Hello,
I've noted, for the first time, some unusual behaviour from my solar system. The system is composed of a MPPT150/45, a Multiplus II 3000watt - 120v, 10k watt 48vdc lithium battery, and 2200 watts of solar.
A 48vdc bus bar is the common attach point between the battery (2.5 meters of 4 awg wire), the output of the Solar Controller (1 meter of 4 awg wire) and the input to the Multiplus (50cm of 4 awg wire). The unusual behaviour was noticed when the battery was charging and was just below 57 vdc (the max float voltage is set in the solar controller to 57vdc). The inverter was drawing about 500 watts at the time. The solar controller was feeding the system about 1200 watts just before the event occurred. As the bus voltage was reached the maximum float voltage set in the solar controller, the solar controller output dropped toward "0". The load shifted from being supplied by the solar controller to being supplied from battery. As the higher demand shifted to the battery, the battery voltage drooped by 0.1 to 0.2 volts which caused the solar controller to begin to output more current (since the bus voltage was now below the maximum float voltage). The higher output from the solar controller resulted in reduced demand on the battery, which caused the bus voltage to go back up, and the solar controller would again start to shut down its output. The output of the solar controller cycled between 1200 watts down to "0" and back up to 1200watts every 10-20 seconds. The bus voltage correspondingly varied from 56.9-ish to 57volts. I watched the system "cycling" for 3 of 4 cycles before I deliberately changed the load on the system to break the cycle.
Is this behaviour normal?
PS - I've also currently dealing with a error 28 on the solar controller with my Victron Supplier. This issue may be related to that problem however there is so little information on error 28, I don't know.
