Hello,
I am building a small robot based on SG90 servos. In order to make it autonomous, I'd like to use a 4.8V NiMH battery to power the 16 servos I'll need (max they take is about 4.8V, so it seems to be the best choice of battery type). In order to avoid using another battery specifically for the arduino, I'd prefer to be able to connect the 4.8V to it. I've read that powering directly from the 5V pin is undesirable (mixed info, but leaning towards possibility of regulator/board damage), so I was going to solder a couple of pins directly to the underside of the USB connector where power comes in: that way the safeguards such as the fuse are in place. Will probably have to remember to unplug the battery every time I plug it into the usb to avoid competing power sources, but seems like it should work.
The question: I don't know if 4.8V is enough for the arduino and attached sensors to operate properly. Can I use it directly, or would I need some kind of step-up voltage converter? I feel that using a separate power supply would not be efficient.