Hi,
I am using 12v 2amp smps circuit to power TFT graphic lcd ,nema 17 and big easy driver.I am thinking about that use a 11.11v 8800mah battery as a backup supply incase of a power outage. How could i implement this circuit with charging of a battery and giving main smps supply to this load?Is this posible by using relay?If not possible then help me to find out other circuit

 

A simple diode and resistor charger would suffice, you probably could just put the battery across the 12V psu output as it is only 0.9V difference...

 

Hello,
I want to measure voltage of a 11.1v 4400mah li ion battery continuously with arduino uno?
How could i measure by resistor divider network?What are the value of resistor(watt & ohm) that i use?
Please help me on this.

 

You just need to use two resistors to give you the voltage that you want from full charge, so say a 1K and a 10K 1/8W, will give you 1V in your Arduino at 11V full, and will decrease linearly.

 

Thank you for your fast response.Could you elaborate this wattage rating of this resistor ?
How have you selected this resistor with specific ratting?I am very eager to know about that.
Thanks

 

Hello,
I also nned to charge 11.1v 4400mah li ion battery with Lm 317 ic with constant current and constant voltage.So how could i implement this with auto cutoff from cc to cv.
full charge voltage of battery: 12.6v

 

Hello,
I also nned to charge 11.1v 4400mah li ion battery with Lm 317 ic with constant current and constant voltage.So how could i implement this with auto cutoff from cc to cv.
full charge voltage of battery: 12.6v

I did specify the wattage if you read the post correctly,,

The two resistors are to drop the voltage across the battery, your 10K is to Positive and 1.1K to Negative, your Arduino goes to the middle.

As for charging a Li-on you're better using a deadicated chip rather than a LM 317.

 

Thanks , Li Ion battery has 3s2p configuration. And have nominal voltage 11.1v ,4400mah.Could you suggest me Specific ic ?