AM radio noise from SB2000E

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jauguston
jauguston Registered Users Posts: 20
Just installed two 130w Kyocera's and a SB2000E on my motorhome and the system is tearing up my AM reception on the vehicle radio. The noise goes away as soon as I pull under the storage cover and the system shuts down. Any ideas if I can do anything to fix it??
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  • Solar Guppy
    Solar Guppy Solar Expert Posts: 1,989 ✭✭✭
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    Re: AM radio noise from SB2000E

    You bought a charge controller that is NOT FCC class B certified ... its basically a nice AM transmitter.

    Your might consider satellite radio, trying to engineer any fix to the charger is unlikely to resolve your reception issues.
  • jauguston
    jauguston Registered Users Posts: 20
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    Re: AM radio noise from SB2000E

    Guppy,

    You call it a transmitter, I haven't checked yet but do you believe the noise is coming through the air or is it coming through the 12v electrical system. There is a relay that connects the chassis 12v charging system to the house 12v electrical system when the engine is running to charge the house batteries from the engine alternator. Could the noise be coming through that path?

    We have satellite radio but my wife is not very happy that she can't listen to some of the talk radio people she likes. And you know the old saying "If the wife is not happy nobody is happy" :-D

    Jim
  • BB.
    BB. Super Moderators, Administrators Posts: 33,476 admin
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    Re: AM radio noise from SB2000E

    AM radio is a "low frequency" RF emission that is, usually, conducted out of the electronic's box by its wiring. Generally, it does not carry far as cables are very poor antennas at that frequency range.

    However, there is an E-Field conduction path (capacitive) from the the cables, through the air, to any nearby receivers. Of course, it could be conducted through the vehicle's DC system--but I would not guess that to be the primary source of interference injected into your radio. Opening the switch (or fuse) between your house wiring and your vehicle wiring may help you check this as a source. If it is a source of AM noise--then you could use a DC to DC converter designed to charge house batteries from the vehicle battery/alternator. The converter should provide enough isolation to prevent AM noise in your vehicle wiring.

    Things to try--Take a "walkman" style portable radio set to some weak AM station and walk around your RV and see where the EMI is high and low. If possible, route any wires from your charge controller as far as possible from your AM radio and its antenna.

    Make sure that your AM radio antenna is not anywhere near AM noise detected by your "walkman" sweep. Also, check that the antenna cable is properly ground, both at the radio side, and the antenna side.

    Have the wiring to/from the solar charge controller separate from all other wiring (farther the better). Do not bundle it all into one big cable run. If you need to cross other wiring, try to do it a right angle.

    Twist the +/- cables (or at least, bundle tie them tight together) so that any differential noise in the cable is best shorted with its mate.

    (Note: I will leave the Ferrite Beads in as a suggestion--but the more I think about it the less I think it will work on this low of frequency range--if you had noise in your FM reception, then FB's are a good suggestion--you can still try the wire wrap/short as it is cheap and easy to try--but it probably won't work either)

    Look for ferrite rings and other shapes that you can run your cables to/from your charge controller through (or even take a wrap through the ferrite ring). These work better at high frequency rather than at low frequency--but if your desperate, it might be worth a shot. Install these ferrite inductors near the solar charge controller (withing a foot or so or less--keep the "antennas" short).

    Never have tried it and it is just a shot in the dark--but it might help... Instead of, or in addition to the ferrite inductors, try taking any 12-16 awg stranded wire (just regular hook-up wire) and wrap it around the wiring to/from the controller. Take at least a few turns then solder or wiring nut the two stripped ends together. In theory, any RF current coming out of the current should induce an equal and oposite current in the shorted wire--preventing the RF from going past the wire (this is what was being done with the ferrite rings/inductor too). Again, I don't hold out much hope for this to work--but it is easy to try.

    Also, make sure that the solar controller box (assuming it is metal and can be grounded) is well grounded to the RV ground metal chassis (screws, short pieces of braided cable, whatever).

    Use the "walkman" AM noise sniffer to check the wiring from the solar controller... If the output wiring is the "noisy" wiring--move the controller close to the battery bank itself.

    Find the "noisy" wiring to/from the controller, and shield it (preferably with a good ground at one or both ends of the shield). You could try EMT conduit, copper pipe, and you can even buy copper tape and tack solder the laps every few inches (or with AM every foot or so would be OK too).

    Or, get a simple PWM charge controller and replace the MPPT version. I remembering reading one controller manual that it even had a switch that cut radio noise (I assume it went from PWM at 100's-1,000's of times per second to simply On or Off every few seconds).

    Solar Guppy might be able to point you towards brands/models that are quieter. If you can get access to other working solar controllers, the walkman test is quick and easy to check. Note that the noise may differ between when bulk charging (switch is closed) and finish charging (switching electronics are turning on and off quickly to reduce current flow from the panels).

    There are other things to try--but that would include installing RF bypass caps line to line and line to chassis ground--but I would not suggest them as it is easy to short things out by using the wrong parts or adding components and having things touch. Also, to work well, there needs to be a good sized inductor involved too... Probably not practical in this application.

    But, as SG says--it is really quite difficult to for an end user to make a noisy electronic device quiet.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • crewzer
    crewzer Registered Users, Solar Expert Posts: 1,832 ✭✭✭✭
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    Re: AM radio noise from SB2000E
    Or, get a simple PWM charge controller and replace the MPPT version. I remembering reading one controller manual that it even had a switch that cut radio noise (I assume it went from PWM at 100's-1,000's of times per second to simply On or Off every few seconds).

    Bill,

    Right you are. The Morningstar Tristar and ProStar PWM charge controllers can be user set for either PWM or on/off regulation.

    Regards,
    Jim / crewzer
  • Solar Guppy
    Solar Guppy Solar Expert Posts: 1,989 ✭✭✭
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    Re: AM radio noise from SB2000E

    Xantrex C40/C60 series ( and any other C models ) switch at 400 hz, no RF to deal with

    As for all the "grounding" suggests, an RV has no earth ground, just two different potentials. True pwm ( buck , mppt ) charge controller operate in the 20-50 khz range and throw off harmonics that can easily travel 100's if not more feet and its usually thru the input/output wires. proper magnetics that use differential means is the only way to keep this from being radiated from the chargers ( common-mode chokes ). Its a dirty "secret" of the charger market, no units are FCC class "B" compliant as this doesn't apply to the "mobile" market. But the same charger in a house and its required to meet class "B" ...

    The soon to be release Xantrex WX-60 will be 100% UL and FCC compliant charger and to my knowledge the only Mppt controller that is certified to FCC Class "B" emissions
  • mike95490
    mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
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    Re: AM radio noise from SB2000E
    jauguston wrote:
    Guppy,

    You call it a transmitter, I haven't checked yet but do you believe the noise is coming through the air or is it coming through the 12v electrical system.
    Jim

    You could install some automotive style noise filter caps, that may shunt the noise in the 12V lines
    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 ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
    || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

    solar: http://tinyurl.com/LMR-Solar
    gen: http://tinyurl.com/LMR-Lister ,

  • BB.
    BB. Super Moderators, Administrators Posts: 33,476 admin
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    Re: AM radio noise from SB2000E

    From my experience of designing larger computer systems and networking boxes--I don't subscribe to the theory that "earth ground" is anything I worry about when designing a system (except if I am trying to use the IIRC the "ground wave" method of transmitting AM frequency radio waves (from what I have read, is is not easy to create an efficient antenna for low freq. RF like AM).

    When I am talking about grounding to the RV chassis--that is just the equivalent of putting a metal can around everything that you can, and were the wires come out, using shielding to short the RF energy back to the source in as short/low impedance path, as possible (if the shorting loops are too large and far apart--you effectively have just created another radiator). Think of an aircraft... Has lots of relatively powerful transmitters and sensitive receivers--and you are 5-10 miles away from "earth ground".

    When creating a site to do Class A and B RF measurements, we did put down a ground screen on the ground (or under the parking lot) to create a stable/repeatable environment so that the RF energy is consistently directed when doing measurements between setups (10 and 30 meter ranges).

    And we never worried about AM radio noise. AM RF was not even measured during normal Class A scans. And around the home and office--you have all of those Class B PC's and most of the time, you still cannot get any decent AM stations on your radio (part of can be the result in being enclosed in a steel beam/aluminum framed/re-bar concrete office building.
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • crewzer
    crewzer Registered Users, Solar Expert Posts: 1,832 ✭✭✭✭
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    Re: AM radio noise from SB2000E
    The soon to be release Xantrex WX-60 will be the first and only 100% UL and FCC compliant charger ...

    Henry,

    This statement might be worth reconsideration. The Morningstar TriStar controllers are UL-listed, CE certified, and the operator’s manual (page 4) indicates they comply with Part 15 of the FCC rules.

    UL: http://www.morningstarcorp.com/products/TriStar/info/TS_UL.pdf
    CE: http://www.morningstarcorp.com/products/TriStar/info/TS_CE.pdf
    Manual: http://www.morningstarcorp.com/products/TriStar/info/TS_Manual.pdf

    The OutBack MX60 has been ETL certified to UL standard 1741. The old rev. 6.2 manual indicates the MX60 been certified to EU Emissions spec EN 50081-1 (1992) and EU Immunity spec EN 50082-1 (1992). I’m far from an expert on these matters, but it’s my understanding that these two EU specs are comparable to FCC Part 15.

    ETL: http://www.outbackpower.com/pdfs_general/mx60auth.pdf

    Regards,
    Jim / crewzer
  • Solar Guppy
    Solar Guppy Solar Expert Posts: 1,989 ✭✭✭
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    Re: AM radio noise from SB2000E

    Thanks crewzer, I updated the line ...

    To my knowledge, the MX60 has NO filter(s) for emissions and fails "A" & "B" by large margins, I'm sure bOB can update the status for us :-D

    The morning star units are just like the Xantrex C series and I wouldn't expect issues with emissions as there is no high-speed switching happening internally
  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
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    Re: AM radio noise from SB2000E

    jauguston,
    try obtaining a few .01uf ceramic disc capacitors and place these across the output of the controller + and -. if you can find a value of ceramic disc capacitor that is preferably higher like .05uf or .1uf you can use these as these will short out much of the radio energy to ground so it is important to do this as close to the controller as possible. (12vdc will not pass through a good capacitor btw.) inside the controller would be nice if there is a provision to mount them. be careful not to allow any shorts between the + and the - as there is little room between the leads so if you need to you could solder insulated wire extensions to the caps and just encase the cap in plastic wrap or heat shrink tubing thus preventing any shorts. the idea is to take the radio energy and short it out before it can escape to other equipment. this isn't foolproof, but it should reduce the interfering energy significantly and possibly make the reception tolerable. i'm not sure if radio shack is still stocking electronic parts still or not. if they are be sure the cap voltage rating is higher than that which you will be using and do NOT confuse these caps with the polarized electrolytics.
  • jauguston
    jauguston Registered Users Posts: 20
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    Re: AM radio noise from SB2000E

    Niel,

    Thanks!

    No offence meant to the other posters but most of the other "possible " solutions don't seem practical at this point for me. I have a local independent electronics supply store that should have or be able to get anything like you suggest. With that source available what would your "This would be my very best guess suggestion for the right part". If you have a number of option ideas give me all of them if you will and I will get several.

    The controller is not in a box, simply surface mounted in a hole in a cabinet wall. It is easy to get at the back side. I did the install myself.

    Jim
  • boB
    boB Solar Expert Posts: 1,030 ✭✭✭✭
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    Re: AM radio noise from SB2000E

    "To my knowledge, the MX60 has NO filter(s) for emissions and fails "A" & "B" by large margins, I'm sure bOB can update the status for us"

    I can't remember how much the MX60 goes above the A and B reference lines, but it may be much better than the 2000. There weren't
    a lot of complaints, but I understand that OutBack is working on FCC certification. There actually is a bit of RFI reduction in the MX60. It's better than it would be for sure. Even an FCC class B certified controller will emit some EMI and may cause interference. I remember that the Trace (Xantrex) C40/C60/C12 had been reduced to FCC class B specs (at least in a certain frequency range) but there were STILL complaints, although it had to do with the crystal oscillator ending up making interference on some hams' favorite frequency. You cannot totally get rid of RF interference. You can only reduce it. Class B certified will radiate some also.

    First, try to find out where the interference is coming from. The Battery side and/or the PV input side. Does it still interfere if you remove the PV input only ?? Does it only interfere in the day when it is charging ?? That would eliminate the basic internal logic, although I can't remember if the SB2000 has a microprocessor or not. The uP would always be running and clocking.

    Make sure the PV input lines are twisted together or at least running as close together as possible. This will help reduce common mode
    interference. Also, as has been mentioned I think, try wrapping a turn or two of BOTH PV wires through a ferrite toroid or try clamping
    one of those ferrite magnetics around those wires and see if that helps. Try that on the battery side plus and minus wires as well.
    these should be installed close to the controller.

    You can also try adding a decent capacitor across the input and/or output wires (differential filtering) or 1 cap from plus wire to ground and 1 cap
    from minus wire, to ground, (chassis), or something called "ground" which in your case would be the RV itself I guess. But try them
    to the SB2000 case. (does the SB2000 even have a case?)

    Also, move the radio itself away from the SB2000 or it's antenna. Remember that the SB2000 input and output wires ARE antennas,
    and should be moved away from the radio if they are running by it.

    Can the radio run on a temporary battery by itself ?? If so, try that to tell you if the interference might be coming into it on
    the battery line. If that was the case, then it would be pretty easy to fix the interference I would think. It's probably
    not going to be that easy though I bet.

    boB
    K7IQ

  • boB
    boB Solar Expert Posts: 1,030 ✭✭✭✭
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    Re: AM radio noise from SB2000E

    "To my knowledge, the MX60 has NO filter(s) for emissions and fails "A" & "B" by large margins, I'm sure bOB can update the status for us"

    I can't remember how much the MX60 goes above the A and B reference lines, but it may be much better than the 2000. There weren't
    a lot of complaints, but I understand that OutBack is working on FCC certification. There actually is some RFI reduction means in the MX60. It's better than it would be for sure. Even an FCC class B certified controller will emit some EMI and may cause interference. I remember that the Trace (Xantrex) C40/C60/C12 had been reduced to FCC class B specs (at least in a certain frequency range) but there were STILL complaints, although it had to do with the crystal oscillator ending up making interference on some hams' favorite frequency.
    You cannot totally get rid of RF interference. You can only reduce it. Class B certified units will radiate some RF also.

    First, try to find out where the interference is coming from. The Battery side and/or the PV input side. Does it still interfere if you remove the PV input only ?? Does it only interfere in the day when it is charging ?? That would eliminate the basic internal logic, although I can't remember if the SB2000 has a microprocessor or not. The uP would always be running and clocking.

    Make sure the PV input lines are twisted together or at least running as close together as possible. This will help reduce common mode
    interference. Also, as has been mentioned I think, try wrapping a turn or two of BOTH PV wires through a ferrite toroid or try clamping
    one of those ferrite magnetics "beads"around both wires and see if that helps. Try that on the battery side plus and minus wires as well.
    these should be installed close to the controller.

    You can also try adding a decent capacitor across the input and/or output wires (differential filtering) or 1 cap from plus wire to ground and 1 cap
    from minus wire, to ground, (chassis), or something called "ground" which in your case would be the RV itself I guess. But try them
    to the SB2000 case. (does the SB2000 even have a case?)

    Also, move the radio itself away from the SB2000 or it's antenna. Remember that the SB2000 input and output wires ARE antennas,
    and should be moved away from the radio if they are running by it.

    Can the radio run on a temporary battery by itself ?? If so, try that to tell you if the interference might be coming into it on
    the battery line. If that was the case, then it would be pretty easy to fix the interference I would think. It's probably
    not going to be that easy though I bet.

    boB
    K7IQ

  • Solar Guppy
    Solar Guppy Solar Expert Posts: 1,989 ✭✭✭
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    Re: AM radio noise from SB2000E
    boB wrote:
    Solar Guppy was rumored to have said "To my knowledge, the MX60 has NO filter(s) for emissions and fails "A" & "B" by large margins, I'm sure bOB can update the status for us"

    I can't remember how much the MX60 goes above the A and B reference lines, but it  may be much better than the 2000.  There weren't
    a lot of complaints, but I understand that OutBack is working on FCC certification. boB
    K7IQ

    Thanks for the update boB, you are quick, just like beetlejuice, say your names 3 times and you appear :-D

    I can't see how they could fit the filters in the MX60 box ... its a major PITA ... power robbing just to keep the hams happy :-P ... ( Just a little humor boB!! )
  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
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    Re: AM radio noise from SB2000E

    jauguston,
    the capacitors are fairly cheap and if you can get .1uf for the input and the output of the controller that would be good. twisting the wires and using a toroid are also good suggestions. if none of these work then look for a bad connection either on the pv system or most probably on the radio. a bad connection can setup a circumstance where it acts like a diode and starts rectifying radio signals even from controllers. this bad connection could also be in the alternator or battery system in addition to the antenna wire for the radio. heck it could even be a flakey fuse so look around. if your vehicle has alot of rust on it this also could be the cause as it would be introducing bad connections along the ground of the vehicle.
    let me know how you make out on this.

    guppy,
    "power robbing just to keep the hams happy ..."
    i doubt rf filtering is robbing power from anybody or anything!! not humorous to this ham. :x :-P :x
  • boB
    boB Solar Expert Posts: 1,030 ✭✭✭✭
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    Re: AM radio noise from SB2000E

    "Thanks for the update boB, you are quick, just like beetlejuice, say your names 3 times and you appear"

    I LOVE that movie !! I just happened to check the forum today. It was luck.


    "I can't see how they could fit the filters in the MX60 box ... its a major PITA ... power robbing just to keep the hams happy tongue ... ( Just a little humor boB!! )"

    You're sure right about trying to fit a real filter being a PITA ! Especially one that works well.

    boB


  • Solar Guppy
    Solar Guppy Solar Expert Posts: 1,989 ✭✭✭
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    Re: AM radio noise from SB2000E

    Hey Neil,

    I know MANY solar users are hams as some designers and I support FCC class B compliance, even though the industry in general ignores it ( Mppt controllers as apollo, BZ, Blue Sky. Outback all are not compliant ). Its really though to make high power switching supply's ( 1-3 kw+) be nice emi wise. It is power robbing with the common-mode chokes, its increases the costs .. the efficiency loss it is about 1/2 - 1% percent at 48V operation for the SC-60 ... I'm glad to see Outback is becoming compliant, I hope other "new" products do the same!.

    I read over at www.dslreports.com all the time, one topic that comes up over and over is "broad band over powerlines" The FCC is completely asleep at the helm on this as some electric company's turn there wires into "ham" interference generators. Its a DOA concept that for some reason beyond what I can understand seems to keep popping up like mushrooms that anyone with the most basic understanding of RF would just go "huh" that will never work.

    There is a very vocal percentage that believes some-how this would bring broadband to remote areas, which it never could and its all out war between the BBOPL camps and hams. I understand the importance of hams, especially living in Florida and our habbit of hurricanes ... sorry it touch a nerve!


  • Solar Guppy
    Solar Guppy Solar Expert Posts: 1,989 ✭✭✭
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    Re: AM radio noise from SB2000E
    boB wrote:
    "Thanks for the update boB, you are quick, just like beetlejuice, say your names 3 times and you appear"

    I LOVE that movie !!   I just happened to check the forum today. 

    One of the few movies I NEVER get tired of watching, everytime I notice something new in the background!
  • boB
    boB Solar Expert Posts: 1,030 ✭✭✭✭
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    Re: AM radio noise from SB2000E

    "I know MANY solar users are hams as some designers and I support FCC class B compliance...."

    I'm a ham and I support the reduction of EMI to at least FCC specs and lower, whether or not it is certified.

    "even though the industry in general ignores it ( Mppt controllers as apollo, BZ, Blue Sky. Outback all are not compliant )...."

    Did xantrex spend the money to FCC test ALL of these controllers ??

    "It is power robbing with the common-mode chokes..."
    Only if you use lossy material. You gotta find the good stuff. A lot of it IS bad and lossy. Not all.

    boB
  • boB
    boB Solar Expert Posts: 1,030 ✭✭✭✭
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    Re: AM radio noise from SB2000E


    What IS a bitch and PITA is to "squeeze" the proper filtering into the proper place in the circuit where
    they're trying to keep things very tight for some of the same reasons. (small loop area etc.)
    boB
  • jauguston
    jauguston Registered Users Posts: 20
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    Re: AM radio noise from SB2000E

    Niel,

    I hate to interupt with a on topic post but I will make it short. The wire I used is the 8ga that is supplied from NAWS. It looks like it is twisted and has a fancy UV resistant jacket and costs a bunch :-D

    One run (26') is uncut from panel to controller with another piece of the same stuff (6') spliced into the first run. Same wire (4') from controller to battery bank.

    Jim
  • boB
    boB Solar Expert Posts: 1,030 ✭✭✭✭
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    Re: AM radio noise from SB2000E

    Jim, I just read Bill's (BBs) post. I should have read it completely first since he pretty much said everything and more that I said.

    Have you tried the portable radio experiment to see where the interference is worse ?? And were you able to
    to separate the 12V radios' power from the normal 12V power in the RV to see which end the interference is coming from ?

    boB
  • Solar Guppy
    Solar Guppy Solar Expert Posts: 1,989 ✭✭✭
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    Re: AM radio noise from SB2000E
    boB wrote:
    "It is power robbing with the common-mode chokes..."
    Only if you use lossy material.  You gotta find the good stuff.  A lot of it IS bad and lossy.  Not all.
    boB

    The power loss I have seen first hand is in the additional chokes on both the input and output even with the best micro-metals cores, the I2 losses for common modes is VERY hard to keep low as its a fight on one hand you need high turns count for lots of inductance vs low turns count for low current squared losses ... The losses in the common mode in everything I have seen can exceed the losses of the actual buck inductors .. disclaimer, I haven't seen the WX's final filtering ..

    Xantrex has on-site ability for emissions sniffing in Burnaby ...
  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
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    Re: AM radio noise from SB2000E

    jim,
    alright, the wire may be ok, but you still have steps to take in finding/curing the interference. do follow some of the suggestions and hopefully one or more of them will solve the problem. let us know the progress.
    note: being the interference is low frequency in nature, the toroid will have less effectiveness compared to the use of the capacitors. as was stated, though we really don't know the exact cause of the interference so this means you need to start being a sleuth. causes are more elussive as you generally find the cause by finding the cure. many times it isn't a total cure either, but enough of a reduction to be tolerable.
    guppy,
    i wasn't being that serious. :lol: nerve didn't get frazzled. :roll: :wink:
  • BB.
    BB. Super Moderators, Administrators Posts: 33,476 admin
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    Re: AM radio noise from SB2000E

    Actually, it is pretty easy to check and find non-compliant units with a few minutes of testing. When they fail, the usually fail by a lot (10-20 db). Those spikes stick up like a sore thumb. Put the antenna close, map a few suspect frequencies--backup to 10 or 30 meters. Check power level while rotating table and switching from vertical to horizontal antenna polarity.

    It is harder (more time, money, and a quiet area) to do the through testing to ensure a system is compliant.

    Regarding using the capacitors to short out the noise--typically, I could guess that the noise you are seeing is common mode noise. That is best shorted from line to ground (chassis ground). Differential noise can be helped by running the +/- cables next to each other and, if possible, giving them a twist every foot or so (at the AM frequency--higher frequency would want to twist every inch or so).

    The other issue with caps, is to short out the noise, you really need a impedance (inductor usually) between the source of the noise and the "shunting" cap. Otherwise, the capacitor really does not do too much if the source of the noise is of very low impedance (at the RF frequency of interest--which I would expect the output of a switching power supply to be--especially if it has no inductors/filters on the output). That is another reason that I did not suggest the capacitor on the supply outputs and inputs.

    Another (admittedly far-fetched) concern is that for AM RF, the caps would have to be fairly high value caps. Hanging high value caps on the end of a noisy switching power supply and long cable runs could cause a resonate circuit (tank) and other issues (peaking emissions at another frequency or even interfere with the regulator feedback loop stability). I actually had this problem back 20 years ago with a disk drive hanging on the end of 3-4 feet of wiring (+5, +12) and the combination of the power supply switching edges and the disk drive (remember the first 30 MByte ST506 5 1/4" disks?) mounted against a sheet metal surface (on insulated standoffs) cause RF noise on the power lines to capacitive couple into the read circuits because of the proximity of the chassis/ground plane--causing high error rates. To cure this on the computer system already in production I had to use heavy/short copper braid from the PS Ground to Chassis Ground to prevent the sharp edges from propagating out into the distributed power wiring harnesses.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • boB
    boB Solar Expert Posts: 1,030 ✭✭✭✭
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    Re: AM radio noise from SB2000E

    Guppy said:
    "disclaimer, I haven't seen the WX's final filtering .."

    From what I hear, they've changed the WX many times now. Doesn't even have a toroid anymore. Their MPPT algorithm may have also changed somewhat. I don't know for positively sure of course. I remember the Burnaby facility fairly well. I hear that Rob Baumgartner and wife are having a baby these days. Did he work on the filtering ?


    Bill (BB) said:
    (remember the first 30 MByte ST506 5 1/4" disks?)

    So you did some engineering work on Seagate drives, Bill ? CooL ! I may even still have one of those drives ! I should
    plug it in and see if the bearings are still good. And the data.

    boB
  • BB.
    BB. Super Moderators, Administrators Posts: 33,476 admin
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    Re: AM radio noise from SB2000E

    Actually, I am trying to rack my brain here... It may have been the first 50 MByte 5 1/4 disks from CMI. They were working with IBM to come out with the first small / high capacity drives.

    I was working at a mini-mainframe company (if you remember Wang--we were a smaller competitor of theirs) in the magnetic storage area as an electrical design engineer fresh out of college.

    At the time, we where looking for high capacity/high performance drives and, at that time, found Micropolis to great drives.

    We got one pallet of CMI drives, but I found some serious problems with them, and we sent them back (had Century Data make one more run of 14" platter 10 MByte drives to hold us through until we could bring another vendor in with good product).

    The CMI drives, and unfortunately, the company too, become just so many fishing weights.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • jauguston
    jauguston Registered Users Posts: 20
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    Re: AM radio noise from SB2000E

    Guys, I just had a thought that might cure my problem but it seems like it might be too easy so please tell me what would be wrong.

    As soon as the red charge indicator light goes out like when I pull under the RV cover or night comes the interference stops. What bad will happen if I put a switch on the + lead coming from the panels and just shut them off from the controller when we are traveling? On the road traveling is about the only time we listen to the radio so that would make DW happy.

    Jim
  • boB
    boB Solar Expert Posts: 1,030 ✭✭✭✭
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    Re: AM radio noise from SB2000E

    "What bad will happen if I put a switch on the + lead coming from the panels and just shut them off from the controller when we are traveling? "

    Nothing bad should happen. That will work fine. Just make sure the switch or breaker is rated for DC current and the proper
    amount of current and voltage of course. Otherwise, you have to make sure that you only switch it off when the red light
    goes off or there is no (zero) current going through the SB2000E to the battery at that time.

    If you don't use the proper switch, it ~could~ melt because of not being able to extinguish the DC arc if the DC current is high when switching
    off.

    This information also satisfies one of the question I was asking... Did it make interference all the time. Nope, only when charging.
    Doesn't really help fix the problem though.

    Later on maybe you can try some of that other stuff, but for now just switch it off like you said.

    Hey ! Maybe you could just put a piece of tape over that red light !! :-D

    boB
  • jauguston
    jauguston Registered Users Posts: 20
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    Re: AM radio noise from SB2000E

    Bob,

    Any automotive switch that is rated for 20a should work as far as I can see. Lots of equipment now adays is 24v like the German cranes I ran for many years so they should not have an problem with the 20-21v the panels will produce at max. I don't see why I would have to worry about current going to the controller when I shut the switch off. They are intended to interupt current flow. Some of the circuits in the cranes would switch 24v 20a hydralic oil cooling fans with no problem. If I was switching the circuit from the controller to the batteries I can see there might be issues but I don't see the problem on the PV side. If I am missing something please enlighten me. I am not to old to learn - I hope (-:

    Jim