Having inverter issues

Discussion in 'The Projects Forum' started by Khurram Moon, Dec 22, 2012.

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  1. Khurram Moon

    Thread Starter New Member

    Dec 22, 2012
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    Hi1
    I have a Cyberpower inverter CPS 1200EI with LCD display and Exide Battery NS 200 after 7 months of working perfectly. My inverter now keeps on charging the battery. Now it is winter season and power outages are only 1 to 2 hours a day. I regularly top up the battery with distal water when it is needed. Last time when only 23 watts bulb was running on the inverter for an hour and when main electricity came inverter kept on charging the battery. I checked the battery and it did not heat up even after the charging of 4 to 6 hours. Then I turned the inverter off removed all the cables and toped the battery with some distal water and then it remained off for one day then I connected the cables and inverter started charging the battery again in off position. This inverter charges the battery even when the button of inverter is in off position. After charging for 2 hours inverter did not stop, I turned off the main electricity supply the turned it on within few seconds and then inverter automatically stopped the charging after 30 seconds. Now my question is that whether there is some thing wrong with the inverter or the battery? But for the time being inverter seems to be working fine.
    There is another thing which I have noticed. When the main supply is on and my computer is running and if I cut off the main for inverter then my computer neither restarts nor shuts down but when main is cut off by the power grid then my computer shuts down and lcd monitor runs on the inverter then I have to restart my computer. This is a strange thing which I do not understand.
     
  2. Khurram Moon

    Thread Starter New Member

    Dec 22, 2012
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    There has been a change. Now my inverter keeps on charging the battery however, the battery doesn’t heat up even after the charging of 4 hours. If power outages last for an hour (at a time) and only 60 Watts load is running on the inverter and when main power supply is restored then inverter tends to charge the battery for approximately 3-4 hours. When I manually turn off the input to inverter (after it has charged the battery for 2 and half hours or so) then I turn the main on again within 3 seconds, then inverter stops charging the battery after 30 seconds. This thing is strange.

    Looking forward toward your suggestions.
     
    Last edited: Dec 25, 2012
  3. SgtWookie

    Expert

    Jul 17, 2007
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    Since you have not supplied any voltage measurements, the best that we can do is guess.

    I'll guess that your battery has a shorted cell, so that it is not capable of accepting a full charge; the charging circuit "thinks" that your battery is not fully charged, so it keeps on charging it.

    While the battery is charging, see if there is one or more cell rapidly bubbling; if so, that is a shorted cell.

    Try using a new battery and see if the charge cycle terminates normally.

    If you want better answers, then give us some voltage readings from the battery terminals. Also, tell us what the average ambient temperature is, and what the battery temperature is.
     
  4. Khurram Moon

    Thread Starter New Member

    Dec 22, 2012
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    Hello sorry for late reply

    Following are the reading from the battery;

    • Inverter remained off for 24 hours and input of inverter from main socket was disconnected and the reading on battery terminals was 12.5V.
    Hydrometer readings are as following;
    Cell no 1= 12.4
    Cell no 2= 12.4
    Cell no 3= 12.4
    Cell no 4= 12.7(I added 30 ml distal water in this particular cell and then the reading was 12.3)
    Cell no 5= 12.4
    Cell no 6= 12.4
    • Then I inserted the input of inverter into the main’s socket and inverter charged the battery for 45 minutes and terminated charging the battery after that. I took the readings on the battery terminals and it showed 13.7V. (the inverter manual states that this inverter charges the battery on 13.7V).
    • Then I cut off the main and checked the out put on one of the socket’s for output voltage of battery and it showed 192V however, LCD indicator on inverter was showing 220 V as output voltage.
    • After 5 minutes I resorted the main’s input to inverter and it started charging the battery for approximately 40 minutes then I turned off the power button of inverter and it stopped charging the battery immediately.
    • Voltage reading on battery terminals was 13.7V while the inverter had stopped charging the battery.
    • After 3 minutes voltage dropped to 13.4 V.
    • After 20 more minutes voltage further dropped to 12.9V.
    • Then I removed the inverter’s input from the main and inverter was also in off position after 2 more hours voltage reading was 12.6V.
    • After the passage of 15 hours battery output voltage was 12.5V and voltage has remained the same even after 36 hours. (inverter is still in off mode while the input of main has been disconnected however, inverter cables were connected all the time with the battery.
    It is quite strange that when my inverter keeps on charging the battery for some time and then I rapidly turn off main’s input to inverter and then restore it some times inverter stops charging the battery and some times it doesn’t.

    It is still unclear whether there is a problem with the battery or inverter is the actual culprit. Battery does not heat up what so ever neither any cell is bubbling rapidly.
     
  5. SgtWookie

    Expert

    Jul 17, 2007
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    Well, it looks like the inverter's charging circuit is the problem. "Spikes" (line transients) might have caused the problem with it. Do you have a schematic for your inverter? If so, scan it and post it in an attachment; .png format images are preferred as they are not "lossy" like .jpg format files. If you don't have a schematic, then start tracing out the circuit and post photos of it.

    It is difficult to take good pictures of circuit boards. The best lighting is outdoors on a cloudy day, as the light is very even and there are no harsh shadows.

    My time on the board is very limited nowadays, as I am in the middle of a construction project.
     
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  6. Khurram Moon

    Thread Starter New Member

    Dec 22, 2012
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    Sir now when the main was out for 25 minutes and only 120 Watts load was running on the inverter and when main came back inverter charged the battery for one hour approx and afterwards terminated the charging by it self. Do you think that inverter is taking bit longer to recharge the battery? Sir for the time being I only have this manual and not the schematics. Please view the attachment.
     
    Last edited: Jan 3, 2013
  7. Khurram Moon

    Thread Starter New Member

    Dec 22, 2012
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    Strange Phenomenon

    Battery Fully charged and inverter terminated the charging by it self. I turned off main and checked inverter’s output directly from inverter’s AC out let and the reading was 176 V while there was no load on inverter. However, LCD indicator on inverter screen was showing 220 V output.

    2nd Step:
    I connected the phase wire in inverter’s out put socket and turned on 2x 23 Watts bulbs and inverter showed 184V output voltage in another socket of the room. Gradually volts increased to 192V.
    When I tuned of the both bulbs (when there was no load on the inverter it once again shows 179 V in the same socket).
    3X 23 Watts bulbs load on inverter, reading in socket showed 195V.
    4X 23 watts bulbs load on inverter, reading in same socket increased to 198 V and then I turned on a 40 Watts tube light and volts increased to 205V.
    4x bulbs+ 2x tube lights, voltage in socket 202V.
    Then turned every thing off, meaning there was no load on the inverter and reading in socket gradually reduced to 179V.
    I repeated these steps three times and readings were strange. However, voltage output of inverter seemed to fluctuate while increasing the load or decreasing it. When there is some load on inverter during power outage then output voltage is better as compared with the inverter running without any load.

    3rd Step:
    2x 23 watts bulbs load on inverter, reading in socket = 191V.
    3x 23 watts bulbs load on inverter, reading in socket = 195V.
    4x bulbs + one 40 watt tube light, reading in socket = 202V.
    4xbulbs + 2x 40 watts tube lights, reading in socket = 199V.
    4x bulbs load on inverter and when I turned off both tube lights reading in socket was 212V.
    Turned off all loads and reading from socket was once again 179V.

    Meanwhile, when main is restored the LCD indicator on inverter shows the voltage which precisely corresponds with the voltage readings in the socket i.e inverter LCD indicator shows 129V as well as regarding on socket shows 128 V or 127V.
     
  8. SgtWookie

    Expert

    Jul 17, 2007
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    Why don't you contact the manufacturer of the unit?

    It doesn't seem that the battery has a problem, since your cells have a consistent specific gravity reading.

    13.7v should be the "float" voltage. The battery should really be charged at 14v to 14.5v. If it's always being charged at 13.7v, the battery will eventually become sulfated (the plates will become covered with a light-colored goo which is non-conductive) and will no longer accept or release a charge.

    When the battery is about 25°C/77°F and fully charged, you should read 12.7v to 12.8v after the surface "float" charge is removed.

    Since you don't have a schematic, and I'm assuming that your meter is not a true RMS meter, you won't be able to make accurate voltage measurements, and it will take far too long to attempt to troubleshoot the problem from the other side of the planet. Besides, I have a very limited amount of time to look at the Forum nowadays, as I am in the middle of a home addition/construction project which I wish to complete quickly and properly (not always mutually exclusive).
     
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