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

[MrDerrick]

I will follow this closely.

 

Three of my neighbors who have solar city installs share the same transformer secondary with me.

My THD as measured by my PS Audio power plant has gotten quite bad.

 

I do not live in the sun belt, 17403 zip, and poor sunlight affects output which appears to have a direct influence on how clean the inverters operate.

Strong sunlight = low THD, low sunlight = high THD.

 

I can hear the effects on my audio system, power supply noise and loss of SQ.

Late nights are the only time that I can thoroughly enjoy listening in the summer.

Thank god winter is coming.

[One and a half]

36 minutes ago, MrDerrick said:

I will follow this closely.

 

Three of my neighbors who have solar city installs share the same transformer secondary with me.

My THD as measured by my PS Audio power plant has gotten quite bad.

 

I do not live in the sun belt, 17403 zip, and poor sunlight affects output which appears to have a direct influence on how clean the inverters operate.

Strong sunlight = low THD, low sunlight = high THD.

 

I can hear the effects on my audio system, power supply noise and loss of SQ.

Late nights are the only time that I can thoroughly enjoy listening in the summer.

Thank god winter is coming.

Thank you for this interesting observation. To achieve low THD, the inverter a) has to be capable of producing better than 2% THD, and b) have a low impedance source or strong enough to cope with large di/dt when the switching devices work.

 

If the sunlight is poor, the internal resistance of the solar cells decrease the source impedance as seen by the inverter. If the source impedance is higher, there's less energy , or quality energy that the inverter needs.

 

One way around this is to add more capacitance to the DC bus network for the inverter, however the solar cell array may not have enough strength to support the capacitance. Difficult issue. Not a great fan of inverters or UPS for audio equipment, trading voltage stability for grid strengths and noise closeness certainly has a fine line between pros and cons.

[Meridimac]

On 11/3/2021 at 9:20 AM, Jud said:

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.)

 

 

 

We are also in New Mexico with plenty of sunshine and a 40 panel 13.6KW ground-mounted array. No audio degradation that I’ve noticed, but maybe the Shunyata Denali conditioning accounts for that.

[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.

[One and a half]

8 hours ago, Jud said:

 

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.)

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

[AudioDoctor]

14 hours ago, Meridimac said:

We are also in New Mexico with plenty of sunshine and a 40 panel 13.6KW ground-mounted array. No audio degradation that I’ve noticed, but maybe the Shunyata Denali conditioning accounts for that.

 

Along that same line of thought, I was wondering if an isolation transformer would be beneficial in a scenario with solar and grid connected power sources and their associated equipment.

[Superdad]

3 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.

Well a high wattage audio power amplifier—with a 50/60Hz input signal—produces nice low-distortion AC. 

But not very efficiently unless you use a Class D amp. And of course one needs to design it to run directly from the DC of solar panels or batteries. 
 

By the way, as I recall the original PS Audio Power Plant “regenerator” units were just Class AB power amps with internal fixed (and variable, including waveform) 60Hz input. As one would expect they were really large for the output wattage. Not sure the topology in their models of recent decades. 

[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.

[Crom]

On 11/3/2021 at 12:43 AM, austinpop said:

 

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

 

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!

Our home is the same. 1-1.3kW just to exist...must be all the NAS boxes in the basement! Thanks for a really interesting article @austinpop I was very apprehensive about the noise introduced into our home's circuit by 2 x inverters but the effect appears to have been negligable. I have not embarked on the battery journey yet and our first 'battery' purchase is likely to be an EV! I will follow your journey with interest!

[Warren Roos]

Did what you did but three years back in Davis California. At the time 425 panels didn't exist so we needed 42 panels for our 12.35kW  system.  (Some of your readers may not know that a system of solar panels with more out put requires a larger and more expensive inverter.  In California our electrical utility dictated how much power we could generate based on past usage.)

 

Unlike you, our ROI on the panels is under six years as our peak fee is 42 cents per KW. For the batteries the ROI is maybe two years. All in that makes for about eight years. We are semi rural and lose power on average around four times a year. High winds or fire can also cause outages. 

 

Two years ago we put in two Tesla batteries; that decision was based on cost/rebates. (translation …wish I put in 3 or 4 batteries) Because this is California. permission to operate took about a year and we received no credits for our generation back to the gird. That was just shy of 8MW.  But that’s another story.

 

We have simply adjusted some electrical use habits such as doing laundry, running the dishwasher, charging an EV and doing  preemptive cooing during peak solar times. This works in our favor for ten months of the year.  I’m thrilled on the many mornings where we wake up with “juice” still in the batteries. Yearly gird used is under 10%.

 

Like you I use a top power conditioner and an EtherREGEN (making use of the optical out as well). I can’t tell any sound difference when “running” on our utilities power, the batteries or solar.

[austinpop]

Progress update: My system finally passed inspections and received PTO!

 

[The Computer Audiophile]

1 minute ago, austinpop said:

Progress update: My system finally passed inspections and received PTO!

 

Nice! 

[The Computer Audiophile]

Part 2 is up!