I´d like to tag along with this thread - Adafruit have a charger that it says can be used on both Lithium ION and LIPO - PowerBoost 500 Charger - Rechargeable 5V Lipo USB Boost @ 500mA+ : ID 1944 : $14.95 : Adafruit Industries, Unique & fun DIY electronics and kits. There is no mention of any jumpers to be changed for battery types. I´m trying to get up to 24 hours life from an MKR1000.