3.6V 40mAh NI-MH Rechargable Battery With Solder Pins For Clock Memory Chip Doorbell PLC Motherboard NI MH Button Coin Cell - AliExpress
Blog - RC Batteries: LiPo Vs NiHM - Why LiPos are Better
Amazon.com: Brightown 12 Pack Rechargeable Battery AA, NiMH Pre Charged Double A Battery for Solar Lights and Household Devices, Recharge up to 1200 Cycles : Health & Household
How does Internal Resistance affect Performance? - Battery University