As Victron have just released their new Microgid firmware for the Multiplus and Quatro inverters, there are no tags for that yet. I have watched the three introductory Videos, https://victronenergy.wixsite.com/victronenergynews/post/microgrid-training-updates
and an considering whether to upgrade my existing off grid system to use the new Microgrid topology.
Existing system:
Currently I have two Multiplus 24V3kVA inverters in parallel, with 13.2kWh lithium battery, 2 x 70A charge controllers, and a 3.5kVA gen set. With a daily use of ~15kWh, and just over 5kWp of solar, this system is self sufficient, and the generator only runs for about 10 to 12 days a year, when there is exceptionally cloudy weather. Gen runs are typically 5 - 7 hours a day when needed. The BMS is a bespoke design, and also controls the Solar charge controllers and the inverters. This has been running for over 5 years now.
Problems: Whilst the AC capacity is good, the batteries are beginning to show their age. Also the generator is undersized for the current loading. Charging has to be limited to ~900W, and the generator can still trip out on overload as the fridge compressors cycle.(No AirCon). The generator could be replaced by a larger model, but for such limited run time, this seems a bit of a waste. While the generator is running, although the 2 parllel multi’s accept this as a charge source, the workshop multi does not. Also, in the workshop is a 3kW table saw, when this starts, the workshop multi also switches to invert mode. (Table saw is on the AC input of that multi).
To modify this to a Victron Microgrid, all the existing inverters would need to be upgraded with the new firmware. The two parallel inverters would also have their AC connection changed to AC in from AC out1. (Victron’s introductory videos make no mention of any loads connected to AC outs). This means that to charge the batteries from the Generator, a new AC/Dc charger is needed. I think that the cheapest option for this would be a new Multiplus2 inverter, as this can be controlled by a GX system - via a Mk3/USB adapter, as it is not part of the main group. The bespoke BMS control system would need to be replaced with a Cerbo GX and CAN-Bus BMS. (a copy of the workshop control setup). PV and a charger would also be needed at the workshop, as in Microgrid mode, the inverters cannot charge the batteries from the microgrid. The dedicated charger would prevent generator overloads, and could be set to a constant 1800W charging load, which could reduce run time. Whilst considering the economics of this upgrade, I would like to know if I’ve missed anything in the control topology. Particularly for the DC charging: will an auxiliary Inverter be controlled by the CVL/CCL (DVCC) when connected via a Mk3?
