new on solar energy

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  • voyagervoyager Solar Expert Posts: 35
    Re: new on solar energy
    BB. wrote: »
    OK--GT inverter--Then that is fine.

    The wire size from the array to the GT inverter is capable of supporting 50 amps (according to your code)?

    Also--You should have a dedicated branch circuit from your main AC panel to the GT inverter. The dedicated circuit should be:

    2,500 Watts * 1/110 VAC * 1.25 NEC derating = 28.4 ~30 amp minimum 110 VAC branch circuit

    Or based on your 900 Watt array:

    900 Watts * 1/100 VAC minimum * 1.25 Wiring derating * 1.25 Solar derating = 14 amp ~15 amp minimum branch circuit rating with 900 Watt solar array

    If you do not plan on adding more panels to the 900 Watt array, then a 15 amp circuit is "enough"... If you plan on installing more panels--Then you may want to install a 30 amp branch circuit (check the inverter's rating/installation manual--I am taking some guesses here).

    -Bill

    Bill, I installed the 12 AWG 4 wire cable (Red/Black/White/Green-Ground) for the GT inverter installation. The output of the GT inverter is connected directly to a 30 Amp branch circuit from the main panel.

    I am not sure if the 12 AWG 4 wire cable, supports 50 Amps. Do you know if it is OK?

    I know that the main panel, supports 120 VAC and 220VAC but I am not sure if it supports the 900 Watts or 2500Watts of the inverter.Tomorrow, will accompany me during installation, an electrician specialist. I will ask him if the main panel of my house support 900Watts / 2500 Watts and 30 Amps of the inverter.

    The inverter manual say:

    AC Output Power: 2500 Watts
    AC Output Voltage Range: 110V ~ 120V
    AC Output Frequency range: 60 hz for 110V
    Total Harmonic Distortion (THD): <5%
    Power Factor: 0.99
    DC Input voltage range: Marked 28V ~ 48V
    Output Current Waveform: Pure Sine-Wave
    MPPT Function: Yes
    Over Current Waveform: Yes
    Over Temperature Protection: Yes
    Reverse Polarity Protection: Yes
    Island Protection: Yes
    Stackable: Yes
    Maximum temperature range: -10°C ~ 65°C
    Normal temperature range: 0°C ~ 40°C
    Storage temperature range: -15°C ~ 75°C

    And this is the led situation of the inverter:

    Attachment not found.

    - Juan
  • ILFEILFE Solar Expert Posts: 364 ✭✭
    Re: new on solar energy

    I thought using home made panels for grid tied applications would not meet code, due to the fact that they were not manufactured panels?
    Or, am I wrong here?

    Let me clarify this by saying that I am speaking of legalities and electric code within the United States.
    Paul
  • voyagervoyager Solar Expert Posts: 35
    Re: new on solar energy
    ILFE wrote: »
    I thought using home made panels for grid tied applications would not meet code, due to the fact that they were not manufactured panels?
    Or, am I wrong here?

    Let me clarify this by saying that I am speaking of legalities and electric code within the United States.

    Hi Paul I am living in Monterrey (Mexico)

    I spoke with the power company and is legal to install grid tied solar. They dont have problem using home made panels.

    I have the old mechanical meter that turn "forward" when buying electricity and that run "backwards" when feeding excess power to the grid. That is my case. The power company offered me to change the meter to the correct one free, in case that my utility meter can not run "backward"

    - Juan
  • mike95490mike95490 Solar Expert Posts: 8,292 ✭✭✭✭✭
    Re: new on solar energy
    Anti-Island protection
    That tells me it's a strictly grid tie inverter, and would not need batteries. If you use batteries, it will flatten them in minutes as it turns battery power into grid power, and then you have dead batteries all night. Next day, the batteries will never charge, as the inverter sucks all the power. And if your grid goes down, your inverter will shAnti-Island protectionut off too. (pesky Anti-Island protection)
    Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
    || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

    solar: http://tinyurl.com/LMR-Solar
    gen: http://tinyurl.com/LMR-Lister ,

  • BB.BB. Super Moderators, Administrators Posts: 29,241 admin
    Re: new on solar energy
    voyager wrote: »
    I am not sure if the 12 AWG 4 wire cable, supports 50 Amps. Do you know if it is OK?

    No, 12 AWG will (typically) only support ~20 amps maximum (US NEC)... I do not know what is "legal" in Mexico.

    Using the US NEC, pretty much the minimum to support ~50 amp breaker, you would need 8 AWG wire (there are insulation, temperature, and conduit fill factors too--If you are following the NEC):

    https://lugsdirect.com/WireCurrentAmpacitiesNEC-Table-301-16.htm
    I know that the main panel, supports 120 VAC and 220VAC but I am not sure if it supports the 900 Watts or 2500Watts of the inverter.Tomorrow, will accompany me during installation, an electrician specialist. I will ask him if the main panel of my house support 900Watts / 2500 Watts and 30 Amps of the inverter.

    The main panel--There are several "rules" that need to be followed (in the US). First one, is what is the box rated in terms of supported circuit breakers. Usually, 15 amp would be the minimum that any current box would support--And they can go much larger.

    The second--Again in the US, there is the maximum current you are allowed to put on the main bus bars. We would use 120% of the bus bar/box rating.

    Say your box is rated for 125 amp main breaker+bus bars. The 120% rating would be:

    125 Amps * 1.20 = 150 Amps total

    Then the maximum GT Inverter branch circuit would be:

    150 Amps total - 125 Amp main breaker = 25 amp maximum GT branch circuit.

    You can also (in some cases) derate the Main Breaker:

    150 Amp total - 100 Amp main breaker = 50 amp maximum GT branch circuit.

    And then there is where to install the GT branch breaker(s)... If the Main breaker is at the "top" of the bus bars--Then the GT branch circuit breaker(s) should be installed at the "bottom" end of the bus bars (opposite end of bus bars from main breaker).

    Note--Your GT inverter is 110 VAC output--So, if you have 120/240 VAC split phase power (typical North American service), you could put a (for example) 25 Amp 110 VAC breaker on the "black" phase and a second 25 Amp breaker on the "red" phase. Or you could put a pair of 25 amp breakers if your GT inverter had 220 VAC output.
    The inverter manual says:

    AC Output Power: 2500 Watts
    AC Output Voltage Range: 110V ~ 120V
    AC Output Frequency range: 60 hz for 110V
    Total Harmonic Distortion (THD): <5%
    Power Factor: 0.99
    DC Input voltage range: Marked 28V ~ 48V
    Output Current Waveform: Pure Sine-Wave
    MPPT Function: Yes
    Over Current Waveform: Yes
    Over Temperature Protection: Yes
    Reverse Polarity Protection: Yes
    Island Protection: Yes
    Stackable: Yes
    Maximum temperature range: -10°C ~ 65°C
    Normal temperature range: 0°C ~ 40°C
    Storage temperature range: -15°C ~ 75°C

    There should be a Maximum Amperage output rating for the GT inverter too (something like 28 Amps maximum at 110 VAC).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • ILFEILFE Solar Expert Posts: 364 ✭✭
    Re: new on solar energy
    voyager wrote: »
    Hi Paul I am living in Monterrey (Mexico)

    I spoke with the power company and is legal to install grid tied solar. They dont have problem using home made panels.

    I have the old mechanical meter that turn "forward" when buying electricity and that run "backwards" when feeding excess power to the grid. That is my case. The power company offered me to change the meter to the correct one free, in case that my utility meter can not run "backward"

    - Juan

    Thank you for clarifying that. If you stated where you lived it elsewhere in the thread, I must have missed it. I too, am not living in the US. I live in Cambodia at the moment. There are many things regarding electrical power that we can do here, which would not be within guidelines of the National Electric Code or legal in the US.
    Paul
  • voyagervoyager Solar Expert Posts: 35
    Re: new on solar energy
    mike95490 wrote: »
    That tells me it's a strictly grid tie inverter, and would not need batteries. If you use batteries, it will flatten them in minutes as it turns battery power into grid power, and then you have dead batteries all night. Next day, the batteries will never charge, as the inverter sucks all the power. And if your grid goes down, your inverter will shAnti-Island protectionut off too. (pesky Anti-Island protection)

    Thank you mike95490. I am not going to use batteries at this moment.
  • voyagervoyager Solar Expert Posts: 35
    Re: new on solar energy
    BB. wrote: »
    No, 12 AWG will (typically) only support ~20 amps maximum (US NEC)... I do not know what is "legal" in Mexico.

    Using the US NEC, pretty much the minimum to support ~50 amp breaker, you would need 8 AWG wire (there are insulation, temperature, and conduit fill factors too--If you are following the NEC):

    https://lugsdirect.com/WireCurrentAmpacitiesNEC-Table-301-16.htm


    -Bill

    Hi Bill, based in your commentaries, I am going to use a 30A Midnite Circuit Breaker (I have this circuit breaker too). I understand that is enough for 900 Watts panels (14 ~ 15 Amp). In my case the cable that I am using is 12 AWG 90°C Copper Conductors. I understand that it can support 30 Amps (NEC Table). The diagram has change as follows:

    Attachment not found.

    - Juan
  • voyagervoyager Solar Expert Posts: 35
    Re: new on solar energy

    Hi Bill, it is me again.

    I received the response about your question of the inverter:

    "our inverter 2500w and ac 110v ,if you want to know the max current for output , that is 2500w *0.87 effiency / 110v=19.77A"

    The system is working perfect since yesterday at 2pm. It is generating a average of 529 Watts per hour with the 2 panels. Let see what happen today with the average. Yesterday the system stop producing electricity at 7pm and today it begun to produce electricity at 8:30am.

    Yesterday, I did a test with a minimum of electricity use in my house (like when nobody is in the house, only some things consuming like refrigerator, clocks, some appliances,etc), and electric meter stopped completely.. I will go with company power because they are going to change free the electric meter for a Bidirectional one.

    Now I am going to begin to build the third one panel and begin tests to heat water as a boiler and also have savings on the gas bill.

    Thank you.

    - Juan
  • BB.BB. Super Moderators, Administrators Posts: 29,241 admin
    Re: new on solar energy

    Juan,

    A little change to your equation... usually the Wattage (at should be) the output rating of the inverter--So, no derating needed there:
    • 2,500 Watts / 110 Volts = 22.7 amps

    And then to derate the branch circuit using the NEC value:
    • 22.7 amps * 1.25 NEC derating = 28.4 amps ~30 Amp rated branch wiring and circuit breaker minimum (to run full 2,500 Watt or VA load).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • ILFEILFE Solar Expert Posts: 364 ✭✭
    Re: new on solar energy

    Juan,

    Do you happen to have any larger images of your panels? I have to say, your work appears to be as good as any industrial produced panel I have seen.

    I am truly impressed, sir.
    Paul
  • voyagervoyager Solar Expert Posts: 35
    Re: new on solar energy

    Thank you BB for all your help and information.
  • voyagervoyager Solar Expert Posts: 35
    Re: new on solar energy
    ILFE wrote: »
    Juan,

    Do you happen to have any larger images of your panels? I have to say, your work appears to be as good as any industrial produced panel I have seen.

    I am truly impressed, sir.

    Thank you very much Paul. I started 40 days ago without any knowledge about solar panels and now I have my system running. I have worked hard to develop my invention of the process always with a big support of the people of the forum, I am very grateful. I am going to build the third panel and it is going to be better that the first two panels. All the time I have more a more ideas.

    This afternoon, it was a very rainy and cloudy day in Monterrey. However, the panels were generating energy until 7:30 pm without problems.

    The company power is going to change free the electric meter for a Bidirectional one the next week.

    Do you know, how can I share with the forum larger images?

    - Juan
  • ILFEILFE Solar Expert Posts: 364 ✭✭
    Re: new on solar energy

    Um, email them to me and I will put them on a hosting site for you, if you want?

    yahoo (dot) paul (@) gmail (dot) com

    I have to go out for a bit to run an errand, but will be back in an hour or two.
    Paul
  • voyagervoyager Solar Expert Posts: 35
    Re: new on solar energy

    Hi Paul. Sorry for the delay. I sent the picts to your email.

    - Juan
  • ILFEILFE Solar Expert Posts: 364 ✭✭
    Re: new on solar energy
    voyager wrote: »
    Hi Paul. Sorry for the delay. I sent the picts to your email.

    - Juan

    For those interested in viewing larger photos of Juan's work, you may view them at the following link:

    Juan's photos on DropBox - 1600 x 1200 pixels
    Paul
  • voyagervoyager Solar Expert Posts: 35
    Re: new on solar energy

    Thank you Paul. The panels at today are working without any problem. I will be posting status regularly. I think I will have the third panel ready the next week.

    - Juan
  • ILFEILFE Solar Expert Posts: 364 ✭✭
    Re: new on solar energy
    voyager wrote: »
    Thank you Paul. The panels at today are working without any problem. I will be posting status regularly. I think I will have the third panel ready the next week.

    - Juan

    Happy to help, sir, any time.
    Paul
  • voyagervoyager Solar Expert Posts: 35
    Re: new on solar energy

    Hi Bill, I just wanted to inform you that the panels are working properly. I have seen no variation in the amount of power being generated. We have had days of heavy rain and strong winds, and the panels have remained stable.

    Something that caught my attention was that last week we did not have service from the electric company by a problem in the area.

    I thought, that the solar panels will continue giving energy to the house. And this was not the case, since the inverter stopped working until the service was reactivated by the electricity company. From what I understand, the inverter requires to have service of the electricity company to function.

    Can you explain me, what I have to do to use electricity from the solar panels even when we do not have service of the electricity company? I am interested that inverter remains with the same function to be "grid tie".

    Thank you,

    - Juan
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: new on solar energy
    voyager wrote: »
    Hi Bill, I just wanted to inform you that the panels are working properly. I have seen no variation in the amount of power being generated. We have had days of heavy rain and strong winds, and the panels have remained stable.

    Something that caught my attention was that last week we did not have service from the electric company by a problem in the area.

    I thought, that the solar panels will continue giving energy to the house. And this was not the case, since the inverter stopped working until the service was reactivated by the electricity company. From what I understand, the inverter requires to have service of the electricity company to function.

    Can you explain me, what I have to do to use electricity from the solar panels even when we do not have service of the electricity company? I am interested that inverter remains with the same function to be "grid tie".

    Thank you,

    - Juan

    You need batteries, and/or a different inverter.
    No grid = no output from a standard GTI.
    A hybrid type GTI will have batteries (and a charge controller) and can continue to supply critical loads when the grid goes down.
    Also SMA has a new model with a built-in 'emergency' power system that can supply a limited amount of power when the grid goes down without batteries.
    The only other option is a separate battery-based inverter that can be AC coupled to your existing system.
    None of these options are cheap or easy to implement.
  • BB.BB. Super Moderators, Administrators Posts: 29,241 admin
    Re: new on solar energy

    ore
    voyager wrote: »
    Hi Bill, I just wanted to inform you that the panels are working properly. I have seen no variation in the amount of power being generated. We have had days of heavy rain and strong winds, and the panels have remained stable.

    Panel voltage will remain about constant at Vmp (once you have minimal direct sunlight)--And will vary with temperature (cold, higher Vmp-array, etc.). Assuming the MPPT function of your GT inverter is working correctly.
    Something that caught my attention was that last week we did not have service from the electric company by a problem in the area.

    I thought, that the solar panels will continue giving energy to the house. And this was not the case, since the inverter stopped working until the service was reactivated by the electricity company. From what I understand, the inverter requires to have service of the electricity company to function.

    The GT inverter will attempt to hold Vmp-array steady while varying Imp-array to keep Vmp stable (i.e., if Vmp starts falling, the GT inverter will dial back on the current a little bit).

    So--Power=Vmp*Imp or really Power= Vmp * Ipanel based on amount of sun.

    The second 1/2, of the issue is that a GT Inverter's 120 VAC output is "in parallel" with the 120 VAC utility power.... Very much like your alternator for the car is in parallel with the car's lead acid battery. The lead acid battery holds ~12vdc, and the alternator adds current to keep the (charging voltage of the battery). If the 12 volt battery bank "goes near dead", the alternator cannot generate enough voltage/current to keep the battery bus at 12 volts.

    Pretty much how the GT inverter works. It looks for 120 VAC +/- ~10%... If the line voltage falls too much, or goes too high (or the 60 Hz frequency goes out by +0.5 Hz or more), the GT inverter will shut down to prevent electrocution (line men) and/or giving low voltage (brown out) to the appliances (in reality, a GT inverter is not designed to regulate to 120 VAC at 60 Hz, it only "follows" the voltage/frequency set by the much larger AC utility generators). A "small" GT inverter could never supply enough current/power to run the home, let alone the rest of the neighborhood.
    Can you explain me, what I have to do to use electricity from the solar panels even when we do not have service of the electricity company? I am interested that inverter remains with the same function to be "grid tie".

    More or less, you have two options. One is the traditional Off Grid AC inverter and battery bank. The Solar panels + charge controller provide energy to the battery bank, which the Off Grid inverter uses to produce 120 VAC @ 60 Hz power to run your home. You cannot connect an Off Grid AC inverter directly the to the grid and share (feed back power) back to the grid.

    The second option is a "Hybrid" AC inverter... It combines the function of a standard AC Inverter+Charger and the battery bank+solar panels+solar charger (as above). You connect:

    AC mains to AC1 input on the Inverter+charger+internal AC transfer switch and both to the DC battery bank and an AC sub-panel.

    When the AC mains are "up", the AC power goes through the inverter to the sub-panel to power your loads. The inverter+charger can charge the battery bank (like a UPS). And, the Hybrid inverter can take "excess battery charging current" (when batteries are full) and dump that power to the grid (i.e., the AC inverter uses the grid like a dump load).

    When the AC mains fail, the AC Transfer switch fails and the Hybrid Inverter turns into an "Off Grid" AC inverter powering your sub-panel from the battery bank.

    There are several types of Hybrid inverters with various AC and AC generator inputs, GT capability, and other capabilities.

    The problem is that if your AC mains power is relatively stable with few outages (and outages that last less than 1-2 weeks), a backup genset+GT Solar is better than going with a Hybrid Inverter + Battery bank (and still should have a backup up genset too--for bad weather and 2nd AC backup power).

    In general, GT Inverter+Solar panels + backup genset + stored fuel (or natural gas, etc.) is usually more cost effective. The large battery bank needs replacing every 3-8+ years--Depending on battery quality, maintenance, type, how much is is used, etc.

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