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By stavbodik
#64292 Hello ,

For powering my project I am using 3.6V 19Ah battary .

I am asking myself if the ESP can work on 3.6V , there is any reason to use LDO ?

I did read that the power consumption is lower in deep sleep mode when using LDO,

May you give me reasons for using LDO ?

And yes I need to save batteries life time as long as I can.

Thanks !
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By schufti
#64298 Hi,

1st) an ldo only has a low dropout voltage, say: can work closer to the empty battery level.
example:
standard regulator would need 1V difference -> won't work below 4.3V battery voltage
ldo only needs ~0.3V differende -> can work down to 3.6V battery voltage.

2nd) quiescent current: for low energy profile you need regulator with only some µA qc compared to standard with 10mA and more.

3rd) if it is an standard LiIon battery, it has about 4.2V freshly charged, what is too much for esp8266, and 3.2V allmost empty what is too low even for ldo.
a LiFePo4 has 3.6V freshly charged and 3.2V allmost empty what is perfect for esp8266 w/o regulator.
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By stavbodik
#64325
schufti wrote:Hi,

1st) an ldo only has a low dropout voltage, say: can work closer to the empty battery level.
example:
standard regulator would need 1V difference -> won't work below 4.3V battery voltage
ldo only needs ~0.3V differende -> can work down to 3.6V battery voltage.

2nd) quiescent current: for low energy profile you need regulator with only some µA qc compared to standard with 10mA and more.

3rd) if it is an standard LiIon battery, it has about 4.2V freshly charged, what is too much for esp8266, and 3.2V allmost empty what is too low even for ldo.
a LiFePo4 has 3.6V freshly charged and 3.2V allmost empty what is perfect for esp8266 w/o regulator.


Hi schufti thanks for your reply ,
Yes my question was specially for case 3 where my battery is freshly 3.6V and almost empty at 3.2V ,
So as I understand I don't need to use any regulator at all,Regulator is needed only when the input voltage Is higher then max voltage the device can handle.
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By Freecanadian
#64451 Hi, I have played with ESP and Arduinos a bit (but I am not an expert). About a month ago, I ran a test of two days posting DHT-22 data by ESP8266 to WUnderground running on a single 18650 lithium battery, (partly charged to just under 4v). It worked without voltage regulation, but I was probably just lucky that I didn't burn it up.

I am more excited to have found a couple of circuits showing it may be possible to use a Zener diode, a resistor, a capacitor, and an NPN transistor or possibly a Mosfet to build a simple voltage regulator. I plan to try this method, since it seems this circuit can clip the voltage down to spec (based on Zener selected) but also allow lower voltage to flow thru as the battery discharges. The circuit I tested with a simulator showed 0.7v drop with NPN transistor, 5.5v input and 3.3v output at 300 ma, and was based on this circuit: http://electronics.stackexchange.com/qu ... o-nrf24l01

Nick Gammon also used a simpler zener circuit to regulate the charging voltage to the super-cap in his solar powered AtMega328 page: http://www.gammon.com.au/forum/?id=12821

Hope this info might help you.