Mppt controller "wiping out" FM radio signal,, help

icarus
icarus Solar Expert Posts: 5,436 ✭✭✭✭
I know there are smart minds out there,, perhaps some that can solve this one.

I dicovered an interesting problem today,,,

A bit of background, we use a Pioneer auto type radio cd/player. It is connected to an A/B antenna switch. Out side are to Fm antennas, one a directional Yagi type, and the other a hi-gain 6' vertical antenna, cut for the lower range of the FM broadcast band.

We are in an extremely fringe area, ~150 miles from the broadcast, but out reception is fairly reliable. What I discovered is that especially at low sun light levels the controller almost wipes out all Fm signals. I don't know yet if it does it at higher light levels, and I never noticed it before. Switching off the controller brings the raid right back.

The controller is ~ 30' from the radio, and about 15' from the base of the antenna. I tried shielding the controller with tin foil, and doubled up the ground, all to no avail.

Any suggestions?
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Comments

  • halfcrazy
    halfcrazy Solar Expert Posts: 720 ✭✭✭
    Re: Mppt controller "wiping out" FM radio signal,, help

    Which controller is doing this?
  • icarus
    icarus Solar Expert Posts: 5,436 ✭✭✭✭
    Re: Mppt controller "wiping out" FM radio signal,, help

    Duh,,, sorry, the Rogue 3024 controller.

    Tony
  • halfcrazy
    halfcrazy Solar Expert Posts: 720 ✭✭✭
    Re: Mppt controller "wiping out" FM radio signal,, help

    Is the controller in bulk or has the target voltage been reached? I have not experienced any FM interference from the Rogue but I have noticed The FM60 puts a tiny noise in the area of 104 FM but only when it has hit the target voltage and I presume switched to PWM mode.
  • Solar Guppy
    Solar Guppy Solar Expert Posts: 1,989 ✭✭✭
    Re: Mppt controller "wiping out" FM radio signal,, help

    Well, you have come across one of the reasons controllers from MorningStar or Xantrex cost more, They have FCC class B certification. It is designed in, filters, PCB layout, the mechanics of the chassis and enclosure all work together to get the EMI down.

    The Outback FM's are very Noisy RF wise, BlueSky is a broadcasting station its so bad
  • westbranch
    westbranch Solar Expert Posts: 5,183 ✭✭✭✭
    Re: Mppt controller "wiping out" FM radio signal,, help

    And is the MX the same?

    Eric
     
    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
  • halfcrazy
    halfcrazy Solar Expert Posts: 720 ✭✭✭
    Re: Mppt controller "wiping out" FM radio signal,, help

    it may be me but the FM seemed louder than the MX noise wise
  • lorelec
    lorelec Solar Expert Posts: 200 ✭✭
    Re: Mppt controller "wiping out" FM radio signal,, help

    I haven't noticed anything across the FM broadcast band in the past. I just checked with a radio this evening. We have another half hour or so of daylight here, and so I put the antenna of the radio right up against the controller, and then right up against the wiring...and nothing. I've had one customer tell me that he's had some noise on a marine band (>150Mhz), but that's about it. May be related to signal strength or receiver sensitivity or design. I'm sure it's likely that the 3024 produces some RFI. Even Class B allows for a certain amount (I'm no expert, but I don't think they test anywhere near 100Mhz for conducted emissions, which is most likely what a shielded controller is going to have problems with -- noise being carried out via wiring). It's just kind of a part of the game with the nanosecond switching times that we're dealing with.

    The 3024 doesn't have a PWM output. It transitions seamlessly from regulating MPPT at the input to regulating battery voltage at the output at the absorb setpoint. So there wouldn't be any noise associated just with one mode or another.

    Tony, let me know if you can narrow down any particulars when notice the problem at its worst.

    Marc
  • Solar Guppy
    Solar Guppy Solar Expert Posts: 1,989 ✭✭✭
    Re: Mppt controller "wiping out" FM radio signal,, help

    From observations, low power conditions the digital control loop of most controllers hunt quite a bit to attempt to maintain the input target voltage. What this means is the controller will be sweeping/ ramping the duty-cycle and possibly generating a large band of RF.
  • john p
    john p Solar Expert Posts: 814 ✭✭✭
    Re: Mppt controller "wiping out" FM radio signal,, help

    many times this can help RF emissions, Get some ferrite cores and feed the input wires and output wires through them if you can fed the wires 2 or 3 times through each core.
  • boB
    boB Solar Expert Posts: 1,030 ✭✭✭✭
    Re: Mppt controller "wiping out" FM radio signal,, help
    john p wrote: »
    many times this can help RF emissions, Get some ferrite cores and feed the input wires and output wires through them if you can fed the wires 2 or 3 times through each core.

    Also twist the wires together as best as possible. Is the interference still there at night when the controller is not running ? If so, it could be the internal auxiliary power supply. Marc, do you use a switcher in there for the aux supply ? A simple snubber circuit may help tremendously in that and the buck converter section for interference on the FM broadcast band.

    It could be radiating from the PV wires, the battery wires or both.

    The reason for not getting interference could be that the FM stations are very strong compared to ops very weak signals. Capture effect in FM reception will make it so the stronger station will overcome any low level noise signal.

    Another thing you can do is to locate the FM receiver (and antenna) farther away from the power center and run the audio line into the house or wherever you want it. This will fix the problem. I live in a rural area and had to put my FM receiver in the garage to get the one station that I wanted. Wasn't even any inverters or charge controllers nearby.

    boB
  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: Mppt controller "wiping out" FM radio signal,, help

    tony,
    if the stereo can use headphones try using them and disconnect the speakers to see if the problem goes away or at least move the speakers farther from the controller if at all possible. additionally try the ferrite cores on the controller inputs and outputs.

    i have to ask you why you are using vertical antennas? i don't know if canada does something different than the u s, but fm broadcast signals are either horizontal or circular. (horizontal and vertical) if the stations are broadcasting horizontally then you are losing 20db of signal by using a vertical antenna. if they are circular then you lose 3db or 1/2 of the signal! btw the 20db loss means you are getting 1% of the signal.

    if the cable to the antennas is old or lossy then you might want to replace them, but make sure that switch isn't the culprit too by wiring the antenna straight to the stereo and see if things improve. i do trust you are using the proper impedance for the cables. no rg58 for this application.:cry:

    i'm thinking this is a new development and as such something has probably failed (not necessarily the cc) or there are some freak radio conditions presently near you.
  • icarus
    icarus Solar Expert Posts: 5,436 ✭✭✭✭
    Re: Mppt controller "wiping out" FM radio signal,, help

    Wow,

    As usual thanks for the great responses. I'll try to answer your questions in some order.

    Niel, I ma using a Fan-fare vertical because it is less directional than the Yagi. Depending on conditions it works better than the Yagi, hence the A/B switch. Unfortunately, my radio comes from 2 directions ~90 degrees apart so I can't just aim the Yagi. The vertical does have pretty good capture. The Coax is nearly new and is (as far as I know in good shape. As for "freak conditions" do remember, we are very fringe. My major station is ~150 kms way, with another better than 250 kms. (I shouldn't get them at all!) Also we do suffer from Aurora (northern lights).

    It seems to occur when the controller has only a few watts of potential in put. I confess I haven't paid much attention in the last couple of weeks since I installed it, as we are in the midst of our flurry of last minute winter chores, getting stuff over the ice while we can, so I haven't been in listening to the radio during the daylight. Just noticed it last night, now that the sun is up late enough for the controller to be on when the 6 pm hour rolls around. Today is heavy overcast and snowy so we will have to see if I get a chance to test it with more input.

    Marc, I will log and report what it does when. I suspect that this is a once in a life time issue so I wouldn't spend too much energy thinking about it. The reality is that because we are so fringe, all kinds of things induce all kinds of noise into the radio. The satellite modem/router power supplies etc, CFL bulbs, inverters etc.

    Just an FYI, the radio itself is on the far side of the house from the controller,, ~25' away. The antenna leads go directly outside, up the wall and across the roof to the antenna(s) that are 8' horizontal and 15' vertical above the controller. The radio is a Pioneer Car stereo wired with #12 romex house wire, back to the 12vdc load center across the house from the radio.

    Solar Guppy,

    I know that you indeed are an expert, but I think you may be dismissing the Rogue without first hand knowledge. (I also know that you are a great Morningstar fan,, and I understand that) The point in fact is, that my BlueSky controller induces no radio noise ever into my FM receiver, but my Morningstar inverter does induce into AM. I have the Bluesky controller wired with an A/B switch with the Rogue just so I can do continual side by side testing.

    I do think that your second comment about low power conditions is probably pretty close to the mark however.

    bOb,

    I had the thought that the interference might be from the PV wires themselves as well, but if that were the case, the noise should still be there using the other controller,,No?. I don't get any interference at night, (or when the controller is switched off)

    JohnP, Please explain ferrite cores and their installation if you would,

    Thanks again one and all,

    Tony
  • lorelec
    lorelec Solar Expert Posts: 200 ✭✭
    Re: Mppt controller "wiping out" FM radio signal,, help
    boB wrote: »
    Marc, do you use a switcher in there for the aux supply ? A simple snubber circuit may help tremendously in that and the buck converter section for interference on the FM broadcast band.

    I do use a small switcher for the aux supply, and it doesn't have a snubber. The actual converter/controller does already use a snubber, though. Early on I had to take some measures against EMI because it was interfering with the operation of the LCD.

    Marc
  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: Mppt controller "wiping out" FM radio signal,, help

    tony,
    very good on the polarity issue and i'm still unclear as to the directions to the stations. are you saying they are 90 (like s and w) degrees off from one another or both 90 (like e and w) degrees off from you in opposing directions? i am also assuming that by your statement that the yagi is fixed in 1 direction?

    the biggest interference source you have listed there is the modem/router as i've always had lots of noise from any that i've had with interference up and down the radio spectrum and includes the fm broadcast area with it being heavy there. how far up i've seen it was the lower microwave area above 1ghz. now that's bad! it is not an even noise level, but tends to spike on certain frequencies and with varying strengths. with the broad nature of fm capture effects your stereo will certainly find many of these interference spikes when listening and if they are stronger than the radio station signal at the time, away shall go your reception.:grr

    as to a blue sky interfering, maybe, but i have not found any noticeable noise anywhere in the radio spectrum from mine in the past, although i admit not looking for it. when i noticed my interference initially, i thought of the controller, but in disconnecting it and searching around i found it was my dsl modem/router and any that i had after that did interfere heavily. i am recently inactive on the radio and have gotten fios and i have not checked that modem/router for interference as of yet.
  • john p
    john p Solar Expert Posts: 814 ✭✭✭
    Re: Mppt controller "wiping out" FM radio signal,, help

    Icarus ferite cores are like mini doughnuts,obviously made of ferite there are actually different types but for RFreduction it not that important which ones you use, they are usually about 1.1/2" out side dia about 3/8" thick and about 1/2 " high. you just thread the wire through the core so that it wraps around the ferite ring about 3 or 4 times the more the better but difficult with thick cables. most old computer monitors had solid clamp on ferite beads to suppress RF you need to fit them as close to the end of the cable/s going into the controller.
  • icarus
    icarus Solar Expert Posts: 5,436 ✭✭✭✭
    Re: Mppt controller "wiping out" FM radio signal,, help

    John P got it, thanks.

    Neil,

    My major CBC (88.3) station is 150 km E.S.E, maybe maybe 100 degrees. A second, translated low wattage CBC station (90.1) is W.N.W. maybe 280 degrees, 100 kms away. I sometimes can get NPR from Duluth MN 100.5 at ~ 200 degrees ( and ~300 km away) and just to complete the picture on a really good day I can get a Houlton MI NPR at 91.1,, this is skipping over Lake Superior, a total distance of perhaps 500 km away. (At the same angle of the CBC 88.3, 100 degrees.

    So I point the yagi W.N.W and get the sure thing. Off the back side I get reliable 90.1 usually. The vertical usually works with the closer station, but given everything often time you never know which combination will get what. Does this make sense?

    I suspect the root of all the problems is that we are just too fringe!

    Thanks for all the input,

    Tony
  • mike95490
    mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    Re: Mppt controller "wiping out" FM radio signal,, help

    How's AM radio? I'd think AM would get wiped out before FM, since FM is inherently immune to lots of noise. Maybe it's getting into the audio, and not the RF, headphones with all speaker wires disconnected might show that. And, yes Ferrite donuts or clip-on cores right at the controller, on each lead, would help
    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 ||
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  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: Mppt controller "wiping out" FM radio signal,, help

    mike has it spot on why i said about using the headphones while disconnecting the speakers as it would show if the speakers and speaker wires are acting as the antenna for this interference.

    as an aside, i don't know if the signals you are getting are inverting their polarity at times or not, but another antenna type to consider trying would be a quad. the thing is i don't know if you'd want the center frequency to be around 90mhz or the compromise of about 95mhz due to the pickup of a 100mhz station? a single element would give you gain (almost equal to the vertical you use) and a bidirectional pickup pattern that roughly fits your circumstance. the polarity would depend on where the feed point is and it can be fed with 75 ohm cable with less than 2 to 1 mismatching of impedance. odds are it will be about 1.5 to 1 in reality. if you are interested now or later in trying it, let me know. it doesn't sound spectacular, but anybody who has tried the antenna in ham radio will tell you it is an amazing antenna that specifications don't seem to give it justice.

    of course adding height to the antennas can add more signal strength while adding distance between the controller and your antenna. do check all antenna connections both inside and out and if any water may have made its way into the cables they are almost as good as junk adding that during freeze/thaw cycles it could physically start ripping the cables apart from the inside with the cable electrical properties nullified due to water conductivity.

    i know some of this experimental stuff may or may not help with your problem as we don't know the root cause of it at this point and the weather has not improved for you as of yet to do some of this stuff. the ferrites certainly can't hurt and some of those can be clamped on. as was said the more loop throughs made the better the rejection, but if the wire size stops more loop throughs then more can be clamped on or added in series for more effectiveness. if you even have a ceramic disc capacitor around you can put that across the plus and minus leads, be it input or output of the controller, to see if this attenuates the interference any. if you see any improvement or change for the worse in doing anything then let us know as it could give rise to a clue as to the problem. it may just be a little of everything to overcome the problem.
  • icarus
    icarus Solar Expert Posts: 5,436 ✭✭✭✭
    Re: Mppt controller "wiping out" FM radio signal,, help

    Mike, Neil,

    I understand what your are suggesting about speaker wire picking up the interference. I can't do a head set directly, but I might be able to wire a speaker with a tiny short wire. That said, there is no noise on I-pod that is wired into the car receiver with docking kit. I would assume if the speakers were responsible then it would be true with I-pod or CD through the speaker system, Yes?

    As for your antenna suggestions. In reality, I have, over the years come to the "best" simplest solution. Raising the height is not really an option, and in most cases it works reliably well. The Fan-Faire antennae is specifically cut for the lower range of the FM band. As for AM, we get no am signals at all except at night. (Not only that, but there is little to listen to anyway.) Am is drowned out by inverter and CFL noise.

    The reality is, in this day and age, I can get nearly any radio station in N. America on the web, and play it through the stereo, never needing to rely on the antenna systems at all. I have contemplated an wireless internet radio, but that would require me to leave the rounter/modem on all the time, at a draw of ~30 watts, plus the radio. 30*12=360 wh/day,, about half of what we use now! Hmmm!

    Once again thanks for the help. I am watching it this morning as the current ramps up to see if it is still making noise as the current rises.

    Tony
  • icarus
    icarus Solar Expert Posts: 5,436 ✭✭✭✭
    Re: Mppt controller "wiping out" FM radio signal,, help

    A little further update. It seems to induce interference at all current levels and all voltages. Today is bright and sunny, and the PV is putting out about full capacity. It induces a fairly high pitched squeal, as well as a mid range whooshing if that makes sense.

    Thanks to Marc at Rogue for taking an interest, and I look forward to any other smarter minds. Anybody have any idea on how to make some "homemade" ferrite cores to use for a test? We are island bound for the duration now until the ice leave which might be soon, but might usually last until early May.

    Tony
  • boB
    boB Solar Expert Posts: 1,030 ✭✭✭✭
    Re: Mppt controller "wiping out" FM radio signal,, help
    icarus wrote: »

    s. Anybody have any idea on how to make some "homemade" ferrite cores to use for a test?
    Tony

    The quickest way I know of to get one is to steal a ferrite or clamp on ferrite off a computer monitor or digital camera cord or something similar.

    boB
  • icarus
    icarus Solar Expert Posts: 5,436 ✭✭✭✭
    Re: Mppt controller "wiping out" FM radio signal,, help

    BoB,

    Susan says I can't steal the one off her camera cord!

    Other than that we don't have anything that has a ferrite on it... I guess I will just have to wait.

    Tony
  • icarus
    icarus Solar Expert Posts: 5,436 ✭✭✭✭
    Re: Mppt controller "wiping out" FM radio signal,, help

    So I've gone to our site hosts site, and looked at ferrite cores. A couple of questions. Do you have to run a loop or series of loops on the wires? How close to the charge controller do they need to be? Do I put them on the PV side or the battery side? Or both?

    Where else in an off grid system do they make sense. I noticed that they are recommended to reduce the noise from CFLs. Where do you put them then? On a lamp cord? On the wiring of a fixed fixture?

    What about battery cable leads at the batteries? Inquiring minds want to know!

    Once again, thanks for all the help.

    Tony
  • boB
    boB Solar Expert Posts: 1,030 ✭✭✭✭
    Re: Mppt controller "wiping out" FM radio signal,, help
    icarus wrote: »
    So I've gone to our site hosts site, and looked at ferrite cores. A couple of questions. Do you have to run a loop or series of loops on the wires? How close to the charge controller do they need to be? Do I put them on the PV side or the battery side? Or both?

    Where else in an off grid system do they make sense. I noticed that they are recommended to reduce the noise from CFLs. Where do you put them then? On a lamp cord? On the wiring of a fixed fixture?

    What about battery cable leads at the batteries? Inquiring minds want to know!

    Once again, thanks for all the help.

    Tony

    BOTH if the cores are big enough. For the FM band, start with Common Mode filtering which says to put the ferrite around BOTH positive and negative wires.
    If the core is big enough, put more than one wrap on it (just the wires going through the donut once is one wrap.)

    Put as CLOSE to the charge controller as possible. It's actually best to add capacitors too, but the ferrite by itself may help enough. (or not !) Doesn't work 100% of the time unfortunately if it is radiating out of the box itself. Those wires coming out make very good antennas though !

    Something you may also want to try is to turn off the PV input (breaker?) while the CC is actually running. Before the CC turns itself off, see if it still makes interference immediately after you flip that switch.
    Oh, also, you may also be able to try turning off the battery breaker to the CC while it is running so the PV keeps the unit running as well. I know that doing this won't keep those wires (PV and battery) real short, but may offer some insight into what is going on and where interference is coming from.


    boB
  • icarus
    icarus Solar Expert Posts: 5,436 ✭✭✭✭
    Re: Mppt controller "wiping out" FM radio signal,, help

    BoB,

    First, killing the breaker between the battery and the controller kills the noise

    Turning off the PV (On a A/B switch) also kills the noise.

    So would I put one core on each wire (POS/NEG) or would I put a core on both wires at once? Are more turns better? If I can't get multiple turns through the core would 2 cores work better than one?

    Too many questions,

    Once again thanks,

    Tony
  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: Mppt controller "wiping out" FM radio signal,, help

    "Thanks to Marc at Rogue for taking an interest, and I look forward to any other smarter minds."

    gee, how are we that posted before marc to take this comment? i do acknowledge boB to be smarter than i and he echoed the same as i and he also added the controller input/output test.;)
  • icarus
    icarus Solar Expert Posts: 5,436 ✭✭✭✭
    Re: Mppt controller "wiping out" FM radio signal,, help

    OK,

    The plot thickens,,

    Playing around with the A/B switch and the breaker reveals that the Bluesky controller induces a similar noise although not as bad. In the case of the BlueSky, switching off the controller at the breaker kills the noise, but switching it off at the Pv doesn't kill the noise.

    So just to illustrate the situation,

    There are two arrays, one on the roof, which feed in through an interior wall.
    The second array is on the front of the house, feeding under the house coming up through the floor. These two sets of #4 wire become one. Since I have installed the A/B switch (to test the two controllers side by side) both arrays feed into the common side of the A/B, and then the A side feed the BS controller, the Rogue is fed by the B side. The out puts of each controller each feed a separate breaker. The total length of
    Any of these wires (After the A/B is a couple of feet at most). It is beginning to sound to me like the problem is between the battery and the controller(s).

    Any more wisdom?

    Tony
  • Slappy
    Slappy Solar Expert Posts: 251 ✭✭✭✭✭✭
    Re: Mppt controller "wiping out" FM radio signal,, help

    Use "Brass" screen for RF interference.....
  • icarus
    icarus Solar Expert Posts: 5,436 ✭✭✭✭
    Re: Mppt controller "wiping out" FM radio signal,, help
    niel wrote: »
    "Thanks to Marc at Rogue for taking an interest, and I look forward to any other smarter minds."

    gee, how are we that posted before marc to take this comment? i do acknowledge boB to be smarter than i and he echoed the same as i and he also added the controller input/output test.;)


    No offense to you Neil, or BoB or anyone. Perhaps I should have been clearer. I have been in touch with Rogue off line and Marc has taken an active interest in solving my problem, and I think, (though seldom see) that manufacturers taking an active interest in the customers problems even if they are not the direct result of their product. I also believe that when manufacturers/retailers etc step up, they deserve our praise and that was my intention.

    So if I failed to thank Neil, BoB, JohnP, 1/2crazy, eric,S.G, Mike or anyone else,, I'm sorry. And as always, Thanks for the smart minds and helping hearts here,

    Tony

    PS I think we are on the right track, now it will be a matter of executing it right.

    T
  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: Mppt controller "wiping out" FM radio signal,, help

    tony,
    i didn't think you meant anything bad, but worded it wrong. hey, i do that sometimes too.:roll:

    as to this,
    "Playing around with the A/B switch and the breaker reveals that the Bluesky controller induces a similar noise although not as bad. In the case of the BlueSky, switching off the controller at the breaker kills the noise, but switching it off at the Pv doesn't kill the noise."

    it establishes that the bs radiates a noise via the pvs, but did i overlook the rogue results with input and out disconnections? was it not the rogue we were really concerned with?