ESP32 Forum

I'll be using my ESP32 WROVER v4.1 Dev kit to demonstrate a PoC for my project. I'll be using both WiFi and BLE, SD, and LCD. I only need it to last about half a day to demonstrate. I have a USB to Wall plug for when I can connect it to the wall; however, I'd like to demonstrate battery capability as well.

Does anyone have any suggestions for a good set of batteries I can use? I have a handful of AA NiMH batteries (2,000 mAH) and some battery packs with barrel jack connector. If I plug into the barrel jack on the WROVER, will a pack of 4 in series be enough? mAH it should be fine, but I wasn't entirely sure about the voltage and how the barrel jack is connected on the board.

According to https://www.espressif.com/sites/default ... eet_en.pdf:
NiMH AAs have a nominal voltage of 1.2V. So either two or three in series should give a viable output voltage.

Worth noting that page 16 of that datasheet recommends using a power supervisor to ensure that the voltage does not drop below 2.4V. Two of your NiMH cells might not reliably produce >=2.4V.

With regard to runtime, at 80mA you'd get slightly less than a day at the rated average.

My two cents - get some nice 18650 cells (I like the Samsung 30Q) and a 3.3v voltage regulator - 2x 30Q in parallel would give you ~3 days runtime.

Thanks for the response! I guess I was looking for specifically the barrel jack for the WROVER Dev Kit 4.1. The diagram says 5V input; however, I just wanted to know if 4 NiMH would do the trick. I can't find any documentation that says there's a regulator behind the barrel jack. I can add another AA (5 in total) just in case.

Hi czuvich,

Basing on ESP-WROVER-KIT V4.1 Schematic, there is NCP1117 voltage regulator behind the barrel jack. According to the datasheet it has max 1.2V dropout voltage. To be on the safe side I would use 5 x NiMH batteries.

Thank you for both the recommendation and data sheets!