Delayed startup of Grid Tie Inverter

2

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  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Delayed startup of Grid Tie Inverter

    We're all glad to see you back, SG! :D
    Not having your vast knowledge of system components we can only go by the info given (even if it does seem a bit odd).

    Say, can you answer about sixty-eleven other questions that have come up which I'm sure you know? :p
  • nielniel Solar Expert Posts: 10,311 ✭✭✭✭
    Re: Delayed startup of Grid Tie Inverter

    good to have you back henry as some of us were beginning to wonder what happened to you. i hope all is well.

    don't tell anybody, but the patients run the asylum.:roll::p
  • BB.BB. Super Moderators Posts: 26,768 admin
    Re: Delayed startup of Grid Tie Inverter

    I thought we were running "catch and release" here.

    Welcome back Henry!

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • balee123balee123 Solar Expert Posts: 86 ✭✭
    Re: Delayed startup of Grid Tie Inverter
    That perfectly fine, the Sunties are rated to 125V, where is all this silly talk of 80V come from? ... geez, go away for a year an who is running the asylum?

    The front-end of the Sunties is 150V components, no different than say boBs MX60's ... The Voltages listed by the OP are the typical mppt range, not open circuit values, but there is nothing in the code to turn off the units ... and I know as I have worked on the firmware :)

    as to the OP's issues, if these are not UPG models ( and they should have been upgraded in 2003 for free ) no ac detected is just that, AC, not DC


    So are you saying that this thread's discussion around the subject of temperature affecting when the inverters start producing is moot?
    If so, I still do not understand why the STXR inverters do not start producing even though the panels have reasonable amount of sun hitting them (sometimes doesn't start until after 11 am).
    Also, what would cause the inverter to not detect any AC. My grid from the local utility appears fine. My kill-a-watt meter shows a standard 120V and 60Hz at all house outlets measured.
    My believe my inverters where upgraded in 2003.
  • Solar GuppySolar Guppy Solar Expert Posts: 1,959 ✭✭✭
    Re: Delayed startup of Grid Tie Inverter
    balee123 wrote: »
    So are you saying that this thread's discussion around the subject of temperature affecting when the inverters start producing is moot?

    Correct, your making conclusions, the code will attempt to start running at anything over 60V with sufficient enegry to run the inverter
    balee123 wrote: »
    If so, I still do not understand why the STXR inverters do not start producing even though the panels have reasonable amount of sun hitting them until much later in the day.

    Whats the angle of the panels at?, have you verified that you haven't lost some strings ( try running one string at a time when it works ) The Suntie needs about 100 watts available to get running
    balee123 wrote: »
    Also, what would cause the inverter to not detect any AC. My grid from the local utility appears fine. My kill-a-watt meter shows a standard 120V and 60Hz at all house outlets measured. My inverters where upgraded in 2003

    A Kill-a-watt won't tell you what is at the terminals of the Suntie, you need a DVM for that. Verify you have 240vac at the inverter breaker connections in the inverter. If both units are doing it at the same time it has to be wiring related, I would check all the connections and tighten them ( with power off of course at the source feeding the sunties ). If only one of the two are doing it and you have verified power at the inverter, its likely internal to the inverter, there is no resources for repairing these inverters that I know of.
  • inetdoginetdog Solar Expert Posts: 3,121 ✭✭✭✭
    Re: Delayed startup of Grid Tie Inverter
    Correct, your making conclusions, the code will attempt to start running at anything over 60V with sufficient enegry to run the inverter



    Whats the angle of the panels at?, have you verified that you haven't lost some strings ( try running one string at a time when it works ) The Suntie needs about 100 watts available to get running



    A Kill-a-watt won't tell you what is at the terminals of the Suntie, you need a DVM for that. Verify you have 240vac at the inverter breaker connections in the inverter. If both units are doing it at the same time it has to be wiring related, I would check all the connections and tighten them ( with power off of course at the source feeding the sunties ). If only one of the two are doing it and you have verified power at the inverter, its likely internal to the inverter, there is no resources for repairing these inverters that I know of.

    There is one simple test that can be made if the panel array is accessible: Early on a winter morning when you expect that the GTI should have started, throw a tarp completely over ONE panel in the string (assuming it is just one series string) and see if the inverter starts up. If it does, then the output voltage is the problem. If it does not, then you need to look for a different explanation.
    With one panel completely shaded, the string voltage under even a small load will drop by roughly the Voc of that panel. (The completely unloaded string Voc may not drop much if any light at all is getting to the panel.)
    SMA SB 3000, old BP panels.
  • ggunnggunn Solar Expert Posts: 1,973 ✭✭✭
    Re: Delayed startup of Grid Tie Inverter
    inetdog wrote: »
    There is one simple test that can be made if the panel array is accessible: Early on a winter morning when you expect that the GTI should have started, throw a tarp completely over ONE panel in the string (assuming it is just one series string) and see if the inverter starts up. If it does, then the output voltage is the problem. If it does not, then you need to look for a different explanation.
    With one panel completely shaded, the string voltage under even a small load will drop by roughly the Voc of that panel. (The completely unloaded string Voc may not drop much if any light at all is getting to the panel.)
    For better or worse, here's how I understand it. Early in the morning there is plenty of voltage available but hardly any amperage. If the inverter tries to start up and starts trying to extract power from the PV, the load it places on the array immediately drops the voltage below where the inverter can operate.
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Delayed startup of Grid Tie Inverter
    ggunn wrote: »
    For better or worse, here's how I understand it. Early in the morning there is plenty of voltage available but hardly any amperage. If the inverter tries to start up and starts trying to extract power from the PV, the load it places on the array immediately drops the voltage below where the inverter can operate.

    Except that it detects Voltage first, says "too high" and doesn't try to start.

    Although as SG has informed us these inverters actually have a maximum input of 150 Volts, so this is not what is happening. Where the OP got those <80 Volt figures for maximum I don't know.

    Instead there appears to be a problem detecting AC present at the output for some time, which keeps the inverter from starting. Why this "goes away" after things warm up a bit is a mystery. Possibly some thermal action on a wiring connection.

    If it were just a matter of not producing as much power in Winter, that is understandable as the panels may not be at the "ideal" angle for that time of year and the sun simply isn't as intense. Even the superconducting in cold won't make up for that.

    Is a puzzlement. :p
  • balee123balee123 Solar Expert Posts: 86 ✭✭
    Re: Delayed startup of Grid Tie Inverter
    Except that it detects Voltage first, says "too high" and doesn't try to start.

    Although as SG has informed us these inverters actually have a maximum input of 150 Volts, so this is not what is happening. Where the OP got those <80 Volt figures for maximum I don't know.

    Instead there appears to be a problem detecting AC present at the output for some time, which keeps the inverter from starting. Why this "goes away" after things warm up a bit is a mystery. Possibly some thermal action on a wiring connection.

    If it were just a matter of not producing as much power in Winter, that is understandable as the panels may not be at the "ideal" angle for that time of year and the sun simply isn't as intense. Even the superconducting in cold won't make up for that.

    Is a puzzlement. :p

    Got the <80 volts off the side of the inverter (see pic). But as SG stated, I guess this is mppt operating voltage.

    BTW I had that same thing happen again this morning, where it is very cold (for San Diego, 45 F) and clear and the inverters both start up almost as soon as the sun rises. I get my maximum production in the winter on days like this as the inverters start up much earlier in the day and do not shut off until the end of the day.

    I did have a thought regarding this weird behavior.........the type of morning(s) described above are very low humidity. There is no dew or condensation on anything. The mornings where there are delayed starts are morning where there is condensation (especially on cold metal surfaces). My inverters are rated for outdoor installation and are mounted outside on the northside of the house. Could this be leading to issues with the AC not being detected and the inverters delaying their start? Just throwing out another piece of data.

    Attachment not found.
  • balee123balee123 Solar Expert Posts: 86 ✭✭
    Re: Delayed startup of Grid Tie Inverter
    balee123 wrote: »
    Hi. I am the OP and had an interesting thing happen this morning. This was one of the coldest morning here in San Diego; it was in low 40's as the sun started to come up....burrrrrrrrrrrrrrr ;). There were no clouds or marine layer this morning and almost as soon as the sun rose, the inverters started producing. For what it's worth, the sun now rises directly perpendicular to the panels, i.e. ~90 degrees to the direction the panels are facing (~200 degrees). Can anyone explain this in light of this thread's recent discussion?

    Here is the quote of my first description of this phenomenon from earlier in this thread.

    BTW the panels are angled at about 20 degrees. This was done to maximize solar production in the summer months and to get the largest CA rebate back in 2001 when this system was installed. You got a larger rebate if your system maximized production during the months where the grid might be over taxed during the days from AC usage and potential heat waves.
  • Solar GuppySolar Guppy Solar Expert Posts: 1,959 ✭✭✭
    Re: Delayed startup of Grid Tie Inverter

    I'll repeat this as the posts continue about more mythical reasons the inverters aren't running keep getting posted, when you have the AC NOT DETECTED message, use a DVM and find out what is the AC Voltage measurements starting at the inverter and work backwards, this is your issue. It you don't want to do this, at least take a screw driver and tighten all the AC connections from the main panel breaker to the Suntie's breaker ( with the power off of course ). This sound like a thermal issue with the AC wiring ( cold contracts )

    The "range of operating voltages" was intended to keep people from trying to put 5 12volt nominal panels in series, once the Suntie see's anything more than 60 Vdc on its input, it will every 5 minutes attempt to go online. The 5 minute is the UL1741 requirement. Lets end now and forever this silly talk it has anything to do with the input voltage being to high when cold, it has nothing to do with your problem.
  • boBboB Solar Expert Posts: 940 ✭✭✭
    Re: Delayed startup of Grid Tie Inverter
    I'll repeat this as the posts continue about more mythical reasons the inverters aren't running keep getting posted, when you have the AC NOT DETECTED message, use a DVM and find out what is the AC Voltage measurements starting at the inverter and work backwards, this is your issue. It you don't want to do this, at least take a screw driver and tighten all the AC connections from the main panel breaker to the Suntie's breaker ( with the power off of course ). This sound like a thermal issue with the AC wiring ( cold contracts )

    The "range of operating voltages" was intended to keep people from trying to put 5 12volt nominal panels in series, once the Suntie see's anything more than 60 Vdc on its input, it will every 5 minutes attempt to go online. The 5 minute is the UL1741 requirement. Lets end now and forever this silly talk it has anything to do with the input voltage being to high when cold, it has nothing to do with your problem.


    Where you been, Henry ?? You OK ??

    boB
  • Solar GuppySolar Guppy Solar Expert Posts: 1,959 ✭✭✭
    Re: Delayed startup of Grid Tie Inverter
    boB wrote: »
    Where you been, Henry ?? You OK ??

    boB

    Hello boB!, all is well and I'm doing great, thank you for asking :)

    I've been out of RE for 2+ years now, so don't loiter around these parts much ..
  • balee123balee123 Solar Expert Posts: 86 ✭✭
    Re: Delayed startup of Grid Tie Inverter
    I'll repeat this as the posts continue about more mythical reasons the inverters aren't running keep getting posted, when you have the AC NOT DETECTED message, use a DVM and find out what is the AC Voltage measurements starting at the inverter and work backwards, this is your issue. It you don't want to do this, at least take a screw driver and tighten all the AC connections from the main panel breaker to the Suntie's breaker ( with the power off of course ). This sound like a thermal issue with the AC wiring ( cold contracts )

    The "range of operating voltages" was intended to keep people from trying to put 5 12volt nominal panels in series, once the Suntie see's anything more than 60 Vdc on its input, it will every 5 minutes attempt to go online. The 5 minute is the UL1741 requirement. Lets end now and forever this silly talk it has anything to do with the input voltage being to high when cold, it has nothing to do with your problem.

    In my last post, I may have given you the wrong impression that I believe this problem is still related to the input voltage being too high due to cold temperatures; I do NOT, due to your expertise in this area and what you have posted. I was trying to provide information in suport of that since the inverters actually do start and work in some of the coldest temperatures early in the morning. Not sure if I made that clear. Could be due to my bad wording or dealing with this type of internet communication. I do very much appreciate your expertise on the subject matter.

    So I had the "No AC Detected" message come up on the inverters and at the same time measured the AC Voltage on each side of the AC Main breaker which separates the inverter from the grid and the voltage was steady at 240 Volts on each side. I also tighten all connections that I could find after seeing this message and continued to see the same fault after activating power to the inverters again. There was no 5 minute count down activated after restarting the inverters. This is still a puzzle to me, although in the end is not hugely affecting my overall production over the year.
  • solar_davesolar_dave Solar Expert Posts: 2,330 ✭✭✭✭
    Re: Delayed startup of Grid Tie Inverter

    This seems a bit bizarre to me, I don't think my inverters will even start or display without AC connected. Perhaps the frequency is off the starting limits. But only when it is cold or early in the morning? Again all speculation on my part.
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Delayed startup of Grid Tie Inverter

    Not sure if this has been asked before or not: are the inverters outside where they are getting cold?
  • balee123balee123 Solar Expert Posts: 86 ✭✭
    Re: Delayed startup of Grid Tie Inverter

    They are outside on the north outside wall of the house. Inverters rated for outdoors.
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Delayed startup of Grid Tie Inverter
    balee123 wrote: »
    They are outside on the north outside wall of the house. Inverters rated for outdoors.

    Yes, but that introduces the possibility that the cold temps are affecting the Inverters' operation due to failed component or solder joint. It gets cold, doesn't detect the AC properly, warms up a bit, then connects. If you measure proper AC Voltage at the inverter(s) when that "No AC" message is displayed it kind of narrows it down to something wrong within the inverter itself.
  • balee123balee123 Solar Expert Posts: 86 ✭✭
    Re: Delayed startup of Grid Tie Inverter

    Solar Guppy,

    Is there anything else that could cause the messages "AC Not Detected" and "AC Mains Low" even though there appears to be a constant 240V measured at the AC breaker inside the inverters? I am just using a $20 VOM to measure the voltage.

    I've attached pictures of the serial numbers of these inverters to confirm they are UPGs.

    Attachment not found.Attachment not found.
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Delayed startup of Grid Tie Inverter

    Manufacture/install date 2003? Nine year old inverters. Not a hopeful sign. :blush:
  • balee123balee123 Solar Expert Posts: 86 ✭✭
    Re: Delayed startup of Grid Tie Inverter
    Yes, but that introduces the possibility that the cold temps are affecting the Inverters' operation due to failed component or solder joint. It gets cold, doesn't detect the AC properly, warms up a bit, then connects. If you measure proper AC Voltage at the inverter(s) when that "No AC" message is displayed it kind of narrows it down to something wrong within the inverter itself.

    How common are failed solder joints?

    In older inverters, what are the most common things that lead to eventually needing to replace them? Grid-tied or off grid.
  • BB.BB. Super Moderators Posts: 26,768 admin
    Re: Delayed startup of Grid Tie Inverter

    For thermal cycling, failed solder joints are very common (check components, connectors, wires soldered to board, things like FETs that are soldered to board but are bolted to heat sinks, etc.). Even contact surfaces (tin to tin will not, usually, last as long as gold to gold)--pull plugs/pluggable board to boar, etc... There is "Gold Mist" an "oil" for gold on gold connections. Standard tin on tin "greases" (I am not sure I would recommend anything containing silicon--problems with silicon out-gassing and getting into contacts/mechanical relays--can create "glass" in the presences of arcing when switching). Check leads from "transformers" and other off board to on board connections.

    Electrolytic and oil filled Capacitors--leak oils/electrolytes to outside, overheat/expand/leaks (replace)...

    Other common failures relate to air/water/etc. leaks along lead frames to internals of electronics. Also failed internal die bonds--Obviously stuff you cannot "fix" without replacing.

    You may fix with "inspection"/resoldering/cleaning contacts/looking for corrosion. Of course, you have about as good of chance of "bricking" the inverter too. FETs and other some other circuits can be easily damaged by static discharge (such as using a brush or compressed air for cleaning).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • balee123balee123 Solar Expert Posts: 86 ✭✭
    Re: Delayed startup of Grid Tie Inverter
    balee123 wrote: »
    Solar Guppy,

    Is there anything else that could cause the messages "AC Not Detected" and "AC Mains Low" even though there appears to be a constant 240V measured at the AC breaker inside the inverters? I am just using a $20 VOM to measure the voltage.

    I've attached pictures of the serial numbers of these inverters to confirm they are UPGs.

    Attachment not found.Attachment not found.

    Today I shutdown and then restarted the entire system. I have down this many times before with no issues. Upon restarting the system, one inverter, the STXR2500, seemed to "get stuck" and would not boot up, while the STXR1500 booted up normally. The LCD screen of the STXR2500 is shown in the attached photo. I tried rebooting several times and still could not get the STXR2500 to start. After letting the inverter "rest" with everything turned off, I attempted to reboot several more times and finally it kicked on.

    Solar Guppy...............any idea what does this LCD screen mean?

    I'm getting a very uneasy feeling.....:cry:

    Attachment not found.
  • Solar GuppySolar Guppy Solar Expert Posts: 1,959 ✭✭✭
    Re: Delayed startup of Grid Tie Inverter
    balee123 wrote: »
    So I had the "No AC Detected" message come up on the inverters and at the same time measured the AC Voltage on each side of the AC Main breaker which separates the inverter from the grid and the voltage was steady at 240 Volts on each side.

    Which breaker? your Main Breaker panel or the AC breaker in the Suntie wiring compartment?.

    If both units at the same time display AC NOT PRESENT, its not the units but the actual utility feed, upload a picture of you using a DVM, in the Suntie wiring compartment on the side of the breaker with wires doing into the inverter board compartment across the 240V ...

    As for the Start-up picture with the LCD stuck, not sure, could be the LCD is getting hung, possibly temperature related or about a dozen other things in the unit ...

    If the AC NOT PRESENT is only one unit at a time, pull the rain shield, then the inverter panel that's under it and tighten the AC connections and re-seat the CPU card ribbon connector

    Another avenue you can take is use FishBowl, a PC monitoring program, which connects to the Sunties DB9 port via an RS-232 Port to a computer and it will tell you exactly what all the operating parameters are, makes finding issue like this much easier. I'd recommend you use a laptop as they are floating and wouldn't be effected by the non-isolated RS-232 port on the Suntie

    Just click the Suntie link on the main page of www.solar-guppy.com
  • inetdoginetdog Solar Expert Posts: 3,121 ✭✭✭✭
    Re: Delayed startup of Grid Tie Inverter
    If both units at the same time display AC NOT PRESENT, its not the units but the actual utility feed, upload a picture of you using a DVM, in the Suntie wiring compartment on the side of the breaker with wires doing into the inverter board compartment across the 240V ...

    Depending on the design of the inverter (and I am not really familiar with the Suntie) there are at least three things that need to be present for AC to be "detected"

    1. Voltage. In addition to the 240 volt line to line, some inverters also look at the individual line to neutral voltages. If the incoming voltage is very unbalanced because of a high resistance neutral and unbalanced loads in your house or even a POCO problem, then the AC may not be acceptable. That is, 100 volts and 140 volts add up to 240, but will not meet the requirements.
    2. Frequency. It is harder to measure frequency unless you have a top-end digital meter, but the inverter will require that the frequency both stay within narrow limits and be stable for some period of time before it is accepted.
    3. The impedance of the grid needs to be and remain low, so that a test current pulse from the inverter will not be seen to cause a large voltage change. This is part of the design of many anti-islanding circuits. A high resistance wiring connection on the AC side (wires contracting in the cold?) can cause this to fault even if the voltage and frequency look OK. (Hence the need to check all of your AC connections.)
    SMA SB 3000, old BP panels.
  • sdcoffeeroastersdcoffeeroaster Registered Users Posts: 5
    I know this is a very old thread but I am having a similar problem with my SPR-2000 Sunpower inverter.  The system is about 10 years old and the inverter is in the garage with the array on the south facing 2nd story roof...no obstructions.  I recently installed 2 extra panels and now have two strings of 6 spr-215 sunpower panels.  My display reads about 275volts Dc in the early morning before the inverter turns on and this should no be preventing the array from starting..

     I typically have been seeing a start up around 7:45 am this time of year due to a hill in the back yard.   This is what I saw even after adding the two extra panels.  I also have 3 of my panels that are spr-240's since they were replaced last year on warranty (brown cells). We had a high wind event here recently while I was away.  Upon returning home I noticed the startup was not happening until 8;45am or so about an hr later than normal.  And then it would go to about 1000 watts instantly or so.  I have a mixture of MC3 and MC4 connections as well.  I've been thinking this might be a connection issue caused by the high wind but not really sure.  I also thought it was from the very cold but sunny days but it was around 58 F this morning when it was delayed.  The delay doesn't seem to happen unless it's sunny out.  And otherwise it behaves normally all day long.

    On a side note, my inverter will not go beyond about 1950 watts on the display.  This is actually only 1815 watts.  But within the +/- 10%.  But I did expect it to go to 2000 watts on the display at least, which is 1850 watts actual and that's what I was getting with the 10 panels before I added two more.  Not sure why it stops at 1950 but I'm guessing it has to do with the increased voltage.  I've added active fan cooling to the inverter to keep things cool with the increased load.  I realize that with about 2.6 kw array I will "top out" during the afternoon at what the inverter thinks is 2000 watts.  I just wish it was more accurate in it's limitation.
  • BB.BB. Super Moderators Posts: 26,768 admin
    Get a DC current clamp type dmm and measure the current on each string.

    If the current is more than 10% different between strings, look for bad panels and electrical connections.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • sdcoffeeroastersdcoffeeroaster Registered Users Posts: 5
    Thanks Bill.  Three panels were replaced by sunpower last year with spr-240 under warranty so 2 of those new ones are on one string and one is on another string.  The old ones had very hot running brown cells (EVA layer issue).  One of the used panels I bought also has a cell that is light brn.   My 7 original spr215's are 10 years old now.  I'm pointing this out because the two string might be a lot different.  I do have a clamping dmm but it's not very stable.  One from Harbor freight but I think an EE friend might have a better one I can borrow.  The HF one changes with orientation.  Maybe I can get sunpower to give me one more spr-240 to replace the one with the brown cell and better balance things out.

    Today I was going to record everything at startup...nice and sunny, 51 deg.  Well it started up early and read 250 Voc and went to about 229 V and 4 W about 1.5 hrs earlier than yesterday when it suddenly shot up to almost 1000 watts.  I'm going to check connections first today since this seems to have started about 2-3 months after adding the 2 used panels and right after a 2-3 day high wind event here.  Those MC3 connectors don't seem all that good and maybe I didn't fully tighten the new connections.  Thanks again 
  • sdcoffeeroastersdcoffeeroaster Registered Users Posts: 5
    BB. said:
    Get a DC current clamp type dmm and measure the current on each string.

    If the current is more than 10% different between strings, look for bad panels and electrical connections.

    -Bill
    My current clamp arrived and I'm measuring DC current today.  So far the two strings are within about 0.02-0,05 amps of one another and I'm up to about 900 watts.  I'm measuring every 100 watts to 1800 watts today.  The inverter has behaved lately.  I did change out the terminal block for AC out on the board.  I could not tighten the screw on the black wire (screw broken) so I found the exact replacement and now I have a good connection there.  That was a pain to un-solder and re-solder since the connector and the board traces really soak up the heat but I got a good solder joint by gradually removing and replacing this 3 terminal block and fed enough solder back into the joint.  I don't think this was the issue and I do have MC4 connectors that I want to replace on a couple of panels at the end of the string one day.

    This time of year where it's sunny and cool, my array is maxing out from about 10;45 am to 1:45 or so since I have more than 2 kw.  I did add active cooling on the inverter which works very well but I need to check the panels to see if they might be getting hot.  I only have one brownish cell in my entire array and my old panels that had brown cells ran very hot when I measured the brown cells so Sunpower replaced those.
  • BB.BB. Super Moderators Posts: 26,768 admin
    With the current matching the two strings so closely, either everything is OK, or the two strings have identical problems (unlikely, but possible).

    So is all working OK for you now? 10+ years on a central GT inverter is not bad--I would be saving money for a replacement (electronics last about 10+ years, and units over ~5 years old are difficult to get repaired / find replacement parts).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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