and CFL's all run fine with it. I tested an electric fan to give me an idea of how it works with motors. The fan ran only slightly slower than normal. That actually surprised me. Over voltage alarm never went off with the charger connected.
SUN 2000P/12-120 2000 Watt (Sold under various names)
Maximum Efficiency >88%
No load current draw <0.2A
Over Voltage Shutdown 15.0 +/- 0.5V DC
Price: $170 w/shipping on ebay.

Opinion: These are commonly found on Ebay listed as a stackable inverter with a bunch of B.S. about being Semi-Pure Sinewave. Truth is the waveform is almost square. No load testing backed up the claim of low draw. The current hovered around 150mA. Over voltage shutdown was a problem. The inverter alarm went off at 14.7V. The electric fan test had it running at about 1/2 speed. The motor did not sound real healthy either. Tests with everything else was fine.

Conclusions:

The Vector inverters have impressed me. I have smaller ones that I've used for various projects. They are well made and appear to be what is claimed. My 2k inverter was toasted when a transfer switch failed and fed grid current into the inverter. Black & Decker is repairing it under the two year warranty.

The Sun inverter has the ability to bond its output with multiple like units. There is an advantage to that especially when combined with low standby current. If the low voltage alarm issue can be fixed these can be of value. In my case it will be used as a backup.

Please contribute experiences with MSW inverters. I'm sure there are others that either don't need, or can't afford to go with Pure Sinewave.
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Comments

  • Photowhit
    Photowhit Solar Expert Posts: 6,006 ✭✭✭✭✭
    #2
    Re: Comparison of cheap MSW Inverters
    vcallaway wrote: »
    Opinion: These are commonly found on Ebay listed as a stackable inverter with a bunch of B.S. about being Semi-Pure Sinewave. Truth is the waveform is almost square. No load testing backed up the claim of low draw. The current hovered around 150mA. Over voltage shutdown was a problem. The inverter alarm went off at 14.7V. The electric fan test had it running at about 1/2 speed. The motor did not sound real healthy either. Tests with everything else was fine.

    The Sun inverter has the ability to bond its output with multiple like units.

    While I have no experience with the 2000watt version, I had a stackable 1400watt version which I assume was made by the same people as it was stackable, in a 24volt version I regularly ran an airconditioner for 2 summers. I also ran 2 10" fans and found no difference when I switched to a true sine wave inverter.

    I had found liturature on line that at idle they had a square wave and switched to a multistepped wave under load. I found only the microwave was required about a 1/4 - 1/3 less time when I switched to a true sine inverter.

    The on board fan died after about a year and I used it open flipped upside down with a computer fan running on it at all times for the next year, thinking I would switch it out and put 2 computer fans running in series off of the same power supply. A wasp, I think, finaly shorted it out.

    This unit did not like the monthly equalizing and shut down due to over current protection when voltage went above 30 volts (or so). Another reason I suspect they are similar. Home power did a short article comparing types of inverters last issue I think. They to found these semi sine wave inverters to cut out before 15 volts.

    Vcallaway? don't tell me your in Callaway Co Missouri?
    Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites,  Midnite E-panel, Magnum MS4024, Prosine 1800(now backup) and Exeltech 1100(former backup...lol), 660 ah 24v Forklift battery(now 10 years old). Off grid for 20 years (if I include 8 months on a bicycle).
    - Assorted other systems, pieces and to many panels in the closet to not do more projects.
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  • vcallaway
    vcallaway Solar Expert Posts: 157 ✭✭✭✭✭
    #3
    Re: Comparison of cheap MSW Inverters

    Probably the same company. Here is the Mfg. Website.

    I have a friend bringing over a oscope this weekend. I want to check out the waveforms from that inverter myself.

    I usually get asked about Golf Clubs.
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  • Photowhit
    Photowhit Solar Expert Posts: 6,006 ✭✭✭✭✭
    #4
    Re: Comparison of cheap MSW Inverters

    Thankyou!

    I actually bought Ningbo solar panels earlier this year and they were very well made, the heaviest frame I've seen in panels, though they are also the largest panels I own.

    I live in Callaway Co MO and I'll be at Callaway Gardens (near the golf stuff) around Columbus GA in a week!

    Ooops looks like Ningbo solar is a different company...
    Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites,  Midnite E-panel, Magnum MS4024, Prosine 1800(now backup) and Exeltech 1100(former backup...lol), 660 ah 24v Forklift battery(now 10 years old). Off grid for 20 years (if I include 8 months on a bicycle).
    - Assorted other systems, pieces and to many panels in the closet to not do more projects.
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  • john p
    john p Solar Expert Posts: 814 ✭✭✭
    #5
    Re: Comparison of cheap MSW Inverters

    poonamt93 wrote: »
    Every invertor (DC to AC device) by nature gives you a "pulse width modeulated" (PWM) sine wave. the only way to get a pure AC sine wave is from an "alternator" like what the power companys use to provide power to your homes and businesses...(not like whats in your car has..where it converts AC to DC 12 volts)
    so your WL's , if they work plugged into a wall socket, they should work with an invertor..cause PCBs vagabond uses a cheapy little PWM invertor....


    IM not sure where you got that information but it has a lot of errors
    not every DC to AC inverter is PWM, A simple cheap square wave inverter is not pulse width modulated. they dont give a sine wave at all.. not ever.Auto alternators by their very name give out AC same as power companies supply but obviously at a far lower voltage. they have diodes fitted to convert the AC to DC for use in the vehicle.You ever tried to charge a battery with AC.??

    AND AS FOR THIS...cause PCBs vagabond uses a cheapy little PWM invertorHAVE NO IDEA WHAT YOU ARE TRYING TO SAY..:confused::confused::confused:
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  • vcallaway
    vcallaway Solar Expert Posts: 157 ✭✭✭✭✭
    #6
    Re: Comparison of cheap MSW Inverters

    Looks like the post you were responding to was deleted. Probably a good thing.

    The Vagabond he was talking about is a portable inverter pack designed for use with studio strobes. It is a pack with a pure sine wave inverter and SLA battery. The Paul C. Buff (PCB he was referring to) flashes only work with pure sine wave power.
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,613 admin
    #7
    Re: Comparison of cheap MSW Inverters

    He was a link spammer out of India... Posted a bunch of sort of random info on-topic posts, then added signature spam links after the first few posts.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • 2manytoyz
    2manytoyz Solar Expert Posts: 373 ✭✭✭
    #8
    Re: Comparison of cheap MSW Inverters

    Vector is apparently now owned fully by B&D, per the Vector MFG website.

    I've been using Vector MSW inverters for a couple of years excusively for my indoor and outdoor CFL lighting. Works very well.

    The parasitic idle current is an issue for my small scale solar setup as well. I've measure the current of some of my inverters:

    http://2manytoyz.com/noload.html

    Here's what the actual waveform looks like:

    scope.jpg

    Some of my applications:

    inverterlaptop.jpg

    lights1703-s.jpg

    direct_connect2.jpg

    vaninverter.jpg

    http://2manytoyz.com/cflinverter.html

    http://2manytoyz.com/gridless.html

    I have a couple of PSW inverters also, but they have a higher idle current, and my loads don't care about the type of waveform.
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #9
    Re: Comparison of cheap MSW Inverters

    I wish every inverter had a picture of its output waveform available.
    Most would be too embarrassed to show it. :p

    That one looks pretty darn square.
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  • 2manytoyz
    2manytoyz Solar Expert Posts: 373 ✭✭✭
    #10
    Re: Comparison of cheap MSW Inverters

    Nah, that's a NICE MSW.

    Check out the waveform from this old UPS:

    upspanel.jpg

    upswaveform.jpg

    Now that's a squarewave!

    Here's the grid at my house:

    grid1634.jpg

    And the waveform from my Prosine 1800W:

    1609.jpg

    Better than the grid!
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  • mike95490
    mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    #11
    Re: Comparison of cheap MSW Inverters
    2manytoyz wrote: »
    Some of my applications:
    vaninverter.jpg

    I want the Lightning Strike app!
    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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  • 2manytoyz
    2manytoyz Solar Expert Posts: 373 ✭✭✭
    #12
    Re: Comparison of cheap MSW Inverters

    You mean the dirty windshield app? ;)

    Does kind of look like a lightning bolt!
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #13
    Re: Comparison of cheap MSW Inverters
    2manytoyz wrote: »
    Nah, that's a NICE MSW.

    Check out the waveform from this old UPS:

    upswaveform.jpg

    That looks a lot like my last ECG. :p

    And we always new grid power was "dirty". *rim shot*
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  • vcallaway
    vcallaway Solar Expert Posts: 157 ✭✭✭✭✭
    #14
    Re: Comparison of cheap MSW Inverters

    Attack of the Zombie thread :)

    Since it is back I'll post an update.

    The SunP 2k ebay special has been connected now for aprox 2 years. There have been numerous power outages lasting anywhere from a few minutes to a couple of days. So far everything has worked as expected.

    The only thing that does not like running on this inverter is my refrigerator.
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  • davidwillis
    davidwillis Solar Expert Posts: 104 ✭✭
    #15
    Re: Comparison of cheap MSW Inverters
    vcallaway wrote: »
    Probably the same company. Here is the Mfg. Website.

    I have a friend bringing over a oscope this weekend. I want to check out the waveforms from that inverter myself.

    I usually get asked about Golf Clubs.

    Did you ever test the inverter on the oscope?
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  • vcallaway
    vcallaway Solar Expert Posts: 157 ✭✭✭✭✭
    #16
    Re: Comparison of cheap MSW Inverters

    We did. It was pretty much identical to the Vector inverter it replaced. It did have a lower standby draw as advertised.
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