Calculating Resistor Size for 3V Battery

[John1397]

Found this online I added 3 volt battery how do you figure out what size resistor to use?

 

[berkeman]

You cannot use a 5.1V Zener diode in a regulator for charging a 3V battery...

And Zener regulators are pretty sloppy anyway -- in general it's a lot better to just use a 3-terminal linear regulator. And battery charging can be a fairly complicated matter, depending on which battery chemistry you are working with...

 

[Tom.G]

@John1397, As berkeman stated...

You cannot use a 5.1V Zener diode in a regulator for SAFELY charging a 3V battery...

Since you didn't give many details, here is the scenario:

If you really insist on this approach, do it out doors, nothing around that you want to keep (like people, animals, or houses), and don't mind destroying a battery, then a 35Ω, 50Watt resistor would be about right.

Oh, and stay up-wind of it.

I really recommend that you take heed of the approach by @berkeman though.

That said, here is a sight with a great amount of information about batteries and how to charge and use them: https://batteryuniversity.com

Cheers,
Tom

 

[berkeman]

If you really insist on this approach, do it out doors, nothing around that you want to keep (like people, animals, or houses), and don't mind destroying a battery

LOL

 

[dlgoff]

... battery charging can be a fairly complicated matter, depending on which battery chemistry you are working with...

Indeed.

For the OP, check out https://batteryuniversity.com/index.php/learn/.