Low Battery Indicator while plugged into arduino

Weird issue started with one of my proffies. i have a lot of sabers and this is the only one that started to do this.

All of a sudden arduino wont recognize the board (to select the right port) forcing me to boot/reset. Additionally, it loops “low battery” warning while plugged into arduino but not while turned on with battery… saber works recieves flash just fine and works fine with battery in it…

Battery readout is always a little weird when connected to USB. (For V2 boards)
The code tries to work around it, but if that doesn’t work, it will say that. That part is probably nothing to worry about. We can make a code change if it bothers you.

I just wonder if its the same cause of arduino no longer recognizing the board and greying my port? This saber use to be fine…Nd both of these issues started at the same time last night. I flashed my board, forgot to include some styles for the crystal so i went to reflash and these started happening when my board got plugged in. I checked other boards to make sure their port was recognized and available. Good to go for them.

I wonder if something happened to the + connection in the USB port?
That could potentially explain both problems.
Maybe try a different USB cable?

Tried just using a different data cable to see if the one you’re using to connect to the board may just be finicky? I just finished a flash for someone who’s data cable was internally damaged and only occasionally wouldn’t work. It either wouldn’t read the board or wouldn’t supply power. Got 'em a new one and there’s been no issue since. Grab a new cable and see.

Tried a new cable. Same issue. Dont even know anymore…

Doesn’t really make sense to me either.
I assume that you do not have a battery plugged in, since you’re getting low voltage warnings. I’m not sure what would cause that, but it would seem to be something related to the VBUS input from usb.

Also, board not showing can also be a VBUS problem. ProffieOS doesn’t start the USB connection until VBUS shows up to save power. (STM32 BOOTLOADER starts usb regardless.)

However, if VBUS was just missing, then the board wouldn’t get any power without a battery… so it’s semi-missing??

Maybe check if the USB port is actually providing 5 volts?

dumb question…how would i go about checking the voltagage of the USB port? Also, yes when connected to computer i don’t have a battery inserted. Your theory is likely accurate being that both of these issues began at the exact same time lol.

Probably the easiest way is to measure between the top end of D61 and GND.
(See the partmap for details.)