How to replace your Garmin Edge 520 / 820 Cycling Computer’s Battery.

How to replace your Garmin Edge 520 / 820 Cycling Computer’s Battery.

Battery Replacement Guide

Why Replace Your Battery? Over time, batteries lose their efficiency. You may notice your device no longer holds a charge as well as it used to. My unit, for instance, started failing to last a 2-hour ride with NAV on after about 4 years. This is a clear sign it’s time for a battery replacement. If you’re not comfortable opening your device, any phone repair shop can handle this for you in about an hour. However, if you enjoy DIY projects, this guide will help you tackle the task.

Tools You’ll Need:

  • Replacement battery
  • Removal tools (usually included with the replacement battery)
  • Hair dryer or heat gun
  • Glue (Loctite Extreme or E6000)

Steps to Replace the Battery:

Open the Unit: This is the most challenging part. Warm up the unit’s sides with a heat gun to soften the glue, but be cautious not to overheat, as this can damage the LCD. Once warm, carefully pry open the unit from the edge using a prying tool. Use a suction cup to help open the unit, being extra careful around the LCD.

Access the Battery: Cautiously fold the front panel to the side. Remove the four screws holding the motherboard in place. Disconnect the battery from the motherboard by removing the small sponge over the connection and prying away the black connectors.

Remove the Battery: Use the pry tool to slowly remove the battery. Do not use a heat gun to soften the glue holding the battery, as heating the battery is extremely dangerous. After removing the battery, cut the wires connecting to the unit’s speaker, ensuring not to cut both negative and positive wires together to avoid a short or explosion. Cut as close to the battery as possible to leave enough wire for reconnecting the new battery.

Install the New Battery: Reverse the previous steps to install the new battery. Before closing the unit, ensure it powers on. If not, recheck all connections. If everything works, apply glue around the unit, close it, and use some weight to hold the front panel while the glue cures. Any excess glue can be removed later once it’s cured.


  • Connecting the battery connector to the motherboard can be tricky. Snap it back in place and use the original sponge to hold the connection.
  • Loctite Extreme is recommended over E6000 for a cleaner application with more control.
  • I replaced my battery with an aftermarket one rated at 2100 mAh, three times the capacity of the original Garmin battery. After a 2-hour ride with GPS NAV on and the unit at 80% brightness, I still had 80% battery left. Alternatively, you can use the original Garmin battery rated at 750mAh, though it’s more expensive.


Belows are the links for the tools and components 

Loctite Extreme Glue
E6000 Glue

Electronics Opening Pry Tool Repair Kit (if your replacement battery didn’t come with it)

Aftermarket Garmin Edge 520 / 520 plus / 820 battery Replacement - 2100mAh 

Disclaimer: The author is not liable for any damages arising from the use of or inability to use this guide, or any actions taken as a result of using this guide.

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