# ESS “Only critical loads” discharges battery when a non-essential AC-in load is added, despite DC PV **URL:** \ **Category:** DIY\ **Tags:** multiplus-ii, ess, diy, cerbo-gx\ **Created:** [8 August 2026 12:04 UTC](https://community.victronenergy.com/t/ess-only-critical-loads-discharges-battery-when-a-non-essential-ac-in-load-is-added-despite-dc-pv/61428 "2026-08-08T12:04:44Z")\ **Posts on this page:** 4\ **Page:** 1
**Author:** ![charliefdt](https://avatars.discourse-cdn.com/v4/letter/c/aca169/32.png) [@charliefdt](https://community.victronenergy.com/u/charliefdt)\ **Post date:** [8 August 2026 12:04 UTC](https://community.victronenergy.com/t/ess-only-critical-loads-discharges-battery-when-a-non-essential-ac-in-load-is-added-despite-dc-pv/61428/1 "2026-08-08T12:04:44Z")
I have a three-phase ESS where I am seeing behaviour that appears inconsistent with “Self-consumption from battery” set to “Only critical loads”. I captured two states approximately one minute apart, with essentially identical PV production and essential loads. In the first one PV covers the essential load and surplus PV charges the battery (expected). In the second one adding a non-essential load upstream of AC-in caused the battery to switch from charging to significant discharge. **13:03 — non-essential/EV load OFF** PV: 2642 W Essential loads: 1876 W Non-essential AC load: 0 W Grid import: 114 W Battery: **+771 W charging** SOC: 59% **13:04 — non-essential/EV load ON** PV: 2640 W Essential loads: 1894 W Non-essential AC load: 5277 W Grid import: 2850 W Battery: **−2076 W discharging** SOC: 59% Adding 5277 W of non-essential load caused grid import to increase by 2736 W and battery power to change from 771 W charging to 2076 W discharging, a swing of 2847 W. The DC PV alone was already greater than the essential AC-out load: 2640 W PV \> 1894 W essential load. Yet the appearance of the upstream/non-essential load caused substantial battery discharge. This appears contrary to the documented purpose of `Only critical loads`, which Victron describes as restricting battery power to essential loads and preventing the battery from being discharged into non-essential loads. The ESS manual specifically identifies systems with an external grid meter, significant non-essential loads and feed-in disabled as the relevant use case. With 2640 W of DC PV and only 1894 W of essential load, I would expect no battery discharge to be required for the essential loads. Is this expected ESS behaviour, or could Only critical loads be calculating the allowable battery contribution from the gross AC-out load without correctly accounting for DC-coupled PV? L.E.: moved the system specs to the end of the post for readability: System 3 × MultiPlus-II 48/5000/70-50, one per phase VE.Bus firmware: 2623558 Cerbo GX Mk2, Venus OS v3.75 ESS mode: Optimized with BatteryLife Pylontech CAN battery 3 × BlueSolar MPPT 150/35; all PV is DC-coupled ESS settings Grid metering: External meter Grid meter required: Yes Self-consumption from battery: **Only critical loads** Multiphase regulation: **Individual phase** during the reproduction below Grid setpoint: 150 W AC-coupled PV feed-in excess: Off DC-coupled PV feed-in excess: Off Limit inverter power: Off System AC import/export limits: Off No intentional peak-shaving limit L.L.E.: Another example where all PV power is directed to compensate non essential load: ![image](https://europe1.discourse-cdn.com/victron/original/3X/2/6/26bde2cb18ead71be95b7ef9a666dd4412779a63.png) ---
**Author:** ![system](https://europe1.discourse-cdn.com/victron/original/1X/21a9a7b5db7c6339715f993568736a7053199995.png) [@system](https://community.victronenergy.com/u/system)\ **Post date:** [8 August 2026 12:04 UTC](https://community.victronenergy.com/t/ess-only-critical-loads-discharges-battery-when-a-non-essential-ac-in-load-is-added-despite-dc-pv/61428/2 "2026-08-08T12:04:45Z")
Unlisted on 8 August 2026 12:04 UTC ---
**Author:** ![system](https://europe1.discourse-cdn.com/victron/original/1X/21a9a7b5db7c6339715f993568736a7053199995.png) [@system](https://community.victronenergy.com/u/system)\ **Post date:** [8 August 2026 12:10 UTC](https://community.victronenergy.com/t/ess-only-critical-loads-discharges-battery-when-a-non-essential-ac-in-load-is-added-despite-dc-pv/61428/3 "2026-08-08T12:10:12Z")
Listed on 8 August 2026 12:10 UTC ---
**Author:** ![charliefdt](https://avatars.discourse-cdn.com/v4/letter/c/aca169/32.png) [@charliefdt](https://community.victronenergy.com/u/charliefdt)\ **Post date:** [12 August 2026 06:52 UTC](https://community.victronenergy.com/t/ess-only-critical-loads-discharges-battery-when-a-non-essential-ac-in-load-is-added-despite-dc-pv/61428/4 "2026-08-12T06:52:03Z")
I was really hoping to get some sort of feedback from my fellow renewable energy enthusiasts, I need community help on this one! I’ve recently switched to Victron and already suffer from a sense of “need to learn fast and take control of my system” after discovering that the installers I used and talked to know very little on the software side. Hijacking all solar from the essential loads when I turn on large nonessential ones is something I was not expecting at all. Please let me know if you experience the same / is the “normal” algorithm or I should try to debug my settings