ESP8266 Community Forum

- Thu Apr 30, 2020 11:33 am #86833 Hi,

For quickly describe my project.
I have build a weather station with some sensors and I use EspEasy firmware.
This station is powered with a LiPo 3.7v 800mAh.
This LiPo is charge by 2 solar panel (5v) and a module TP4056.
I control the current and power with a INA219
This project at this step, works.

But I want to add a SG90 servo motor for change the solar panel orientation.
After many tests my SG90 servo motor doesn't turn.
It turns when the battery is full charged and sometime it doesn't turn.
SG90 works well when I powered the ESP with the USB port but it's not the final expected behaviour.

After reading some articles, the conclusion is probably because the LiPo don't have enought intensity.
The SG90 want about 550mAh I think.

Have you already use a SG90 with a LiPo battery and have you a advice about the battery capacity I need ?
Thanks

- Fri May 01, 2020 4:21 am #86843 According to the datasheet a SG90 needs between 4.8V and 6V (typically 5V), so a 3.7V LiPo is about 1V less the required minimum.
You might want to consider using a 2 cell (7.4V) LiPo and a dedicated charging/power circuit that is able to use the solar cell's energy to charge the LiPo and turn the LiPo's power into a steady and usable 3.3V and 5V supply for your project.

2 Cell LiPo's are readilly available for little money, because of their wide use by RC- and airsoft-hobbyists and also special charging/powering modules for them should be relatively easy and cheap to find as well.

Assumption is the mother of all f*ckups. At least: that's what I'm assuming.

- Fri May 01, 2020 8:20 am #86860 Yes.
On first time I use a booster voltage for push the voltage from 3,3v to 5v but I have approximativly the same behaviour.
And what I don't understand it's why it's works perfectly when the ESP is powered by the USB port and the servo motor is powered by a 3,3v pin ?