Category Archives: Tinkering

Running, Tinkering

Garmin Surgery. New Battery and Cleaned Contacts.

My Garmin Forerunner 305 has served me well for almost 6 years. Recently, it’s started shutting off randomly. I considered buying a new GPS, but figured I’d do some research into the problem first. I found a few places online where people said that it might be a loose contact. I decided to see what I could do before giving in and buying a new unit.

I took a utility knife and cut along the seam to release the adhesive. It took a little bit of prying to finally get it apart. It came into two pieces, the top with the screen and stuff and the bottom with the battery and power board. The contacts on the screen side stick up/down to meet the flat contacts on the power board. Mine had one contact with a little corrosion. I cleaned it and then lightly bent the contacts up, so they’re would be a little more pressure to the board.

Two halves and an old battery.
Two halves and an old battery.
Little finger contacts getting tired after all these years. Needed some encouragement.
Little finger contacts getting tired after all these years. Needed some encouragement.
The fingers need to make solid contact here. A little corrosion on the right. Pencil eraser cleaned it up.
The fingers need to make solid contact here. A little corrosion on the right. Pencil eraser cleaned it up.

Since I had it open, I looked to see what I could find about replacing the battery, and if I could maybe upgrade to one with more power. I found this page by kevhash3, Garmin Forerunner 305 battery replacement experiment. It was quite helpful. I ordered a 1300mAh 3.7V ipod mini battery that fit in the watch, like the one in the write up. A couple days later I had my battery and proceeded to follow kevhash3’s instructions.

Good enough for me. The tiny speaker was damaged when removing the old battery. I turned all sounds of long ago anyway.
Good enough for me. I insulated the wires with electrical tape and taped the battery in place. The tiny speaker was damaged when removing the old battery. I turned all sounds of long ago anyway.

I finished up and used some marine adhesive that I had from a prior project to seal it all up again. My Garmin works just fine again. No random shutoffs. I’ve only used it a couple times since then. I also haven’t had a chance to put the new battery to the test.

While I was kind of looking forward to getting a fancy, new GPS with more features than I’d know what to do with, my 305 does everything that I really need. Maybe it’ll last another 6 years. Or maybe I’ll decide to upgrade after I increase my mileage some more.

Now if only I could figure out how to upgrade the antenna.