ESP8266 Community Forum

- Thu Jul 11, 2019 9:27 am #83065 > This web page looks at the current consumption at startup.
> https://www.ondrovo.com/a/20170207-esp-consumption

Wow. Great link. Thanks. And that's for the exact same item (01s module) that I'm working with.

So there is an extended burst of 430 ma draw on power up, and then during operation there are periodic (but shorter) 430 ma bursts?

"They occur every 100 ms and are about 700 us long"

Hmmm. No, I don't have a capacitor on the Vdd pins of the 01 module - I know what you mean about having a large-value cap causing a high current inrush and being the cause of diode failure. But wow, those 8266 modules are noisy buggers when it comes to power.

The article talks about a "blocking capacitor" - I assume they mean a cap on the module's power input. Which they don't mention a value for.

The diodes I'm fooling around with were from a ebay purchase from china. $2 for a bag of 100 diodes (10 different diodes, 10 of each type).

I'm surprised that those USB ftdi (or equivalent) serial interfaces can supply the power for those spikes without kacking. I have one of those USB things designed specifically for the 01s module, and now I see why there is a large electrolytic cap on the board.

I know a fully charged Li ion is like 4.2 volts, but I was using one that was giving 3.95, and the diode dropped that to 3.65 which is the absolute max that I've read the 8266 can handle. I know a better solution would be to regulate that down to 3.3, but I don't have any of those handy at the moment.

Another thing that threw me initially about the 01s module is the need to solder a pullup resistor to GPio-0 and CH-PD pins to make it work when it's not plugged into anything.

- Thu Jul 11, 2019 6:54 pm #83070 Hi Sum~guy, I can’t find the link but hopefully another member will have the link to hand and post it. The post consisted of measurements of current consumption with reference to supply voltage and as I remember appeared to be credible. The result was that the current drawn by an ESP was very close to an expentional graph. So at close to 4V it wouldn’t surprise me if the start up current could well be over 1A.
There is a big difference between USB power supplies and cells/batteries. In this day and age most USB power supplies are just chargers and will not supply 1A at power up due to internal limitations. Cells/ batteries however will supply a huge amount of current from start up if requested.
I must admit this is less than ideal but I have a couple of projects using diodes to drop the voltage from Li ion’s and have used silicon diodes with a 0.7V drop across them. I found that whilst out of specification the ESP runs quite well down to 2.7V and draws even less current extending cell/battery life.

- Fri Sep 20, 2019 3:05 am #83859 The only explanation for the broken diode I can come up with is the inrush current to the onboard Vcc capacitor (which is quite large).

For "normal" operation count on 10-600 (!) mA load (varying on the wlan activity).

- Fri Sep 20, 2019 10:44 am #83872

Hmmm. No, I don't have a capacitor on the Vdd pins of the 01 module - I know what you mean about having a large-value cap causing a high current inrush and being the cause of diode failure. But wow, those 8266 modules are noisy buggers when it comes to power.

There is a capacitor on the module. It looks small but it's quite a big value.