You can use a dimmer with a trans for your project . I think if you use a iron core transformer thus you can use it for this mater.
you need circuit like this:
The main transformer usually has a separate winding rated around 140V. Phase angle control is used to chop the voltage from the main line and feed into the separate winding. The phase angle (delay) at which the triac is fired controls the RMS and average chopped voltage, which affects the battery charging current. The microcontroller controls the charging and adjusts the firing phase angle to control battery charging.
The main transformer usually has a separate winding rated around 140V. Phase angle control is used to chop the voltage from the main line and feed into the separate winding. The phase angle (delay) at which the triac is fired controls the RMS and average chopped voltage, which affects the battery charging current. The microcontroller controls the charging and adjusts the firing phase angle to control battery charging.