Anbody know how to setup a Sunny Island to export and import power without disrupting a DC coupled solar array?
I have a customer with a large (10 year old 12kW array, 6 Outback inverters, 2 failing Trace SW inverters) that needs to replace the trace inverters in order to maintain his grid interconnection. I have been trying to do it with a Sunny Island, but as sophisticated as it is - am having trouble getting it to export excess power during the day (in order to keep the three charge controllers cranking) and import makeup power at night (she runs her A/C all night and does not have near enough battery). Obviously, these folks want to be "green" without sacrificing..... Lets not go there. I'm finding the Sunny Island has a lot of sophisticated operating modes, but it is hard to figure how they interact. So far the SMA techs tell me the only way to do a DC coupled setup is to use special internal codes to shut down the grid connection during the late afternoons to prevent it from exporting too much power, then reconnecting sometime in the night to help out the battery. Trouble is when it reconnects, it wants to do a full battery charge cycle and the next morning the batteries are full with no where to put the solar power. We can decrease the allowed charging current, but then may not be able to keep up with the night time load (depending on weather conditions).
It just seems like there ought to be a way to export and import power to keep the battery with a certain SOC range.
I have a customer with a large (10 year old 12kW array, 6 Outback inverters, 2 failing Trace SW inverters) that needs to replace the trace inverters in order to maintain his grid interconnection. I have been trying to do it with a Sunny Island, but as sophisticated as it is - am having trouble getting it to export excess power during the day (in order to keep the three charge controllers cranking) and import makeup power at night (she runs her A/C all night and does not have near enough battery). Obviously, these folks want to be "green" without sacrificing..... Lets not go there. I'm finding the Sunny Island has a lot of sophisticated operating modes, but it is hard to figure how they interact. So far the SMA techs tell me the only way to do a DC coupled setup is to use special internal codes to shut down the grid connection during the late afternoons to prevent it from exporting too much power, then reconnecting sometime in the night to help out the battery. Trouble is when it reconnects, it wants to do a full battery charge cycle and the next morning the batteries are full with no where to put the solar power. We can decrease the allowed charging current, but then may not be able to keep up with the night time load (depending on weather conditions).
It just seems like there ought to be a way to export and import power to keep the battery with a certain SOC range.
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