Run my lithium batteries safely

[Joling]

I'm building a device that needs to run from Lithium batteries.

I am well aware they need to be charged/dis-charged properly to avoid damage and explosions.

To my knowledge a charging system has two components which are the managed charging and cut-off once charged and discharge protection when the batteries voltage drops.

I found a board that uses the common TP4056 controller(http://www.kynix.com/Detail/962982/TP4056.html) to charge the lithium battery and cut-off once charged. It also has discharge protection at 2.5V.

I have two questions:

 

l So this means I can hook up the above (or any) Lithium batteries to the charging board as well as my device and it would run well from the batteries until they got too low, at which the board would cut off the supply to the device leaving the device isolated from the batteries until charged again.

l It says the discharge protection is at 2.5V isn't this well below the safe discharge voltage of a lithium cell. I thought you should never go below 3V?

 

    I apologize if this question is rudimentary however I'd like to make sure when dealing with constant use of lithium batteries.

[builderb]

Ive been using one of these to provide battery back-up to my weather station. Charges from a USB Micro B plug, can output to USB A, a terminal block, or direct soldered wire. There's a pin you can read a LOW value on when the voltage drops below 3.2v, and trigger a safe shutdown. If you can read analog values, you can also read the battery voltage directly. Not as cheap as a bare IC, but it works well and takes a lot of the hassle out of battery use and integrated charging.

 

https://www.adafruit.com/product/2465