Victron Multiplus keeps dropping to float too early — anyone else had this?

Been having the exact same issue with my Multiplus II 48/3000. It hits around 80% SOC and just decides it's done — drops straight to float like it's fully charged. Drives me absolutely mad when I'm trying to top up before a potential power cut.

I've gone through the absorption voltage settings in VE.Configure a dozen times but nothing seems to stick. Currently running Fogstar Drift lithium cells and I'm wondering if it's a BMS communication issue rather than the Multiplus itself being faulty?

A few things I've tried so far:

• Adjusting the absorption time (set it to adaptive, then fixed — neither helped consistently)
• Checking the battery temperature sensor readings
• Updating the firmware via VictronConnect

Nothing has reliably fixed it. Some days it charges perfectly to the top, other days it bails out embarrassingly early.

Has anyone managed to sort this through DVCC settings? I've read conflicting things about whether enabling or disabling it makes a difference with lithium setups. My main concern is having a properly full battery for emergency backup purposes — a half-charged bank is pretty useless when the grid goes down at 2am.

Would be curious whether this is more common with certain battery brands or if it's genuinely a Multiplus configuration rabbit hole. Anyone running a similar 48V lithium setup who's cracked it?

@MandyMorris had almost identical with my static caravan setup last summer. Turned out my absorption voltage was set too low in VE.Configure — it was hitting the voltage target quicker than expected because my Fogstar Drift lithium cells have a pretty flat charge curve.

Worth checking a few things:

• Absorption voltage — is it set correctly for your battery chemistry?
• Tail current — what's yours set to? If it's too high, Victron thinks it's done early
• Battery temp compensation — if enabled on a lithium, it can skew the readings

Are you running lithium or lead? Makes a big difference to how the Multiplus decides absorption is "complete." Also, what does your SOC actually read on a BMV or SmartShunt when it drops to float — is the 80% figure from the Multiplus itself or a separate monitor?

@MandyMorris check your battery capacity setting in VEConfigure — if it thinks your pack is smaller than it actually is, it'll rush through absorption like it's got somewhere better to be. Caught me out with my Fogstar Drift cells last winter, had it set to 100Ah when I'd actually got 200Ah. Multiplus thought it was done in half the time. Also worth checking your charge current limit isn't throttling things so hard it never properly saturates the cells before the timer kicks float in. VRM logs will show you exactly where it's bottling it if you've got a Cerbo on there.

@MandyMorris worth checking your Repeated Absorption settings in VEConfigure — specifically the interval and duration. If the Multiplus has recently done a full cycle, it'll skip absorption on subsequent charges until the interval timer expires. Caught me out on my boat build running Fogstar Drift 100Ah cells.

Also, what's your Tail Current set to? If it's too high relative to your actual pack size, the unit decides absorption is "complete" prematurely because current has already tapered to that threshold. On a large LiFePO4 bank especially, the default values are often nonsensical.

Pull up your VRM data or local CCGX logs and look at the actual charge current at the point it transitions — if it's dropping to float whilst still pulling decent amps, that's a configuration fault rather than a battery issue. Post the screenshot and we can pinpoint it properly.

@MandyMorris one thing nobody's mentioned yet — check your tail current setting in VEConfigure. This is the current threshold at which the Multiplus decides absorption is "complete" and transitions to float. On my narrowboat setup with a 280Ah Fogstar Drift LiFePO4 bank, I had this set far too high (default values don't suit larger lithium packs well). The charger was seeing the tail current threshold hit at 80% because the pack was accepting charge rapidly up front, then the current dropped quickly — triggering an early float transition.

For lithium, tail current is typically set around 2-4% of bank capacity. Worth cross-referencing with your BMS charge specs too — sometimes a BMS-imposed current limit is causing the apparent current drop that tricks the Multiplus into thinking absorption is done.