Hi All
Our plan for a months worth of mods has now turned into a summer worth of mods as Francesca is trailer bound on our drive
Anyway question is I was planning on installing a solar charge controller to the left of our galley (26x) in some new boxing, I was also going to install a fm/dab radio in the same boxing, so before I construct the boxing will the SCC cause reception problems for the radio
If so I can move the SCC somewhere else (out of the way) but I love controls in good eyeline not hidden away
Thanks in Advance
—
Stephen and Julia
Francesca
Macgregor 26x (2003)
Hi Francesca,
I think it's unlikely to cause reception problems but as the charge controller uses a digital signal to run the comparator circuit it may introduce noise into the audio circuit of the radio depending on the signal frequency and how well each is shielded. To be on the safe side I would separate them. We have a Pioneer car radio/cd and a simple cheap solar controller on our 26M - the radio is above the table and the charge controller about 2 meters away under the steps and there is no interference.
Mike C Tarka 26M
Hi Mike
I'm struggling to think of were else I could put the SCC where I can still see it
My other half mentioned the head, but I'm not keen
Anyone else got any experience ?
Stephen and Julia
Francesca
Macgregor 26x (2003)
Switch mode power electronics, like charge controllers and most modern power supplies are notoriously electrically noisy. A lot depends on the manufacturers concerned. Both the SCC and DAB radio should comply with EMC (electromagnetic compatibility) standards.
I know we aren't in the EU anymore but the replacement regime isn't in place yet either so:
In theory all electronic products within the EU must comply with two directives.
2014/35/EU The Low Voltage Directive, as amended, and
89/336/EEC The Electromagnetic Compatibility Directive, as amended.
This is normally done by compliance with specific product standards and/or:
EN 61000-6-1:2005 Electromagnet compatibility. Generic standards. Immunity.
EN 61000-6-3:2007 Electromagnet compatibility. Generic standards. Emission.
If this regime were strictly adhered to incompatibility between electronic equipment would be rare but not impossible. However the reality is that many products, even those claiming CE compliance do not conform to the required standards.
I would check the certificate of conformity to see what standards they claim to be designed to. Don't simply trust on the presence of a CE mark they are utterly meaningless, especially as there is also an almost identical Chinese Export mark. The second thing to look for is the country of origin. Products manufactured in Europe are far more likely to comply than those made in Far East, Eastern Europe or the USA.
The simple solution might be to test wire both the SCC and DAB radio and try them in very close proximity. If you can't find a problem then install them as you want.
If you do find a problem try the following:
Wire the supplies to each item separately all the way from the battery distribution panel so that they don't share much common supply current path and route the wiring away from each other (at least 100mm apart helps enormously).
Do the same with any speaker wires coming from the radio.
Use screened wire to connect the supplies and speakers. Connect the screen to 0v (battery neg) at one end only (the end nearest the supply). This shields the wires from acting like aerials.
Place cheap RF cores around the pairs of supply wires, locate these close to the equipment. These absorb a good amount of higher frequency noise.
Place the SCC inside an all metal enclosure (ideally stainless steel for the marine environment). Connect the enclosure to 0v (battery neg). This forms a Faraday cage and blocks almost all radiated EMC issues.
Place local decoupling filters on each of the supply and speaker cables close to the equipment. I can help specify these if you get this far and still have a problem.
If none of these simple measures help then you are in to a world of pain designing a proper EMC mitigation system or buying a different SCC from a better manufacturer.
Good luck,
Dave.
Dave Newton Sailbadthesinner
Blimey ! Steve,
Dave's answer is the most precise and technical you are going to get anywhere - well done Dave.
But I bet you wish you had never asked now !!
I'm sure it will be OK though - once you get it all sorted make sure to post your solution,
Regards,
John
Yes but I cheated, most of the above I lifted straight out of my lesson plan for an EMC training course I (used to) run. Since I no longer have any students to torture I thought I'd make you all suffer instead.
Best regards,
Dave.
Dave Newton Sailbadthesinner
Hi Dave
Thanks for the very thorough answer to a question I was hoping was yes or no
Yes I suffered
John, yes your right that will teach me
Because I cant be bothered with testing the close vicinity of them both and the possible influence, I'm going to install the SCC about 6 foot away above the table aft seat that backs onto the head (so I can run the cables inside the head in trunking then through the wall and straight into the SCC
Thanks again
Stephen and Julia
Francesca
Macgregor 26x (2003)
I like your thinking Dave.
I tried to keep it simple but liked your response. I don't think the cheap (and sometimes not so cheap) little solar charge controllers we all tend to use are too bothered about EN 61000 compliance even when they sometimes quote it in the specs. As you suggested I agree that the only real test is to try it. My experience is its easier to replace a noisy unit if you can rather than try to mitigate the effects - although a makeshift faraday cage can work. I may be a bit bias but my experience is that some eastern companies consider EN and other EU standards as just a 'quality mark' without necessarily the need to demonstrate compliance. I used to regularly see CE marks on things that can't be CE marked. It drives any of use concerned with compliance and performance mad!
Mike - Tarka 26M
Caveat Emptor.
Don't worry once the new UKCA scheme is up and running it won't take long for the far east to start printing the stickers. I did find an Eastern European electrical product with a BSi approval license number that, when I checked, related to a steam control valve last approved in the 1970s.
The problem is often determining if the interference is being radiated or conducted into the victim equipment. I have seen a small fortune spent on RF screening and compliance testing, only to find the noise is coming in on supply cables due to harmonic voltage drops. 'No amount of loft insulation will keep you house warm if you don't shut the doors and windows!'
Dave.
Dave Newton Sailbadthesinner
Dave
Please keep up that level of explanation, I generally get away with my GCE physics and years of playing with/building amplifiers, radios and computers. The occasional read of some proper science directly relevant to something of interest is very useful. These days I can turn to Youtube, but that does require sifting through the rubbish before you find a good presentation. Despit early criticism of Wikipedia, I now find it one of the best sources for information, its system of moderation and referencing seems to be working incredibly well with the articles I research.
Regards Jonathan
Jonathon,
I am the world's worst visionary. When I first heard about Wikipedia I was totally dismissive that it could possibly be of any value. I didn't believe many people with genuine informed knowledge would be willing to contribute and I was certain that it would simply degenerate into a forum for ill informed, indefensible opinionated drivel. I now have to eat my words. I was similarly sceptical about youtube (there I was a little closer to the mark).
I am a cynic who never grew in to a swan.
Dave.
Dave Newton Sailbadthesinner