I have a Multiplus 48/5000/70 operating as a UPS connected to a 48 battery bank. I have dissabled the charger of the Multiplus in VE Configure.
I have recently purchased a SmartSolar charge controller MPPT 250/60 to charge the batteries/supply the inverter. When connecting the the charge controller to the DC bus (with the batteries isolated) there was considerable arcing. I was expecting no voltage to be present as the Multi's charger was off. However there is 39Vdc from the Multi present on the DC bus.
Is this voltage normal with the charger is off? Is it safe to connect the Multi and the charge controller to the bus or can either of them be damaged?