Anyone else had grief with a Victron MultiPlus 24/2000 dropping to float too early on a half-full battery?

Been scratching my head over this one for a few days now. My MultiPlus 24/2000 keeps cutting the bulk charge short and jumping straight to float when the batteries are nowhere near full — we're talking around 50–60% SOC according to the BMV-712. It's a 200Ah lithium (Winston cells, 8S configuration) sitting at a nominal 24V. The charger just seems to give up too early, usually after about 45 minutes of bulk regardless of how discharged the bank actually is.

I've gone through the settings in VictronConnect and the absorption voltage is set to 28.4V, float at 27.0V, and I've got the absorption time set to "adaptive." From what I can tell the adaptive algorithm is calculating a short absorption based on... something I don't fully understand, and I suspect that's where it's falling over. The bulk phase is ending before the cells have really had a chance to fill up properly.

Has anyone dialled in a fixed absorption time on a lithium setup like this, or is there a better way to handle it? I know some people disable absorption altogether on LiFePO4 and just use a tight float, but I'm not sure that's right for Winston cells specifically. Also worth mentioning I've got a Cerbo GX in the system — wondering if any of the DVCC settings might help here.

@SimonGrant almost certainly a tail current issue. The MultiPlus ends bulk/absorption when current drops to a set percentage of battery capacity — if your bank is undersized in the config, it'll hit that threshold way too early.

Check your VEConfigure settings:

• Charge current — is it set correctly for your actual bank?
• Battery capacity (Ah) — this directly affects the tail current calculation
• Absorption time — set a minimum to override premature switching

On my narrowboat with a 200Ah Fogstar Drift LiFePO4 bank I had identical behaviour until I corrected the capacity figure in VEConfigure. The default tail current is 4% of configured capacity, so a wrongly low Ah figure means it terminates embarrassingly early.

Also worth checking whether you've accidentally enabled the "BatterySafe" algorithm — it can behave oddly with certain chemistries.

What chemistry are you running and what's the Ah figure currently configured?

@SimonGrant had the exact same faff with mine last winter — turned out my Fogstar cells had a much lower internal resistance than whatever Victron's defaults assume, so the tail current threshold got hit embarrassingly early like the batteries were bragging about being full when they weren't.

Dig into VictronConnect and bump your absorption time to a fixed duration rather than letting it go adaptive — Charger > Expert mode is where the good stuff hides. Also worth checking your battery temp sensor is actually seated properly; mine had worked loose and was feeding nonsense readings that made the algorithm go full drama queen.

Hey @SimonGrant, worth also checking your absorption voltage setting whilst you're in VictronConnect. If it's set too low, the batteries can reach it quickly even when they're not actually full, which tricks the charger into thinking it's done more work than it has. I'd cross-reference whatever voltage you've got set against your battery manufacturer's spec sheet — particularly the recommended absorption voltage at your ambient temperature, as colder temps can sometimes throw things off too. What cells are you running exactly? That might help narrow things down further.

@SimonGrant my van did exactly this until I realised the battery capacity setting in VictronConnect was wildly wrong — had it pegged at 100Ah when I've got 200Ah of Fogstar fitted, so the tail current threshold was triggering at basically half charge 🤦