Accidentally recharging AA batteries :O

Other Hardware General Electronics
1

I noticed something really interesting just now. I have a breadboard 3V3 Arduino powered by 3x AA batteries (NH15-2300). The VCC from the six-pin FTDI header is plugged into the VIN line, the same line as the battery (+) terminal, so both are on the "high" side of the regulator.

Leaving the FTDI breakout plugged into this guy for like 15 minutes recharges something like ~200-300 mAh. This became clear because now I am sending a voltage reading with every sensor reading, so I can watch the voltage readings shoot up and stay up.

Should I worry about this? Could the batteries OVER charge if left like this?

2

Didn't really see any spec on maximal charging current on the battery, which was my main concern. I bet it's not too bad, just not an ideal charging cycle, like you only used 10% of the power and start charging the battery then use 20% and charge it again. I would disconnect the power from the programmer to the arduino. All they need to share is the ground besides the signal lines. They don't need to share power. In most cases they shouldn't, just IMHO.