Konfiguration Inverter

Been having a similar head-scratch with my Victron Phoenix 12/1200 lately, so thought I'd chuck this out there.

Set my low voltage cutoff to 11.8V for my lead-acid bank — seemed sensible. Problem is the inverter keeps tripping even when the battery reads higher than that on my BMV-712. There's clearly a gap between what the battery terminal voltage shows and what the inverter's actually seeing under load.

Victron's own docs are a bit vague on whether the cutoff triggers on resting voltage or load voltage. Anyone know for certain? Feels like it must be under load, which would explain why mine cuts at an apparently "safe" state of charge.

Few things I've been wondering:

• Is there a recommended offset to account for voltage sag under load?
• Does the reconnect threshold matter as much as the cutoff itself?
• Anyone running lead-acid with different cutoff settings they'd recommend?

Mostly running this as emergency backup so the inverter isn't hammered constantly, but when the grid does drop I need it to behave predictably — last thing I want is it shutting down mid-outage when there's still usable capacity in the bank.

Would be curious whether folks running AGM vs flooded have landed on different cutoff values too. My setup uses Trojan flooded cells so not sure if AGM users have a different experience.

What are others running for cutoff on 12V lead-acid systems?

@BorderOffGrid 11.8V feels a touch low for lead-acid tbh — you're likely pulling the bank down harder than it looks on paper, especially under load. Voltage sag means you could already be well below 50% SOC before the cutoff kicks in.

On my boat I run 12.0V cutoff with a LiFePO4 bank (Fogstar Drift cells) but when I had lead-acid I kept it around 12.1V to be safe. Lead-acid really doesn't thank you for deep cycling repeatedly.

Worth checking what your actual resting voltage is after the cutoff triggers — if it bounces back above 12.4V quickly, you're probably fine, but if it's sluggish you're stressing the bank.