Best way to go

loonie
loonie Registered Users Posts: 10 ✭
in Grid Tie and Grid Interactive Systems #1
Hi, We have been off grid for over 10 years. Currently we have 12 BP 90w 12v panels, 8 BP 75w 12v panels, 1 XL1 bergey wind turbine, xantrex SW4024MC2 inverter made 12/06 with revision 4.01 option MC2.2 . We are having the grid installed and are trying to figure out if we go grid tie or sell the re equipment. If we can grid tie without to much extra cost that is what we would like to do but if we have to buy another 2500 to 3000.00 dollar inverter I think it would be a 7 to 10 year payback and probably not be worth it. We live in Maine that dose have net metering and has a rate of 14.5 any thoughts and suggestions would be appreciated. Thanks
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #2
    Re: Best way to go

    With 1680 Watts of old panels it probably is not worth investing another $2,000 in a GT inverter.
    The SW4024 is getting old too. On the whole you probably wouldn't get much $ from selling this equipment either.
    My advice is to just keep it as back-up and/or run some loads from it to reduce the utility bill since the capital investment has already been made.
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  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    #3
    Re: Best way to go

    that's a tough call on what to do with it all, but coot is right about the inverter getting old. you could possibly keep the pvs being productive with either a central type gt inverter or the smaller pv mounted gt inverters, which is probably the better option being you have 2 different pv models and are not always easily mixed and matched for gt.

    if you choose to sell any of it then feel free to list it on this forum in the for sale thread in general solar topics.
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  • peakbagger
    peakbagger Solar Expert Posts: 341 ✭✭✭
    #4
    Re: Best way to go

    I would advertise the equipment in Unvle henrys and craigslist for a "camp system" or a "preppers" system. Many preppers tend to shoot first ask questions later, so you may be able to hook one if you are willing to get paid in cash.
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  • icarus
    icarus Solar Expert Posts: 5,436 ✭✭✭✭
    #5
    Re: Best way to go

    Loonie,

    I sent you a PM about this subject,

    Tony
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  • Photowhit
    Photowhit Solar Expert Posts: 6,006 ✭✭✭✭✭
    #6
    Re: Best way to go

    If you decide to part it out, I'd be interested in the Xantrex SW4024MC2, I'm setting up a 24V system, but was cut back to 16 hours the last 4 months, and will use a prosine for a while. The Prosine can't be made code compliant even though it carries the proper UL listing. So it would be nice to have an inverter that would 'meet' code, until I can buy a new proper unit. I know it would be expensive to ship, just shoot me a price.
    Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites,  Midnite E-panel, Magnum MS4024, Prosine 1800(now backup) and Exeltech 1100(former backup...lol), 660 ah 24v Forklift battery(now 10 years old). Off grid for 20 years (if I include 8 months on a bicycle).
    - Assorted other systems, pieces and to many panels in the closet to not do more projects.
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  • Ralph Day
    Ralph Day Solar Expert Posts: 1,022 ✭✭✭✭
    #7
    Re: Best way to go

    Why not use the grid like a generator|? I have my SW4048 rigged with the grid coming in on AC2, It's just a breaker flip and we are using grid power and charging, or conversely, flip and we're using no utility power, just renewables.

    If you've lived off grid for so long you already have the habits necessary to keep your utility bill really low. I might use $15 worth of bought electricity in the winter months, next to none in the summer. Maybe wait until your renewable stuff bites the dust, then look at a grid tie system.

    Ralph
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  • loonie
    loonie Registered Users Posts: 10 ✭
    #8
    Re: Best way to go

    Thanks for all your replies. The 4024 I have has sell back to the grid but not acceptable to the power company. The gti unit can still be found but are usable only with a higher software version. Ralph your comment got me to digg out the manual and I found that there is a LBX mode that I haddn't reilized.Thanks, this dosn't require utility aproval and acts like you said. The utility acts like the generator. The reason we decided to go with the grid is winter time generator running and we are looking at the mini splits to keep cool and cut down on how many times this agging body gets warm with firewood.

    Gary
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  • Ralph Day
    Ralph Day Solar Expert Posts: 1,022 ✭✭✭✭
    #9
    Re: Best way to go

    My system has 240v grid power and 240v generator power available. It passes through an autotransformer 240->120. When I say throw a breaker, that's the breaker, to energize the transformer and power to the inverter. Because I want to use both utility and generator I have a generator panel which has a make or break breaker (only one can provide power at one time).

    I don't try to use any automatic control of generator (before, when off grid) or utility, I just rely on my being able to remember I'm on grid, or off grid. Batteries get more cycling in the summer when there's lots of sun, but this time of year it's nice not to have to worry about whether to run the generator or not after some cloudy days. Total use with loads and float charging is approximately 8kwhrs per day.

    Your batteries will be ready for any outages, and you still have grid power at your disposal (Xantrex will float charge and pass through utility power to the loads, just like when you were on generator power). Just be sure to check your batteries regularly. Float charging still uses some water and the sg's will creep up past 1`265. Just spending a day without the utility power on will drop them down again.

    I still have the GT interface, but it doesn't meet the UL grid tie/intertie requirements now. But if you set up your utility like your generator you don't need any net metering agreement. You'll have to insist on a small transformer (another cost, the hookup) for such a small service. My total load wouldn't exceed 60amps 240vac loaded to max and that's provided by a 10kva transformer in these parts (Hydro One in Ontario).

    Good luck.
    Ralph
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  • loonie
    loonie Registered Users Posts: 10 ✭
    #10
    Re: Best way to go

    Thanks Ralph, Sounds like the way to go for now. At least I shouldnt have a power bill in the summer we always made more then we used,( except for the monthly connection fee) and utility back up in the winter should be a lot cheaper then propane for the gennie.
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