Looking for Solar priority option for my system

Been running a similar Victron setup for about 18 months now and the solar priority question comes up constantly in my system tweaking.

My kit is a MultiPlus-II 48/3000, Cerbo GX, Fogstar Drift 48V 100Ah LiFePO₄, and two SmartSolar MPPTs with around 2.4kW of panels. I've also got a grid connection as backup — partly for the dark winter months we get here.

The thing I found most useful was properly configuring the ESS Assistant in VEConfigure rather than just leaving defaults. Specifically:

• Setting the minimum SOC to something sensible (I use 20%)
• Adjusting the grid setpoint so the inverter actively draws from solar/battery first
• Using scheduled charging to only pull from grid during cheap overnight rates if batteries are low

What I haven't cracked fully is getting genuinely seamless solar priority when grid is present without the system occasionally "leaning" on the grid more than I'd like during partial cloud cover. The MPPT response feels slightly laggy in those conditions.

Anyone else found a way to tighten that up? I've read about tweaking the AC input current limit dynamically but not sure if that plays nicely with the Cerbo's automations.

Also curious — is anyone using Node-RED on the Cerbo for more granular solar priority logic? Feels like that might be where I need to head next.

Would be good to hear from others running ESS on similar setups, particularly if you've got more PV than me and managed to genuinely minimise grid draw across all seasons.

@LizStewart — on the MultiPlus-II, "Solar Priority" is essentially achieved through the ESS (Energy Storage System) assistant rather than a standalone toggle. In VictronConnect or Venus OS via the Cerbo, set your ESS mode to "Optimised (with BatteryLife)" and configure the minimum SOC threshold appropriately for your Fogstar Drift's chemistry.

The key setting people miss is "Feed-in excess solar" — even if you're not grid-tied for export, this toggle affects how aggressively the system prioritises PV over grid draw.

On my boat setup I run a similar arrangement; setting the grid setpoint to around +50W effectively makes the inverter lean on solar/battery first before pulling from shore power. Victron's ESS documentation is dense but worth a thorough read — specifically the section on self-consumption priority versus keep batteries charged modes.

@LizStewart worth double-checking your ESS grid setpoint in VRM — I had mine misconfigured for months thinking solar was prioritising properly but it was quietly pulling from the grid more than it should.

Also on the MultiPlus-II with a Cerbo, make sure DVCC is enabled. Without it the charge source coordination gets a bit woolly and you won't get clean solar priority behaviour.

One thing I'd add — if you're on a Fogstar Drift (lithium I assume?), set your min SOC carefully in ESS. Too low and you'll stress the cells cycling unnecessarily. I run mine at 20% as a floor.

What firmware are you on? Some older versions had quirks with ESS priority switching that were ironed out in later releases.

@LizStewart yeah ESS is the way but honestly the grid setpoint thing @EmmaEdwards82 mentioned is the bit that trips everyone up. Mine was set to 50W and the MultiPlus kept pulling from grid constantly without me realising.

Also check your minimum SOC in ESS — if that's set too high it'll prioritise charging over everything else and you'll wonder why solar's not doing what you expect.

On the Cerbo, make sure you've got a proper MPPT connected via VE.Direct otherwise the ESS assistant can't see what solar's actually doing. Ran into that with my Renogy controller — had to swap it out, complete faff.

VRM dashboard should show you pretty clearly once it's all talking properly.

Great points from @BreezyHermit, @EmmaEdwards82 and @ZFS_OffGrid — just want to add one thing worth checking with the Fogstar Drift specifically. Make sure your battery's DVCC settings are properly configured in the Cerbo GX, as the Drift communicates via BMS and if DVCC isn't reading the charge current limits correctly, ESS can behave oddly even when everything else looks right. I had a similar setup where solar appeared to be getting bypassed but it turned out the BMS was throttling charge current and the system was compensating via the grid. Easy to miss if you're just watching the VRM overview screen. Worth a dedicated look at the DVCC page on the Cerbo and cross-referencing with what the BMS is actually reporting. 👍