Plug in PV appliance.

denlowdenlow Posts: 8Registered Users
Anyone else catch this article on CNET about a system to just plug PV panels directly into a 120v outlet (panel mounted micro inverter)?

How do you suppose this might work as a supplement to an off-grid battery based system?


  • firerescue712firerescue712 Posts: 89Solar Expert ✭✭
    Re: Plug in PV appliance.

    Wouldn't this be like a grid tie situation? Would it not need the approval of the power company? I love this idea, if it is legal and approved. I can see the power companies saying no to this because it could send an electrical current through the power lines in the event of a downed power line, thus jeopardizing the safety of the linemen.
  • denlowdenlow Posts: 8Registered Users
    Re: Plug in PV appliance.
    .... it could send an electrical current through the power lines ....
    The web site claims an "auto shut-down" if power is lost.
  • BB.BB. Posts: 26,187Super Moderators admin
    Re: Plug in PV appliance.

    It is the "plug and play" that is the issue...

    First, when you put different power sources on a generic home outlet, it is possible to supply to much current to a circuit and cause of fire if a) too many loads are plugged in or b) if there is a short to ground somewhere.

    When you just plug an AC power source into the circuit--you add the current of the 15 amp breaker + the couple amps of current from each plug-in device... You can easily add add another 15 amps of 120 VAC solar panels to the circuit and now you have ~30 amps of available power on a circuit that can only carry ~15 amps safely before the circuit breaker would have tripped.

    Second, there is mounting the panels, conduit/UV resistance wiring, and structural issues with the installation. Yes--it will work if you plug it in, but it may blow off in a storm, insulation may fail and start a fire, or you may get a lightning strike and bring the energy into your kids bedroom (and a 100 other "accidents" waiting to happen).

    Lastly, the new power meters from the utilities can do some pretty neat/weired stuff... The new digital meters "phone home" and can easily report back if you are generating more power than you use (my home averages around 250 watts much of the time, a 1,000 watts of solar panels will report back 750 watts of power generation). The utility has the option of turning you in, pulling your electric meters (or remotely turn off your power these days), and even get your home "red tagged" by the local inspectors.

    And the very old meters would simply turn forward when you used power and turn backwards when you generate power. The new meters may work that way (my approved GT system does exactly that), or they may not turn backwards (you give the utility free power), or they may even turn forwards (the utility charges you for giving them free power).

    There are simply too many issues that will prevent a "legal" plug and play system for an "old" home.

    If some day, new homes are required to put a "plug on the roof", engineered for structure mounting of panels, and the utility makes net metering "standard" practice for all homes--Then--yes, you could have much closer to a plug and pay system... But even then, I have seen codes change, especially around solar, and what somebody tries to get "pre-wired" may not be legal 10 years from now without changes/upgrades anyway.

    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • nielniel Posts: 10,311Solar Expert ✭✭✭✭
    Re: Plug in PV appliance.

    try reading these threads on the subject matter.
    i can say this arrangement is not safe and would not be approved by ul as a system as they present it.
  • solar_davesolar_dave Posts: 2,313Solar Expert ✭✭✭
    Re: Plug in PV appliance.
    niel wrote: »
    try reading these threads on the subject matter.
    i can say this arrangement is not safe and would not be approved by ul as a system as they present it.

    Try this link instead
  • rollandelliottrollandelliott Posts: 755Solar Expert ✭✭
    Re: Plug in PV appliance.

    I wonder what 120 micro inverter they are using? They only 120v micro inverters I have heard of are the junk ones on ebay that are horribly ineffcient.

    anyways at $1100 for 240 wattts, its way over priced. the panel is worth $240 and the micro inverter is probably worth about $240 as well, or a total of $480.

    I guess that makes the plug they add on the end worth $620!!!!! Nice markup! Now I know why they call it Green Technology! LOL.
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