I'm working on a little 3D printed robot (Otto DIY) with an ESP8266 and four servos, and I need to feed it with batteries.
As a first thought, I considered some 18650 cells I had lying around, with a TP4056 charger and an MT3608 step up for powering everything. It didn't work, the ESP turned on but the servos didn't move. I tried everything but I had no luck, so I kept testing the robot with a 5V 1A Samsung charger. Then, a new idea came to my mind. I had a 5V 2A TP-Link power bank. Because of the size, I couldn't use it, but it powered everything perfectly. I found a much smaller and more suitable 5V 1A power bank (oh, just like the Samsung charger that worked just fine), but it didn't. It did just the same as the 18650 cells with the step up.
As I have little knowledge of electronics, I no longer understand the problem. The charger and the power bank are the same voltage and current, so why do they work differently? And most importantly, which is the best way to power this robot having in mind these details? It can't be too big or heavy; this little robot falls easily.