Won't run on battery power

[Stumpy_L]

I am working on a remote greenhouse monitor. I have a BME280 sensor connected to a ESP32 development board. I can connect the ESP32 via WiFi to my home router and send the readings to ThinkSpeak. I also have a NRF24L01 connected that sends the readings to a Arduino Mega that I have a TFT display in my house. I put the ESP into deep sleep for 15 minutes between readings. All of that works fine.

I am now trying to get it to run on battery power. I made a solar charger based on Random Nerds project with the exception I use a HT-7333A for the LDO. If I connect the output of that to the 3.3v pin on the development board it does not work. I have an LED to show that the loop function is running, when the ESP goes to sleep the LED goes out. The LED never comes on. I can run a simple blink sketch and that works fine.

I assume it's a power problem or that I am not applying the power at the right pin but that is what I am asking about. The output of the charger board is a steady 3.3 volts with about 0.001 volts of ripple. When I measure the current draw it jumps between 40 and 70 milliamps. I also tried connecting a buck/boost to the charger and had 5.2 volts on the 5 volt pin but that also did not work.

As I've seen other projects, YouTube mostly, running projects this way I am not sure what I am doing work.

Thanks for any help and comments
John

[ESP_Sprite]

HT73xx only does 250mA, that's not enough for an ESP32 (needs 500mA min) plus whatever your sensors use.

Aside from that, your reset circuit may be an issue: if you manually reset the ESP, does it come up?

[xien551]

Hey, Stumpy_L.

So far as I know, the develop board has a LDO named AMS1117, your input power voltage has a large scale up to 20V. If it has a mini usb power port, you can power it by connecting to your computer. If you have a mobile phone portable power, may be you can use it. The 5V mobile phone charger also works, it often supply ~1A current. Do not use fast-charger for safety.

Remember, if your battery is not large enough, which means it can not afford large current, it will bring about disaster, especially for Lion-battery.

[ESP_Sprite]

Do not use fast-charger for safety.

That's an interesting statement... to my knowledge, all fast-charging protocols revert to standard 5V output unless they detect fast-charging protocol communication. Do you have different experiences?

[pataga]

I am using an HT7333A with ESP32-C3 (have also used it with ESP32) for a project with low deep-sleep current requirements. Advantage of HT7333A is the low drop out voltage (suitable for Li-Ion batteries) and very low quiescent current ~4uA.

But you have to add a large capacitor on the 3.3V line ( e.g. 330uF 6.3V tantalum ) to act as a low ESR storage tank for the > 450mA current pulses drawn on Wifi transmission bursts (on ESP32, default TX power level). Else you will get brown-out resets.

This project (automatic watering system) is running off a tiny 200mAHr Lipoly battery as an experiment. The battery itself has an internal resistance that increases with discharge that would make it unusable even at half-discharge. I have added a solid polymer (very low ESR, very low leakage) 1500uF 6.3V capacitor in parallel with the battery terminals (before the battery over-charge/discharge protection board) to compensate.

Checking to see how long this continues to work, so far 1 month + with no issues.

https://github.com/har-in-air/ESP32_AUTO_WATER

Also as mentioned, (with ESP32 at least) the usual reset pin 10k pullup + 100nF pulldown circuit isn't reliable. I use 2.2K and at least 1uF, i.e. strong stable pullup is required. Ref : Check the schematics for well designed ESP32 dev boards e.g. Adafruit or DF Robot.

[Stumpy_L]

Thanks for all the comments, here's what I've done. The original circuit I am using used a MCP1700 LDO, also a 250 ma output, so I've changed mine to a TC1262-3.3v which has a 500 ma output, put it still doesn't work, actually it did for 2 sleep cycles set for 30 seconds, then stopped. I think between the WiFi, BME and the NRF24 it's drawing more than the 500 ma. I did disconnect the NRF24 but that didn't help, I think WiFi is the larger current draw. I'll look for a LDO with a 1 amp output. I do have a 100uf and a 100nf in parallel across the LDO but I'll increase that to at least a 330uf. I'm using a 3000mah Li-ion battery.

Two other things I tried. I put a buck/boost on the charger for a 5.2 volt output and attached that to the 5v pin but I think the current limit prevented that from working. I also tried a USB battery, 7.4wh, 5v 1 amp output plugged into the micro USM connector on the ESP. It runs for 1 sleep cycle then after about a minute the red power LED on the board goes out, I left it to see if it would come back on when the sleep cycle reset, it did not.

Where there is no Vin like on an Arduino is putting the external power to the ESP 3.3v or 5v pins the correct way?

I'll try a higher current LDO and larger cap across it and see if that helps.

Thanks again for your help
John

[xien551]

That's an interesting statement... to my knowledge, all fast-charging protocols revert to standard 5V output unless they detect fast-charging protocol communication. Do you have different experiences?
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Are you sure the development board supporting the fast-charging protocols, maybe they did not contain the protocols chip.

My NVIDIA Jetson board is damaged because I using a fast-charger which could also supply 9V voltage. The package told me that I need a 5V 3A charger.

I email nvida and accused them. They have apologized, acknowledged the problem, and agreed to change my board.

[Stumpy_L]

Thanks for all the comments. I had posted a reply earlier today but it does not appear to be on the thread. I changed the HT-7333 with a TC1262, that has a 500ma output but that did not help. I disconnected the NRF24L01 but it still needs more power. I have ordered some AMS1171 LSO's and 330uf caps, should be here tomorrow.

I also tried a USB 7.4wh 5v 1 amp battery that I plugged into the micro USB port on the board. It powers the board up and does one sleep cycle then the red LED on the board goes out. I waited for another sleep cycle to end but it didn't power back up.

I'll let you know how I make out with the new LDO and caps.

Thanks again for all the help
John

[pataga]

Are you sure the development board supporting the fast-charging protocols, maybe they did not contain the protocols chip.

If the board does not have a battery to charge, or does not support fast charging, there would be no USB communication compliant with the fast charging protocol specification.

The fast charger should therefore use the default 5V setting. If not, either the charger is faulty or cheap and dangerous (sees any activity on the data lines as a trigger to set fast charging mode).

[xien551]

If the board does not have a battery to charge, or does not support fast charging, there would be no USB communication compliant with the fast charging protocol specification.

The fast charger should therefore use the default 5V setting. If not, either the charger is faulty or cheap and dangerous (sees any activity on the data lines as a trigger to set fast charging mode).
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I think you are right. The normal qualified fast-charger should active like this.

However, the fast-charger in china maybe not very reliable. One of my Bluetooth ear-pods, the package said that do not use the fast charger. I think issues that fast-charger damage ear-pods often happens.