I'm an engineer working at Enphase, working on the envoy's software. It just feels so cool to see Dave talk about the Enphase system.
@crazyboy2006cashier2 жыл бұрын
Reach out to Dave, and do a guest video call with Dave for the channel?
@chrishettinger63142 жыл бұрын
Harsh, I love my 68 Enphase IQ7 inverters! Rock solid and excellent data reporting.
@gork422 жыл бұрын
Hey there real actual nice human person at enphase. I want to integrate lifepo4 locally at each miv. Do you have a solution yet? I’d like to buy it, but I’ll build it if need be.
@ugetridofit2 жыл бұрын
So did you want a gold star?
@steelcuts2 жыл бұрын
@@ugetridofit Probably as much as you want attention?! 🤣 And yes, if we all would live in the same kinda strange way of living and thinking as you are, i would get all of them engineers at enphase a gold star. Good job guys!
@wouldntyouliketoknow98912 жыл бұрын
I work on macro inverters. Utility scale. Up to 4MW for a single inverter in some cases. And on those puppies, they disconnect the DC input and AC output from the inverter via contactors when the inverter is idle, for exactly this reason. Otherwise they would be a giant VAR suck. However, sometimes you can order them with what we call NIGHT SVC (Static Var Compensator) mode, which allows you to send a signal to the inverter to reconnect its AC output so that the output caps are back in the circuit, and thus the inverter can act as a capacitor bank at night.
@Jody_VE5SAR2 жыл бұрын
This video is much more accurate than the first go... thanks for re-doing it. I've got 36 IQ7+, and your first vid had me seriously considering a contactor disconnect.
@usmanganijanvekar2 жыл бұрын
I worked in the tester development & deployment of a autoline for these Enphase Invertors. I follow you from long time, and it's proud to see you using a product tested by the testers developed by my team. :)
@J_i_m_2 жыл бұрын
⚠ SPOILER ALERT ⚠ Short answer: around 7w for the envoy & q-relay and near 0w real power for the micro inverters. Long answer: there is also a capacitive load of about 1µF per inverter which will cause some power dissipation in the wires.
@USNEM2 жыл бұрын
Thank You ..this due has to make a 30 minute video for this lol
@EEVblog2 жыл бұрын
40 minutes. I challenge you to go edit the video and make it shorter while not removing any technical content or commentary.
@petehiggins332 жыл бұрын
@@EEVblog Please take this as constructive rather than negative criticism but you do have a tendency to say everything about five times.
@threeMetreJim2 жыл бұрын
That may be true, but don't you want to find out why, and what the details are?
@mcflonomcfloonyloo52362 жыл бұрын
@@threeMetreJim Your comment doesn't exactly follow what @number 33 said
@laurentallenguerard2 жыл бұрын
I have bought a very expensive but very optimized Unique 12/24V fridge. It uses about 600 Wh per day. It must be smaller than your family's fridge though. It works very well, but a bit slow, you must not put hot items in it, but now I have ice cream off grid! When I started to live off solar panels (and a little wind), I was worried about the night consumption of the charge controller screen and monitoring. But after a few years, I realize this power consumption is neglectable, I boil water all the time, cook and get coffee, I mean, one coffee in the morning must use the same amount of energy as the charge controller over one year! If I get a decent water heater with an element inside instead of my current oven element with a pot, I will save thousand times more energy that trying to optimize the generation system. There are other more important things to do, such as not forgetting the computer powerred on while doing something else.
@59jm242 жыл бұрын
My mac desktop while sleeping uses about 2 watts. The whole deal, modem phone etc 5 watts
@briansauk68372 жыл бұрын
Suggestion to really show apparent vs. real power: Put it on a scope. Differential probe on channel one (safety first) and current clamp probe on channel two. Open a math channel as the product of one and two. The cycle mean will be the real power. The phase shift between channels one and two will let you calculate P.F. You could compare the vrms and irms with P.F. to the math channel result. Would make a nice video…
@stdorn2 жыл бұрын
I also had my system set to top off a battery bank before switching on the enphase system. I installed a DC distribution system that ran, Co detector, alarm clock, wifi router, cable modem, network hub, cell phone, laptop, ecig, and basically everything with a DC wall wort. In the event of power outage 600ah battery could power an inverter run some of my more important electronics.
@rabbithazel30342 жыл бұрын
I reckron future homes should have 12v (or 19V) sockets, feeding 220v to them is meaningless
@EEVblog2 жыл бұрын
@@rabbithazel3034 Big losses in the long cable runs.
@ewicky2 жыл бұрын
@@rabbithazel3034 Copper isn't getting any cheaper. If anything, we should introduce smaller capacity circuits to save copper. But it'll be at mains voltage for efficiency.
@SeanBZA2 жыл бұрын
@@EEVblog Yes hard to do, low voltage, heavy cables and any conversion from mains will have fixed loss based on peak power rating. DIY is easy with low voltage, though power is limited, and you will have to provide your own point of load conversion. 12V or 24V, and small converters is doable, and often done in small off grid systems, but again a niche use. I do however have a single 30W panel providing power to a battery and some lighting and other loads, simply because I live in South Africa, and rotational load shedding and power loss is an all too common thing, so some power is better than none. At least I still have power, unlike a few large areas in the city, still without power after 3 months from heavy floods. Sorry to Aus if you are having issues getting LHD Toyotas, as the factory was under 2m plus of water, and all the in process vehicles, and all those destined to be shipped, went into a crusher, aside from those washed out to sea.
@arthurmoore94882 жыл бұрын
@@EEVblog The answer is simple. Mains voltage, but at 250kHz! That way you could just put tiny transformers in everything without having to have all the circuitry. What could go wrong. ;) At least you don't have to contend with 120V mains.
@AintBigAintClever2 жыл бұрын
The couple of watts drawn at night seems to match what I see at home. Eight IQ7 inverters and an Envoy S Metered, which I think is on the solar panel side of the production CT, and right now (11:39pm) it's showing a production power of -7 watts. When it comes to battery storage take a look at the dedicated units for the task such as the Sofar ME3000SP. Hook it up to a 48 volt battery bank and it'll draw up to 3kW of excess power (that would go to the grid) or supply up to 3.3kW on demand. Basically it tries its best to stop your meter turning, in either direction.
@sandman01232 жыл бұрын
Thanks for the thorough coverage! 😄 To go off on a tangent about PFC, I find it really annoying that for example when it comes to power supplies with PFC, manufacturers crow from the rooftops, telling the amazing PFC value their PSU has. Except, they only give you one value at an optimal (high) load. However, PFC can be very poor at low loads. In typical applications the typical load may be only 50% of maximum PSU load capacity (or even less), where PFC specs are a LOT worse. They really should be be publishing graphs showing what happens across the entire load range. Same goes for efficiency, although it's more common to publish efficency curves, at least.
@qzorn44402 жыл бұрын
a very important subject on the factory floor and now at home when using inverters to keep clean grid electricity, which can be a big issue with VFD AC motor drives and 5th, 7th, etc. harmonics. those inverters usually need additional inductors and capacitors as per installation requires so not to pay for wasted reactive power "foam on the beer" 😎 thanks, great video
@SeanBZA2 жыл бұрын
I would say the relays disconnect if they see a line voltage with the panels feeding in of over 253VAC for a sustained period, probably 5 minutes, and then disconnect to drop line voltage for the grid in your area. Disconnect will be at the furtherest points of the feed from each transformer first, simply because of the line resistance between the houses and the transformers, as that will have the largest swing in voltage, especially as the entire feed line to the transformer has solar panels feeding in, so the furtherest panels have to raise their generation voltage higher to feed in power. Then likely they wait for 5 minutes after the voltage has dropped below a hysteresis point, probably 243VAC, before they connect the panels again. 5 minutes to give a chance for grid company on line tap changers to do a tap change at the MV power stations, and drop to a lower tapping point, to reduce the voltage they see reflected back to them from all the residential transformers they feed, accepting more power in at the lower mains voltage, to feed back to the system to the large loads that are still using it. Otherwise if you do not have tap changing and no residential disconnects your nominal 230VAC will go out of the upper bound of 253VAC, and the rise has been known to get to 270VAC in cases, so the relays are definitely needed. Yes trip points, delays and hysteresis is likely all remotely programmable, and they probably have a very wide range as well, along with giving good data to the overall health of the system, so the data is available, but the setpoints are likely not exposed to be adjusted, only for the manufacturer to set, not even the installer is likely to have access to them. But no doubt sniffable by simple traffic analysis of the data over the power line, and then you can get the protocol, and the commands that are sent, to get a probable command set to try, though there is good chance of scrambling the device during this process.
@liam32842 жыл бұрын
Disconnection should follow AS-5777.2, one problem is voltage at inverter terminals is higher than at switchboard.
@liam32842 жыл бұрын
Line voltage is complicated. If enough inverters were connected, voltage at the far end of the line would fall, due to reactive loading.
@video99couk2 жыл бұрын
Many modern installations don't use micro-inverters, instead they use DC Optimisers. They work in a different way, you still have a main inverter, but achieve the higher efficiency and eliminate the single point failure / shading problems of a string system. DC Optimisers keep the panel wiring at high voltage (lower current) so not heavy cables. Both solutions allow you to monitor the output of each panel.
@NebukadV2 жыл бұрын
10:03 Apparent Power S is NOT the (linear) sum of Active Power P and Reactive Power Q, but instead S²=P²+Q²
@TheHuesSciTech2 жыл бұрын
Yes, this. It's also weird that at 14:00, he points at the bit where the Apparent Power changes from negative-to-positive -- but that's actually just a bug in the maths done by the graphing tool; apparent power is always positive. To be fair, that's a mistake in the software, not by Dave, but it is still ultimately nonsensical that he points at the point where the apparent power changes sign as being any kind of meaningful thing.
@glashio2 жыл бұрын
Thx Dave, just decided to buy 14 Sunpower Maxeon panels installation with integrated IQ7A micro inverters. 🇳🇱
@taylorbespoke2 жыл бұрын
The newer IQ8H does list night time power consumption as 60mW, which seems reasonable.
@EEVblog2 жыл бұрын
Oh, interesting. None of the 7 series have that. UPDATE: checked the datasheet and it still doesn't have it.
@awxomexd2 жыл бұрын
Dave, there's a DC linkage cap at the input (solar panel side) to your CCT box. They use the freewheel diodes to rectify the AC into DC to maintain the charge. These inverters act as a real load (at night) to adjust the phase angle of the current. I also agree. The 1A would come from the grid, even in a solar+storage configuration. The battery will supply that current but the grid will charge the battery. Therefore, the current comes from the grid.
@kevinheimann76642 жыл бұрын
At my company we have the hole factory coverd with solar and with that the power faktor is nicely held at around 0.95 with the power factor correction in the NSHV turned off. Also these Shut off relais are intresting here in Germanny we get a device installed from the grid provider that also talks over the powerline that gives a signal that has to shut off the solar/generator probably similar communication technique
@robertadsett52732 жыл бұрын
Generally, they n my expertise, grid scale inverters can deliver any combination of real and reactive power as long as their apparent power limit isn’t exceeded so they can provide reactive power compensation while exporting power. The more advanced versions can adjust reactive power based on grid conditions or a command from the utility. Also Dave didn’t mention it but the Addition of real and reactive power to get apparent power is a vector addition not a scalar one so 1W+1VAR doesn’t equal 2VA
@losttownstreet34092 жыл бұрын
Some bigger solar installations (2MW - 10 MW) get ratings from the net provider for maximum apparent power and maximum ratings for anything. It's more for the bigger systems which must be able to disconnect from the grid operated by the net provider. They don't have these relays but big 30kV/110kV switch cells and you need a special license to operate these switches (hot sticks ... ppe; 240V/380V is low voltage system; 30kV is medium voltage system and 110kV and above is high voltage system). If there are to much of this systems in small homes they might get commands from the grid control center too, it may be manages by enphase (more control of the grid if they control all enphase inverters remotely).
@ChrisSmith-tc4df2 жыл бұрын
Given that the average home these days has many electronics and appliances with line filtering in them, I wonder how many uF of capacitive reactance a typical home presents to the mains.
@EEVblog2 жыл бұрын
Yeah, would be interesting to add it all up.
@threeMetreJim2 жыл бұрын
Anyone wanting a real in depth read of how micro inverters work can have a read of the Microchip app note AN1444. It's a little dated, but still relevant.
@nightshadelenar2 жыл бұрын
for the power billing, some countries actually bill residents for VA and not W, which smart meters measure in both VA and W, and can be changed at any time. not relevant to solar, but surely to the majority.
@topherteardowns46792 жыл бұрын
Dave Jones, flying spaghetti monster amongst mere mortals. Science bless you 🙌
@EEVblog2 жыл бұрын
May you be touched by His Noodly Appendage!
@BRADASSOFFGRIDHOMESTEAD2 жыл бұрын
Just use the street lights to make power, ha! I had 9.25kw envoy system at my old house. It was pretty neat to see all the data. Now I just have an OFF-GRID setup 11.25kw with midnite solar and magnasine command center.
@SvetzBowman Жыл бұрын
At 32:55, where you're talking about lower inverter efficiency for lower amp draw... a single Enphase battery uses multiple microinverters to invert power. At low power draws, where a large monolithic inverter would suffer a huge efficiency penalty, Enphase only need turn on a minimum number of microinverters ensuring they are always closer to the sweet spot. I also suspect that because the individual microinverters have relatively small ranges, the sweet spot is a lot wider than a single huge monolithic inverter.
@stdorn2 жыл бұрын
There also used to be a lot of data that you could pull from the inverters when the system first came out and for some reason they disabled a bunch of the things that you could graph and chart it used to input voltage, input current, track temperature of the inverter along with some other parameters and then one day they just did a software update and all of a sudden half of the things that it could graph disappeared.
@EEVblog2 жыл бұрын
I can still get graphs of DC voltage, AC voltage, DC current, Freq, and temp
@RS-ls7mm2 жыл бұрын
I just got a system and was surprised on how little data there was. Seems to be designed for people who are not engineers:)
@EEVblog2 жыл бұрын
@@RS-ls7mm What system? My enphase one has all that data and more. There is nothing it doesn't have that I would want, apart form the mentioned ability to control the Q relays.
@RS-ls7mm2 жыл бұрын
@@EEVblog Its an IQ8+ system. The data is mostly fun charts on total energy production. There is only one secondary display for current power production. No voltage, no temp, no current charts.
@EEVblog2 жыл бұрын
@@RS-ls7mm Really? That sucks if that's the case. Sure you are looking in the right place? Mine are IQ7+. I'm lokking to get more, so if that's true with te IQ8 then that really sucks
@The4Crawler2 жыл бұрын
I did some power factor testing on my off-grid inverter system a few years back and saw between 10% and 30% DC power reduction with "improved" power factor on a freezer and a drill press motor: kzfaq.info/get/bejne/p8yPja96vrqUgqM.html This was on a low frequency Tripplite sine wave inverter/charger, so that may make a difference.
@AndyFletcherX312 жыл бұрын
I've seen similar figures with my Victron 48/5000. A poor power factor can definitely impact battery life in an off-grid system.
@liam32842 жыл бұрын
it depends on topology. There are a lot of good designs for low loss passing of reactive power, but many like the H7 are patented.
@piconano2 жыл бұрын
Just watched your video. Excellent job.
@TheMobilefidelity2 жыл бұрын
I have Chinese micro inverters on my roof, Deye brand. They seem to shut down entirely when panel voltage drops below a certain level. I can't even access their management interface at night. I suspect the microcontroller that provides the Wi-Fi connection is fed from the DC bus, as the management interface is still accessible when I disconnect the circuit breakers that connect to the inverter.
@EEVblog2 жыл бұрын
Makes sense. No real need to access at night if you continually upload data.
@JurassicJenkins2 жыл бұрын
From my research Enphase is the way to go. But what do I know 🎈
@MrMegaPussyPlayer2 жыл бұрын
17:10 BigClive found out that some are not even real capacitors. Some are failed runs, not filled with electrolyte.
@truckerallikatuk2 жыл бұрын
Only in junk level products that buy rejects from Shenzen...
@wpherigo12 жыл бұрын
Fascinating. I remember my EE prof talking about how it’s called imaginary power, but it can kill you! Our power systems courses were terrifying. Safety talks, several wooden rods so you can separate a power source from the victim. It’s an interesting discussion as to whether consumers can power their own houses independently or if they have to connect it to the grid. During peak generation do they disconnect your solar array and your house is only powered from the grid, or is your house powered solely from your solar array?
@hersenskim2 жыл бұрын
In a grid-connected inverter system the power flow is managed using phase angle. Thus it is always synchronized to mains but the phasors of inverter and mains differ
@arthurmoore94882 жыл бұрын
Almost always it's house powered from the grid when the relays shut off power. Importantly, however, the circumstances which cause this aren't really peak generation. Rather, it's a mismatch between generation and load. Say you have all the ACs going during the day, and a cold snap happens. AC's turn off. The generator no longer has the load slowing it down, so it speeds up. You see a voltage and frequency spike until it can be dampened. The whole frequency voltage thing is another interesting thing, and there are videos on that as well. The thing with grid tied inverters is they have to match the voltage and frequency being supplied. So, you can get into a feedback loop of ever rising voltage as two separate systems each think the other is "the grid". Which is why having emergency cutoffs is important. Though, we can see other problems as well. Going back to the frequency thing. Look at what almost happened to Texas for how this can go horribly wrong.
@hersenskim2 жыл бұрын
After reading your comment again I realized you asked a different question than what I initially thought. The way Load is controlled between different sources of generation is via LFC (load frequency control). It is a phenomenon that comes from rotary generators - when they get loaded, their spinning speed decreases and their frequency drops. The inverse is also true. With a decrease in demand (electrical load) their frequency increases. Inverter manufacturers have incorporated this "old" form of grid-scale load control into their inverters, programming them to have a frequency "band" within which the inverter's load gets controlled (@50Hz - 100% power, 50.3Hz - 75% power, 51.2Hz - 0% power) and a cutoff upper bound above which the inverter switches off, to prevent what the above comment mentioned. This is also the mechanism we use in AC coupled PV micro-grids where different brands of inverters cannot communicate via cable, so we program the battery inverter to up the frequency when the batteries are getting full. It's not a binary "on" or "off", but more of a continuous control band
@liam32842 жыл бұрын
working on an inverter some years ago, wanted to get standby power under 1 watt, but wifi modules are surprisingly power hungry. We shut off every non essential rail until the sun comes out.
@arthurmoore94882 жыл бұрын
The trick is mentioned, but it's only as a quick aside and easily missed. Enphase uses power line data transfer. Same as those ethernet over power line boxes, or going further back, the X10 home automation systems. An ASIC with a simple protocol shouldn't use much power. The largest problem comes from signal integrity. Because AC power is horribly noisy.
@BRADASSOFFGRIDHOMESTEAD2 жыл бұрын
BTW I've found having panels on east and west to outperform south facing panels. Grid-Tied, and Off-Grid.
@zaphodb7772 жыл бұрын
And I have analog single stator meters on both of my panel sets, and also use Enphase microinverters on my grid tied solar... Also a net meter that was installed by the power company. The interesting thing is, on a brightly moonlit night, like the ones you can see colors on... I have seen some, not a lot, but some generation. Lunar and Solar power... what a trip huh?
@6Diego1Diego92 жыл бұрын
I will never understand power analysis like Dave
@junkerzn73122 жыл бұрын
Seems like everyone wants to get into the battery game. There is even a standard for off-grid and grid-disconnect situations to allow battery inverters to tell micro-inverters and grid-tie inverters to reduce the amount of power they send to the micro-grid/home-grid. The battery inverter shifts the frequency up from 60hz to 62hz or so (something like that) to regulate the amount of power the solar inverters inject onto the line. Without that the solar inverters would push the voltage all the way up to their maximum (typically 130VAC or 140VAC in the U.S.) and then probably either shut-down or start hicup'ing (turning completely off, then on again), when what you really want instead is regulated load-support for whatever is running in the home plus whatever the battery system can take (if anything). And because the standard is fairly new, various inverters either don't implement it or implement it with different frequency ranges and various brands tolerate different voltage limits before they trip-off. So it's a bit of a mess right now. -Matt
@liam32842 жыл бұрын
AC coupling, feels like a "show off" by inverter companies to me as an EE graduate.
@chasingcapsaicin2 жыл бұрын
Here we were/are billed apparent power, they upgraded to digital and actually still do because the meters can record it.
@TheHuesSciTech2 жыл бұрын
Where is "here"? *facepalm*
@peterhargrave22462 жыл бұрын
I often wondered why I see the clamp meter run to about 0.1 amp per inverter when I start up the Enphase kits prior to the inverters starting up properly.
@nixxonnor2 жыл бұрын
It is Big Power Grid that makes the solar inverters to make shure there is no net payback for injecting solar power to the grid ;)
@ernestplaatjes79017 ай бұрын
I have a grid tie system with 4 350 watt panels and 4 enphase m215 inverters, I turn the power off to the cottage in the winter and back feed to the net metering program to build credits, but unfortunately I'm finding they consume more power at night then what they produce, my last bill showed I used 35kw and only produced 2 kw, so I may connect a relay to power them down at night.
@guanglier Жыл бұрын
hello, nice video ! will be great to have a efficiency test bench to get a curve, because they don't give one... they said 98% efficiency, max in power 450W and max out 250W ... IQ7+
@KG4JYS2 жыл бұрын
Yeah outside of youtube videos on the topic, I've never heard of apparent power. Residential power in the US (220VAC) isn't apparent power based.
@piconano2 жыл бұрын
Would you be able to show the guts of a micro-inverter? I'm curious as how the circuit works.
@stdorn2 жыл бұрын
The old model I have is completely epoxy filled to make sure water cant get. I imagine that the newer ones are as well.
@piconano2 жыл бұрын
@@stdorn They all are.
@yagoa2 жыл бұрын
get some inverter fridges and run them off DC, works like a charm :)
@michaelgraff69782 жыл бұрын
The answer is yes.
@_BangDroid_2 жыл бұрын
I'm not an expert and may be wrong, but don't the new smart electricity metres in the UK measure apparent power?
@mjmeans7983 Жыл бұрын
I want a microinverter system. But it MUST have an on-premises web interface for local management. I refuse to be dependent on a cloud-based system.
@ToBeDefined852 жыл бұрын
My DaveCad license is running out. Are there any special offers announced for the coming months?
@cccmmm1234 Жыл бұрын
Of course you end up paying for VARs. Maybe not directly, but indirectly the power company has to pass that on somewhere. It's a bit like saying you get roads for free, forgetting you're paying g tax.
@ema47702 жыл бұрын
Italy residential we pay apparent power, so this will sux here
@charlesashurst1816 Жыл бұрын
And the answer is: Wait for it. No. Storage capacity of the Tesla PowerWall is NOT degraded by reactive load. In fact, their interface seems to have buillt-in power factor correction. You know? I think I'll buy a Tesla car. At Julian day 287 06:00, our irrigation pump turns on. It's a 120 Volt pump, so it presents a 1.5 kW load on leg 2 of our household. Notice the reactive power of that pump around 1 kW. But notice the load that is presented to the PowerWall. The load is evenly distributed between leg 1 and leg 2 and the reactive power is flat zero. I've put the data logger charts on my Facebook page.
@charlesashurst1816 Жыл бұрын
The string of 12 Enphase microinverters has a constant reactive load, which set me off down this rabbit hole of reactive load in the first place, of about 0.1 kW, but this reactive load is not presented to the PowerWall when the PowerWall becomes the sole soure of electricity. By the way, Logan Power and LIght has not been the source of any of this power, although they have the recipient of our surplus electricity for several months now. Our household has had two sources of power, solar panels and PowerWall. The PowerWall reactive power remains flat zero until it stops charging from the solar panels and then it presents a reactive load 0.3 kWatt. This reactive load does not present itself to the solar panels, though, and the string of Enphase microinverters remains at its constant 0.1 kWatt of reactive power.
@psychosis73252 жыл бұрын
Pretty jealous. I'm only making 30kwh on good winter days in Tassie off 10kw of enphase gear... Still well paying for its self over the year but its amazing how much difference the latitude makes.
@Hobypyrocom2 жыл бұрын
can you please make a short video explaining your browser addons and how and why are you using them?
@WizardTim2 жыл бұрын
I assume the battery system you're looking at will be grid-tie only due to the rest of your system's existing hardware limitations so there won't be a practical demo of "following the VA"?
@EEVblog2 жыл бұрын
If I install a battery system, yes it will be grid-tie. I am in suburbia, not a remote area. This is not speculation for my own system, it's somethign to consider if you have a grid-independent system. The one I mentioned in the video is a small portable unit and I'm thinking of wiring it in seperately just for the fridges. No thought yet on a big battery storage system, need to upgrade my solar array first.
@floringheorghe61362 жыл бұрын
could you use these inverters with a battery pack of the same nominal voltage as the panels and charge them during the daytime, then, at night use a relay to switch from panels to batteries and use the inverters?
@koolaid32242 жыл бұрын
Awesome video Dave! Have you done any reviews of different systems. Have been thinking about get a solar system!
@EEVblog22 жыл бұрын
Sorry, nope, just the ones I've installed on my house.
@shitheadjohnson27972 жыл бұрын
survival power!
@spyderbender2 жыл бұрын
My enphase system has been running for 11 months now, and at night the whole system draws 7 watts at night. (Envoy and 20 micro inverters.)
@adairjanney710910 ай бұрын
I would go with a string inverter personally dont see how those are going to handle large inductive loads
@it_geek2 жыл бұрын
I think this calls for a teardown (please buy a cheap [not working unit] from ebay or something)... even if it is potted. ;-)
@TimSavage-drummer2 жыл бұрын
How comparable are "power optimizers" with a central inverter to the Microinverters? Am getting a 10KW array installed next week (Wollongong, weather permitting), so will be able to start being a data nerd on the data soon after.
@EEVblog2 жыл бұрын
Don't know, haven't looked into them.
@bascomnextion56392 жыл бұрын
There are people who get charged for power factor and these would be large users so the micro inverters may not be so good for them.
@ugetridofit2 жыл бұрын
Jeez, I would be tossing those fridges and freezers if they were turning on and off that many times in an hour
@berndrosgen17132 жыл бұрын
What happens when everyone has such a thing on the house, Dave. What will be the ramifications for the grid? You can't use it on business buildings right? Otherwise I would have to turn on my electric motor over night.
@shaynegadsden2 жыл бұрын
Your main spec is wrong it isn't +/- 10 it's +10 - 6 it use to be +/- 6 but they increased the + when they reduced our official voltage from 240v to 230v to keep all existing systems within spec
@kabbak2 жыл бұрын
If I understand correctly, No inverter real power, but real source and connector power required
@joopterwijn2 жыл бұрын
Dave, does the sunnyboy has standby power? And I wonder if you could measure the production current and voltage (power) before the conversion on a panel. And then also the output power on AC side. Give you (and us) a view in power used by the converter in production mode.
@billjohnson33442 жыл бұрын
The Sunnyboy does have standby power, but it is only 1W. SMA is known for their low quiescent draws (among other things). He mentioned that in his other 2nd channel video - that turned into this one with better info.
@berndrosgen17132 жыл бұрын
Common Dave, ideal capacitor. 10VA!=10VAr You still need bigger transformers and hence you have more losses in the grid! And yes, you pay indirect for the grid infrastructure and losses.
@liam32842 жыл бұрын
smaller, most grid loads are inductive, balanced by capacitive loads or dedicated capacitor banks.
@berndrosgen17132 жыл бұрын
@@liam3284 That is wrong. For idle or in the low power case (night), the capacitive effect of the cables dominate. In south Germany, the capacitive power demand is also higher compared to the south (less wind turbines and more PV). They installed additional shiftable inductive loads for the night. Why would somebody connect PV during night time? And the main problem is still the active power. Switch is off at night time! Do the software update. We need to save energy. Start with small things if possible.
@mrgreenswelding28532 жыл бұрын
Can you put in a second inverter but plug it in the power point? Or straight into the power box?
@jtb25862 жыл бұрын
Isn't it beneficial to go to DC in your home when you have a battery system independed of the grid? There are so many losses in the conversion, seems like a waste
@littlejackalo53262 жыл бұрын
Yeah, sure. Switch everything over to super expensive DC appliances. Then hope you never have to use mains power. Go look at your choices for DC reefers. They're expensive, tiny, and very basic. If you have no option of using mains, like in a wilderness cabin, sure, it may be good. But in a normal home, it's not practical in any way.
@jtb25862 жыл бұрын
@@littlejackalo5326 I have no idea what a reefers is.
@rodrigomaero2 жыл бұрын
You may not pay for apparent power, but tecnically you'll pay for the cable loss of the current running through the cables in you house so that VAr if too big might take some real W with it
@EEVblog2 жыл бұрын
Watch the end of the video where I calculate this.
@rodrigomaero2 жыл бұрын
@@EEVblog oh so sorry! I always comment at the end but only made it half way through and had to hit the bed :P So pretty much negligible power loss on the cables, and probably you have thicker wires than calculated in your house
@janbottorff46422 жыл бұрын
Hi Dave, could you do a video on how solar inverters interact with the common split-phase 120V/120V here in the US. The Enphase inverters only put out 240V, not 120V. If the loads in my house are not perfectly balanced between the phases, I'm puzzled how exactly this works. I assume the 240V is exported through the meter and the street transformers, due to the center tap, can send the same energy back as 120V? If 1 A was flowing across the 240V lines (240W), and my load was drawing 2A at 120V (still 240W) on one leg, what does the flow look like to the meter? There is significant legislature debate here in California (and other places) to change the net metering plans such that the energy you export is not nearly as valuable as the energy you import, so it might be nothing like "net" metering anymore. The power companies are arguing why should they pay you $0.35/KWN for power to the grid when they can buy power wholesale for $0.06/KWH. They leave out the detail that the KWH from their wholesale generator 100 miles away going to my neighbor's home has much higher transmission costs than the KWH from my my solar panels going 100 feet to my neighbors home. In one proposal, you get credit at the wholesale rate for power you export, like $0.06/KWH, but pay $0.35/KWN for power you import. Load smoothing batteries could help a lot for a day or two, but don't at all help if I want excess energy exports in the summer to build up a net balance in an account to run a heat pump in the winter. If this much worse net metering becomes reality, I don't want to get paid $0.06KWH for the power I send to the street transformer to be turned into 120V, only to buy it back for $0.35KWH. I read there are potentially devices that could do the split-phase conversion on my side of the meter. Thanks!
@liam32842 жыл бұрын
Might be hard for him, split phase is rare in Australia. In rural places you can find 240-0-240, but almost nothing is wired for 480 volts. Everything else is 415Y230.
@surenbono60632 жыл бұрын
...mybe in the future these devices could find the best yield with auto switching parallel to series vice versa
@charlesashurst18162 жыл бұрын
Me too almost exactly. Had 2400 watt PV using Sunny Boy and Fronius inverters. And then I got 12 more panels with Enphase IQ7s. And I too saw the 1 Amp at night and went HUH? Thank you thank you thank for this. No worries whatsoever while I'm grid tied. But. I've got two Tesla PowerWalls too. If we get a Texas in Utah and the grid goes down for two weeks, a lost KWattt-hr or so from the PowerWalls that I could have tossed into my all electric heat pump furnace could be missed. Not a major worry, but I would like to know how much the reactive power of not only the IQ7s but all the other reactive loads in my house degrade the storage capacity of my PowerWalls. Would it pay to install an adaptive power factor correction gizmo, not a phony baloney one, but a real one?
@MrMegaPussyPlayer2 жыл бұрын
7:33 Again. I as stupid electronic noob, would put a transistor on the output side that is triggered by having power on the input side of the converter ⇒ converter uses no power if none comes in.
@ipullstuffapart2 жыл бұрын
Enphase related, Dave I wonder if you have heard about Enphase breaking local API access on the latest envoy firmwares. I've firewalled my Envoy away from the internet now so it can't update or reach enphase servers.
@EEVblog2 жыл бұрын
Haven't heard.
@ipullstuffapart2 жыл бұрын
@@EEVblog Short story is the new firmware nerfs local auth. New firmware requires user authentication from enphase servers now. If enphase goes bust or decides to drop support, bye-bye goes access to your monitoring data.
@billjohnson33442 жыл бұрын
Yes, they've changed it. Now certificate based instead of username/password based. Only applies if you are talking to the Envoy directly. If you use their cloud service, there is no change. No a good idea to firewall the envoy. Eventually the local storage will fill up if the database doesn't get purged.
@ipullstuffapart2 жыл бұрын
@@billjohnson3344 Thanks for the advice. I just had a look into this and you are right, the dumbass Envoy firmware only clears the DB storage when it finished uploading it to the mothership. From the Homeassistant forums, I can see that power cycling the envoy clears the DB, so it's some sort of volatile storage. One could throw a DIN rail Shelly in with the envoy to power cycle it on a schedule. It looks like my envoy will hold about 10 months of data before being full (9% after a month and a half offline)
@billjohnson33442 жыл бұрын
@@ipullstuffapart I don't believe the database is in volatile memory. Lots of stories in the past of people having their Envoy bricked from the database filling up, and power cycling was not a remedy. I also don't think it would make sense to have the production / consumption data be in volatile memory, since power outages combined with connectivity issues would result in that data being lost. So I think that is indeed stored in flash. And yes, I remember reading like something around 1 year was the amount of time for a non-internet connected Envoy to become unhappy without talking to the mothership. There is probably some way to clear the database with a REST query to the unit also.
@MrButuz2 жыл бұрын
My sunny boy 2.5 uses 1.5w overnight measured. i.e insignificant. I'd be willing to wager if you actually measured the watts flowing back out up on your roof AC wire you'd be suprised (in a bad way).
@charlesashurst18162 жыл бұрын
Excellent video. Love it. But let me get this straight. Say it's winter in Utah and dark for 16 hours per day. My IQ7s draw 1 Amp at night purely reactive power. I've verified that. We're not talking "Wattful" power but power that nonetheless is sapping the storage capacity of my PowerWalls. By how much? Is it simply reactive power X time? 1 Amp X 0.240 KVAC = 0.24 KWatt for 16 hours = 3.84 KWatt-hr per day = 26.88 KWatt-hr per week. Ouch. I would like to have thrown that 26.88 KWatt-hr into our furnace if there's a massive grid outage like during the winter of '21 in Texas.
@charlesashurst18162 жыл бұрын
If someone says, oh just get a gasoline generator, I'll just scream. Oh wait. If one had a carbon-neutral synthesized hydrocarbon instead of fossil hydrocarbon, it could be a viable option. So what if the carbon-neutral synthesized hydrocarbon costs $2.50/liter? I'd use it rarely to extend the range of my vehicle for a long trip or if the grid goes down.
@littlejackalo53262 жыл бұрын
@@charlesashurst1816 what solution would a generator solve anyways? Certainly not to run all night, right? I could care less about the carbon footprint, because it would be a negligible concern when the cost and hassle would prohibit it. Generators use around 3L/h, so in a day it would use 60-100L per day. That's 20-25 gallons a day. Even if you had a fuel tank to feed it, and you didn't need to fill an onboard tank, that would cost around $100usd a day. Modify can afford that. That's an average considering everything from you using less power during the night, to you having 4h more dark time than average, which you are awake and using more power, but doesn't account for anything more than a window banger AC unit. A generator for nighttime supply (normal operation, not emergency use) is absolutely unfeasible. Even with a big 20 kW while-house generator, that is feed from natural gas from the street (often cheaper than gas or diesel, and no need to fill the gas tank), it wouldn't be affordable. Even in a disaster scenario, a 10kW generator uses a gallon an hour to power essentials. You would have to have an obscene amount of gas on supply. There is almost no situation where a generator is useful in a disaster scenario. You'd need 100 gal of gas to make it through a week. Nobody is storing that kind of gas, and city supplied natural gas is usually down in a natural disaster scenario. ReEeEeeE cArBon nEuTraL "sYnThEsiZeD hYdRoCaRbOn"
@charlesashurst18162 жыл бұрын
Ok, I've made the voltage/current/power measurements on our Enphase IQ7s and on our Tesla PowerWall. I wish I could attach the scope screen images. Bottom line to the question: Do your Enphase IQ7s rob energy from you Tesla PowerWall at night? Theoretical answer is yes but the practical answer for us seems to be no. At night while our household consumption was at its minimum, I verified that the IQ7 were indeed drawing about 1 Amp in almost completely reactive power. But when I looked at the voltage and current from the PowerWall, the current and voltage were close to in phase. Apparently, because all the other sipper loads of the house, the doorbell transformer, the internet router, and miscellaneous loads, the reactive power of the IQ7s is somewhat swamped out by the miscellaneous loads. Bottom line, I don't think there's any practical value to installing an adaptive power factor correction device to the PowerWall or to install a timer that would disconnect the IQ7s at night. There is value in going through the house and eliminating as many of the sippers as possible.
@nathantron2 жыл бұрын
So I have a question... Could you theoretically eliminate all of the Alternating current and change everything over to a + - direct current system? Would appliances still work?
@FelonyVideos Жыл бұрын
The answer is yes, and more and more companies are making DC versions of their equipment. Water well pumps and fridges for sure. You can already get low voltage DC lights Check out the RV world. You still need a manager to do MPPT and to do battery charge management, though. Your savings though, is not really all that great. You need all special DC appliances. People don't like doing this because higher voltage DC can be quite dangerous compared to AC. Arcs don't automatically extinguish, so the fire hazard is much more. If you contact the DC, it tends to lock your hand onto it, so electrocution is also much more likely.
@stdorn2 жыл бұрын
When they first came out I purchased a few of the Enphase m190 inverters and had a very small system I was concerned enough about night time power draw that I used a couple of solid state relays in my solar panel circuit breaker box and set it up so if the panels weren't producing at least two or three volts that cut the AC to the grid tie inverters and envoy. I know I measured how much power they were taking at the time but it was close to 15 years ago and honestly I don't remember I just know it was enough that I was not wanting to waste the power. I think my envoy took about 5w assuming 12 hour average night that's 21kw a year it would have taken me about 10 days of generation to cover. I also planed ahead for degradation of the panels and used 250 Watts worth of panels for the 190 W inverter.
@jb56312 жыл бұрын
5W is nothing thought; those solid state relays + related circuitry might have costed more than that little bit of consumption.... Plus your missing out the potential PFC.
@stdorn2 жыл бұрын
@@jb5631 As a total Electronics geek I've been collecting parts from various places over the past four decades. As a result it's been many decades since I've spent anything on components to put together anything that I needed to build. I got a whole bag full of brand new solid state relays my employer threw out. So setting up this control circuit cost me exactly nothing. If you figure 5 watts per hour this figure is probably a little low the Envoy specs say it can draw up to 7 Watts and about another watt for all my inverters. Assuming an average of 13 hours of off time of day (and this is probably also conservative as the system doesn't start up until a few hours after Sunrise, shuts down a few hours before Sunset, is partially shaded by the configuration of my roof in the evening, and this figure doesn't even take into account cloudy days as well as the fact that I'm fairly Far North), that comes to 65 Watts every day. That is 23,725 Watts of wasted power every year. I set the system up in 2009 that's 13 years which comes to a total of 308,425 watts of wasted electricity. Including distribution fees and taxes I pay roughly 18 cents per kilowatt hour it means it saved me a total of 55 dollars while costing me nothing. And this is very easily a conservative estimate considering actual time the system runs per day is probably far less than 11 hours over the course of the year. I also got to enjoy designing and setting it up. Another way to look at this is my fairly small system so far his generated two and a quarter megawatts so you could also look at this as if I hadn't done it I would have lost 13.7% of my generated power if you look at it this way that's actually quite a significant difference. I'm not charged for power factor and I've never noticed issues with say a motor starting up slow because of current lagging voltage so power factor correction isn't really something I cared about.
@000000055472 жыл бұрын
@@stdorn you forgot to account the heat dissipation of the SSR. Any semiconductor has a resistance, and for AC SSRs it ends up being around 1.5w of heat per amp. So if you're producing 1kw, you just lost 12w regardless of 120 or 240 cause in 240 you would still need two SSRs which would cancel out the energy saved with the higher voltage So if your system is producing 5kw you are losing 60w into the SSR that would have otherwise gone into the grid. And those 60w even if you only make 5kw for 1h, would be more than enough to compensate for the 5w the inverters lose overnight without any SSR in the middle.
@stdorn2 жыл бұрын
@@00000005547 you're absolutely right I never once considered the loss of the solid state relays. I don't know how I never thought of that. As I was trying to determine cost effectiveness before I installed a larger system I only had two inverters so max output was about 400 watts. Some quick math with your one and a half Watt numbers show I lost almost exactly as much as I thought I was saving. Although being able to shut the grid tie inverters down did serve another purpose if I wanted to be able to send all of my solar power to my battery Banks. When I get a chance I'll have to check the specs on my SSRS and see what the actual numbers come out at.
@shakaibsafvi972 жыл бұрын
Hi. I've seen some of the micro-inverters and their electronics. Found that these micro-inverters are not pure sine wave. Just wondering if all are designed that way. would you be willing to do a tear down of one of your units :)
@liam32842 жыл бұрын
not pure? poor harmonic filters? have a scope trace or power analyzer results?
@shakaibsafvi972 жыл бұрын
@@liam3284 did this about 5 years back. Unfortunately don't have data !! Apologies :(
@uiopuiop34722 жыл бұрын
Enphase sounds "like" Inphase and htats cool!!!!
@joeyjustin68952 жыл бұрын
What About A Clear Night. Doesn't the moon light make for activity
@FelonyVideos Жыл бұрын
Can I license a copy of DaveCAD, or find it at the play store? 🤣
@AndreLuizGamadeAndrade Жыл бұрын
someone can help me ? i´ve a 10kw solis inverter and by the night he is consuming 30W, i measure that with a Fluke 435 serie II analyzer, i dont now the cause of it.
@nightshadelenar2 жыл бұрын
in 848, that cap was 5uF.
@xntumrfo9ivrnwf2 жыл бұрын
Why do we make the assumption that if we have a grid connected system with a battery, the apparent power draw at night will almost certainly come from the grid?
@davefiddes2 жыл бұрын
Depends on regs and how things are configured but battery/solar inverters are configured to generate with a static Power Factor of 1.0. The VARs have to come from somewhere for the system to balance and therefore it comes from the grid. I think that many inverters are clever enough to actively power factor correct but they don't because it reduces the system efficiency for the home owner.
@xntumrfo9ivrnwf2 жыл бұрын
@@davefiddes thank you, this makes sense
@chrishettinger63142 жыл бұрын
Dave, check out the channel "Ben's Solar and Battery". He opens up a I7+ and depots it.
@IanScottJohnston2 жыл бұрын
With the cost of electricity doubling (and more come October) here in the UK I am looking at battery systems (again!) and Dave's idea of fridges/freezers etc only has me thinking!......and not to mention also measuring the standby power on my Bosch solar inverter itself etc. Hmmmm!
@EEVblog2 жыл бұрын
I'm onyl thinking of the fridges because a company is supposed to be sending me a 3.2kWh portable battery pack for a teardown or whatever, and I have no other major use for it. So I thought I thought it might make an interesting video of just powering the fridges with it with a mechnical time during the day to recharge it from the existing solar. Power failures are so insanely rare here that it onyl makes sense to protect the fridges and maybe a few light and a power point or two.
@melovescotch2 жыл бұрын
Could you place a large enough Inductor/transformer on the inverter output could you balance it out?
@SeanBZA2 жыл бұрын
No, the inductor large enough would also draw power in core and copper losses more than the saved power. On a grid tie the 3W use in power off would still slowly add up, but the reactive power would help offset the in house loads, which even with LED lamps are needed, because of the non linear power draw of most modern switching power supplies. Only an issue if you are using in conjunction with an inverter to boost power capacity during the day, and no grid connection, so easiest to use a relay and daylight switch to disconnect the panels entirely, or use DC output panels to feed the inverter solar charge input directly instead. This issue is only there for grid tie panels, which is not going to worry you in normal use, as the extra filtering of the 1uF total filter per panel actually reduces the overall power factor of the house, as most of the load during the day and night is either inductive or non linear with a bridge rectifier, so extra filtering capacitors and inductors in parallel to the load does help.
@tlhIngan2 жыл бұрын
Non-residential users are charged on power factor, not apparent power. Apparent power as you noted is made up of real power (what you pay for) and imaginary power (which averages to zero over an AC cycle), but as you said, imaginary power leads to real currents. That's what non-residential users pay for if they fail to keep their power factor in check. It's not hard to do either - they just have a big box of capacitors at the power input to the building, usually switchable in and out to keep the power factor in check. Also, almost all loads are primarily inductive - motors are everywhere used to drive the compressors of your fridge and air conditioner, motors driving fans that keep you cool, etc. In the past, residential uses of power were mostly resistive - heating coils used in appliances like ovens and stoves and heaters, lights, etc. But these days it's gone inductive as people buy fridges and air conditioners and fans. That's why power companies never need to correct for too much capacitance on the line - there is almost never enough capacitance - so there will be bit capacitor banks at substations (they call them "reactors"), and there will be capacitor banks along power lines as well, and of course, non-residential customers will have banks of them switched in and out because almost all industrial machinery is inductive - driving motors and such.
@nickush75122 жыл бұрын
Mate, just imagine if we had politicians like you !! Highly intelligent, knows what they are talking about (hahaha.. just imagine !!); could speak clearly, concisely, intelligibly with genuine humour (no pre-penned BS re-worked insertions from earlier gabble from thier script writers or stolen from previous political diatribe mongers (Reagan, May and others); based upon real-life knowledge and experience; backed up with honest corrections/new, relevant additional data, appropriately inserted..... I could go on but I think the point is adequately made.... Just imagine !!! Thanks a bunch Dude, always a pleasure :)
@mfbfreak2 жыл бұрын
Ah, the world in which politicians have knowledge about their domain. How beautiful that would be. Alas. Chances of that happening are slim. I think most people with knowledge are aware that they'll be in the minority and that they can debate and discuss all they want, but eventually just be overruled by a horde of populists going for a quick voter grab non-solution that sounds nice but makes things worse in the long run.
@nickush75122 жыл бұрын
@@mfbfreak Haha... for sure mate, I am not so naive... my comment was not so much a wish for better govenance, am not into being governed by any measure, it was more by way of a compliament.
@EEVblog2 жыл бұрын
If be a terrible politician, I'd want to run it as a dictatorship, it's the only way to get things done.
@berndrosgen17132 жыл бұрын
Disconnect the it over night, there is NO benefit connecting it during night time!
@RS-ls7mm2 жыл бұрын
What happened to the last video on this?
@TripleJ852 жыл бұрын
I was looking for it yesterday - I guess Dave had a bigger think about it and rolled it in to this new and improved version (with less scary conclusions)
@EEVblog2 жыл бұрын
@@TripleJ85 Yes, the other video was not clear, I said watts a lot when I meant VA (bad habbit) etc, and this added a lot more detail. And it's more polished, hence the move to the main channel.
@tsmwebb2 жыл бұрын
I wonder if the relays disconnect from the grid in a power out?
@arthurmoore94882 жыл бұрын
That or the inverters turn off. Every grid tied system I've ever heard of has that as a requirement. Otherwise a downed powerline would stay energized!
@tsmwebb2 жыл бұрын
@@arthurmoore9488 Makes sense. I suppose that using the relays to disconnect would also prevent the caps from discharging down the line.
@Soapy5552 жыл бұрын
My PV inverter shows it uses about 70w at night, it was installed 2011
@EEVblog2 жыл бұрын
Woah, real power? What model?
@rushymoto2 жыл бұрын
So if you are syncronized to the mains and you want it at unity, The voltage is likely pushed up as a VAR control to push the waste onto the grid. OR dose it use capacitors to correct the factor of the load in the house? I am a diesel generator engineer and when a building is running on a standby set the capacitor correction has to be isolated as it upsets the regulator on the gen set. And if synched to the mains the utility tends to have a spec to follow on the VARs in order for customers to not push the waste onto the grid. As i understand it the power factor is the angle difference between the Volts and the Currant, caused by the inductance or resistance of the load. So a resistive heater will be at 1 and a PC switching power supply could be at 0.7
@soulrobotics2 жыл бұрын
Can anyone from Spain and EEVblog suggest me a solar panel system? io live in Alicante where the sun never goes... roof orientation east -west with south inclination.
@nhzxboi2 жыл бұрын
Question: Do you segment your panel groups with diodes? For instance, when sun shines on half of the group and not on the other half, the groups in the shade are a drain on the rest that are in the sun. Diodes can thwart this but, the current drop across a diode separating groups of PVs is a deficiency in and of itself. I built a 13kV solar tracking system back in 2009 and discovered, at least in that case, the diodes helped more than harmed. System "turned" on and made power much earlier and later in the day than the same system w/o diodes. I.e. the voltage got high enough for IGBTs to output a useful voltage earlier and later. How much did I lose in terms of power because of the diodes? I don't really know. Overall experience building that solar tracker: Not really worth the cost. Although it is still working today and has collected data since 2009. I haven't looked at the data for a long time. One sort of loses interest after a while. I do know that the electric meter is still running 'net backwards' for the building the thing is hooked up to.
@xponen2 жыл бұрын
if every panel has their own micro-inverter then we don't need to connect them in series anymore, no need for high voltage DC to reduce wire losses because each micro-inverter already convert low voltage 12v dc to a high voltage 120 / 240 v ac. With micro-inverter each panel is independent of other panel so no need to worry if 1 panel is in shadow, so no longer needed to string them with bypass diodes.
@nhzxboi2 жыл бұрын
@@xponen I like discussing these things. #1 question in my mind with multiple inverters and by mathematical recursion, many 'micro- grids', who is in charge of synchronization? In the early days of me experimenting with commercial PV inverters, there were times that the grid-connected inverter remained on when the main utility disappeared... a dangerous thing. Firmware update corrected that in that situation. But, as these things proliferate on rooftops and fields, I can see the local logic of the micro-grids deciding that they are the utility and remaining on just because they're fooled by their other buddies on the local network. Really seems like a mess to me for devices that are very very inefficient(PVs) in terms of energy density and area. I am very much a fan of nuclear. PV manufacture is extremely energy consuming. Average folk think the things grow on trees. They don't. They're made in China using coal as energy source. I am very skeptical about the real benefit of PV.