I’m trying to power a Sparkfun ESP32 Lora gateway off the Pololu 3.3v step up/down regulator, it is rated to a current capacity of up to 1000 milliamps and my two boards draw 5-40ma and 70ma respectively.
They power fine off a USB into the ESP32 but I’m having issues getting the 70ma device to boot at all and the lower power draw seems to occasionally (20% of the time range) get stuck in a brown out boot loop when it comes out of sleep to send via the LORA.
A 1000uf capacitor helped with the lower power ESP (on two of 3 boards) but nothing has solved the higher power ESP from browning out except booting it via USB then booting the battery powered pololu step-up/down and disconnecting the USB.
I’m obviously doing something wrong, I just don’t know what.
Circuit is Lipo (4.05v) > Polulo input > Polulu output (3.35v) > (optional 1000uf capacitor on output) > ESP32 (w/LORA)
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Can you link the Pololu device you are using, they have many different types ?
I have use a number of Pololu devices and have been impressed with their performance.
They usually have Vin GND Vout, pretty hard to mess up.
Maybe the device is just faulty.
Anyway let us know what you are using and I can look deeper into it, might find something.
Cheers
Jim
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Hi Jim,
The main two items are these linked below
Also had temp/humidity sensors connected via piicodev cable and a 18560 via the solar charger
I did my best to isolate the issues to only the ESP32/Pololu by keeping everything else disconnected from the breadboard/out of the boot code.
Cheers,
Byron
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Hi Byron
Why is this there. There is already 60µF on the converter output. This will look like a short circuit at power up and may be contributing to your problem. The 60µF would also be a short but an additional 1000µF will increase the time that it is in this state very considerably. If you have fitted it remove it and try again.
Cheers Bob
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Hi Robert,
Thanks I’ve taken it off. I’ve added a connector from Vin to SHDN to keep it on all the time and I’m hoping it stops the day 3-7 crashes that I have had.
There is nothing worse than an occasional bug that takes days to trigger but then stays triggered.
Cheers,
Byron
EDIT: My assumption is the crash is happening when the current required spikes from <5ma to >40ma (maybe even >100ma) for the hourly readings signal transmission.
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Hi Byron,
Had a look at the products you listed above.
Assume you are powering the ESP32 via to 3V3 I/O pin. The info on this device lists up to 170mA depending on what the device is doing. 80 to 100mA steady state and much lower if in sleep. These measurements are at the 5V USB connector. Converting to 3V3 the current would be higher. Still the Pololu board should be able to handle this as it is well within its spec.
I have one of the Solar Lipo Charger boards and it works well only charging a battery. It did not work so well when I tried a situation like yours powering something and charging at the same time. It can provide up to 500mA, but that is with ideal sun position on the solar panel. If the circuit draws more than the charger can provide the battery begins to drain.
Maybe the battery is not being charged enough each day and that is why it takes a few days to occur.
But, I could be totally wrong. The capacity of the battery and size of the solar panel are also factors. There needs to be enough power from the charger to top up the battery and at the same time power all the devices during the day light hours. The battery needs enough capacity for night time operation. Even a small shadow on the panel greatly reduced the effectiveness of the charger. Clouds over the sun also reduced the available power.
Just some initial thoughts.
Hope you figure out what is causing the problem.
Cheers
Jim
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Hi James
A little bit higher but not a direct conversion. Conversion efficiency has to be factored in, typically in the order of 85%. So assuming this figure 100mA @ 5V input would equate to 129mA at the 3.3V side.
Cheers Bob
EDIT. Going the other way, if you need 100mA @ 5V OUT the input at 3.3V would be 178mA.
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