Make sure the type of batteries to the charged (gel or lead-acid batteries ) matches the displayed details ("GEL" or "Acd" , respectively). If it doesn't, contact our dealer. now a test is run on the batteries voltage to decide if the charging process should be stared or not. If the battery is not connected to battery charger,the display will show the word "bat" the word will stay on even if the test is failed (for instance, reversed polarities or incorrect battery connection) If the test is passed. the display will show the battery voltage for approximately 5 seconds and the battery will begin to be charged. the charging cycle progress will be shown by red (3),yellow (4) and green (5) LED indicators. At the end of the Charge , when the green indicator(5) is on,Unplug ther cord from the socket and operate the machine.