ret60sp
New Member
There's a guy on Youtube claiming to be able to power his whole home, charge one or more Tesla(s) and do it with two 6k inverters, four batteries and 12k of solar PV.
Most of yall already know most of this. Some don’t. Not criticizing the approach here – just sharing a different approach based on the various experiences we encountered as we started with our first 4.1 Kw solar system and have now progressed to the 16.8 Kw system we have today.Note: Its actually against the law in every state to attach a power system to your home, if your home is connected to the grid, and said system is not completely inspected by a licensed and bonded agent of the utility service. Also, you might not be covered by your homeowner insurance in the event something goes haywire if it wasn’t approved and inspected by your utility service. Its called “an interconnect agreement”. Simply having an interlock installed in your primary load center may be insufficient and a violation of your utility service providers power agreement, city, county, state or National Electric Code requirements. That breaker in your panel doesn’t provide much of an “air gap” to disconnect your system from the grid. Conversely, a true manual and/or automatic transfer switches will “air gap” the disconnect sufficiently to prevent almost all possibility of a power bridge. So know what the code is for your locality before connecting an inverter or standby generator into your electrical system.
A homeowner can save a bunch of money if everything they install is MANUAL. The problem with little or nothing being automatic is little or nothing is protected from errant voltage (lightning / EMP) that originates from the grid. MANUAL also requires the homeowner to be HOME when the power fails, otherwise all of their frozen and refrigerated goods will be thawing out starting the moment the lights go out.
A fully AUTOMATIC system is (arguably) twice as expensive as a manual system. Sure there are exceptions. And yes, fully automatic means just that – completely hands off.
AUTOMATIC means the system continues to power the appliances when the grid fails. If sufficient quality components are installed and the system is hardened against lightning/EMP there is a very good chance nothing will fail and all of your freezers and refrigerators will continue in operation uninterrupted. You’ll come home to the lights on, hot water being available and your home environment being comfortable, even if the grid power is down.
A MANUAL system that experiences an outage with the homeowner away from home will result in a decline in the set point temperatures for all of the various appliances – resulting in a “call” for those appliances to turn “on” as soon as power is restored. This creates a whole new problem in itself. When the homeowner returns home and notices that the lights are out, and turns on the MANUAL system, ALL of the appliances that have thermostats (water heater, HVAC, refrigerator, freezer, spa, pool, etc) will instantly be in “call” (need to be “on”) and with so many appliances in demand at the same time, the battery based inverter system will trip into overload. The homeowner will then have to play the shell game to incrementally isolate the things they want on first and last to recover their living environment.
An AUTOMATIC system (typically costs a lot more) includes an Automatic Transfer Switch (ATS) that disconnects the system from the line side of the grid when grid power fails. This is an interconnect requirement to prevent homeowners from accidently designing systems that can kill a lineman up the street trying to restore grid power.
Well designed automatic systems will delay the start of a standby generator if sufficient power is available via battery or PV to meet the load demand. As the batteries deplete, and with no PV present, smart inverters can be programmed to use the two wire start feature to automatically start a standby generator, which will then be used to recharge the batteries and meet the load demand of the appliances installed in the home. Typically, as the charge reaches about 95% the smart inverter will send a “stop” command to the generator, disconnecting the generator and resuming battery only usage until grid power is restored, the sun comes up or it enters into another standby generator run cycle.
MANUAL systems are easily overloaded. Its easy to demonstrate that a system might be able to run a household for 15-30 minutes without a problem. The real measurement is to turn the grid power off, touch nothing else, and see how long it will operate before the combination of subsequent events causes an overload. Bring a flashlight – its going to happen.
On a manual system its inevitable to overload. It will especially overload if the homeowner is not home. All it takes is for the water heater and the spa to be on at the same time and the HVAC system have a “call” and POP! And that’ll be the end of the power going to your refrigerators and freezers until you get home and go through the manual switchology to isolate those large appliances. Oh, sure, some inveters will reset themselves and turn back on, only to again encounter an over demand and trip off again. Some inverter manufacturers software will recycle this three times and then stay off.
Oh, and don’t think it’ll be a simple switch this and that and everything will be normal in 20 minutes. Not so fast. Those refrigerators and freezers might have 2-10+ degrees to recover, and that’ll mean the duty cycle will be 100% for an hour or more as they cool things back down. Then your water heater will have the same demand, as will the spa and HVAC systems. It could take HOURS to bring things back to normal, assuming you have enough battery power stored to accomplish the task. In a manual system, It can take longer to restore normalcy than the amount of time the power was actually off.
So while you are running around trying to hobble together a power management plan and an order of merit for what needs power first, someone in the house throws something into the microwave and this high power consumer trips the inverter as you are sitting there trying to squeeze out the best efficiency options you might have thought you had. Or, your wife starts a hair dryer after taking a bath, and the combination of the water heater (5500 watts) trying to restore the heat in itself after her bath, combined with the 1600 watts draw of the hair dryer, and the 1100 watts drawn from the coffee maker, and suddenly everything gets quiet. Poof! Lights out!
What most people need to know is: Without batteries attached to a charger/inverter, solar panels will turn off when the power goes out. That means they will NOT supply power to anything unless they can (at a minimum) detect a stable sine wave that (here in the US) meets the UL-1741 standard. Most standby generators will not meet this standard, and any attempt to use a small generator in tandem with solar panels will result in damage or a dysfunctional system.
Small generators (typically <20Kw) can’t maintain 60 hertz plus or minus 0.5 hertz, nor can they maintain the voltage at 120/240 VAC plus or minus 7. Our 20Kw B&G generator won’t produce stable enough power to satisfy the tight parameters designed in to all microinverters, so a large (< 5K) inverter is required to manage the standby power source. You simply cannot use microinverters with a standby generator alone. This might surprise some, and folks on here might claim that they’ve got it to work, but it (UL1741) is intentionally designed to preclude these things working together reliably. I know, because we had to replace our microinverters on the first setup twice and go to a standard MPPT controller/inverter and eventually wire that Solaredge system away from the standby generator power source.
We now have three primary load centers. #1 is controlled and powered by the twin 12k Sol-Arks, getting its power from grid, solar, battery and standby generator. #2 is powered by grid and standby generator only. #3 is powered by grid only, but has the Solaredge feeding into it to reduce the grid load demand during the day.
Most of yall already know most of this. Some don’t. Not criticizing the approach here – just sharing a different approach based on the various experiences we encountered as we started with our first 4.1 Kw solar system and have now progressed to the 16.8 Kw system we have today.Note: Its actually against the law in every state to attach a power system to your home, if your home is connected to the grid, and said system is not completely inspected by a licensed and bonded agent of the utility service. Also, you might not be covered by your homeowner insurance in the event something goes haywire if it wasn’t approved and inspected by your utility service. Its called “an interconnect agreement”. Simply having an interlock installed in your primary load center may be insufficient and a violation of your utility service providers power agreement, city, county, state or National Electric Code requirements. That breaker in your panel doesn’t provide much of an “air gap” to disconnect your system from the grid. Conversely, a true manual and/or automatic transfer switches will “air gap” the disconnect sufficiently to prevent almost all possibility of a power bridge. So know what the code is for your locality before connecting an inverter or standby generator into your electrical system.
A homeowner can save a bunch of money if everything they install is MANUAL. The problem with little or nothing being automatic is little or nothing is protected from errant voltage (lightning / EMP) that originates from the grid. MANUAL also requires the homeowner to be HOME when the power fails, otherwise all of their frozen and refrigerated goods will be thawing out starting the moment the lights go out.
A fully AUTOMATIC system is (arguably) twice as expensive as a manual system. Sure there are exceptions. And yes, fully automatic means just that – completely hands off.
AUTOMATIC means the system continues to power the appliances when the grid fails. If sufficient quality components are installed and the system is hardened against lightning/EMP there is a very good chance nothing will fail and all of your freezers and refrigerators will continue in operation uninterrupted. You’ll come home to the lights on, hot water being available and your home environment being comfortable, even if the grid power is down.
A MANUAL system that experiences an outage with the homeowner away from home will result in a decline in the set point temperatures for all of the various appliances – resulting in a “call” for those appliances to turn “on” as soon as power is restored. This creates a whole new problem in itself. When the homeowner returns home and notices that the lights are out, and turns on the MANUAL system, ALL of the appliances that have thermostats (water heater, HVAC, refrigerator, freezer, spa, pool, etc) will instantly be in “call” (need to be “on”) and with so many appliances in demand at the same time, the battery based inverter system will trip into overload. The homeowner will then have to play the shell game to incrementally isolate the things they want on first and last to recover their living environment.
An AUTOMATIC system (typically costs a lot more) includes an Automatic Transfer Switch (ATS) that disconnects the system from the line side of the grid when grid power fails. This is an interconnect requirement to prevent homeowners from accidently designing systems that can kill a lineman up the street trying to restore grid power.
Well designed automatic systems will delay the start of a standby generator if sufficient power is available via battery or PV to meet the load demand. As the batteries deplete, and with no PV present, smart inverters can be programmed to use the two wire start feature to automatically start a standby generator, which will then be used to recharge the batteries and meet the load demand of the appliances installed in the home. Typically, as the charge reaches about 95% the smart inverter will send a “stop” command to the generator, disconnecting the generator and resuming battery only usage until grid power is restored, the sun comes up or it enters into another standby generator run cycle.
MANUAL systems are easily overloaded. Its easy to demonstrate that a system might be able to run a household for 15-30 minutes without a problem. The real measurement is to turn the grid power off, touch nothing else, and see how long it will operate before the combination of subsequent events causes an overload. Bring a flashlight – its going to happen.
On a manual system its inevitable to overload. It will especially overload if the homeowner is not home. All it takes is for the water heater and the spa to be on at the same time and the HVAC system have a “call” and POP! And that’ll be the end of the power going to your refrigerators and freezers until you get home and go through the manual switchology to isolate those large appliances. Oh, sure, some inveters will reset themselves and turn back on, only to again encounter an over demand and trip off again. Some inverter manufacturers software will recycle this three times and then stay off.
Oh, and don’t think it’ll be a simple switch this and that and everything will be normal in 20 minutes. Not so fast. Those refrigerators and freezers might have 2-10+ degrees to recover, and that’ll mean the duty cycle will be 100% for an hour or more as they cool things back down. Then your water heater will have the same demand, as will the spa and HVAC systems. It could take HOURS to bring things back to normal, assuming you have enough battery power stored to accomplish the task. In a manual system, It can take longer to restore normalcy than the amount of time the power was actually off.
So while you are running around trying to hobble together a power management plan and an order of merit for what needs power first, someone in the house throws something into the microwave and this high power consumer trips the inverter as you are sitting there trying to squeeze out the best efficiency options you might have thought you had. Or, your wife starts a hair dryer after taking a bath, and the combination of the water heater (5500 watts) trying to restore the heat in itself after her bath, combined with the 1600 watts draw of the hair dryer, and the 1100 watts drawn from the coffee maker, and suddenly everything gets quiet. Poof! Lights out!
What most people need to know is: Without batteries attached to a charger/inverter, solar panels will turn off when the power goes out. That means they will NOT supply power to anything unless they can (at a minimum) detect a stable sine wave that (here in the US) meets the UL-1741 standard. Most standby generators will not meet this standard, and any attempt to use a small generator in tandem with solar panels will result in damage or a dysfunctional system.
Small generators (typically <20Kw) can’t maintain 60 hertz plus or minus 0.5 hertz, nor can they maintain the voltage at 120/240 VAC plus or minus 7. Our 20Kw B&G generator won’t produce stable enough power to satisfy the tight parameters designed in to all microinverters, so a large (< 5K) inverter is required to manage the standby power source. You simply cannot use microinverters with a standby generator alone. This might surprise some, and folks on here might claim that they’ve got it to work, but it (UL1741) is intentionally designed to preclude these things working together reliably. I know, because we had to replace our microinverters on the first setup twice and go to a standard MPPT controller/inverter and eventually wire that Solaredge system away from the standby generator power source.
We now have three primary load centers. #1 is controlled and powered by the twin 12k Sol-Arks, getting its power from grid, solar, battery and standby generator. #2 is powered by grid and standby generator only. #3 is powered by grid only, but has the Solaredge feeding into it to reduce the grid load demand during the day.
