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

boB

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

icarus wrote: »

If I can't get multiple turns through the core would 2 cores work better than one?
Tony

Yes. You got it ! That would normally be the case anyway. Sounds like you may want to try it on the battery side first, but usually means a larger size ferrite donut hole.
boB

lorelec

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

Tony,

You'd said at one point that in the past you hadn't noticed any noise from the Bluesky. With the A/B setup it seems to be behaving differently...so could the switches, wiring, or controller placement be responsible for your problem with the Rogue and/or Bluesky? Does moving things around make any difference?

Marc

icarus

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

Marc,

I had the system wired temporarily and I didn't really notice the noise. (That said I couldn't say if it made the noise or not as I wasn't paying particular attention) Just the other day, I wired the whole thing in "permanently" keeping the A/B switch in line just because it was easier to wire, and it allowed both controllers to be on line in the event that one fails.

The move to "permanent" location only moved the Rogue 1' and the A/B switch about a foot. Nothing else changed.

Niel, (and Marc) I noticed as I was playing around with things last night that the BS controller does indeed induce some noise, although not nearly as much as the Rogue. The solution wishes to be for the Rogue going forward however.

BoB,

You never know what you will find kicking around the middle of nowhere. I found an old sat modem power supply and lo and behold, it had a removable ferrite! I have tried it on the Pos from the PV, the Pos from the Battery, and the negs,, no change resulted in the noise trying it anywhere! I will get some bigger ones, and more of them sometime after the ice leave and I get some time.

To Slappy. I had thought of the copper screen trick earlier, and I swear I had a bunch lying around, but an extensive search netted nothing. If you were to screen something, what would you screen,,, and how? Will Aluminum screen do any good?

Once again thanks to everyone for your input,

Tony

Once again, thanks to all for your help.

mike95490

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

nails are soft iron, may not be as good as ferrite, but if you have a bunch, wrap a handfull around the wire, nail goes lengthwise, along the wire, (maybe a strip from a nail gun) and the iron may help/hurt the noise.

GreenerPower

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

Tony, have you looked at this thread to see if any thing similar you can apply to reduce RF interference noise. If possible, try similar test using, say 4 small gel-cell batteries, to feed 48V to the CC directly with short wires instead of from the PVs to see if the interference goes away. Then you know whether it's from the PV feeding wires or not, then start trouble shooting from there.
GP
Marc, would it be OK to feed the Rogue CC with 48V from gel-cell batteries ?

icarus

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

Well I wrapped the one ferrite core that I found around each wire leading to the controller, and then around as many as I could, each time to no avail. I will now have to wait until I can get some more ferrites, and open up the wall to play with the wires.

Thanks for all your help,

tony

BB.

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

Note with Ferrite cores--You need to put them around the +/- pair of DC cables for any effect. If you put just one + or - cable through a Ferrite, the DC current will saturate the core and it will not be cable of reducing RF noise (the +/- pair through the Ferrite cancel the DC portion of the magnetic fields).

Make sure all +/- wire runs are right next to each other--no big loops of wire (will act more like a radio antenna).

Typically, EMI open air noise will be from the cable in the 30-180 MHz range. Above that frequency, it is generally from 1/4 wave length "slot antennas" in the metal box.

If you have a small portable radio--move it around the wiring/box and see if you can find a hot spot.

I have done this with AM radios and whip antenna--either short the antenna with your hand, make it very short, or cut a piece of short wire to use as a probe.

Or, you may try wrapping the radio in aluminum foil (leave a bit open) to cut its sensitivity (I have not tried that)--and see if you can get the radio to be just sensitive enough where you can find the source of the noise when moving it around your installation.

-Bill

mikeo

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

I had the system wired temporarily and I didn't really notice the noise

Tony just out of curiosity I took my fine old 1978 Panasonic RF2200 receiver to where I have a Rogue charge controller set up. The radio shows broad band noise within about 3 feet of the charge controller, but at 7 feet no effect at all with broad band and no noise spikes as I tuned over the FM band. I live on the fringe of the NPR station I listen to as well and am in a deep valley with a 600 ft bluff 1/2 mile from my house between me and the radio station. The old RF2200 will usually pick up the station well during most hours but sometimes around sunup, the signal fades away and a religious station in Missouri comes in on the same frequency.

icarus

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

Bill,

Thanks for the info on using the ferrite cores.

Mikeo,

I will did up a portable radio and try to see if there is a hot spot somewhere I can't really wrap the antenna as it is 35' in the air, and I am not going to bring it down for this.

Finally, I know I had some copper screening, and after enough searching I found a 5x4' piece. I wrapped the entire wall on both sides with copper screen, covering the controllers, the a/b switch etc and,, no change!

What would a proper copper screen install look like?

Tony

BB.

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

Tony,

Do you have any portable radios (or MP3 players with FM radio) to do the test with?

Also, you can try disconnecting the FM radio from the main battery bank and run it off its own battery--double check that the interference is not coming up the DC power lines (conducted noise).

Figuring out if it is a radiated vs conducted noise problem (radiating from Charge Controller Box, from its wiring and getting into the radio via the antenna or the DC power line)--will tell you what to focus on.

Try disonnecting the antenna from the radio... Does the noise remain (conducted up DC power line?). Then try connecting just a wire to the center terminal of the antenna (noise? then radiated). If no noise, possibly a bad ground shield on the antenna lead (are you using an antenna amplifier?).

At the frequencies you are looking at (88-108 MHz), I doubt that it is radiating from the box (in the lab, we would be removing paint from any box connection points (want electrical connections) and jamming aluminum foil in any gaps.

Since 108 MHz is around 9'--the quarter wave length is > 2 feet... There are no possible gaps on the controller that are that large--so I would guess that you do not have any "slot antenna" radiation.

That really leaves the sets of wires coming in and out of the box... If you can run the wiring through ~10 feet of conduit, grounded back at the box (paint removed, metal fittings)--that may also reduce the amount radiated energy too (more than 10' really does not help much more in the distributed capacitance reduction of radiated power).

You could try taking 5' of aluminum foil, cut in half lengthwise, and wrapping the leads (careful of shorts) making your own temporary conduit. Make good electrical contact back at the box.

-Bill

lorelec

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

I've been playing around with the controller here a little bit more trying to duplicate your noise, but have been unable to. I do get some interference on AM radio if the radio is close enough, which doesn't surprise me. But from 88-108MHz on the FM band I get nothing...not even at frequencies where there's nothing being broadcast. It doesn't matter if the radio & antenna are sitting right in front of the controller, on top of the wiring, or anywhere else. I wish I had some better insight into this for you, Tony! Try some of the suggestions that others here have mentioned to see if you can narrow down where the noise is coming from. As for putting a battery in place of the PV on the input of the controller...I don't recommend it, but doubt it would hurt anything. I'm not sure it's going to offer any revelations, either. If noise if being conducted out wiring, then it's almost definitely on the PV side of things. The battery side of things might have some ripple, but it's triangular in shape and so less prone to generating high frequency harmonics. The input ripple tends to be more of a square wave.

Marc

boB

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

lorelec wrote: »

I've been playing around with the controller here a little bit more trying to duplicate your noise, but have been unable to. I do get some interference on AM radio if the radio is close enough, which doesn't surprise me. But from 88-108MHz on the FM band I get nothing...not even at frequencies where there's nothing being broadcast. It doesn't matter if the radio & antenna are sitting right in front of the controller, on top of the wiring, or anywhere else. I wish I had some better insight into this for you, Tony! Try some of the suggestions that others here have mentioned to see if you can narrow down where the noise is coming from. As for putting a battery in place of the PV on the input of the controller...I don't recommend it, but doubt it would hurt anything. I'm not sure it's going to offer any revelations, either. If noise if being conducted out wiring, then it's almost definitely on the PV side of things. The battery side of things might have some ripple, but it's triangular in shape and so less prone to generating high frequency harmonics. The input ripple tends to be more of a square wave.

Marc

Marc, maybe you could swap controllers with him ? Maybe this is just a fluke of that one unit. Something unstable or something like that ?
Just an idea.

And BB, great suggestions !
boB

Slappy

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

icarus wrote: »

Marc,


To Slappy. I had thought of the copper screen trick earlier, and I swear I had a bunch lying around, but an extensive search netted nothing. If you were to screen something, what would you screen,,, and how? Will Aluminum screen do any good?

build it like a cage/box, that surrounds the problem area, ....Movie Theaters thought about, lining the new buildings with this stuff to cut out cell phones signals so people could watch the movies with out interruptions during the show, but that got struck down, "cell phone rights":grr ....

here is an small article on brass screening...
http://www.copperinfo.co.uk/news/press-releases/pr707-brass-shielding-prevents-rf-interference.pdf

icarus

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

I don't think we need to worry about swapping the controller! The fact that the Blue sky does it as well indicates to me that it is a general wiring problem. I will live with it until I can do a proper rewire with ferrites etc. Won't be until sometime later in the summer though. We are island bound ( nearly a month early!) due to bad ice. In fact I made one last emergency trip today and that will be the last time on the ice except for "safe" excursions early in the morning. The month of May (when we are usually ice bound we are going to be traveling, and then the summer busy season. I'll let everyone know about progress then.

I did play around with a portable radio, and it's receptions/capture is really poor so it is really hard to tell if it is effected or not. I also placed copper screen on the roof, between the controller and the antennas, again to no avail.

When I return, I will add ferrites to all the DC wiring that I can access and see what happens.

Once again,,, Thanks to all!

Tony

Solar Guppy

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

For this type of test its important to use real PV panels, not a power supply for the power source. Power supplys have a much lower impedance than actual long wiring and PV panels, they also have filtering on the power supply's output that works to dampen the RF. Even with PV panels, I suspect the hodge-podge of the OP's panels is part of the issue as being a better radiator of the RF

This is very typical of single phase, unfiltered buck designs. Bucks work by chopping up the input voltage with a near square wave transitions. Its these transitions harmonics that are the cause of the RF. I suspect the FETs in this product are very fast, much faster than what is used in the typical 150V charger.

Its unlikely, short of building a secondary metal box, with delta-y caps and a large common mode, common couple choke that you will get the reduction your hoping for. I've been in two company's developing these chargers and meeting emissions requirements for Class B is a big undertaking.

boB, how is your certification going for your new controllers?

boB

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

Solar Guppy wrote: »

boB, how is your certification going for your new controllers?

How did you hear about that ?

boB

Solar Guppy

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

Some old Trace Guys?, No wait the moles work at the other Arlington RE place?, no maybe it was from the recent trade show :roll:


LOL ... I figured if you getting close to releasing your new controllers as posts would indicate you would be in the middle or through it by now

westbranch

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

From:

"The official MidNite Solar Classic watch
Feb 7, 2010

The tracking software boB is completing ........boB is making happy noises, so we assume that means things are working as planned. boB just says “the
competition is going to be pissed”

May 2010 is the planned trigger date."

Tells me it will happen soon as long as boB stays happy:D:D:D

cheers

halfcrazy

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

Yep boB is making happy noises. It is all coming together fast now some of the user interface stuff is really cool and it will talk to you.

54d18

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

I believe that I am the customer that Lorelec mentioned, the one with the
Marine band radio problem, I have tried a capacitor accross the PV wiring
right at the controller, and the noise is still there. It is only there, off and on,
while the controller is operating, it is not there when it is "Sleeping"

My next attempt to correct will be adding a Choke in series with the PV
wiring at the controller.

Anyone have any thoughts or ideas on correcting this problem?

GreenerPower

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

lorelec wrote: »

...If noise if being conducted out wiring, then it's almost definitely on the PV side of things. The battery side of things might have some ripple, but it's triangular in shape and so less prone to generating high frequency harmonics. The input ripple tends to be more of a square wave.

If RF is radiating via PV wires, RF screening won't help since the outside antenna is the one picking those up. Build a small "screen box" around your radio receiver, running it from its own battery if possible. If the noise is still there, definitely it comes from the antenna and the PV wires is radiating it.
Probably trying focus on putting ferrites on PV wires first and do shielding as Bill's suggestions.
GP

icarus

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

Final note,

It seems that both controllers make the noise, with the BS making less by a bit. I think the issue is the PV wiring into the controllers since this is what I changed last week. I probably won't get around to changing anything for a bit,, but when I do, I will report back. I am going to move the PV wires and add ferrites, but I don't want to tear the wall apart until I can get some ferrites, and that will be a couple of months.

Thanks again,

Tony

niel

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

tony,
if in your adding the 1 ferrite that you noticed no improvement at all then i think adding more of them will be the same result. it does not hurt to add them anyway seeing as how down the road it could help alleviate a potential problem seeing as how you are needing a quiet radio noise floor, but the current problem is another matter i fear. it is difficult to diagnose and cure rfi as it is, but doing it via a forum is a shot in the dark.

AntronX

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

If you disconnect PV wire from input of the controller, and I mean physically remove wires from the input terminals of the controller, and not with the A/B switch - does the noise go away or not?

If it does not, then your controller is radiating through the battery side. The interference could be RF or it could be in the form of high frequency DC ripple on the battery bus.

If its DC ripple then its affecting your FM radio through supply power input. To test for that, disconnect the radio from your 12V system and power your radio from separate 12V battery physically located right next to radio.

If its RF noise then disconnect antenna cable from FM radio itself.

If you are still lost, start posting detailed pictures of your setup. We may spot something.

icarus

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

I did disconnect the antenna from the radio and it doesn't seem to have any effect.

Like I said, I am sort of done messing with this for a bit as I've lots on my plate and this comes under the category of,, when time suits.

We are in the middle of spring breakup and therefor island bound until the ice leaves. I t presents a bit of a hardship this year as it has caught us a bit unprepared because it ihas come a month early!

So who says ice is white? (what you are seeing is 10 meters of open water between the shore and the lce. The ice as of night before last was 19", but getting very rotten, and is decidedly unsafe to travel on! The ice turns black as melt water perks down through the pores in the ice, creating candle ice,, ice that may be 2' thick but has no strength. And it fails without warning!)

AntronX

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

icarus wrote: »

I did disconnect the antenna from the radio and it doesn't seem to have any effect

Next try powering stereo from separate 12V battery. I suspect DC ripple based interference. Your car stereo may need few good low-ESR electrolytic capacitors across it's power leads.

Kamala

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

icarus wrote: »

... creating candle ice ...

Having been born, raised and still living and working (and occasionally ice fishing) in Minnesota, I am familiar with rotten ice and black ice (here black refers to the stuff that condenses on roadways from vehicle exhaust gases when temps are well below 0°F. Ghostly, dangerous stuff at speed!)

But I have never heard of candle ice. Makes sense the way you describe it.

We hit 26°C in St. Paul today. Depending on the jet stream, you may be free sooner than you planned. Maybe not. GOD, I love the north country. (OK, Tony, the near north.)

Well, anyway, good luck with your noise problem. And your other projects/commitments.

Enjoy!

BTW, nice pic!

K

icarus

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

I come up with a way cool work around. I bought my self a myine IRA internet radio tuner. It does require me to keep the modem/router on, but it only draws 1000ma @ 9 vdc,, less than 5 watts @ 120vac. It picks up any internet stream or podcast from any radio (or internet) station anywhere!

This little device then feeds into the stereo from an AUX input. (they do make stand alone table radio devices as well). So after a few minutes of programing the IRA, I get all the distant NPR stations directly from the web, as well as my local CBC station. (Plus a billion others should I so desire.

I probably will keep the antennas up, in case the sat modem system goes down, although it would be nice to get rid of the 30' lighting mast on the roof of the house.

So anyone who lives in really fringe area, but has web access should consider this option.
It uses ~ 128kbs of band width to run, not insignificant on a satellite modem where the speeds can fall as low as ~200 kbs when traffic is high. (and your ISP fair access policy may throttle you back). That said, the audio quality is nearly as good as CD, and certainly better than my FM.

Tony

niel

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

you solved it by going around it, which as long as it works is fine. now as to the draw of the modem/router, 1000ma or 1a at 9v is 9w not counting efficiency losses. how do you figure it's less than 5w from 120vac?

icarus

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

The router/modem each draw about 10 watts depending on the transmit power of the TRIA. The internet radio power supply brick, shows ~9vdc 1000ma. The kill-a-watt shows it drawing ~ 5 watts. So the whole shebang, with clear reception is drawing ~12 watts for the Pioneer radio depending on volume, the modem and router draw 20 and the Internet radio draws 5, for a grand total of ~ 37 watts. Depending on the day, the additional draw on the system might be ~100 wh. Not insignificant on my system, but no the end of the world either.

I will get some ferrites sometime this summer and see if I can cure it for real, but this is the real cure for bad reception. (assuming the internet modem continues to work!

Tony