Cascadia solar controller whine/RF interference? Snake oil works?

[LittleDog]

The mppt controller makes a tiny whine when charging the battery sometimes. It isn't that bothersome on its own, but my CB radio is picking it up on all channels, and it messes with the channel scan. Weirdly, GMRS wired in series with the CB to Aux 3 and chassis doesn't seem to pick up anything.

My wires are everywhere right now, as I haven't decided on final locations yet. I'm worried that some of those crazy loops and twists are exacerbating the problem:

I stuck all the loose ferrites I could muster onto the wiring going in and out of the solar controller, and it actually reduced the interference maybe 80%.

Had to give up for the day as stupid clouds kept passing by every few seconds and changing the controller output, so I couldn't tell what variable was changing. More sun equalled more whine.

The ferrites are bulky and I am already limited by wire length so don't really want to get larger ones and start looping more. Any ideas?

I'm still going to get more, and various-sized ferrites, since this was as good a real-world example as I've ever seen that they work. Could always start making a necklace towards the battery.

And probably (maybe) change the radio ground from the classic "little hook that you bent into the wire after extra-twisting it in your fingers" to a proper connector.

Are there regulators or something that people use to help isolate the RF noise for charge controllers? Would that reduce solar generation, but also keep electronics happier?

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[Left Field]

Chasing radio noise always seems like a black art to me but I've usually had some success after trying a few things. The ferrite clamps are always a good starting point.

Some more ideas to try:

1) Disconnect the CB antenna and listen (no mic!). If it's quiet, then the noise is radiated by the wiring and is being picked up through the antenna. If it's still noisy, then its 'conducted' and is being fed through the power wiring. This can help you know what to attack.

2) An alternate method is to power the CB from a different (separate) battery. If the noise goes away, that could confirm conducted interference coming in through the 12V leads.

3) Twisting power/ground wire pairs (solar and CB) can sometimes help as it reduces the radiated emission by cancelling out the radiated noise signal on the wire pair.

4) Adding a small capacitor across the each power and ground pair near the CB and near the solar controller inputs and outputs can help short out high frequency noise. Experimentation with capacitor sizing can help. 0.1 to 0.5 mfd might be a decent starting point.

5) Changed wire routings. Sometimes keeping wire pairs near/along metal chassis can help and of course increased distance between CB power and the solar wiring.

6) Moving the ground points. Sometimes it can help to have the ground originate near the power source, but not always. Sometimes a very short, stout ground works best.

7) Mount the MPPT controller. Having a direct controller case to chassis ground may help shield or shunt off some of the electrical noise emissions.

8) Contact the controller tech support. They may be able to offer filtering, wiring or installation tips.

9) Try a different CB. Some models do not have particularly good noise rejection.

Good luck!

 

[LittleDog]

Chasing radio noise always seems like a black art to me but I've usually had some success after trying a few things. The ferrite clamps are always a good starting point.

Some more ideas to try:

1) Disconnect the CB antenna and listen (no mic!). If it's quiet, then the noise is radiated by the wiring and is being picked up through the antenna. If it's still noisy, then its 'conducted' and is being fed through the power wiring. This can help you know what to attack.

2) An alternate method is to power the CB from a different (separate) battery. If the noise goes away, that could confirm conducted interference coming in through the 12V leads.

3) Twisting power/ground wire pairs (solar and CB) can sometimes help as it reduces the radiated emission by cancelling out the radiated noise signal on the wire pair.

4) Adding a small capacitor across the each power and ground pair near the CB and near the solar controller inputs and outputs can help short out high frequency noise. Experimentation with capacitor sizing can help. 0.1 to 0.5 mfd might be a decent starting point.

5) Changed wire routings. Sometimes keeping wire pairs near/along metal chassis can help and of course increased distance between CB power and the solar wiring.

6) Moving the ground points. Sometimes it can help to have the ground originate near the power source, but not always. Sometimes a very short, stout ground works best.

7) Mount the MPPT controller. Having a direct controller case to chassis ground may help shield or shunt off some of the electrical noise emissions.

8) Contact the controller tech support. They may be able to offer filtering, wiring or installation tips.

9) Try a different CB. Some models do not have particularly good noise rejection.

Good luck!

Thanks for the helpful recommendations. To address each point:

1) I forgot to mention that I did test without antenna. Mic was attached though.

2) Didn't test with another battery, but it is definitely the charge controller, as I can hear the tiny whine coming from the box correspond exactly with the speaker interference. Also, the interference stops as soon as I unplug power from the solar panel. CB was fine before the panel.

3) My cables are twisted, but pretty loosely; perhaps one turn in 3-4". I'll try closer turns.

4) This is above my pay grade. If all else fails, I might hit the books and give this a shot, or find someone smarter to help.

5) Yeah , I noticed that the interference would change as I moved things around, like moving a radio/touching an antenna Unfortunately, the Auxiliary power lines and the chassis bolt I used are right behind all of my cable loops coming in from the panel.

6) I found a random, thick, green ground cable that I'll try patching in. But that chassis bolt under the door check-strap hook seems the best spot the way I have things now.

7) I didn't think of this. I'll try grounding the brain-box first.

8) Will do, if I keep having problems.

9) I've a few laying about, but I'm pretty certain it is just the charge controller at this point. Currently it is a President McKinley I put in a few months ago is pretty fancy though, so maybe older models are less sensitive.

Thanks for all the suggestions.

 

[Left Field]

If you haven't tried it already, might be worth trying a couple ferrites on the CB 12V and ground inputs - closer to the CB the better.

Twisting the 12V wires is primarily for preventing them from acting as a transmitter antenna for interference created within the controller. Based on the disconnected antenna test it appears it may not help much but it won't hurt either if its easy to do. Some folks get some success from wrapping the wire pairs in foil or braided wire shielding, but again that is along the lines of the twisting. Won't hurt but may or may not help.

Another possibility (if any feasible options exist), is to maximize the separation between the 12V CB wiring and the solar wiring, including where the power and ground connections are made to the vehicle.

The charge controller sounds pretty confidently to be the culprit; the only reason for a CB swap would be as you had mentioned - the possibility of a different unit being less sensitive / better immunity from electrical interference.

Maybe some of the ham folks will weigh in with a few more tricks up their sleeve...

LF

 

[Blade1668]

It's a PTA but try wrapping the ground and power wires with metal shielding wrappings, temp you can try aluminum foil just don't "ground out hot wires with it. It could help if it does then you can get insulated foil to do it with for permanent fix.

 

[JimLee]

You might just have a bad MPPT controller, mine makes zero noise, audible or comms interference.

 

[LittleDog]

I received a bunch of clip-on ferrites a few days ago, in 5,7, and 9mm cable sizes. I went crazy and put them on willy-nilly.

The main problem has been intermittent cloud cover these past few days. I've been unable to test at full load. What worked the first day turned out to be horrible the second day.

After many adjustments, it seems good now, but I'll need to wait for the next super sunny day.

@Blade1668 do you mean that aluminum wrap with the bubble wrap in-between?

 

[LittleDog]

You might just have a bad MPPT controller, mine makes zero noise, audible or comms interference.

Where is yours mounted? I didn't notice noise until I put it in the cabin. Didn't notice any noise when it was under hood, but moved it due to overheating.

I hope it isn't the controller, I hate dealing with warranties. I waited 7-8 months after purchasing before weather got warm enough to install.

Controller seems to be working correctly, but I'll try to figure out how to take some readings when the sun comes out.

 

[Blade1668]

I received a bunch of clip-on ferrites a few days ago, in 5,7, and 9mm cable sizes. I went crazy and put them on willy-nilly.

The main problem has been intermittent cloud cover these past few days. I've been unable to test at full load. What worked the first day turned out to be horrible the second day.

After many adjustments, it seems good now, but I'll need to wait for the next super sunny day.

@Blade1668 do you mean that aluminum wrap with the bubble wrap in-between?

Just some aluminum foil, I'm not sure the bubble wrap would work. But I've seen metal foil shielding wiring before to block RF interference

 

[JimLee]

Where is yours mounted? I didn't notice noise until I put it in the cabin. Didn't notice any noise when it was under hood, but moved it due to overheating.

I hope it isn't the controller, I hate dealing with warranties. I waited 7-8 months after purchasing before weather got warm enough to install.

Controller seems to be working correctly, but I'll try to figure out how to take some readings when the sun comes out.

Mines under the hood, but I've been under there many times looking at the lights and working on other things while it was charging and I never heard it whine. It may be something thats cyclic that ive never heard, id have to admit, but is yours cyclic or constant? Ive also got my MPPT conected to the same common terminals on my battery as my CB and im getting no radio interference. Believe me i was curious when I first installed it, ive been in aviation avionics for over 30 years now and radios are a big part of our job, as is EMI protection and prevention. I'll listen to mine again in the morning when its got full sun and its cool out, maybe its just something ive missed. I think it's possible that you may have some interference going from running those MPPT cables into the cab, but if your contoller is whining and mine is not it might be worth considering. I'll let you know.

 

[LittleDog]

Mines under the hood, but I've been under there many times looking at the lights and working on other things while it was charging and I never heard it whine. It may be something thats cyclic that ive never heard, id have to admit, but is yours cyclic or constant? Ive also got my MPPT conected to the same common terminals on my battery as my CB and im getting no radio interference. Believe me i was curious when I first installed it, ive been in aviation avionics for over 30 years now and radios are a big part of our job, as is EMI protection and prevention. I'll listen to mine again in the morning when its got full sun and its cool out, maybe its just something ive missed. I think it's possible that you may have some interference going from running those MPPT cables into the cab, but if your contoller is whining and mine is not it might be worth considering. I'll let you know.

Thanks, and you're probably correct about my haphazard wiring into the cab. The Cascadia wiring comes in alongside a GMRS cable and PA speaker cable, and the radio antenna is on that side too. I noticed sometimes heavy AM interference yesterday.

It wouldn't be noticeable under the hood, I think. But in the cabin, in the passenger footwell, it drove me crazy. The dog looked at it cock-eyed for quite a while, until I unplugged it.

Mine emits a constant high-pitched whine, sometimes warbling squeal, not cyclic, when charging. Volume is definitely correlated to sun intensity. Controller noise is duplicated exactly in CB radio interference, but confusingly not on GMRS, even though the two radios are daisy chained.

Funny thing for you, on CB channel 19 a year or so ago, I picked up an airliner calling out altitudes while coming in for a landing outside of Newark EWR. I was going down the Turnpike, and the entire time I wanted to tell them, "your radio is bleeding everywhere!" but didn't want to deal with a potential, enormous, FAA fine. Does that sort of thing happen often?

 

[JimLee]

Thanks, and you're probably correct about my haphazard wiring into the cab. The Cascadia wiring comes in alongside a GMRS cable and PA speaker cable, and the radio antenna is on that side too. I noticed sometimes heavy AM interference yesterday.

It wouldn't be noticeable under the hood, I think. But in the cabin, in the passenger footwell, it drove me crazy. The dog looked at it cock-eyed for quite a while, until I unplugged it.

Mine emits a constant high-pitched whine, sometimes warbling squeal, not cyclic, when charging. Volume is definitely correlated to sun intensity. Controller noise is duplicated exactly in CB radio interference, but confusingly not on GMRS, even though the two radios are daisy chained.

Funny thing for you, on CB channel 19 a year or so ago, I picked up an airliner calling out altitudes while coming in for a landing outside of Newark EWR. I was going down the Turnpike, and the entire time I wanted to tell them, "your radio is bleeding everywhere!" but didn't want to deal with a potential, enormous, FAA fine. Does that sort of thing happen often?

Ok, so I've checked it (MPPT controller) twice this morning, both times it was actively charging and there is no noise at all I even pressed my ear up against the unit itself and heard nothing. This is with the vehicle not running and nothing else turned on. I personally think you have a noisy MPPT controller that is inducing that noise onto the power line. Now, will a manufacturer warranty that, that's an unknown. Some manufacturers don't consider electronics noise to be a failure condition on these consumer grade components as long as all other functions are working properly. I would double and triple check the ground your MPPT is connected to as grounding problems can lead to noise. If you don't want try and get a new one I myself would replace the majority of the wiring from the MPPT controller to the batt with a twisted shielded pair of wire, but it is important that if you do this the shielding be grounded at both ends. If you want to go this route I can help you make sure the twisted shielded pair is installed and grounded correctly. Now, is your MPPT controller whining all the time when charging, even with the vehicle and all accessories off? Or can you only hear it while running and or with certain things turned on? I believe from your above statements that it is all the time but just want to be sure. The reason I ask is that there is always a possibility that something else is inducing the noise onto the MPPT power circuit.

All my experience in aviation has been on the military side, but I know commercial aircraft use the same or very similar radio systems as ours, slightly less technical as they don't do things like encrypted secure voice or frequency hopping, but I have seen the transmission tuners on military grade equipment drift so far as to bleed onto other radio bands, it's not common but it happens.

 

[LittleDog]

Ok, so I've checked it (MPPT controller) twice this morning, both times it was actively charging and there is no noise at all I even pressed my ear up against the unit itself and heard nothing. This is with the vehicle not running and nothing else turned on. I personally think you have a noisy MPPT controller that is inducing that noise onto the power line. Now, will a manufacturer warranty that, that's an unknown. Some manufacturers don't consider electronics noise to be a failure condition on these consumer grade components as long as all other functions are working properly. I would double and triple check the ground your MPPT is connected to as grounding problems can lead to noise. If you don't want try and get a new one I myself would replace the majority of the wiring from the MPPT controller to the batt with a twisted shielded pair of wire, but it is important that if you do this the shielding be grounded at both ends. If you want to go this route I can help you make sure the twisted shielded pair is installed and grounded correctly. Now, is your MPPT controller whining all the time when charging, even with the vehicle and all accessories off? Or can you only hear it while running and or with certain things turned on? I believe from your above statements that it is all the time but just want to be sure. The reason I ask is that there is always a possibility that something else is inducing the noise onto the MPPT power circuit.

All my experience in aviation has been on the military side, but I know commercial aircraft use the same or very similar radio systems as ours, slightly less technical as they don't do things like encrypted secure voice or frequency hopping, but I have seen the transmission tuners on military grade equipment drift so far as to bleed onto other radio bands, it's not common but it happens.

Thanks for the offer! You've already been a big help.

I added a ton of ferrites and moved some of them around, then added a few more twists and re-ran the ends of the controller wires. The noise from the controller itself is 99.8% gone.

Still have a lot of ferrite chokes left over, so I've been sticking them on everything. CB doesn't get anything from the controller, and has never been quieter!

Only tradeoffs: I'm getting a lot of weird squeals and warbles on AM radio now, that don't match any other noise. That, and there is so little slack in the wires now, my mounting options are limited.

Before all the ferrites, I did notice that the controller noise was modulated by location, as I could move it around and the tone and intensity would change. Maybe I can make it an off-road theremin.

Thunderstorm just chased me back inside, but tomorrow looks like a super sunny day. Hopefully I'll have time to throw more magnets at jeep gremlins then.

Thanks again for your all your advice.

 

[JimLee]

Thanks for the offer! You've already been a big help.

I added a ton of ferrites and moved some of them around, then added a few more twists and re-ran the ends of the controller wires. The noise from the controller itself is 99.8% gone.

Still have a lot of ferrite chokes left over, so I've been sticking them on everything. CB doesn't get anything from the controller, and has never been quieter!

Only tradeoffs: I'm getting a lot of weird squeals and warbles on AM radio now, that don't match any other noise. That, and there is so little slack in the wires now, my mounting options are limited.

Before all the ferrites, I did notice that the controller noise was modulated by location, as I could move it around and the tone and intensity would change. Maybe I can make it an off-road theremin.

Thunderstorm just chased me back inside, but tomorrow looks like a super sunny day. Hopefully I'll have time to throw more magnets at jeep gremlins then.

Thanks again for your all your advice.

No problem, I think the AM problem is just the proximity of the wiring to the factory radio antenna cable. Let me know if you need any more help/suggestions, I'm happy to help where i can.

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