I'm using a powerbump, input: 3.7v-6v Outputs: 3.3v, to provide the power I'm using 2 CR2025 coin cell batteries(3v each), meaning the powerbump gets 6v, the esp gets the exact 3.27v(I've measured with a multimeter),

But the chip still keeps on brownouting, when I start BLE on the chip

  • The ESP32 is quite power hungry when using the bluetooth or WiFi. Read this: lastminuteengineers.com/esp32-sleep-modes-power-consumption - button cells provide very little current. You may find it's not enough. Add one more button cell and see if that improves things. Maybe replace one CR2032 with a pair of CR2016's to use the same space but double the voltage (with reduced capacity for reduced runtime of course). – Majenko Nov 7 '19 at 13:52
  • @Majenko The third cell adds another 3 V to the supply voltage. The regulator is specified with 6V and now gets 9V. I think that's not a good idea. The third cell has the same inner resistance than the other ones. So if the current goes above a certain amount the voltages breaks down. So I do not think this would help. One could use two or three pairs in parallel. But the best solution would be to replace the cells by a more powerful source. – Peter Paul Kiefer Nov 7 '19 at 14:40
  • If it's the powerbump I designed then it's 16v max input, not 6v, and it's a buck regulator, so the higher the voltage in the higher the current you can get out. – Majenko Nov 7 '19 at 15:08
  • @Majenko If you have two cells you double the voltage and also the inner resistance of both cells together. The current where the inner voltage drop gets so high that the voltage breaks down and can not feed the converter, stays the same. The converter is not the problem, the cells are. Event if you have more voltage on then bug converter and so it needs less current to draw, I doubt that would be enough to avoid the effect. And the cells also discharge very quickly. If the converter is specified with 16V max then my warning is obsolete. Sorry, I didn't know about that. – Peter Paul Kiefer Nov 7 '19 at 17:51
  • @PeterPaulKiefer There comes a point where the current being required from the batteries needed to provide the desired output current is low enough that the internal resistance of the batteries doesn't provide enough voltage drop to cause a brownout any more. What input that voltage is at though is the main unknown at the moment. As for battery drain, sleep modes can mitigate most of that. But I certainly agree that button cells are a poor choice unless you are specifically using circuitry designed to run at very low currents. The ESP32 isn't really that. – Majenko Nov 7 '19 at 18:04

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