Solar power and audio

I am seriously considering going with the Tesla solar roof sometime in the next five years. This system converts DC power to AC and uses a battery cell for storage.

If solar systems become somewhat common over the next 10 years how will that change things for audiophiles? Will power plants still be necessary if a majority of the power comes from solar? Will things get more complicated due to integration of the solar panel output, battery output, and grid output?

It may make audio sound better if one harvests the DC direct from the panels and bypass AC to DC rectification which our equipment currently uses. One big challenge would be keeping voltage constant; batteries decrease voltage as they discharge and solar cell output varies constantly with available light.

The systems are fascinating. My neighbors have an expansive restored prairie with a large solar farm. They have both DC and AC outputs. The system is setup to interface with the Tesla batteries once they are available. Neat stuff.

My sense is that most of the inverters that convert DC to AC are really dirty (i.e., chopped waveforms instead of nice sine waves, similar to what you get from a cheap UPS). Maybe they would market audiophile grade inverters. Going direct to the panels/batteries with DC avoids that but raises the issues Elk mentions, plus you need big batteries to lower impedance without voltage sag. These are technical issues and there will be technical solutions but nothing is as simple as it seems.

"My sense is that most of the inverters that convert DC to AC are really dirty "

That is correct. I am offgrid with solar and from experience trying numerous inverters can say that I have failed to find virtually any brand which outputs an audiophile-grade power. As a result I am forced to use some intense power conditioning including dc offset correction. I do have a Powerplant arriving this week. Of course that is a real piece of nonsense in that now I will be using essentially 2 inverters in series: DC from batteries to AC to DC again inside Powerplant and back to AC.

My present inverter was supposedly a world class, best-in-class, inverter but outputs junk. I called the manufacturer in Texas and they knew what the problem was before I described it. All I had to say was “audio” and they answered “it is screwing up your amp? … our inverter outputs a 25kHz control wave on top of the 60Hz sine wave in order to produce a pure sine wave … just buy a conditioning power strip”.

There are virtually no high quality inverters available. The best have distortion specs over 2% and seem to use class D technology.

Paul, if you are out there anywhere, here is a product idea: simply take a Powerplant and add a 12 volt input. The Powerplants at present create DC internally. I need to tap into that. There is a real need for audiophile-grade inverters and basically PS Audio already has such a product but, as explained, it is not truly usable because of input constriction to AC.

Someday the high quality inverter market will be a billion dollar market. All PS Audio needs is to add that DC input jack to fully utilize their unique regenerator/inverter technology.


Welcome, founded!

Interesting stuff.

Have had a solar installation here for 3.5 years but is connected to the grid. Going off grid is uber expensive (roughly 3 - 4 times the up front cost) due to cost of batteries and having to oversize everything account for variable weather conditions. The state government mandated incentive program we’re on limited annual output to our annual demand, so 18 panels worked (85% of demand) and fit the space (above south facing deck that allows for a lean to structure against the house).

The incentive means we get paid $0.24 per kWh for the power we generate versus the $0.14 per kWh we pay for what we use (have 2 meters). The result is we net from the utility roughly $400 per year. It’s a hoot to get checks from the utility! And no worries about the quality of power.

Looked into wind, but up front cost were the same, but here only produced 1/3rd the power and being mechanical could (and often do) breakdown, having placement restrictions, and possible complaints from neighbors. Even looked into geothermal for space heating/cooling when we built 15 years ago, but it irked me to no end that below 20F it converted to running off electric resistance + furnace fan. Nowadays would consider newer geothermal technologies or the latest in mini-splits if starting over.

Speaking of which we also have a whole house automatic standby generator (grid connected solar shuts down with loss of utility power so repair workers don’t get zapped). Haven’t noticed any power aberrations while it is serving the house. Adding a whole house automatic standby generator is still way cheaper than going off grid.

I have had a 10kw Solar System that is Grid Connected for four years now. With the addition of the P-10 Power Plant I can tell you that there is NO Difference in the Quality of the AC that I get from the grid or my Fronius Inverter. I always run about 3% THD before the P-10 Cleans it up. Solar is great for the Planet but my experience is that the cost ends up being about the same as before I added this system. In the long term some savings may show up as the rate I pay to the Solar Company is fixed while the utility rates are open to increases. The P-10 made a huge difference in the sonic performance of my system.

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“It may make audio sound better if one harvests the DC direct from the panels and bypass AC to DC rectification which our equipment currently uses. One big challenge would be keeping voltage constant; batteries decrease voltage as they discharge and solar cell output varies constantly with available light.”

Those were once my thoughts. However, even transmitting DC in a house requires large gauge wire. But there is one audio component that I do run straight off the DC: the David Berning design BAM-235 power amp built by Milbert designed for automobiles and 12 volt input. It is spectacular. According to Mr. Milbert, I am the only owner he knows of who runs such a setup. And I do have the exact problem described in the above quote … my DC voltage varies with the battery charge controller. The Milbert is designed for a max input of 13.9 volts but the charge controller runs the voltage up to 14.2 volts during peak charging. That caused me to burn out the Milbert once. Of course a voltage regulator would solve that problem. Basically at present I can only run the Milbert after the batteries reach full charge. AC does have some benefits as Mr. Tesla knew.

“Maybe they would market audiophile grade inverters.”

Here we are on the PS board. Who is “they”? And here I am waiting for Fedex to deliver a new Stellar Power Plant P3. It should be here within an hour. The published specs of the P3 indicate it will beat any other commercial inverter intended for residential usage.

The way I figure is that a regenerator is basically two inverters (AC to DC then DC to AC) bolted together with an amp thrown in for spice. So I have my table saw setup with a diamond blade so I can cut the P3 in half and use the DC to AC part on my solar array.

Seems PS is into the Blue Ocean stuff. I do not really know about oceans in Colorado other than the Blue Sky stuff, Skies Unlimited. At present PS is a prisoner of the box of their dreams … the high end audio thinkbox. No doubt we will see increasingly expensive traditional components as PS continues to grow. Can they grow outside of their dreams? I think they have no idea that in the inverter market of solar they potentially have a Rolls Royce product. Nobody else even comes close.

Now that P3 box should be here in a few minutes. I must be getting one of the first units. After I get the P3 sawn in half I am going to call PS engineering department and find out what the internal DC voltage runs at, grab me a step-up DC to DC converter, and I will be in absolute sound heaven.

P.S. It seems somebody took me too seriously about my diamond saw blade (see post below). I did call my solar system designer and asked about typical solar DC arrangement. The answer was that the majority of systems are 48vdc. The rest are either 24vdc or 12vdc. My two systems are both setup as 12vdc. Nobody has 540vdc battery banks. We are talking about from battery bank to final interior use. Feed from my main solar array to the house is somewhere circa 100volts but that has virtually nothing to do with this discussion. I partially designed both of my systems and personally installed both of them. One is 10 years old and the other is 5.

Solar systems output approximately 540 volts DC that the inverter converts to 240 and 120 volts AC. High voltage DC is even more dangerous than high voltage AC not something anyone should ever want to mess with. One of the PS power Plants do the job intended very well without endangering ones life.

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Reviving this;
Currently listening to Eagles - Out of Eden powered by solar/battery on a cloudy day in ADELAIDE, South Australia.
System consuming about 250w /hr (overnight total consumption is about 500w /hr with system in standby). Been very wet so the battery isn’t very well charged atm, mostly running off the grid.