Anodising question (currnt source)

[marcopolo]

My anodising kit arrived but I may have to start working with it before I get a bench power supply.

I've got a large 12v leisure battery (80Ah) and would like to use it instead of a bench supply. Can I just put a simple power resistor in series to achieve the desired current?

So say my light case is 20in sq. The guide says 100ma/in^2 for 1hr bath so I need 2A roughly.

R=V/I = 12.6/2 = 6.3Ohm (or as close as possible)

So can I just stick this resistance in series (on the positive side of the battery)?
I appreciate the current will drop slightly as the battery voltage drops but due to it's size it shouldn't too much.

many thanks,

Marco.

 

[gadget_lover]

I'm pretty sure it will not work that way.

The reason I say that is your equation assumes there is no other resistance in the circuit. The acid bath will have some resistance, as will your wiring and clamps.

The formula you gave will have the 6 ohm resistor using all 12 volts and 2 amps, dissipating 24 watts as heat. That's a lot of heat.

A constant current bench supply is not that expensive. I'd wait for it

Daniel

 

[marcopolo]

Borrowed a power supply and here is our first anodising effort.:

http://www.geocities.com/telescopiman/MC_E_Blog.html

 

[SquareJ]

That is one awesome build! Impressive.

Jason

 

[1 what]

As SquareJ said "That is one awesome build! Impressive.
...no...... Very Impressive.

 

[marcopolo]

Thanks guys.

 

[wquiles]

That is one awesome build! Impressive.

Jason

+1

Awesome build indeed :twothumbs

Will