Article: The Audio Impact of Solar Panels and Battery Backup: Introduction, Installation & Initial Listen

[Jud]

I’d expect THD slightly worse than the 2% maximum required of most utilities for grid power. I doubt it will make much difference, because the major factor is not external power quality, it’s the noise from internal sources like LEDs, small appliances, the refrigerator, etc. (which is why it’s nice to have a separate circuit for the audio system).  And then of course there are interactions within the system.

 

Congratulations on setting up your solar and battery backup systems. Entirely apart from your audio system, the increased peace of mind will be invaluable.

 

Our house has a solar photovoltaic system and is prewired for backup batteries on the garage wall when we choose to do that. The house was built “green,” so we needed an installation of less than 4kw capacity to provide 100% of our usage (net metering basis). There’s plenty of room for more (Pueblo style house, flat roof with low parapet that shields panels from street view), so we’ll likely add more when we do batteries.

[Jud]

33 minutes ago, austinpop said:

 

Wow, if 4kW meets your usage in New Mexico, you must have a really efficient home. Well done!

 

Congratulations go to our contractor, former head of the New Mexico Green Builders Association. We talked to a family he built a home for before we decided to go with him, and they said “He’ll listen, so he’ll do it the wrong way if you insist, but first he’ll explain to you why he wants to do it the right way.” 🙂

 

33 minutes ago, austinpop said:

 

One of my pending experiments is to chase down what seems like a 1.1kW "ambient" draw in my house. Not sure what accounts for that, but I need to wait until all the civilians in the house are safely away before doing a breaker by breaker analysis. Data is fun!

https://sense.com/thisissense?utm_source=google&utm_medium=&utm_campaign=Non-Brand-SmartShopping&utm_term=&utm_content=&gclid=EAIaIQobChMIwou_hYX78wIVcm5vBB2mkgfOEAQYAyABEgJNO_D_BwE

[Jud]

35 minutes ago, PeterG said:

4kW or 40kW?  If 4, please share (lots) more details.  Thanks!

4, but (dirty little secret) heat is in-floor radiant from a tankless propane boiler and hot water is from the same boiler. The radiant heat (6 zones) is all run by 6 Nest thermostats that have an algorithm specifically for in-floor radiant heat. The algorithm takes care of everything; I told it what temperature I wanted in each zone 4 years ago and haven’t had to touch anything since.  AC though plus all appliances are electric (including an induction cooktop, which is fabulous - my wife, an excellent cook, wouldn’t trade it for anything).

 

The windows have permanent awnings angled and sized to let sun in during winter and shade the inside in summer. Insulation is a combination of closed cell foam and blown-in.

 

Perhaps the most important feature is attention to detail. The house is very tight: During spring winds that can reach 60 mph out of a clear sky, if you weren’t looking outside you wouldn’t notice. (There’s a heat/air exchange system that makes sure the house stays comfortable while keeping the air fresh.)

 

 

 

[Jud]

2 hours ago, jcbenten said:

I assume it is dry there...At least one house in my neighborhood was 0-valued due to mold and another two doors down had the same issue but caught in time.  The closer neighbor mentioned they had to open the house up a bit to breathe.

 

Sorry for the off  topic...

 

chris

Typical humidity is around 15%. But vapor barriers are utilized where appropriate, and I noted the air exchange system earlier.

 

Rather than impose on @austinpop’s very interesting thread any further, may I suggest anyone interested start a thread in the Off Topic section or send me a private message?

[Jud]

1 minute ago, AudioDoctor said:

I am sitting here thinking about this. We have been thinking about putting solar panels on the roof for a while now, and I was thinking why not put the house on the solar circuit, and use another dedicated circuit for the audio system and separate the two? Then, while not being able to listen to music during a power outage, you wouldn't have any potential sound quality issues to worry about either.

I can’t see the switch that flips from grid to solar during an outage causing audio issues, unless you’re Michael Fremer. If the power goes out, listening to music is a nice way to pass the time.

[Jud]

6 minutes ago, AudioDoctor said:

 

I am spitballing ideas here, but it seems to me that separating the two would be the best of both worlds. Additionally, unless you are getting enough energy to refill your batteries every day, then during a power outage I think being smart about power usage would be a good idea as storms get crazier and times to fix damage gets longer. A Class A Pass Amp, even if its the smallest one, would probably drain batteries in no time. But for that brief glorious amount of time, we would also be warm...

 

edit: Here in the frozen north, on even a sunny winter day, we probably wouldn't get enough sunlight to refill batteries every day, as our amount of sunshine is very limited that time of the year.

 

edit 2: I have a personal weather station in my backyard that has a battery recharged by a small solar panel in it, I already know how much solar energy I would get, approximately, through the day and I can also see that amount dropping significantly already.

Moar panels! Moar power! 😉

 

This seems to me like a great argument for a set of really good Class D monoblocks. I love Pass but have also heard Class D sounding terrific.

[Jud]

12 minutes ago, AudioDoctor said:

 

I would love to be able to fit more panels, but that would mean cutting down the big beautiful trees that call our backyard home. Both my wife and I don't want to do that as it seems a little counter productive.

Purely joking.

 

12 minutes ago, AudioDoctor said:

Allegedly the new Marantz Model 30, which while having a discrete (HDAM) front end, has a Class D Hypex module output, and sounds wonderful... I have not heard one personally, though.

 

Was thinking along the lines of Purifi from someone like Nord - would probably be cheaper and might sound better.

[Jud]

16 hours ago, One and a half said:

To achieve low THD, the inverter a) has to be capable of producing better than 2% THD

 

When I was looking 4 1/2 years ago, I found no inverters capable of better than 2% THD, and only a handful capable of equaling that.  Is there anything with better specs now?  (2% THD or better is what most electrical utilities must meet in the US by regulation.)

 

But remember what I noted above: Unless THD gets really high from the source or power factor gets really bad, the primary effect on sound quality will come from the items consuming electricity inside your home, not from the source leading into the house.

[Jud]

14 hours ago, One and a half said:

A vintage brand ELGAR is still produced under that name a house of Ametek. Their SW series can create DC as well as up to 2kHz at line voltages (120, 230V) at 0.25% distortion into a linear load, like a heater. As soon as there's a rectifier anywhere, that distortion increases.

I'm sure Ametek have a DC input inverter in another family, but any programmable power that is used to calibrate other instruments are at $5figures, unfortunately. 

2% for reactive loads is about the best that's available without resorting to specialised filters to improve the distortion.

Elgar-SW.pdf 734.96 kB · 4 downloads

I checked the price on the Elgar (of the wattage needed for my small 4kw installation). It costs as much as my entire system. So not a practical alternative for someone looking to install solar power.