Edwill Posted July 26, 2020 Posted July 26, 2020 (edited) Good day, I have two current issues with my solar generation system, and I think they are related. I hope someone can help. My setup is: Goodwe ES 4.6kW inverter 4 x Wall mounted BYD B-Box 2.5kWh Lithium Ion batteries (totalling 10kWh) connected to the inverter via a BMU. 14 x 330W Canadian Solar PV panels The first issue is that even when my battery is not fully charged and the sun is shining without any clouds - the full PV input isn't being used, as if it is throttled. I am encircling an example below. You can see when there is a high load (my geyser) between 9-10am, the PV is fully utilized. But when the geyser timer switches off, the PV input also drops and the battery only charges at a constant 1.2kWh (the straight line). The PV only goes up a while later when there is a higher load again, when the battery charging goes over 1.2kWh and the full PV generation is used. You can then also see a correlation between PV and load, as if the load determines how much PV is used. According to me it should use all the remaining PV input after the load to charge the battery (when it is not full, as is the case here), despite the load. The second issue, which might be causing the first issue, is that when I do the setup in the PV Master app, the BMU doesn't report a 10kWh option. All I'm getting are the options in the screenshot below. I then select the Battery-Box Pro/Res 7.5 option. The dip switches on the batteries are set up correctly. There is a "Self define" option, but I have no idea what to enter there. I believe this is what the BMU is reporting to the inverter. I am also getting the following "Diagnose Message" in the PV Master app (SOC Delta OverRange Please check the battery capacity setting and charge voltage setting): I hope someone can shed some light on this. Thank you! Edited July 26, 2020 by Edwill Added more information Quote
Edwill Posted July 27, 2020 Author Posted July 27, 2020 (edited) I can see why it is only charging at 1.2kWh, when looking at the parameters. So the BMS reports a charge current limit of 24A, so 53.6V * 23.9A = 1281.04W, which is exactly what I'm seeing. In the BYD battery manual, it seems that the current is affected by the temperature, so if I look at the table below, the calculation is 0.7 * 13 (temp) * 4 (batteries) = 36.4A, not 24A. The dip-switches on the batteries are correct: 100000, 010000, 110000, 001000 and the biggest number (001000) is connected to the BMU. Edited July 27, 2020 by Edwill Addresses Quote
JoeyW Posted July 29, 2020 Posted July 29, 2020 Hi Edwill, Something not related to your problem but where did you manage to pickup a Goodwe ES? and what software are you using to monitor it? Quote
Edwill Posted July 29, 2020 Author Posted July 29, 2020 10 hours ago, JoeyW said: Hi Edwill, Something not related to your problem but where did you manage to pickup a Goodwe ES? and what software are you using to monitor it? I bought it 2 years ago from an installer. Using the normal software provided by Goodwe - SEMS portal and PV Master. Quote
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