Which Cache Battery for Bikepacking?

The question I get asked most about the kLite USB charger is "Which cache battery works best with it?" There are quite a few to choose from but I have had the best result from the Mi Powerbank Pro 1000 mAh.

It has low power charging, ideal for trickle charges even when you are climbing. Many cache battery wont do this. Its nice and slim, so will easily slide into a top tube bag. It also has dual USB output, so you can charge a number of things at night as you sleep or run the Klite main light at full power while you continue to ride without needing to worry your phone/Garmin is going to die.