Interaction of CFLs and inverter

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westbranch
westbranch Solar Expert Posts: 5,183 ✭✭✭✭
in Advanced Solar Electric Technical Forum #1
I have noticed that one circuit in the basement, 3 9W CFL's from stairs to door, always causes the inverters fan to kick in. 
Other circuits, with 5 and 7 of the same 9W  CLF's, do not cause the fan to run... I am suspecting an increase of temp on the main board...

Any ideas as to the cause,  the drives or ? in the CFL's ??
 
KID #51B  4s 140W to 24V 900Ah C&D AGM
CL#29032 FW 2126/ 2073/ 2133 175A E-Panel WBjr, 3 x 4s 140W to 24V 900Ah C&D AGM 
Cotek ST1500W 24V Inverter,OmniCharge 3024,
2 x Cisco WRT54GL i/c DD-WRT Rtr & Bridge,
Eu3/2/1000i Gens, 1680W & E-Panel/WBjr to come, CL #647 asleep
West Chilcotin, BC, Canada
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,439 admin
    #2
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    If you can use a Kill-a-Watt or clamp on AC current meter and measure the current... Many (some or all?) pretty much seem to have a very poor power factor (down towards 0.50)--Which means the lights can draw ~2x as much current vs something with a near 1.0 PF...

    If you have different brands of CFLs--It is possible (I guess) that some have better Power Factor than others.

    Another thing to try--Unscrew the bulbs on the circuit that appears to be drawing more power--Then look at the current/power supplied by the inverter. Is it possible that there is a phantom load you don't know about?

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • softdown
    softdown Solar Expert Posts: 3,821 ✭✭✭✭
    #3
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    Possible short in the wiring?
    First Bank:16 180 watt Grape Solar with  FM80 controller and 3648 Inverter....Fullriver 8D AGM solar batteries. Second Bank/MacGyver Special: 10 165(?) watt BP Solar with Renogy MPPT 40A controller/ and Xantrex C-35 PWM controller/ and Morningstar PWM controller...Cotek 24V PSW inverter....forklift and diesel locomotive batteries
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  • Johann
    Johann Solar Expert Posts: 245 ✭✭✭
    #4
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    I believe that the CFL is interfering with the inverter if the load is low.
    Take 1 cfl out and replace it with an incandescent bulb. Now switch the 2 cfl's and the 1 incandescent bulb on.  This may take care of the problem. It is not really practical for solar applications but may work.
    Cfl's work with high frequencies and this may cause interference with the invereter,

    Try and see if LED's would do better.
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  • PNjunction
    PNjunction Solar Expert Posts: 762 ✭✭✭
    #5
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    This is a stab in the dark, I wonder if the poor power factor of CFL's is causing the fans to kick on.  One string may just have a really poor one in it.

    Typically, cfls are about what, 0.5 to maybe 0.6 at best?  When I switched to the GE or Osram/Sylvania's I got from the home supply store or even my grocery store, the Kill-A-Watt showed about 0.6 minimum to 0.7 pf.

    It is an improvement, maybe not much to matter in the long run, but might be enough to keep your inverter's fan from kicking on?
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  • bill von novak
    bill von novak Solar Expert Posts: 891 ✭✭✭✭
    #6
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    westbranch said:
    I have noticed that one circuit in the basement, 3 9W CFL's from stairs to door, always causes the inverters fan to kick in. 
    Other circuits, with 5 and 7 of the same 9W  CLF's, do not cause the fan to run... I am suspecting an increase of temp on the main board...Any ideas as to the cause,  the drives or ? in the CFL's ??
    If the power factor is poor enough the load on the inverter can "spoof" a current sensor - and if the fans come on above a certain output current, that might fool them into turning on.
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  • 2manytoyz
    2manytoyz Solar Expert Posts: 373 ✭✭✭
    #7
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    CFLs are inductive loads.  Some inverters don't like a lot of inductive loads.  As mentioned, you can add one incandescent (or any other resistive load) in the string, and that should solve the issue.   Adding too many CFLs can actually cause a strobe effect with all the lights blinking on/off.
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