Replace a LiftMaster backup battery with the exact part listed for the opener model. For units using a 485-series battery, disconnect power, open the battery compartment, disconnect the old battery and connect the replacement to the marked positive and negative terminals. The cover location and battery type vary, so check the model first.
Before buying a battery
Read the opener model and battery label. The 485LM is a 12-volt replacement used in compatible openers; a 475LM is a separate backup system, not an interchangeable battery part number. Do not select by voltage alone. Use LiftMaster's 485-series replacement instructions only for the models they cover.
Replace a compatible 485-series battery
- Start with the door closed and keep it unused during the work. Disconnect mains power. The old backup battery can still energize the opener until it is disconnected.
- Wear gloves and eye protection. Open the battery cover identified in the manual; do not remove unrelated electrical covers.
- Disconnect the battery leads carefully and remove the old battery. Keep metal tools and jewelry from bridging the terminals.
- Fit the specified replacement. Connect red to positive (+) and black to negative (-), checking the terminal markings.
- Reinstall the cover, restore mains power and allow the manual's charging period.
- Use the model's battery-backup test and confirm normal operation before relying on it during an outage.
What the symptoms mean
- A battery-status warning or failed backup test is more useful than age alone.
- Reduced speed while running on backup can be normal for the model; slow movement on mains power does not automatically mean a bad battery.
- Repeated beeping can have other causes. Record the pattern and check the manual.
- If a correct, fully charged replacement still fails, the charging system or wiring needs diagnosis.
Handling the old battery
Do not use a leaking, swollen or damaged battery. Keep it upright, protect its terminals and take it to a battery recycler or a retailer that accepts that battery type. Do not put it in fire or household trash.
For LiftMaster opener or battery service, call (916) 838-8182.
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