There are four (4) through-hole connection points near the J4 VDC input connector; a +VBATTERY trace begins here and is routed to the power management device, EU2.
All battery solutions must be completely external to the expansion board except for standard communication and I/O interfaces. The EU2 device serves as the +VSYS voltage regulator.
The battery charger device (EU2) on the expansion board was selected to allow powering of the Intel® Joule™ module from either an external power supply or a battery. The Joule BIOS does not support the ability to enable the EU2 device for battery charging. If battery charging is required, we suggest designing an external solution to power the expansion board that uses a battery charging device designed for the battery chemistry, configuration, and capacity of your target solution.