customized 3.6V Li-SOCL2 D size 19000mAh ER34615 lithium battery manufacturer for NB-IoT/LTE-M, GPS tracking battery production
The lithium thionyl chloride battery is connected in parallel with the HPC, and the lithium thionyl chloride battery charges the HPC with a small current through the voltage difference with the HPC. When powering externally, HPC bears most of the current output.