ZYGY 5PCS 3.7V 500mah Lithium Battery with 5 in 1 Charger for DE35 DE38 DE40 DE50 TB202 TB201 TM201 TM202 TC141 DE44 DE55 TS201 TD202 TD161 Remote Control Car Toy Car Battery:
How to make a simple 3.7 volt battery level indicator circuit - YouTube
Battery Remote Control Helicopter | Control Car Battery Charger | Li-ion Battery - 3.7v - Aliexpress