Series, Parallel and Series-Parallel Connection of Batteries - Diagrams
arduino - Is it okay to connect 2 lithium ion battery in parallel to a charger that can maintenance 4.2V? (more detail in post) - Electrical Engineering Stack Exchange
How To Connect Batteries In Series & Parallel - Power Sonic
How to Connect Lithium Solar Batteries in Series and Parallel?
What's The Difference Between Wiring Batteries in Series Vs. Parallel?
Battery in series- What is the difference battery in series and parallel?
battery charging - How can I use two TP4056 with two li-ion batteries, but single load? - Electrical Engineering Stack Exchange