Inveter AC output voltage too high?

jimmyaz
jimmyaz Registered Users Posts: 114 ✭✭
in Off Grid Solar & Battery Systems #1
Guys,

Something is wrong... HELP.

My component:
24v battery bank
2500W 120V inverter

Everything has been running fine, but the last few days I have notice a few issue.

One of my small tower fan I use stop working the other day... When turn on, it just hum, seem like it's stuck.  I open it up and the motor indeed very sticky.... so I thought maybe it need some oil, so I give it some and it start running again...

But today, another standard 3 blade fan I use in the garage to keep some air moving... it stop working as well... same issue?  What the heck?  I am afraid it's my inverter that has been damaging my appliance.  I open up this fan and got it running again, but it seem it doesn't run as fast as it use to run.  My 6000BTU window AC seem to run, but the fan sound like it's slower as well.  I thought for sure that this thing is pure sine wave because it was able to ran my fan way smoother than my old Haborfreight modified sine wave. 

http://www.ebay.com/itm/Pure-Sine-Wave-Inverter-2000W-Power-Inverter-24V-to-120V-Off-Grid-LED-Display-/201514136004?hash=item2eeb2db1c4:g:sX8AAOSw14xWQZvi

I have this inverter, it say pure sine wave,, .and has been running for the past 2 month no issue... When I first got it, the output voltage was 129-130, so I ask the manufacture and they can I can adjust a POD inside and that has reduced it down to 125v (lowest it can go).

I have checked the voltage, still out 125V.

The scary part is I have been running my new Samsung washing machine and LG Dish washer.....

Any advise?

thanks guys
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Comments

  • BB.
    BB. Super Moderators, Administrators Posts: 33,613 admin
    #2
    More or less, the North American range for AC voltage is ~106 to 132 volts... 125 VAC should be fine.

    In general, running low AC mains voltage is harder on motors.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • jimmyaz
    jimmyaz Registered Users Posts: 114 ✭✭
    #3
    BB. said:
    More or less, the North American range for AC voltage is ~106 to 132 volts... 125 VAC should be fine.

    In general, running low AC mains voltage is harder on motors.

    -Bill
    Hi Bill,

    Any other idea why both of my fan seem to be struggling? seized?   My new SamSung Washer / LG Dish washer are both say Digital Inverter ( I am guessing this convert to DC power for the motor?  so it should have circuitry to provide it from the voltage fluctuate?).  Is there any other variable in the Inverter itself that can cause issue?  Hertz? Frequency? Noise?  Now I am scared to use my expensive appliance.

    The only change I've made so far is adding a old 1.7cu mini Refrigerator to cool the battery... it pull 120watts, but some time when it stop or start it can pull 600watts, I am assuming this is surge.... Could this be the problem? 


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  • BB.
    BB. Super Moderators, Administrators Posts: 33,613 admin
    #4
    It is really difficult to generalize these days with "AC to DC" front end of power supplies (which is what your appliances probably have--A second stage takes the high voltage DC and converts it back into single or multiple phase AC).

    Look at the input placard for the refrigerator--Many destine for the US or Europe will have something like 100 to 240 VAC input 50/60 Hz.

    In the old days, with manual 120/240 selection supplies (or auto-select), there was a band of ~132-180 VAC where the supply could not operate... Today, with many power factor corrected power supplies, they can run from 100-264 VAC just fine (the way they take the input voltage, they can use any voltage between 100-264 VAC just fine).

    On the downside, yes, if you get a surge, it is possible that the input to the power supply can be damaged (certainly, the thermal mass of capacitors, diodes, FETs, etc. is much less than a 1/4 HP copper wound motor). But, in the old days, when you got hit with a 60-80 VAC "brownout", the refrigeration motors would stall/overheat and fail... I doubt a modern fridge would do that (and, in north America, utilties will attempt to shut down instead of let brownouts continue until fixed).

    What does your refrigerator have, and how well it will respond to out of range input voltage--I really cannot tell from here.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • simmtron
    simmtron Solar Expert Posts: 87 ✭✭✭
    #5
    What is your battery bank? Size ,type and number of batteries.
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  • Johann
    Johann Solar Expert Posts: 245 ✭✭✭
    #6
    While the inverter is running and loaded up, did you ever check the output voltage of the inverter?
    Did you check the battery voltage while the inverter is loaded up?
    Wire size and length of  wires from battery to inverter?
    What is your total load that is hooked up to your inverter?

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  • Dave Angelini
    Dave Angelini Solar Expert Posts: 6,894 ✭✭✭✭✭✭
    #7
    Name brand inverter right? An Outback, Schneider Electric, Magnum, or SMA, right? If not I hope you feel lucky!
    "we go where power lines don't" Sierra Nevada mountain area
       htps://offgridsolar1.com/
    E-mail offgridsolar@sti.net

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  • jimmyaz
    jimmyaz Registered Users Posts: 114 ✭✭
    #8
    simmtron said:
    What is your battery bank? Size ,type and number of batteries.
    4x 12v 105ah AGM to made up for 24v 210ah.  Not sure why would the battery would effect anything if the input voltage is always above 25volts, even under load.
    Johann said:
    While the inverter is running and loaded up, did you ever check the output voltage of the inverter?
    Did you check the battery voltage while the inverter is loaded up?
    Wire size and length of  wires from battery to inverter?
    What is your total load that is hooked up to your inverter?

    Yes, I have measured the AC output under 1000watts loads with my RMS voltage meter and it's loaded down to around 124-125v.   Wire from battery bank to Inverter is about 4ft, 2AWG, never get warm or hot... .as the battery never is the main source power source, it's the charge controller/PV is the main source and the wire is 2awg and it's only inches away from the inverter.
    Load to inverter average around 800watts -1500watts.
    Dave Angelini said:
    Name brand inverter right? An Outback, Schneider Electric, Magnum, or SMA, right? If not I hope you feel lucky!

    Sorry, haven't got the money to afford those brand yet.  I would skip a few lunch and go for the Outback Hybrid.... if the local power company would allow me to use Grid Zero mode and not having to sign up solar plan with them.... but that's probably not happening.




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  • Dave Angelini
    Dave Angelini Solar Expert Posts: 6,894 ✭✭✭✭✭✭
    #9
    As long as you have the money to buy new appliances you are fine :)
    "we go where power lines don't" Sierra Nevada mountain area
       htps://offgridsolar1.com/
    E-mail offgridsolar@sti.net

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  • jimmyaz
    jimmyaz Registered Users Posts: 114 ✭✭
    #10
    Dave Angelini said:
    As long as you have the money to buy new appliances you are fine :)
    thanks for NOT being helpful.


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  • Dave Angelini
    Dave Angelini Solar Expert Posts: 6,894 ✭✭✭✭✭✭
    edited August 2016 #11
    You are welcome! Not really trying to help you as it is too late, but others who play around with their power systems and don't realize how some of this cheap equipment can fail and do plenty of damage. I see this every few years on these forums.
    "we go where power lines don't" Sierra Nevada mountain area
       htps://offgridsolar1.com/
    E-mail offgridsolar@sti.net

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