I was tasked with finding a new battery for an old phone, the Samsung S4, and it says it's rated for "3.7V 1800mA" but I can only find Samsung batteries rated at 3.8V. Will there be a problem if I use a 3.8V battery?
I just noticed I have put this in "Graphics Cards", I'm sorry.
If you have an old charging cable of any kind, cut off the male end, connect the red to the positive on battery terminal, and black on negative. just be sure not to short the wires. That's how I got my phone up and running.