Monday, 11 November 2013

Garmin 205 or 305 battery replacement

These GPS running watches are easy to repair/refurbish as long as you catch any watch that starts to play up soon enough.....

both of these watches are basically the same design except on has extra circuitry for the heart monitor, but physically the cases are the same. Garmin charge £50 (ish) to get a refurbished watch back, which I think is far too much to pay when all you might need is a damn good clean out and/or a new battery

The battery you need is the same one/similar to the ipod mini battery, just do a search on ebay and you'll find one the last one I ordered cost an horrendous £2.79 all in including postage

all you'll need is a thin bladed screwdriver or a penknife or in some cases where the glue Garmin use has degraded with sweat/water ingress ....your fingernails will do. 

I've found the best angle of attack if you're right handed is to try the bottom left or right of the watch just above the buttons you'll see a seam, that is where the unit splits apart, if you can get your thumbnail in there and it starts to split open, it doesn't take very much pressure to get it apart.....

Once inside you'll see where the top part electrically joins to the bottom part by spring loaded contacts, don't worry when you pull the watch apart they are two units and are separate items and are not connected by any thin wires or ribbon cables.

Once apart you can prise off the battery as it's only glued down with a blob of glue, be careful though because the battery (obviously) is attached by wires to the base of the unit, I usually cut the wires off quite close to the battery as this gives you plenty of wire to play with when fitting the new battery and there is enough space inside the case to contain the extra wire.

The new battery fitting may require you to snap off a few bits of plastic underneath where the battery sits, as the new battery is just a tad larger than the old one.

You'll need a soldering iron to do the job probably because simply twisting the wires together will not last with the movement of the watch over time, once soldered together you MUST insulated them against each other, they mustn't touch...I use a bit of insulating tape to separate them and tuck them down by the side of the new battery.....

take a look at the contacts on the top of the Garmin shell and the bottom make sure they are clean and do not have corrosion (see picture)

                            bottom of Garmin

If you have corrosion like this and it's not too bad you can clean it up  with a small paintbrush and some toilet limescale remover (it's acid basically) but make sure you wipe off and wipe down with a cotton bud and water to remove the acid afterwards, and dry it thoroughly MUST neutralize the acid !!! 

The one above wasn't too bad I removed the tarnish with a very dilute solution and an artists paintbrush, make sure the contacts in the other top part of the shell are clean as well, I've even used a toothbrush to get the worst of it off, but be careful with the top contacts they are quite delicate.....

                              top of Garmin

as you can see the 2nd & 3rd pin on this Garmin are tarnished through sweat/water ingress.
Also check the tiny speaker which is glued to the bottom of the Garmin shell, if it's badly damaged/corroded, simply clip/cut the wires and remove it and then insulate the wires with tape and tuck them under the battery, not many people miss the beep and for £11 (ish) for a new speaker its simple not worth replacing. once you've removed the battery, you'll have to seal the holes the sound escapes from normally to stop any more water/sweat getting into the device. (more on that later)

Once you're happy everything is cleaned up 

Clean the mating surfaces of the Garmin both top and bottom, clearing out all the old glue, as much as you can anyway, I use a small flat-bladed screwdriver which is  good enough for that job, take care not to cut into any of the circuitry of the lower part of the Garmin whilst doing this.....

once you're happy push the two surfaces together and hold between your thumb and finger and turn on your Garmin, the new battery should have enough life in it to fire it up as Lithium Ion batteries are always partially charged when you get them.

Once you're happy the battery connection is good and the watch seems to function as intended you're good to go onto the next stage.

Sealing the Garmin....

I've found that using a wooden toothpick/cocktail stick and clear bathroom sealant works best but you of course can use anything you like as long as it's waterproof, something like Araldyte but it's unlikely you will ever get it apart again with as much ease as the cuckoo spit glue Garmin seems to be using (joke).... stay away from plastic glues (airfix type) they are not water resistant over time.....and they don't adhere to the type of plastic the Garmin is made of...... contact adhesive is also not a good idea, it's too gelatinous to apply and you'll end up making a right mess of the joint.

Apply enough sealant to form a good seal all the way around the garmin, try not to allow the sealant to drip over the buttons inside the shell.... for obvious reasons...... it doesn't however matter if some of the sealant comes out of the sides you can always wipe off with a damp cloth once you clamped the Garmin together. 

if you've removed a corroded battery you'll need to put a blob of sealant over the holes and press it in with your finger so that it completely seals the holes, ideally you want to see it come out of the other side to ensure a water tight seal.

as for clamping the Garmin together you can use anything, several clothes pegs, insulating tape, a g-clamp, a vice even  ...whatever just do not apply too much pressure....just enough to push the two parts together and keep them there.

leave it to dry for 24 hours, (don't rush it) unclamp and you're good to go :)

obviously give your Garmin a full charge several hours should do the new battery is much higher capacity than the 720mAh Garmin one you've removed. 

Happy Running :)

ps/ Obviously if you do this to a watch which is in warranty you'll lose your warranty, goes without saying........

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