I just purchased an Edge 850, and would like to improve the runtime for touring. I saw the Garmin Charge external battery pack, and I really like how it integrates with the 850, piggybacking underneath the mount. But it appears to cost around $180, and looking at the specs, it is only 3100 mAh capacity. This is striking, because this is the same capacity as some of my older 18650 batteries (for flashlights). I could use one of those batteries in a Fenix ARE-D1 charger/powerbank and it would cost less than $30, and be the same capacity as this $180 powerbank. Moreover, I could use other batteries, like a 5000 mAh 21700 battery, and have several spares, giving me multiples of what the Garmin powerbank has in terms of capacity.
Am I missing something here? Is there some other reason, besides the nice mounting hardware, to get the Garmin power pack? Why not just have a USB cable going from the 850 into a small handlebar bag? And you can have multiple batteries, I just don't get the rationale behind the Garmin battery being so expensive for what it is. If you could replace the battery with your own 18650 or 21700, that would be fantastic, because then you could get the very nice mounting system, and infinite battery replaceability.
Again, am I missing something? How is a power pack with only 3100 mAh capacity priced at $180 today?
