Victron MultiPlus-II 48/3000 keeps dropping to float too early — anyone else had this?

So I've had my MultiPlus-II 48/3000 running for about three months now alongside a 48V 200Ah lithium pack (EVE cells, 16S, Daly BMS). The inverter/charger is connected to a 1.8kW solar array via a SmartSolar 150/45, all talking over VE.Bus and VE.Direct to a Cerbo GX. On paper it's a lovely little system, but I'm pulling my hair out with one specific issue.

The problem is the MultiPlus keeps deciding bulk charging is done and flicking over to float when the battery is nowhere near full. I'm talking 60–70% SoC according to the Cerbo, yet it'll happily sit in float at 53.6V pushing bugger all current into the pack. I've got absorption set to 56.8V and float at 53.6V, and the absorption time is configured to "adaptive" in VE.Configure. My suspicion is the adaptive algorithm is seeing the tail current drop off quite fast (lithium does that) and calling it done prematurely.

Has anyone sorted this with a fixed absorption time instead of adaptive? I'm also wondering whether the repeated charge current from the solar is confusing the MultiPlus about where in the charge cycle it actually is — the SmartSolar is set up as the main charger in the DVCC settings, but I'm not 100% confident I've got everything configured correctly there. Happy to share screenshots of the VRM portal if that helps anyone diagnose it.

@HighlandNomad had almost identical with my garden office setup. Turned out my absorption time was set too short in VEConfig — it was hitting voltage target fast under low load and just rolling into float.

Worth checking your charge voltage settings match what your Daly BMS actually wants. EVE cells in 16S should be around 54.4V absorption, 53.6V float typically, but Daly sometimes has tighter cutoffs that confuse the MultiPlus.

Also — is your BMS talking to the MultiPlus via DVCC or just running standalone? If no comms, the inverter's just guessing really. Even a cheap Victron SmartShunt feeding data through a Cerbo or even a Raspberry Pi with Venus OS sorts this properly.

Mine's been rock solid since enabling DVCC properly. Night and day difference.

@HighlandNomad worth checking your battery capacity setting in VEConfig as well — if it's set lower than your actual 200Ah, the MultiPlus will calculate a shorter absorption period and drop to float sooner than you'd expect. Also, with a Daly BMS you sometimes get voltage spikes that the MultiPlus interprets as the battery being fully charged when it isn't. Try logging via VRM or a MK3-USB dongle and watch what the actual battery voltage is doing during the transition — if it's jumping around rather than holding steady, that's likely your culprit. What charge voltages have you got set for absorption and float? With 16S EVE cells you want roughly 55.2V absorption and 53.6V float as a reasonable starting point, though it depends on your cell specs.

Hey @HighlandNomad, a few things worth checking that haven't been mentioned yet. With a Daly BMS, I'd look at whether it's sending a premature charge complete signal — some Daly units can be a bit trigger-happy with that, especially if the cell voltage balancing is slightly off across your 16S pack. Also, are you running VE.Smart networking or just standalone? If your MultiPlus isn't seeing a battery temperature sensor, it might be applying conservative voltage thresholds that cause it to bail out of absorption early. Worth grabbing a SmartShunt if you haven't already — proper state of charge monitoring makes a massive difference. What absorption voltage are you currently set to? With EVE cells I typically run 55.2V (3.45V/cell) and that might need adjusting depending on what your BMS cutoffs are configured at.

Hey @HighlandNomad, one thing worth adding that nobody's touched on yet — have you got a BMV or SmartShunt in the system? Without proper battery monitoring, the MultiPlus is essentially guessing state of charge based on voltage alone, and 48V lithium curves are notoriously flat. It can easily mistake a surface charge voltage spike for a full battery and drop to float prematurely.

If you do have a shunt, double-check your Peukert exponent and charged voltage threshold in VEConfig — lithium settings are quite different from the lead-acid defaults. Also worth confirming your tail current percentage is set appropriately, something like 2-4% of battery capacity rather than the higher defaults. These two settings together often crack this exact issue. 🔧

Great thread, lots of good suggestions already. One thing I'd add @HighlandNomad — have you checked your absorption voltage setting in VEConfig? With EVE cells in a 16S configuration, you want that sitting around 54.4V (3.4V per cell). If it's set too low, the MultiPlus will hit the target voltage prematurely and assume the battery's full before it actually is, dropping straight to float.

Also worth double-checking your absorption time settings. The adaptive charging algorithm can cut absorption short if it thinks the battery charged quickly last cycle — which can snowball across consecutive days into increasingly early float transitions.

What are your actual measured voltages when it drops? If you can share a VRM screenshot or even your VEConfig charge settings, that'd help narrow it down considerably.

Had this exact issue in my shepherd's hut build last year. Turned out my absorption time was set way too short in VEConfigure — default can be stingy depending on your battery profile.

Worth checking your charge voltage settings match what EVE actually recommends for your specific cells. A lot of people set 58.4V (3.65V/cell) but EVE's cycle life is much better if you back it off to around 57.6V — and the MultiPlus will hit float faster at the lower ceiling.

Also, are you running VE.Bus Smart Dongle or anything giving the charger temperature data? Without it, compensation can throw things off.

@Spider85 and @Liam1998 have covered the BMS comms and shunt angle — both valid. Sort VEConfigure first though, that's the quickest win.

Really interesting thread this — I had something similar crop up with my setup when I first got everything dialled in.

@HighlandNomad one thing I don't think anyone's mentioned yet — what have you set your charged voltage and tail current to in the BMS settings? On my Daly I found the defaults were quite aggressive, triggering a "battery full" signal to the Victron way too early, which would boot it straight to float before absorption had done its job properly.

Are you using the VE.Bus BMS or relying solely on the Daly for charge control signals? That hand-off between the two can cause some odd behaviour if they're not configured to agree with each other.

@HighlandNomad classic Daly BMS doing its passive-aggressive thing — if it's sending a premature "hey I'm full!" signal over the comms, the MultiPlus will dutifully roll over into float like an obedient golden retriever. Check whether you've got the DVCC settings enabled in VEConfig and whether the BMS is actually talking to the Cerbo/CCGX, because if it is, it controls charge termination, not your absorption voltage/time settings. Swap to a JK BMS if you want proper Victron comms without the drama — mine transformed my whole system overnight.