About 18 years ago I installed a (Trace) Xantrex SW4548 grid tie inverter/charger (4.5 kVA 48V) with flooded Lead acid batteries. About 10 years ago I replaced the flooded batteries with 4x Victron Gel 12-220 batteries which have only been used as grid backup so they have not had a lot of use. This was my first introduction to the Victron range of products which impressed me very much.
I delayed for a long time installing PV as my roof is gabled facing East and West but in the past few weeks I have installed 8x 370W PV panels on the west side. I bought an MPPT RS 450/100, a Smart Shunt, a Cerbo GX and an ET112 with RS485 to USB. I wired it all up and set up the VRM portal. The Xantrex supplies critical loads but the stove, heat pump, immersion heaters and a few other loads are supplied directly from the grid. I installed the ET112 as a grid meter just after the main breaker so it measures all power from and to the grid, I also wired a relay to pins 7&8 of the ET112 to signal the second tariff as I have a dual tariff connection. I have the Xanrtex set to sell mode so that when the PV begins to charge the batteries, excess power is fed to the critical loads and to the grid and non critical loads. With enough PV input my grid use drops to zero but it also reaches a stage where it feeds a lot of power back to the grid which is a nice big battery but I have to pay dearly to get the power back.
On the VRM portal I get a lot of useful data but not all correct for instance on the dashboard the "To Grid" box always shows zero. I have been reading a lot on the Victron web site and to have a properly functioning ESS it looks like I would need one of the Victron inverter/ chargers. I was planning to upgrade in the future but not just yet. If anyone here has any suggestions or a workaround I would appreciate it. Thanks.
Jim
