Grounding a Wind and Solar System

Hey folks,

I have a 1.3kW offgrid solar system, with battery bank and propane generator backup. Looking to tie my new Air-X 400 into the system, and it needs a ground. Is it ok to tie the wind generator into the existing system's grounding rod?

The reason I'd like to do it is the wind gen will be about 80' from the solar/battery shed on top of a rocky hill, where digging for a 6' or 8' grounding rod will be really tough. It will be tough enough to get the guy-wire augers in the ground to support the pole. Suggestions?

Chris

Comments

  • BB.BB. Super Moderators, Administrators Posts: 29,985 admin
    Re: Grounding a Wind and Solar System

    My two cents, I would probably just tie the three (or how ever many) augers together with buried "bare" copper wire in a star shape back to the tower (in the center).

    The DC/electrical ground for the wind turbine, I would not attach that at the tower. It should already be grounded back at your battery shed.

    Multiple electrical grounds can be a problem... If you have a near by strike, you will get a voltage gradient across the ground... If you put two ground stakes 100' apart they will have hundreds (or even thousands) of volts across them (and induced as current in your copper wire through any connected devices).

    With a single ground connection, it is much harder for this to happen (there is only one ground "reference" for all of your electrical devices--so you cannot develop a voltage across your grounds).

    Sometimes, in areas with rocky ground, or poor soil conductivity, they will put several ground rods in (and/or bury bare copper wire). The normal way is to lay everything out as a "star" shape, all running back to the center--then make your electrical equipment ground at the center of the star--again, so you don't get any current flow induced into your electrical/safety ground).

    If you have any HAM radio (amateur radio) friends, or search for grounding on HAM sites, you will find a ton of information (and some of it will conflict with other advice on the same site).

    Many times, there is no exactly correct answer--but combining multiple, but conflicting, suggestions can make problems worse.

    Lastly, I am not a big fan of home wind--I would usually like to see somebody add more solar panels instead of spending it on home wind turbines (turbines are "cheap", but lack of "clean and steady winds", towers/masts (short towers in dirty wind, tall towers need cranes to service), cost to erect, cost of maintenance and parts, down time, overall make wind turbines pretty expensive). But, if you have enough solar and batteries, and need power for when the sun doesn't shine, it is hard to argue against trying a wind turbine.

    -Bill

    PS: I would also suggest that you put some sort of Watt*Hour or Amp*Hour meter (don't know the company or product) on your wind turbine so you can see how much energy it is contributing to your system, and recording the data at least monthly.

    In general, it has been very hard to get that sort information from wind turbine owners, even happy ones.

    Lastly, I would suggest a battery monitor to ensure your batteries are properly maintained. Many premature battery deaths are caused by under or over charging.
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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