Kill-a-watt meter failures

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fernandonh
fernandonh Solar Expert Posts: 35 ✭
in Off Grid Solar & Battery Systems #1
I just recently switched from a modified to a pure sine wave inverter. The kil-a-watt I had used for a while died after only a few hours with the new inverter (Pure). I then purchased a new kill-a-watt and it too died within a few hours. It just won't read anything even when plugged into house outlet.

Does anyone have any idea why this may be happening?
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  • zoneblue
    zoneblue Solar Expert Posts: 1,220 ✭✭✭✭
    #2
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    Re: Kil-a-watt

    What model is the new inverter? It does rather point to the inverter. Unless you did something like put a 120 wattmeter on a 240 system ;)
    1.8kWp CSUN, 10kWh AGM, Midnite Classic 150, Outback VFX3024E,
    http://zoneblue.org/cms/page.php?view=off-grid-solar


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  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    #3
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    Re: Kil-a-watt

    there may be a problem with the voltage on the inverter. do you have a dmm or dvm to see the ac voltage on it?
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #4
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    Re: Kil-a-watt

    Neutral not bonded to ground?
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  • fernandonh
    fernandonh Solar Expert Posts: 35 ✭
    #5
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    Re: Kil-a-watt

    The inverter is the following:

    Power Bright APS300-12 Pure Sine Power Inverter 300 Watt continuous / 500 watt Peak 12 Volt DC To 120 Volt AC

    Before it stopped working... it was reading something like 115 v.

    The load on it was a PA speaker, which was reading about 80 watts of consumption.
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  • fernandonh
    fernandonh Solar Expert Posts: 35 ✭
    #6
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    Re: Kil-a-watt
    Cariboocoot wrote: »
    Neutral not bonded to ground?

    Since I don't know what that means, probably indicates that it may be the problem?
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #7
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    Re: Kil-a-watt

    Short cut: does the inverter have outlet built in?
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  • fernandonh
    fernandonh Solar Expert Posts: 35 ✭
    #8
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    Re: Kil-a-watt
    Cariboocoot wrote: »
    Short cut: does the inverter have outlet built in?

    I does, one outlet.

    My concern is that what caused the two kill-a-watt to be damaged may also be the cause for the damaged speakers that just occured. About 3 months ago my Behringer B215D PA speaker had its tweeter blown. I purchased a second identical speaker, and it too had its tweeter damaged.
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #9
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    Re: Kil-a-watt

    With a built-in outlet there shouldn't be the (rare) Voltage spikes that can occur otherwise (only applies to inverters and usually cheap ones).

    I can not see how power source variances should affect speakers on an Amp; something between the two (i.e. component level) should give up first.

    Since K-A-W meters can actually take MSW output without complaint, I am wondering if the inverter itself does have an issue with Voltage spikes. You would not see this on an RMS reading; it would have to be viewed on the waveform or with a high quality DMM that can 'capture' peak Voltages. It would not necessarily occur every time, but over enough cycles repeated occasional spikes could damage equipment.

    Difficult to nail down with standard home test equipment.
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  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    #10
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    Re: Kil-a-watt

    coot,
    you brought up about grounds and if the inverter does have an internal neutral to ground connection and he set the output of the inverter through a standard utility entrance breaker box that is shut off from the utility which would also have a neutral to ground connection that the double grounds could set up ground loops in the system and at times they could be damaging. now it doesn't have to be the entrance box either as another grounding point for the neutral anywhere else in addition to the inverter would set up the loops.

    we may need a further description of how this is wired and to what how.
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #11
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    Re: Kil-a-watt

    Niel;

    Right you are. Perhaps wrong of me to assume that an outlet on the inverter was used to directly power the load.
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  • fernandonh
    fernandonh Solar Expert Posts: 35 ✭
    #12
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    Re: Kil-a-watt

    Hey guys, tks for the comments. Here is a 3-minute video I made about a month ago to a friend of mine. I hope this will give you a clue on what may be the problem with my system.

    https://www.youtube.com/watch?v=G0N_tolGEUk&feature=youtube_gdata_player
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  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    #13
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    Re: Kil-a-watt

    even being signed in on you tube it is saying it is private and won't allow me to view it.
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  • fernandonh
    fernandonh Solar Expert Posts: 35 ✭
    #14
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    Re: Kil-a-watt

    sorry about that.

    http://www.youtube.com/watch?v=G0N_tolGEUk
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  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    #15
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    Re: Kil-a-watt

    off hand i can't see a problem although you need to put the temp sensor on the battery post and not the fuse post.

    you said the red light on the speaker came on so can you tell us what the red light on the speaker means?

    love that little buggy you got there. do the teeth mash?:p

    live close to an airport eh.
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  • fernandonh
    fernandonh Solar Expert Posts: 35 ✭
    #16
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    Re: Kil-a-watt

    Tks! Unfortunately they don't chatter yet, but it's definitely a project for the future. and yes, directly below air traffic :-)

    The red light on the speaker means that the amp is being over-driven. The issue I have is that based on the kill-a-watt reading, before it failed, indicated a power consumption way below the speaker wattage rating. This is a behringer B215D 550 watt. Granted that's peak, the rms is about 300 watts.

    The fact that the current set up damaged two kill-a-watt and two speakers leads met to believe that there must be something wrong.
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  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    #17
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    Re: Kil-a-watt

    too high of a voltage off of the inverter may cause these symptoms and that leads me back to ask what was the measured ac voltage output of the inverter?
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  • silvertop
    silvertop Solar Expert Posts: 155 ✭✭✭✭✭
    #18
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    Re: Kil-a-watt

    When you unplug the Kill a Watt and replug does it restart? Anything over 15 Amps will clear the screen. We have run Behringer powered speakers in the past for our band and I can tell you they are good products, but if the light on the back indicates that you are overdriving you ARE overdriving and you will kill the crossover/speaker. If you need more sound you need to just add one more powered speaker.....:cool:
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  • silvertop
    silvertop Solar Expert Posts: 155 ✭✭✭✭✭
    #19
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    Re: Kil-a-watt

    You can't use a kilowatt meter to measure wattage for your powered speaker. Wattage going into the kilowatt meter is AC. The 300 watts on the speaker is 300 watt converted DC. You are waaaay overdriving.
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #20
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    Re: Kil-a-watt

    I think there may be two different problems here. One being something in the AC supply that's blowing out the K-A-W meters and the other being something in the audio system that is turning on the red light for the speakers.

    Sorry if this is inaccurate but my satellite connection doesn't like video so I have not seen it.
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  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    #21
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    Re: Kil-a-watt

    silvertop brings up a good point here if the k-a-w meter is being used to measure audio power. it is for measuring 120vac house type power only.

    btw silvertop, the audio is not dc as it is ac also, but at frequencies typically in the 20hz to 20,000hz range and not just around the 60hz power frequency range.
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  • PNjunction
    PNjunction Solar Expert Posts: 762 ✭✭✭
    #22
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    Re: Kil-a-watt

    Just out of curiosity, aside from the meter problem, is that a GTI panel feeding that mppt charge controller, or is it a nominal 12v (18v ocv type) attached to it?
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  • fernandonh
    fernandonh Solar Expert Posts: 35 ✭
    #23
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    Re: Kill-a-watt meter failures

    Neil, would I use a multimeter to measure it?

    Silvertop: I doesn’t. I also tried plugging it into the house outlet, and nothing. The reason I feel as if there is something not right is that before connecting the Behringer to the solar system, I tested it at home with the kill-a-watt, and I would turn the volume dial almost all the way and it was EXTREMELY loud and clear. The kill a watt would oscillate between 120 to 200 watts, and light would not turn on. With the inverter, the light would turn on at around 100 watts (kill-a-watt reading). I just purchased two new compression drivers in hopes that the problem with the speaker is the tweeter, and not the amp or crossover. Fingers crossed.

    Cariboocoot: correct; however, I suspect the speakers being damaged (probably related the the Clipping red LED coming on) are related to the same problem that damaged the kill-a-watt. I had the first speaker for about 3 years, and it got damaged within 2 days of usage with the solar system.

    PNJunction: Panel is feeding the controller first.
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #24
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    Re: Kill-a-watt meter failures

    I'm going to go with my original thought that the inverter is at fault here, putting out occasional unexpectedly high Voltage peaks despite the RMS reading being correct.

    The simplest thing to do is to try a different inverter. Not necessarily the cheapest, though. Perhaps you can borrow one from somebody?
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,443 admin
    #25
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    Re: Kill-a-watt meter failures

    One possibility that Marc mentioned earlier... Grounding and Ground Loop issues.

    It is not hard sometimes to get neutral/earth/DC grounding problems. I am wondering if you have a significant voltage difference between Earth Ground, Neutral, DC, and audio ground.

    There may be current flowing through the audio cable grounds from the receiver(?) to the powered speakers and then through the Kill-a-Watt meter neutral/ground connection on its AC grounding.

    Since the meter is blown, it might be worth trying to pop it open and see if you see any cooked components.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    #26
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    Re: Kil-a-watt

    to clarify what i was driving at did you try to measure audio power with the k-a-w or did you keep the meter on the ac power output of the inverter?

    i too keep coming back to the conclusion there's something possibly flaky with the inverter. you said you used a msw inverter before. now did anything blow out with that or was it a case of you just wanted to improve the power source by going to psw?
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  • silvertop
    silvertop Solar Expert Posts: 155 ✭✭✭✭✭
    #27
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    Re: Kil-a-watt

    Digital clipping is extremely damaging it doesn't take much to damage the speaker, a compleatly different world than analog.
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  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    #28
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    Re: Kil-a-watt
    silvertop wrote: »
    Digital clipping is extremely damaging it doesn't take much to damage the speaker, a compleatly different world than analog.

    i agree there seems to be something getting through to the amp and speakers. the spikes in the ac waveform may be bleeding into the amp somehow and when amplified are extremely high powered bursts of audio energy. speculating of course as i don't know exactly what the problem is.

    my previous comment would've been the inproper measuring of the audio power output with a k-a-w as it isn't meant to measure audio power.
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  • fernandonh
    fernandonh Solar Expert Posts: 35 ✭
    #29
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    Re: Kil-a-watt
    niel wrote: »
    to clarify what i was driving at did you try to measure audio power with the k-a-w or did you keep the meter on the ac power output of the inverter?

    Hi Niel, The k-a-w was connected to the inverter via a short extension ford. I then plugged the power cord of the speaker onto the k-a-w.
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  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    #30
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    Re: Kil-a-watt

    ok as it is good to be sure. we often assume people know the proper application of test equipment and when i realized someone who doesn't know could confuse the audio power watts with ac power watts i had to be sure of this.
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