Anyone else had grief with a Victron SmartSolar 100/20 dropping to float too early on cloudy days?

Been running a 200W panel (Risen RSM40-8-200M) into a 100Ah lithium (Fogstar Drift) via the SmartSolar 100/20 for about three months now. Most days it's fine, but on overcast days I keep noticing the controller jumping into float at maybe 70–75% state of charge — usually around midday when the sun briefly peeks through, then clouds over again. The battery app confirms it's nowhere near full.

I've got the charge profile set to 14.2V absorption, 13.5V float, with a tail current of 2A to end absorption early if needed. Wondering if that 2A tail current is too generous given how much the input wattage fluctuates on grey days — maybe the controller is seeing a momentary dip below 2A and deciding it's done?

Has anyone tweaked their tail current settings to deal with this, or is there a better way to handle it in the VictronConnect app? Open to adjusting absorption time too if that's the route to go. Running firmware 1.61 if that's relevant.

Hey @IanWhite, sounds like it might be your absorption time settings. On cloudy days the charge current is lower, so if you're using a fixed absorption time rather than adaptive, the controller might be hitting the voltage threshold and moving to float before the battery's actually full. Worth checking your tail current setting in the VictronConnect app - that's the amps at which it decides absorption is "done." For a 100Ah lithium I'd set it around 2A rather than the default. Also double-check your absorption voltage matches Fogstar's recommendations for the Drift - think they specify 14.2V. Small mismatches can cause exactly what you're describing. 🔧