Well if you're charging 3 or more devices then maybe it's appropriate but that'd last my android for like a month using my maximum conservation techniques but still gps+tracker on for all-day rides.

For extra power on the go I just got this for $15 https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1
edit: looks to be unavailable now, but there are other similar units out there

Use a twofish block holder to attach it to your stem or bar, or electric tape, or throw it in a bag and run a cable down the frame (if you're phone can't make it until the end of the ride).

It includes a 2800mAhr battery but I already had several better panasonic ncr18650b 3400mah batteries and a Nitecore charger. I paid a little more for the amazon USB power pack than other cheaper options just because it allowed removable 18650 cells so I could use my better cells, charge my cells with a better charger, plus carry more in a bag or pocket if needed to swap out when the one in the unit is depleted. They make AA usb power packs too for those that don't want to invest in 18650 cells (but they make really great flashlights that use 18650 cells!) obviously the most common battery in the world you can get at any corner store but you'll go through AA's a LOT quicker!