The 12V Force Charge Mode is specially designed for low-voltage batteries. If a 12V battery has voltage between 0.3V and 2V, this means that the battery has aged or been damaged to some extent. Therefore, it may not be effectively charged with the 9-step charging.
In this case, the Sigma 1 battery charger will force charge your battery for 5 minutes and restore the voltage of your battery to a normal state as much as possible.
How to enter the 12V Force Charge Mode:
1) Connect the charger to the battery clamps/eyelets.
2) Connect AC source and connect battery (when the connected battery voltage is between 0.3V and 2V or 12V, the 12V AGM or 12V lithium mode is selected and the icon starts flashing automatically).
3) Press the "Confirm" button to enter a 5-minute force charge.
Generally speaking, the battery voltage can be restored to more than 2V through the 5-minute forced charging after which the battery can be charged with the regular 9-step charging mode.
Note: Due to the inconsistency in the degree of aging or sulfation of the battery, there is no guarantee that the battery will be restored to a good condition by a 5-minute forced charging mode.