12v / 24v bulbs

[hkogti]

Hi all,

What happens if i replace a 12v bulbs with a 24v?

It works with 50% of the voltage?

[JCM308]

It may either work at 1/2 efficiency or potentially draw twice the current than the same wattage 12V globe.

The first option is ok but the second option is reallllllllllllly bad!!!!

[Treza360]

Have a read through Mickey's thread here about when he replaced his indicator bulbs with those of a different wattage but same voltage. Depending on which circuit they're on you could get the same problem where the indicators flash faster than what they're meant to due to the change in resistance of the circuit.

http://www.vwwatercooled.org.au/newforum/upload/showthread.php?t=24326

http://www.vwwatercooled.org.au/newforum/upload/showthread.php?t=24663

I think what you'll find is that the bulb is likely not to be as bright due to not drawing as much current due to the higher voltage.

It may either work at 1/2 efficiency or potentially draw twice the current than the same wattage 12V globe.
The first option is ok but the second option is reallllllllllllly bad!!!!

Power = Volts * Amps
Power = (Volts * Volts)/Resistance
Power = (Amps * Amps)/Resistance
If we are maintaining the same wattage in the system but increasing the voltage we're actually going to reduce the current in the system hence leading to my comment above about the bulb not glowing as brightly.

You want to keep the voltage the same for the bulbs for them to operate properly. Furthermore you should try and keep the bulb wattage the same as well to avoid what happened to Mickey. Otherwise you're going to have to put an inline or parallel resistor in the circuit like he had to.

Cheers,
Trent

[hkogti]

Thanks for all that info!

Took a while to read

But i still dont have a clue...

The situation is I am trying to replace the number plate feeston, but i bought the wrong set of bulbs, i got 24V instead of 12V, just wondering it will blow the circuit or not...