VHF interference from BZ MPPT solar panel controller

[sailrj]

I have a 50 amp BZ MPPT controller on 2- 230 watt, 24 volt solar panels and get a constant output to my fixed and hand held VHF radios and anyone else within 500 yards. Turn the panels or controller off and interference goes away. Anyone got a solution short of a couple of large ferrite suppressors on the #2 awg feeds to the batteries?? Help, we're heading south down the TennTom and there are not a lot of marine electronic shops

[goboatingnow]

Originally Posted by sailrj

I have a 50 amp BZ MPPT controller on 2- 230 watt, 24 volt solar panels and get a constant output to my fixed and hand held VHF radios and anyone else within 500 yards. Turn the panels or controller off and interference goes away. Anyone got a solution short of a couple of large ferrite suppressors on the #2 awg feeds to the batteries?? Help, we're heading south down the TennTom and there are not a lot of marine electronic shops

Ferrites won't help. It's probably radiated directly. Try extra mu metal shielding or putting it in a big metal box with cooling. It's just bad switcher design , most likely when the switcher in the mppt is either nearly saturated or light loaded

Given the interference goes out to 500 yards and the1/x relationship, boy something wrong or very very Bad design. It may have to be junked.

No easy fix.

Dave

[Paul Elliott]

If ferrites haven't been tried, on *all* wires going to and from the controller, then I suggest that these may indeed help. It's the wires that act as antennas. With the antennas "disconnected" by the ferrites then you only have the circuit board and components as possible noise emitters. The dimensions of these are small enough that the emissions may be significantly reduced.

Putting a metal shield (mu-metal or otherwise) around the device will accomplish very little unless you filter and bypass the wires to the shield. I used to do this stuff for a living when I was designing electronics products. Mu-metal by itself can shield close-in magnetic fields, but it doesn't sound like this is your problem.

I do agree that this sounds like very bad interference, which may indicate a defective controller, or perhaps a poor controller design.

The best approach for ferrites is to run the positive / negative pairs through the same core. With #2 wires you may have difficulty finding ferrites large enough. Depending on the ferrite material and the current level, it's probable that running a single wire through a core will be OK.

[goboatingnow]

I was actually being a little facetious about the shielding. However getting ferries right is not an easy task. There are probably harmonics all over the place. In my view something is wrong here.

Dave

[Dsanduril]

Controllers are by nature somewhat noisy, careful design is required to mitigate. As far as I know, Xantrex and Morningstar are the only MPPT controllers currently available with FCC Part 15 Class B type certification. Without that you're taking the word of the manufacturer that they put it together right.

Living with what you have I too would start with ferrites. Northern Arizona Wind and Sun carries some that fit 0.5" OD cable (along with some smaller sizes). Good luck.

[sailrj]

Very much appreciate everyone's input and glad to know this is not totally uncommon. BZ has made a couple of suggestions, the first was a "filter" in the supply line from solar panels and was a dyi coil of single strain #10 wrapped around a piece of rebar. Did not have any affect. The current recommendation if to install a CB radio filter in the solar panel supply lines to the controller. Not a lot of money and I can get one at Radio Shack- worth a try? I've ordered the suppresors from Arizon Solar and will try that also. Any other thoughts would be greatly appreciated. May have to install a new controller. Thanks again.

[sailrj]

Getting Better!!

The VHF radio interference from the solar panels is still not perfect, but much better than my last post. I twisted the solar panel output pair together and the mppt controller output pair together, added ferrites at the panel and on the controller output. Will be adding the CB radio power filter later this week and hope that helps as well. Will post the final verdict later.

With a little searching the internet, it still amazes me how common this problem is, yet not discussed that much either. Thanks again for all ideas and if anyone else has a suggestion, please share.

[dugout]

Make sure you eliminate, minimize, or address any possible ground loops.

[jeremiason]

We been having a similar problem with our Blue Sky controller and the SSB for over three years. Everytime the output exceeds 5mps you get terrible noise on the SSB speaker.

I have tried frerrites and chokes at both the controller box and the SSB radio, without success.

I finally surrendered and just turn of the breaker between the controller box and the batteries when I am using the SSB, which silences the noise.

I have two ICOM VHF radios on board with seperate antennas and have never heard any noise over them.