SSB noise from solar panels

[TreblePlink]

Originally Posted by Cadence

Is the IEEE still around? Whoever said sinewaves don't have harmonics should do some more reading.

Sorry, but the very definition of a sinewave means no harmonics. Fourier analysis will prove that. Now if something downstream modifies the sinewave, even slightly, then harmonics develop. A triangle wave is rich in 2nd harmonics. A square wave is rich in 3rd harmonics. A pure sinewave has no harmonics. As the sinewave deviates from perfect, harmonics develop. Many practical "sinewaves" are imperfect.

[transmitterdan]

Um...a triangle wave has only odd harmonics. No second, fourth, sixth, etc.

A sawtooth has all types of harmonics.

[Cadence]

Originally Posted by TreblePlink

Sorry, but the very definition of a sinewave means no harmonics. Fourier analysis will prove that. Now if something downstream modifies the sinewave, even slightly, then harmonics develop. A triangle wave is rich in 2nd harmonics. A square wave is rich in 3rd harmonics. A pure sinewave has no harmonics. As the sinewave deviates from perfect, harmonics develop. Many practical "sinewaves" are imperfect.

I guess you are correct if you can find a perfect sinewave other than in theory.

[Jim Cate]

Haven't looked recently, but many public libraries used to carry QST, the ARRL publication. But I suppose that in this internet environment, going to a library is unlikely to appeal!

(The above info relates to myself as a very young ham who couldn't afford to join! Simple arithmetic will show that it was a rather long time ago!)

Jim

[TreblePlink]

Originally Posted by transmitterdan

Um...a triangle wave has only odd harmonics. No second, fourth, sixth, etc.

Thank you for that correction,

[mcerdos]

I have the same issue and am wondering if a solution was found other than turning off the MPPT unit?

[hasse_A]

I had the same problem with my MPPT-regulators.
They went overboard and I replaced them with Sunkeeper PWM which are very quiet. The RFI problem is gone.

[Nicholson58]

Originally Posted by jhe

Hi, I have 400W of solar installed at the stern of my boat which is connected with a Victron MPPT 150/30 controller. I get a lot of noise from this when using my SSB. Is there a way to eliminate this or do people just turn off the solar when using the SSB?

I installed my solar and MPPT controllers with 2-pole circuit breakers. Panels and controllers can be easily shut off any time. This is also convenient for any maintenance necessary. Warning, panels off before controller off. Controller on before panels on.

MPPT controllers work using high speed switching that can cause radio interference. The same is true for PWM lighting. If the switching is in the frequency concerned you will hear it. Most manufacturers realized this some years ago for VHS radios and changed the switching frequency.

[Kolchac]

Noise is generated by Victron. If you decided to connect for example two batteries 20v sequential (which is wrong) instead of parallel, you will need such device as Victron to lower 40v to 13v. To do it without big losses you need electrical transformer, which works with AC only. So you must convert DC to AC before transformer and AC to DC after. If you have fantastic (not existing) equipment you will loose more than 30% on these two conversions.
About the noise. The first step of DC to AC conversion is generating square form of signal. Vertical spike has a spectrum with infinite number of harmonics (white noise), which is a perfect source of problems. Love Victron - live with it.

Generally about a solar. Consider it as a current supply, (not voltage). If you have discharged battery 11v, you can connect directly, without controller solar 20v. Voltage on the battery will be around 11.2v and continuously increasing to 13.5v. At this point you need a controller to disconnect battery and solar.
Who explain me why do you need Victron?

[wholybee]

Originally Posted by Kolchac

Who explain me why do you need Victron?

Not Victron Specifically, but an MPPT controller. The simple explanation. A 100W panel with 20Voc, with max sun, can produce 100W. But it does so on a curve. Loaded down to 12V, it will produce less. And of course at 20V (open circuit), it will produce 0 watts. That 100W is going to be produced in the middle somewhere, probably around 15-17 volts. An MPPT controller will find the voltage where the panels produce the max current and keep the panels there, while then providing the battery with the voltage the battery needs. So, even though a direct connection doesn't have the conversion loss, the MPPT actually gets more power into the battery than a direct connection will.

[Kolchac]

[QUOTE=wholybee; A 100W panel with 20Voc, with max sun, can produce 100W. ...
An MPPT controller will find the voltage where the panels produce the max current .[/QUOTE]

1. You will never get from 100w solar 100w of the energy. 100w of the solar goes from the calculation: they take known irradiation from the Sun on a square meter of the Earth without taking into account atmosphere, altitude and latitude. So if you move Everest to the equator you might have 100w in astronomical noon on the summit.
At the latitude of 40 degrees at noon and 90 degrees positioning the 100w panel, I got a max 7.3 A at a short load. On the 11v battery - 5.5A.
2. The max current from the panel will depend only on the load. Any passive device between the panel and a battery will increase the load, and reduce the current.

Now, when you do need Victron or similar. If you have a solar panel let's say 20v, 10,000w, which can keep on your battery 20v, which will cook your battery.
In real life, 100ah battery can take 25A of current. Use just a simple electronic controller, which eats very little energy, and disconnects the solar from the buttery when it is overcharged. Even if you have 500w panels, and you are crossing the equator, just disconnect one or two panels, other way the controller disconnects all.

Simplicity is beauty, do not use a microscope instead of a hummer.

In previous post i made a mistake:
"two batteries 20v sequential" should be: two panels 20v in series