ESP8266 Community Forum

- Thu Sep 06, 2018 7:17 am #78109 Hello! My first (newbie) question.
I'm not a technical guy so sorry for my basic explanation:

my WeMos D1 Mini (3.3V) is powered by a LiPo (18650) which is fed by a SolarPower (6v, 6W).
The battery charges ok via a TP4056 (with protection).
The WeMos D1 Mini is put in DeepSleep (it wakes up every 8 seconds (testcase )
D0 is connected to the RST-pin
I put a 100K resistor to the A0-pin so I can read out the Voltage of the battery
Data is send to the Blynk-app

Everything worked ok until the battery got too low: WeMos stopped (as expected but doesn't wake up although the battery voltage gets > 3.3V.
After I manually detached and attached the (same) battery, WeMos boots up again and everything works as before.
Am I missing something? Does it need a sort of Push and if so: how?
Thanks for any help!

- Fri Sep 07, 2018 2:57 am #78122 If you mean it didn't recover after battery got too low and you just recharged it then I think that is expected behaviour.

When battery got low the esp8266 would go into an indeterminate state and the sleep / wake up function would stop working. This would not restart just because the battery was recharged. It requires the code to start running again to re-enable the sleep / wake cycle and this is what happened when you removed / restored the battery.

Either put a switch in the power line to make it easier to recover, or you may be able to put a push button to do a pull down on the CH_PD line which will have the same effect as a reset.

- Fri Sep 07, 2018 4:50 am #78132 as it is solra powered, I think it is ment for unattended operation, so a "reset button" would be a poor choice.
There are circuits that monitor the supply voltage and provide proper reset after voltage is stable and sufficient. There are minimum/maximum rise/fall times for PD and RST signals on esp8266 that won't be provided by a recharging battery.

- Fri Sep 07, 2018 6:17 am #78135 Thanks for the answers!
Maybe I had to put it in the 'beginners' section.
Anyway: you both have it right: the Wemos has to recover after low battery and I want this to do unattended.
I don't have any clue how to put a switch in the power line. I cannot find it in any schematic diagram on the net.
What confuses me even more: I made my testcase exact as I found it on the net with a lot of succes replies.
And yes it works as designed, but not after a low battery.
Can anyone point me a bit more in the right direction?
Thanks!