Timeline for ESP32 powered by supercapacitors
Current License: CC BY-SA 4.0
9 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| May 10, 2019 at 6:58 | comment | added | Russell McMahon♦ | ... | As a guide expressing Vl as a % of Vm gives the following available energies INTO the converter. | Vl = 0.8 of Vm - Eavailable = 36%. | 0.7Vm - 51%, 0.6Vm - 64%, 0.5Vm - 75%, 0.4 Vm - 84%, 0.3 Vm - 91% - -> So eg 0.4 or maybe 0.3 Vm is about as low as is useful. For Vm=5V that's 2V or maybe 1.5V | |
| May 10, 2019 at 6:57 | comment | added | Russell McMahon♦ | @dandavis Yes. And higher V. $ usually increases with usefulness :-(. || As a guide only: Energy available = 0.5 x C (Vm^2 - Vl^2) wherte Vm is max charge Voltage and Vl is the lowest voltage at which the converter will operate satisfactorily. In many cases efficioncy of conversion will decrease markedly at low Vin so you do not get vastly more energy by going to the lower voltages. Also, power output capability often also reduces at lower voltages. .... | |
| May 9, 2019 at 19:41 | comment | added | dandavis | you can get 4f 5.5v caps, even cheaply, which should simplify | |
| May 9, 2019 at 4:01 | vote | accept | VladoPortos | ||
| May 8, 2019 at 11:23 | comment | added | VladoPortos | TPS61201 might be good choice for the buck boost it takes down to 0.3V up to 5.5V and provide 3.3V | |
| May 8, 2019 at 10:36 | comment | added | VladoPortos | Thanks Russell, so in the end I would need like 10 of these capacitors + boost converter to make it. that would be too much price wise, but still I might make just one prototype for fun :D | |
| May 8, 2019 at 9:21 | comment | added | Russell McMahon♦ | @VladoPortos That's 68 mA for 30 seconds per Farad. If you need 268 mA x 30 seconds then you need 268/69 =~ 4F | |
| May 8, 2019 at 8:03 | comment | added | VladoPortos | thanks, if I got it correctly this setup would not help me really if its only 68mA, since the ESP32 can draw 260mA with wifi usage..not counting the power needed for eink display update. | |
| May 8, 2019 at 7:50 | history | answered | Russell McMahon♦ | CC BY-SA 4.0 |