question

SOK is really SOC state of Charge but from your list these would be the ones that you are interested in

Boost Charging Voltage 14.6 this is bulk

Float Charging Voltage 13.6 this is float

Does your battery have a BMS?

If it has a BMS, does the BMS performs cell balancing?

Can you see or measure the cell voltages?

Can you adjust the BMS various voltage limits? If yes, adjust them based on the charging description below. If you can't adjust the BMS voltage values, you have to set the chargers and inverters voltages to match the BMS values.

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A 12V (nominal) LiFePO4 battery contains 4 cells inside.

When charging, you should keep cell voltage under 3.6V. Can be lower, but try to not get above this.

Set the Inverter to cut off if battery voltage drops to 12V.

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You only charge with the Multiplus? Or you also have a solar MPPT charger?

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Basically, charging LiFePO4 goes in two stages:

1 - In the first stage ("Bulk" stage) you charge it with constant current (or whatever current your PV panels can produce), until the battery reaches a certain voltage (this threshold voltage at which the charger switches from "Bulk to "Absorption" is the "Absorption" voltage from Multiplus and from MPPT solar chargers).

You can set this "Absorption" voltage in the 3.4V - 3.6V range (depending on if you have or not a BMS and what kind of BMS). So for a 4-cell battery, set "Absorption" voltage in 13.6V-14.4V range.

If your charger can output a higher current than the maximum charging current allowed by the battery manufacturer, limit the current to that maximum allowed value.

2 - When the "absorption" voltage is reached, the charger will maintain that voltage for a certain time and/or until the charging current drops under a threshold ("Tail current").

You will see that the current taken by the battery drops as you charge at constant voltage.

A reasonable value for the "tail current" would be 0.05C (where C is cell capacity - Ah). So if you have 100Ah cells, set the tail current to 5A (in the MPPT charger; Multiplus does not have a "Tail current" setting).

This tail current works well when charging from the grid, but not so well when charging with solar (because the current can drop not because the battery is charged, but because there are clouds).

After the battery is charged, the charger should switch to "Float", where it maintains a lower voltage than the "Absorption voltage". This "Float" voltage should be set in 3.35V - 3.375V range (cell voltage). So 13.4V-13.5V range for the 4-cell battery.

Equalization (the kind used on lead-acid batteries, at high voltage; this is different than cell balancing) should never be performed on LiFePO4.

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The requested "translation":

Over Voltage Disconnect 14.7 V - probably the voltage at which the BMS disconnects the battery

Charging Limit Voltage 14.6 V - probably the voltage at which the BMS instructs the charger to stop the charging

Over Voltage Reconnect 14.6 V - probably the voltage at which the BMS allows the charging again

Equalize Charging Voltage shut off or 14.4 V - maybe the voltage at which the cell ballancing stops

Boost Charging Voltage 14.6 V - not sure

Float Charging Voltage 13.6 V - maybe the recommended float voltage for that battery

Boost Reconnect 13.3 V

Low Voltage Reconnect 10 - not sure (too low to be the voltage at which it allows the discharge again)

Under Voltage Warning Reconnect Voltage 11.5 - maybe this is the voltage at which the BMS allows the discharging again

Under Voltage Warning 11.5 - probably the low voltage at which the BMS gives some warning/alarm

Low Voltage Disconnect 11.0 - probably the low voltage at which the BMS disconnects the battery from the loads

Discharging Limit Voltage 10.5 - sounds similar with the above

Equalize Duration 0 Boost Duration 180 minutes - not sure

There are no cell voltage values. A good BMS also monitors individual cell voltages, not just the battery voltage.

I have a 100AH SOK LiFEPO4 battery, which has a BMS.

I'm using a Victron IP67 charger (12V 25A), and the battery is getting fully charged, but the Victron charge cycle status shows up as interrupted. I'm told it could be due to cells out of balance.

Abs 19m 47s 1.3Ah
Bulk 3h 6m 79.5Ah
Total Charge time 3h 25m, 80.8Ah
This makes sense, as the battery was at 20% SOC before the charge cycle.

Settings:

Also, someone suggested I should set the absorption time to fixed at 30 minutes, but when entering 30 minutes in the setting it reverts to 1 hour.

Any insight is appreciated.