Why when in my system the batteries are charged by a DC DC (Renogy) does the solar panel (Blue Solar) stop charging the batteries? If I disconnect the Blue Solar from the Cerbo GX the photovoltaic panel charges regularly even with DC DC working. I can change this thing ?
This simply mean, that you have somehow different settings in the BlueSolar and the CerboGX.
I do not know, what settings you have in the Renogy DC Charger but it seems, the settings in the CerboGX are lower then the setings of the Renogy, while the settings in the BlueSolar are equal or higher then the Renogy.
Hence, the CerboGX believe, the Batteries are full enough and order the BlueSolar to stop charging. while the Renogy is not controlled by the CerboGX and continue charging.
Another thing you have to verify if the VOLTAGE DROP of the DC cables from the BlueSolar and Renogy to the Battery. If you have Lead-Acid Batteries and set the Chargers to 28,8V and use identical wires from the for the BlueSolar/Renogy, but the Lenght of the BlueSolar wires are twice as long as the one of the Renogy, you will see a significant difference.
E.G. BlueSolar 75/15 with 550Wp Solarpanels and a LEAB ABC 2415 on a 24V/220Ah PzS Battery. For testing I used 2,5mm2 wires on both units and the BlueSolar with 2m and LEAB with 1m. The Voltage drop became several 100mV under full load.
0,5V for the BlueSolar and 1,0V for the LEAB which forced the LEAB to shutdown to early (SOC 80%) while the BlueSolar was strugling getting the Battery to 100% which took 2 days. :-(
Hence if you are On-Grid, set the BlueSolar/CerboGX to a higher value as the Renogy which will reduce the power consumption from the Grid
The issue was caused by the configuration of a smart shunt as a DC system current meter. Setting the shunt as an alternator current meter resolved the problem.
