So like many other cyclists I use a Garmin GPS to track data for my rides. I've had this unit since 2010, and being 2014 now it's at least 3 years from purchase if not more since actual manufacturing date. That said, it is out of Garmin's 1 year warranty.
The battery inside a Garmin Edge 500 is a Li-Ion Battery and is originally rated to last up to 18 hours. While I've never had to use it for 18 hours, sometimes an event/race or training ride would veer into the 14-15hr range depending on difficulty or my mood because. sometimes I'd treat an ultra as a nice jaunt and took things at a mostly leisurely pace. My first two years of use found the battery lasting "as advertised" which was great. Then, towards the end of 2013, I noted that the battery wasn't lasting nearly as long... sometimes a short 6hr ride would result in low-battery warnings by the time I returned home. This is typical as Li-Ion batteries have a shelf-life of 3 years average, even if they are not used extensively. See the link at the bottom of this post for more about Li-Ion batteries.
I called up Garmin to see what the costs would be on a battery replacement, and I was given a quote. This can also be found on Garmin's own site, but you will need to call them to get an RMA Number. I was quoted at $89USD + shipping (to Garmin) + tax (California). Upon receipt they would immediately ship me a "new or refurbished" (most likely refurbished) Edge 500 with a new battery installed. While that's somewhat reasonable compared to buying a new one, I decided to take my own route.
I saw the battery replacement as an opportunity to learn about how my unit is put together and to test out a replacement battery. Besides, I love working with my hands, I love learning new things, and I'm rather enthusiastic about building skill sets.
What follows is a diagram on how to replace your Garmin Edge 500 Battery.
You will need:
-Micro Philips Screwdriver
-T5 Torx Screwdriver
-Pry bar "spudge tool"
-Double sided tape
-Soldering Iron (optional, over built method)
-Hot Glue Gun (optional, easy method)
10 minutes (skilled person)
30 minutes (unskilled person)
---------------------------------------------------------------1. The new battery.
I ordered a new battery from "newpower99.com" - here's the link to the actual item.
I am not in any way affiliated with this supplier and there are many other options available. My purpose is to document what is received from the order and the method of battery replacement for the Edge 500.
This is what you receive in the mail from newpower99.com for the Garmin Edge 500 battery replacement.2. What's the box?
-A green pry tool (plastic)
-A Torx screw driver (T5)
-A micro Philips screw driver
-Battery with leads and connector.
Overall quality of the tools is o.k. They'll probably last far beyond the installation and are good to keep around afterwards, but don't expect these to be heir-loom tools to hand down to your grandkids.3. New Battery
The new battery which will be installed in the Garmin Edge 500. Wh is lower as are mAh. We'll see how this compares to the original battery which operates at a higher power and larger capacity.4. Removing the Torx screws
A composition of the front and back of the Edge 500. On the back side you will find 4 Torx screws (T5) located at the corners of the unit. Remove these screws.5. Pry the faceplate from the lower body.
Even with the Torx screws removed the front plate of the Edge 500 will be held tight against the lower body. Use the green tool to pry the faceplate gently away from the lower body.
With the four Torx screws removed and the front plate pryed off you will see the screen resting on top of the board. The screen lifts easily off the board, it is not bound with any screws.6. Remove the three Philips screws holding the board to the lower body.
With the screen lifted carefully away from the board (easy), you will see three Philips-head screws which attach the board to the lower body. Remove these screws. Do not separate the screen from the board.7. Remove the Board from the lower body.
An image of the main board of the unit held snug within the Edge 500's lower body. The removed screws are pictured at the top of the image. You will need to pry the board away from the body using the green tool.
An image showing the board (with screen) removed from the body of the Edge 500. The green bar was used to pry the board away from the body, it fits rather snug.8. Disconnect the battery (old) from the Board.
A quick picture showing the battery's connecting pin disconnected from the board. It just pulls off easily. The new one will snap in easily as well (pay attention to which side you are pressing down into the connector on the board!)9. Remove the old battery
The battery has been disconnected from the board and lifted off of the body. There is some double-sided tape which held it in place. You will needed double-sided tape on the new battery to old it in place against the body. The battery has two leads coming from the connector down to the speaker, soldered into place. I chose to cut these wires from the battery. Instead of soldering in the new wires, I used a different method for connection (if you don't care for or use the speaker, just disconnect the wires completely and don't attach the new ones leave them in their packaging tape to ensure they never touch each other).
The original battery on the Garmin Edge 500. Note that it reads a higher Wh and mAh compared to the replacement. How will this effect performance? At the very least, 600mAh (new) vs. 700mAh (old) indicates a lower overall capacity. However it is also running at a lower Watt-hour which does not affect the unit's performance from testing.
Side note, I removed the surrounding seal to make working easier.
The rubber seal between the plates on the Edge 500 body is easily removed, no glue necessary. Removing it helps get it out of the way, it can be easily placed back in the channel when re-assembling the unit.10. Attach the new battery's lead wires to the speaker wires.
Instead of removing the old wires to the speaker and soldering in the new wires, I opted for a much quicker and easier solution.
I cut the old wires from the speaker and stripped away a portion of their housing, then twisted them together with the leads from the new battery. Black to black, red to red. A dab of hot glue encased the low-powered wires together. Normally hot glue is not recommended for high powered electricity lines as it would melt, however in this instance it would be fine. The low-heat ensures the glue still flows over the two wires which are wound together and it dries quickly. Soldering is nice, but a bit overkill: the sealed unit will not experience enough movement to warrant internal parts moving around drastically, the hot glue does seal the wires together in a strong form, and I won't have to smell solder smoke. Win-win-win. A hot glue gun, by the way, is a designer's best friend if you're in a charette
You can check to see if everything works by pressing the upper left button on the side of the board - this turns the unit on with the new battery (and gives a beep if you've connected the speaker and actually have the sound preference set)11. Re-assemble the unit!
This is pretty easy: attach the battery's connector to the board (press down gently so it snaps in place, make sure you have the correct side down), put everything back following the previous steps in reverse.
Here is an image after immediately re-assembly. I've powered the unit back on, and it showed that the new battery was charged to 70% from the factory.
Right now (28th Jan, 2014) I've used the new battery twice and it works like normal with no issues to report. I may not get a chance to test the full capacity for at least a few weeks, but I will update this post on my findings.
Finally, some recommended reading about Li-Ion battery maintenance:http://batteryuniversity.com/learn/article/charging_lithium_ion_batteries/1
I hope this post was useful. Thanks for reading!