Using an old lithium battery to power my Arduino


I'm looking into using an old Samsung Lithium battery from an old cellphone to power my Arduino Uno. The battery is rated at 3.7V, 1000mA. I've got 2 questions

[u]1. Charging the battery[/u] I've purchased the following 1A Lithium Battery Charging Board

The board has a fixed 1.2K resistor mounted to facilitate the 1A charging. I read that the charging current should be 37% of the battery capacity, so in my case it would be about 370mA.

Am I correct in saying that I should replace the 1.2K resistor with either a 4K (to have 300mA current) or a 3K (to have 400mA current ?). Would the 4K or 3K option be a safe way to charge this battery using the board ?

[u]Using the battery on Arduino[/u] Now, as my Arduino board expects a 5V input, I guess I also need some kind of DC-DC Converter Step Up Boost Module ? (I tried hooking up the battery to the VIN pin of the 5V Arduino and it did seem to work, but I guess supplying the required 5V would be better).

I was looking at something like this >

This could take my 3.7V battery input and convert it into a stable 5V output, required to power the Arduino.

Would this kind of setup make sense ?

The latter half of your question is answered here: