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The forum is a place where people can interact and have discussions about different topics involving the use of the TRNSYS software package. Here you can post topics for discussion or questions on using TRNSYS and get advice from other users or TRNSYS experts. This forum is not intended for detailed technical support. Users should contact their distributor’s hotline for such assistance.
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Why the TRNSYS dumps power while the battery is not full?
Type47a is designed to be used with an inverter/controller (such as Type48), which allows the user to set high and low limits on the fractional state of charge of the battery. If the inverter/controller's high limit on the fractional state of charge (Parameter 4 in Type 48b) is less than 1.00, the inverter will dump power rather than charge the battery once the battery exceeds its high limit.
Also note that the inverter/controller may only make one decision per time step (either charge or dump), so the actual state of charge reached by the battery may be slightly above or below the limits set in the controller. Reducing the simulation time step will improve the agreement between the specified limits and those produced in the simulation.
ASAlburaiki Topic starter
20/07/2024 8:12 pm
@a_weiss Thank you for your feedback.
I have a follow-up question regarding Type 47 Mode 1. The documentation mentions a simple equation for charging and discharging, but my observations in TRNSYS don't align. For instance, at 8 AM, my PV system produces 128.5 W, with a load demand of 50 W. The excess power should be 78.5 W, but TRNSYS shows 182.5 W charging the battery. The battery’s state of charge increases from 23 Wh to 40.91 Wh in that hour only. The equation for charging the battery is (Battery_capacity(i)=Battery_capacity(i-1)+Energy_excess_1(i)*efficiency_battery;). Could you clarify where the remaining power goes? My settings are High FSOC=0.95, Low FSOC=0.1, and FB=0 (the first priority for array output is always to meet the load) as stated in TRNSYS 16 – Mathematical Reference-section 5.2.2.2 (page 5-43) Thank you very much.
