Replace all four batteries when you notice a marked decrease in the range or response of your remote control, or when you see the low battery indicator (Lifestyle® V25, V35, 235 and 135 systems) on the display.
Replacing the remote control batteries
Slide the battery compartment cover off the back of the remote control
Remove the old batteries
Install four new AA (IEC-LR6) 1.5V batteries, matching the polarity markings (+ and –) to the markings inside the battery compartment
Slide the battery cover back into place