Heltec v3 battery not working

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1

Hi everyone,

I’m a beginner, so I hope it’s just some basic stuff.
Recently I purchased Heltec v3 and flashed the latest beta firmware (2.2.17.dbac2b1). Everything works when connected to USB, but when I try to use the battery, the device doesn’t even turn on.
I have a new 3.7V 1000mAh battery labeled 102535. It has a 1.25 JST connector.
I tested it using a voltmeter, and the result was 4V, so it seems there is some juice in the battery.
I tried both polarizations, and it still doesn’t work.

Serial logs are exactly the same when battery is plugged in or not:

$ meshtastic --seriallog stdout | grep -i power
rst:0x1 (POWERON),boot:0x8 (SPI_FAST_FLASH_BOOT)
INFO | ??:??:?? 1 Set radio: region=EU_868, name=XXX, config=0, ch=0, power=27
INFO | ??:??:?? 1 Set radio: final power level=22
INFO | ??:??:?? 1 Power output set to 22
INFO | ??:??:?? 1 PowerFSM init, USB power=1
DEBUG | ??:??:?? 2 [Power] Battery: usbPower=0, isCharging=0, batMv=0, batPct=0

Do you know what may be the case for the battery not being detected?

2

If you’ve tried both polarities, you might have cooked the charge controller chip.

1 Like
3

Thank you for suggestrion, I thought that too. However I have 4 boards:

  1. On 2 of them I tried polarity A, then after confirming it doesn’t work, I tried polarity B.
  2. On 1 of them I tried only polarity B.
  3. On 1 I didn’t attach battery at all.

As 1 and 2 didn’t work, I assume the problem lies somewhere else.

4

It was a polarity issue. My batteries came with reversed polarity and after reversing it back everything started to work.
I can’t explain why it didn’t work in my earlier test. Maybe the wires were not connected firmly.

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