What absorption and float voltage does a Victron SmartSolar MPPT use for LiFePO4 at 12V, 24V and 48V?

The default lithium preset

That table is Victron's, from the SmartSolar MPPT manual's lithium section, and the manual describes it as the default and recommended setting. Per cell it is 3.55V absorption and 3.30V float. The 48V row is the one a 16S builder is looking for: 56.8V absorption, 52.8V float.

Why float is lower than you might set for lead-acid

The same manual notes that lithium iron phosphate does not need to be held fully charged to avoid premature failure. A 13.2V float sits just above a resting full lithium battery, so the controller keeps the loads covered without holding the cells at the top of their range all afternoon. If a battery maker specifies a different float, or no float, use theirs.

When to change the preset

• The battery maker's sheet says otherwise. Battery instructions override the controller default. Several drop-in lithium brands ask for 14.4V or 14.6V absorption; set that, and keep Victron's 2-hour absorption unless the sheet gives a time.
• Equalization is off in the lithium preset. The manual states equalization is not available for the lithium preset. If you build a custom profile starting from a lead-acid preset, check equalization is disabled before you connect a lithium bank.
• Low-temperature cut-off is disabled by default. It only works when the controller is in a VE.Smart network receiving a battery temperature from a Battery Sense or a battery monitor with a temperature sensor, such as a SmartShunt or BMV-712 with the sensor fitted. The manual says it is only needed for lithium batteries whose BMS cannot block charging in the cold on its own; charging resumes once the battery is 0.5°C above the cut-off you set.

How to set it

In VictronConnect, open the controller, go to Settings, Battery, and choose the lithium preset or edit absorption, float and absorption time directly. The same settings can be changed from an MPPT Control display plugged into the VE.Direct port if you prefer not to use a phone. The controller detects the battery voltage automatically at first power-up; for a 48V bank, check the model you buy is rated for 48V before relying on the 56.8V row.

One number to confirm on the battery side

Make sure your battery's BMS high-voltage cut-off sits above the absorption voltage you set. A 16S pack whose BMS trips at 3.55V per cell will disconnect right at 56.8V; in that case lower absorption slightly rather than letting the BMS do the regulating.