Due to lack of UK G99 certification I have had to swap out the originally supplied and installed 10kv Multiplus II for two 5kv units - which will need to be connected in parallel. I would like to to verify that my game plan for the conversion looks plausible. This system is designed for time shifting electricity, so its currently batteries only, no solar. The Multiplus IIs are 48/5000/70-50 units with very similar recent serial number/dates.
The DC side of the system consists of 6x Pylontech US5000s connected to a Lynx Distributor. These are split into three sets of two batteries each connected via a Pylontech long cable set to the Lynx and 125A fuses. The DC output from the Lynx to each Multiplus II is via duplicate sets of equal length 70mm2 cables. The positive connections are each made via a Marsen 200A fused isolator. Neutrals are directly connected.
The existing AC In and AC Out cabling is 10mm2 60A rated cables. The plan here is to connect each of these cables to a small consumer unit, one for AC In and one for AC Out. These will each hold 2x 32A MCBs and connect to the Multiplus IIs via equal lengths of 4mm2 twin and earth. Cable length for 10mm2 cabling is about 5 meters and for the 4mm2 will be about 80cm.
Hopefully this wiring setup will satisfy the requirements for equal length/resistance AC and DC connections, and individually fused AC connections. I would expect to cut the twin and earth to mm level precision - would that likely provide acceptable tolerance? Should I extend the length or, given such a short length, use 2.5mm2?
I'm expecting that I can config the system before I finally connect A/C side (its a parallel not 3 phase system). Also is it vital to have the BMS CAN BUS connected direct to inverter, or can that be left on the disconnected CerboGX during initial config?
Somewhat confusingly there seem to be several approaches to configuring the parallel system - VictronConnect, VE.Bus Quick Configure or VE.Bus System Configurator. I will need to update fw, install the ESS assistant and config each inverter separately. VictronConnect doesn't seem fully featured enough yet - so probably take the QuickConfigure/VEConfigure route...
I'm expecting that VEConfigure "AC input current limit", "charge current" and any other current defns will be half the required totals. Any other settings that should I be wary of for a parallel system? I also expect that ESS/battery settings done via CerboGX will not require halving.
Appreciate any comments/suggestions.