ESP8266 Community Forum

- Thu Nov 20, 2014 11:07 am #2987 I hacked up a board using 3 AA batteries and a 3.3V LDO (LF33ABV) with 500 mA capacity and 0.35V dropout @ 200 mA. Seems to work.

I'm using NiMH rechargeable AA-s. The LDO will get hotter with alkaline batteries, have not tried that. However, it behaves nicely when the input battery voltage goes below 3.3V, the output voltage follows the input.

The buttons are for GPIO0 and reset (flashing new software). To the right is the serial - USB converter.

Board with ESP-01 and serial - USB converter:

image.jpeg

Naked board:

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- Thu Nov 20, 2014 11:11 am #2988 Also, I think if you're aiming to make a low-power device, which will go longish periods of time between waking up, reading a sensor and transmitting, that a Low Dropout (LDO) voltage regulator would be more efficient than a switching power supply, since the switching power supply would use more power when the ESP chip is sleeping
.

- Thu Nov 20, 2014 4:15 pm #3008 Thank you! I'm very new to these. I hadn't thought about how much power would be wasted on the
supply. Maybe the most efficient is then to really use a Li-ion battery directly. I'll have to experiment with
voltage.
Am I right to infer that LF33ABV uses 50uA when off, and 500uA when on? That's a lot relative to 0.35uM that one can
supposedly get atmega328 to sleep at (according to this excellent page), or 10uA that ESP8266 should use in deep sleep. But, if a AA has 2890mAh, you'd still get 6 years if you only used 50uA. I think I'll start with 3 AA then.

As to AC, yes, best would probably be using an enclosed supply. I was hoping to have something that can fit into an E26 base, or into a wall-mounted light switch.

- Fri Nov 21, 2014 11:49 am #3094 A fullt charged LiIon battery is about 4.2 volts, so you don't want to connect that to your ESP without an LDO or something.