Another 12v Question

[LanceB]

Looking at Park's information regarding resistors to be used in a 12v conversion, the resistor to be used for the radio is a 1.3 ohm 50w. What would happen if I used a 1.5 ohm instead of a 1.3?
Lance

[mars55]

Let's see if we can straighten this out. The voltage dropped cross a resistor is current (in Amps) times resistence (in Ohms). The current draw of my '49 Commodore radio was about 4 amps. So 4 amps X 1.3 Ohms = 5.2 volts and 4 amps X 1.5 Ohms = 6.0 volts. Your 12 volt system is running at about 14 volts with the engine running, so you have radio receiving 8.8 volts with 1.3 ohms and 8 volts with 1.5 ohms. In both cases the radio is receiving more voltage then the 6 volt system, but I think it doesn't hurt anything. So go ahead and use the 1.5 Ohms resistor.

[Park W]

I agree ... the 1.3 should work OK.

[LanceB]

Thanks Mars.

Park, I was having trouble finding the 1.3 ohm 50W, but could find a 1.5 ohm one instead. I know your information called for the 1.3, thats why I was asking about the 1.5. I am going to go with the 1.5 that I found.

Thanks all.