The procedure to replace the batteries is very simple and requires only a Phillips screwdriver and 4 new type D batteries. Follow these steps:
Open the module;
Replace the batteries (the battery orientation is drawn on the back of the support);
When the new batteries are placed, verify if the lights indicators are as show in the image:
4. Done! Everything should be right now.
5. If you want, you can make a final test to ensure that the new batteries are fully charged. For this, with no lights on, press quickly the button (less than a second). The result will be presented by the lights, and the following table represents the possible outcomes.
(*) We recommend the use of alkaline batteries. Some cheaper batteries can have a lower lifetime. If this is the case, search for alternatives.