battery backup

Hello Guys,

I need a battery backup circuit for a 3.3V power supply I am using.
I found this one on the internet but I am concerned that there might be a safety issue with the lithium battery (explosion hazzard?)

Any advice?

I don't need the circuit to charge the battery, I prefer to use a lithium battery because I have many here.

johnsmith123 said:

Hello Guys,

I need a battery backup circuit for a 3.3V power supply I am using.
I found this one on the internet but I am concerned that there might be a safety issue with the lithium battery (explosion hazzard?)

Any advice?

I don't need the circuit to charge the battery, I prefer to use a lithium battery because I have many here.

Click to expand...

hi,
Which type of lithium battery do you have?

https://en.wikipedia.org/wiki/Lithium_battery

ericgibbs said:

hi,
Which type of lithium battery do you have?

https://en.wikipedia.org/wiki/Lithium_battery

Click to expand...

That's the one, CR2032.

Also, I could use two AA Alkaline batteries instead of the lithium, whichever is better.

johnsmith123 said:

That's the one, CR2032.

Also, I could use two AA Alkaline batteries instead of the lithium, whichever is better.

Click to expand...

hi,

This is whats recommended for Li batteries.

https://www.panasonic.com/industrial/battery/oem/images/pdf/Panasonic_Lithium_DesignMemoryBU.pdf

What are you backing up.?

I got the circuit to work (without the resistor)
it works perfectly. When power is removed, the battery power is being used.

I am just worried about any possible danger to the battery popping.
(I do not want a fire in my house!)

working circuit

Here is the working circuit. For battery, I used two AA batteries (3V total).
The Schottky diodes were ones I had. (SD103BDICT)

I used this for a MP3 player/voice recorder setup that does not use a battery (3VDC wal wart).
When the power goes out, the configuration is lost in the player. This is the reason for the battery backup.

It works perfectly now thanks to the information provided by ericgibbs.

Thank you