Long time Victron user here (though only in Campervan environment so far) and I’ve been looking through the various options for a potential solar/battery/inverter system for my home (thinking as much solar as I can get on my roof-maybe 13 panels- a 48V/5000 Multiplus ii and one or two Fogstar 5.12kWh batteries as funding allows) BUT I need it to NOT feed back into the grid should the mains power supply fail OR when the batteries are full (the extra cost and complexities of getting MCS certification and SEG are a factor here, Octopus will consider non MCS certified installations for their SEG tarrifs but the cost is £250 to start off with and you may not get £100 back if they decide they won’t do it-seems like a con to me), I just want to be able to cover my own electricity usage and maybe move to a zero standing charge tariff in the future)
As I understand it, the Multiplus ii can fill these requirements (a further question regarding supplementing battery supply to follow) and the diagrams in the Victron website suggest a Current Sensor is needed to monitor the grid feed in to be able to sense when the grid supply fails and continue to run the Multiplus in “UPS mode” feeding selected critical circuits connected to AC1 out.
The Current sensor (CTR110000500) seems to be sold with a 3.5mm 3 pole plug on the end but I cannot see any matching socket in any of the pictures or connection diagrams. Is it just a case of cutting the plug off and connecting to the INT/EXT/COM Current Sense connection block that I CAN see? And should it replace the COM/INT link that is prefitted in the block terminals, or be across the COM/EXT terminals?
I want the Multiplus ii to run off the 48V DC battery reserves and solar input (SmartSolar MPPT charge controllers connected to the Battery NOT AC Microinverters) as much as it can to keep grid feed costs to a minimum, but should there not be enough inverter capacity to power some intermittently connected load, am I right in thinking the Multiplus ii will supplement the connected load with a draw from the grid for as much as it needs/as long as it needs it, then disconnect when the load goes off? I also don’t want the multiplus to charge the batteries from grid supply automatically, only if I tell it to (maybe using an off peak overnight tariff in winter if the solar can’t recharge the batteries fully)
Thanks in advance for any insights given, Dave.
Hmm, on another thread discussing Multiplus II internal/external current sensors someone wrote this…
msevestre
Hi
if you use a clamp, the setting related to the current sensor must not be changed (and thus, remains “internal”) as the champ is actually connected to same the internal sensor connector on the multiplus.
External current sensor setting must only be used for really external meters, not the CT clamp connected to the MP2 connector.
Matt