Maria Sierra wrote:Yes but why i connect it again with LiOn or FTDI USB (5V) it works again?
As I said in my first post.
At 4 volts the power dip is not below what the ESP8266 needs to operate. But at 3.2 volts the dip disrupts operation. The meter can't measure the sudden drop in voltage. You are seeing the average value with the meter.
I am going to numbers that are for this explanation and I am not saying that this is the exact voltages you have.
Let us say that the ESP8266 will fail (causes a stack error) if the voltage drops below 3.0 volts. Also let us say that the way you are powering the ESP-07 causes a instantaneous voltage drop of 0.4 volts.
When powered from 4.0 volts the 0.4 volt dip causes the ESP to see a minimum voltage of 3.6 volts. And since that is above the minimum 3.0 volts stated above, it continues to work.
When powered from 3.2 volts the 0.4 volt dip causes the ESP to see a minimum voltage of 2.8 volts. And this is below the minimum voltage the ESP needs, and therefore it crashes.
Maria Sierra wrote:wires between ESP and battery are 10 cm long
And that is part of your problem is. You used the right word,
long. What you should have is
short lengths.
And you should not be powering the ESP with more than 3.6 volts. The higher the voltage the greater the likelihood of permanent damage. In your case I think what is happening is the parts are drawing excessive current much of the time but when the ESP needs to draw a peak current, then the power supply voltage drop will help to minimize the potential damage.
Use proper regulation!The ESP8266 goes through a calibration procedure when it starts up. It will draw a high peak current at this time. If the power supply is incapable of supplying the required curren then it will fail. The power supply should be capable of supplying at least 400mA.
What is need in your case is a regulator that has a "low drop out voltage", 500mA current capacity, and low operating current. And you will need proper capacitors and have all this wired at the ESP module. Not 10 cm away. Short wires on everything. If you don't need the length then don't have it.