Garmin Edge 305 - Main unit battery dying?

I bought a Garmin Edge 305 in August 06 from Johnny Appleseed in Melbourne. It's been great. I really like it. I've replaced the heart sensor and cadence sensor batteries a number of times and upgraded the main unit's software a few times. I ride 3 to 4 times a week and have done about 18,000km with this device. But now the battery in the main unit is failing to charge properly. It's a lithium-ion battery and according to the online 'Battery University'. internal odixation in the battery leads to this problem after about 2 years. It's normal and not a memory problem or anything like that. Appleseed refered me to the AU servicer, GME Service in Sydney. They advise that the internal lithium ion battery cannot be replaced and instead they supply a replacement 'reconditioned' unit, with only a 3 month warranty, and wait for it, the cost is AU$180+GST+freight, a total of $209. So after a couple of years of use (less in my case although my battery still has a bit of life in it) I have to pay $209 for another couple of year's use (at best, warranty is only 3 months remember). !!! I'm shocked. Not happy at all.

http://www.megacapacity.com/750.html?gclid=CJjJpZXcmJICFQP_iAodXgwaCA
You could try this. It means you would have to change it yourself.

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leestevens@


http://www.riverlandcyclingclub.com/

Thanks yes - there are a number of possible ways to re-power it. I hadn't seen that site - and I don't know that I'm prepared to open the device up - but a small lithium-ion cell feeding power into it via the usb plug is certainly a possibility. Similar approaches have been recommended for extending the battery life on the road.

I have been reading more about the characteristics of lithium ion cells (see http://batteryuniversity.com/parttwo-34.htm ) and I do wonder if the battery had been reacting to the extremely hot weather we've been having recently, (with temperatures up to 40C). It's now cooled down substantially (as happens in Melbourne) and tonight the battery seems to be taking and holding the charge better.

It was also interesting to read about how the battery charge indicator can lose its calibration, and not show the battery as fully charged when in fact it is. Apparently this can arise with frequent re-charges of partially drained batteries (recommended for lithium ion). So this afternoon I completely drained the battery, then recharged it 'fully'. Whilst this isn't recommended as a regular practice for lithium ion, right now it's indicating a full charge. We'll see what happens. Hopefully the battery has got a bit of life left in it.

But Edge 305 users would be well advised to fully acquaint themselves with the peculiarities of lithium ion cells (see the above battery university site) in order to get the longest possible life out of their Edge.