Interference from solar power

[trackman]

I fitted a new panel recently to double our solar power. At the same time I put in a new Tracer solar controller, to cope with the extra power.

We now have 136W of panels wired in series, so the voltage can go up to over 40 in good sun.

Annoyingly the set up now interferes with our FM radio as soon as there is any significant power there.

The old system with a cheap controller off eBay didn't do this. Both controllers are MPPT btw.

Does anyone have any ideas about how to stop this problem please?

[matty40s]

I havn't heard of this happening with solar controllers.

Maybe it is the panel, all you could do is connect each separately to find out when the interference occurs to pinpoint the culprit??

Are you still using the old controller?

 

Do you have LED's that perhaps are not coping well with the increased voltage?

 

edited to add...

Do you have a MSW inverter?? A possible solution is to twist the DC cables, or shield them (tin foil perhaps??)

 

http://forums.energymatters.com.au/solar-wind-gear/topic462.html

Edited November 24, 2013 by matty40s

[pearley]

My Tracer has done this since I installed it so would assume it is the controller, not panels as we probably have different makes. Generally not a problem as we usually listen to DAB but here in Salthouse Dock there is no National DAB, only local.

 

At least we no that the panels have come on line in the morning!

[Rich]

Annoyingly the set up now interferes with our FM radio as soon as there is any significant power there.

 

We have the same problem and when I mentioned it to our supplier, panels and Tracer, he said that it would be the controller and he could arrange to alter the frequency of the controller to try to alleviate it.

 

As we are now on moorings for the winter with a landline hookup and so no panels we ahven't gone any further but may do next year.

[trackman]

Thanks for the replies all. It looks as though it is the controller from what had been said.

Our experience suggested that very clearly as we could hear the noise on the radio come on as the daylight strengthened in the morning bringing up the power on the panels. Pulling out a connector in the panel wiring stops it too.

A search on the net confirms mppt controllers are likely culprits, as are inverters, but since this happens even when our inverter is totally isolated, it can't be that. The controller is anyway the only new bit of kit beside the 2nd panel.

The expert comment on line says that panels and their wiring make excellent aerials transmitting the RF interference from the controller nicely.

I've emailed the panel supplier for advice.

[Nickhlx]

The bane of a Radio Hams quiet life...

 

I would guess putting extremely large chokes in each lead immediately next to the MPPT Controller, with each being in a shielded box, might slug the interference.

 

I am currently battling with an Immersun I2, which radiates badly on anything below about 10 Mhz, as the output waveform is chopped, leaving sharp edged harmonics on the wiring... and it DOES have already a pretty large filter within the box...

 

Nick

[smileypete]

OP might try some clip on ferrites on the PV and batt leads as close as poss to the unit, plenty on Ebay:

 

http://www.ebay.co.uk/sch/i.html?_nkw=clip+on+ferrite

 

And as others say try twisting/tieing PV cable pairs together, and batt cable pairs together, to minimise 'loop area'.

 

 

Nick

I am currently battling with an Immersun I2, which radiates badly on anything below about 10 Mhz, as the output waveform is chopped, leaving sharp edged harmonics on the wiring... and it DOES have already a pretty large filter within the box...

 

Maybe try a couple of chunky common mode chokes, close as poss to the unit with some low ESR caps across the inputs and outputs.

 

cheers, Pete.

~smpt~

Edited November 24, 2013 by smileypete

[trackman]

Thanks again all. Think I'll start by trying some ferrite chokes on the cables as suggested.

[Sierra2]

Does distance between wiring have any effect?. Is there anything you can do on install to minimise problems mentioned?

 

Also would a VHF radio set be effected?

 

Chaz

[Chalky]

The controller should have been tested to meet European EMC (electro magnetic compatability) regulations that mean that it shouldn't interfere however the installation will affect it. It should contain circuitry to stop the problems by conducting noise to earth and this may be where the problem is. The circuitry may be working correctly however poor earthing means that the earth is now re-radiating the noise. Try replacing the earth wire with as short as possible (even consider changing the other wires to allow this) and be as large a cross section as you can get - ideally braid. You're not looking a the current carrying capability - it's the cables ability to carry radio frequency signals.

Edited November 25, 2013 by Chalky

[FidoDido]

Ah - so thats why I can only get the radio to work occasionally!!! I thought it had gone duff, and would need replacing!

[Chalky]

Ah - so thats why I can only get the radio to work occasionally!!! I thought it had gone duff, and would need replacing!

 

In the automotive industry a few years ago it used to be common to have a single earth wire that was like a Christmas tree connecting a number of devices together. EMC problems usually resulted and the fix was usually to earth the parts properly - ideally by bolting them directly to the body. Try the earth first because without it any other fix is probably going to fail.

[Colin North]

I can vouch for the problem regarding amateur radio. With an MPPT controller the extra power gleaned from the solar panels is fed in as pulses. As the battery becomes more charged the pulse repetition frequency reduces to a 'tick' (2-3 time per second). The only cure I have found if I want to use my amateur equipment during the day is either disconnect the panel(s) or throw a rug over them. As stated earlier - the RF interference stretches way up into the VHF part of the spectrum as witnessed on an FM radio - SWMBO listening to HeartFM. I have not found a cure as any 'slugging' of the lines, either before or after the controller will reduce its effectiveness.

As I normally only use my amateur radio equipment after dark I can live with the problem.

As far as HeartFM is concerned, we move the FM radio to the opposite end of the boat and all is OK.

 

Colin G4GBP

[trackman]

Posts on line say that regulations about RF interference are much less stringent for low voltage DC appliances and so manufacturers of such can get away with this sort of thing. Not great!