- Always use 4 x AA batteries (alkaline only). Any 4 x AA alkaline batteries will work.
- Do not use lithium batteries.
- Do not use 9V batteries.
- Do not use rechargeable batteries, as their voltage can drop in adverse weather conditions.
- When the batteries need changing, the red LED will be permanently lit. The red LED always flashes every 30 seconds when the door is CLOSED.