System going to crap - help

kirbinster
kirbinster Registered Users Posts: 4
in Advanced Solar Electric Technical Forum #1
I've got a nine year old system that consists of 54 Sharp 185W panels connected to 3 Sunnyboy 2500U inverters and one 1100U inverter. I started having problems with one 2500 unit that would only stay online when my A/C was running, typically days when the power company was running lower voltage. Otherwise that unit show (on my sunny control) that it is at 261 volts and trips off line). I have a second 2500U that currently shows MPP but has 0 watt output and one that is only running at half capacity. The only one that is fully working is my 1100 :( Any suggestions on what I should check out to see if these are really inverter issues or problems from the panels.
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #2
    Re: System going to crap - help

    Welcome to the forum.

    It's bad news time: It's probably down to repair/replace the inverter. The Sunny Boy 2500U's are no longer serviced by SMA. As you might guess they're failing too. The latest incidence: http://forum.solar-electric.com/showthread.php?23173-need-repair-ideas-for-a-sma-sunnyboy-2500U Note the link provided in Post #2. A comparable new unit is about $1,700 just so you know.
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  • solar_dave
    solar_dave Solar Expert Posts: 2,397 ✭✭✭✭
    #3
    Re: System going to crap - help
    Cariboocoot wrote: »
    Welcome to the forum.

    It's bad news time: It's probably down to repair/replace the inverter. The Sunny Boy 2500U's are no longer serviced by SMA. As you might guess they're failing too. The latest incidence: http://forum.solar-electric.com/showthread.php?23173-need-repair-ideas-for-a-sma-sunnyboy-2500U Note the link provided in Post #2. A comparable new unit is about $1,700 just so you know.


    I don't know on the SMA's but 261 Volts sounds like a grid tie cut off voltage on the high side. Is the utility driving the line voltage like that most of the time?

    You can get a DC clamp meter and check the panel output voltage and amperage.
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #4
    Re: System going to crap - help

    Silly me; I was assuming the inverters were connected to the same grid. Therefor if the grid was really at 261 and tripping one off-line due to high Voltage it should trip both. And when neither was tripped the one shouldn't be showing zero output either. The one 1100 unit seems to stay running. Sounds like defective 2500U GTI's to me.
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  • kirbinster
    kirbinster Registered Users Posts: 4
    #5
    Re: System going to crap - help
    solar_dave wrote: »
    I don't know on the SMA's but 261 Volts sounds like a grid tie cut off voltage on the high side. Is the utility driving the line voltage like that most of the time?

    You can get a DC clamp meter and check the panel output voltage and amperage.

    No its an issue with the inverter some how measuring the voltage wrong and tripping at the 260v high limit because of it. Right now that inverter says 261 while the other three all say that the voltage is 245. If I go out with a meter I measure just about what the other three say at any given time.
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  • mike95490
    mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    #6
    Re: System going to crap - help

    Check the wires and connections on the 261v inverter. It may be that a poor connection is causing the voltage to not get exported, and it rises above the HV disconnect setpoint.
    only stay online when my A/C was running
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  • kirbinster
    kirbinster Registered Users Posts: 4
    #7
    Re: System going to crap - help
    mike95490 wrote: »
    Check the wires and connections on the 261v inverter. It may be that a poor connection is causing the voltage to not get exported, and it rises above the HV disconnect setpoint.

    Thanks. I actually opened up the connections and checked for corrosion and reinstalled. Still no difference. When I put a meter on it I get the correct reading which matches what the other inverters are telling me :(
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