Power supply design with charging circuit

Question

I am designing a GSM modem power supply circuit.

• The circuit requires a 2A power supply.
• The module SIM800C itself can be powered directly by Li-Ion or Li-Poly battery power.

I am looking at a ready-made charging and output voltage protection PCB like this.

These are commonly found at many places and hence the motivation to use these boards off-the-shelf.

The circuit that I am designing should work reliably (for at least the next 5 years).

I have the following questions:

1. Can I give 5V supply at the input at this circuit and connect battery at the battery terminals. Can I draw supply from the output terminals of the circuit infinitely?
   
2. The power adapter at the input will be connected forever and this is in turn connected to UPS. The battery is only for the unforeseen event when UPS also goes down. Will the circuit above work OK for an extended period application?

Answer 1

https://robu.in/product/micro-usb-5v-1a-18650-lithium-battery-charger-module/

This is TP4056 based 1-cell lithium ion battery charging circuit supports up to 1A with battery protection using (DW01A + FS8205).

Can I give 5V supply at the input at this circuit and connect battery at the battery terminals?

Yes you can.

Can I draw supply from the output terminals of the circuit infinitely?

You don't have to do this, since the module will shutdown its output once the battery gets to its full capacity.

once its shutdown the load draws power from battery again the output will be enabled once the battery voltage just drops below its maximum voltage... this cycle goes on repeating.

i am not saying it will not work. It will work but that is not a good approach.

So better go for some intelligent design to avoid the above case.

The power adapter at the input will be connected forever and this is in turn connected to UPS. The battery is only for the unforeseen event when UPS also goes down. Will the circuit above work OK for an extended period application?

Yeh it will sustain.