Front yard post lamp question

[MarkG]

We have an old lamp in our yard that started out as a gas lamp and was retrofitted to electric with an electric eye many years ago.

It finally needed the post replaced and I'm doing bulbs too, but noticed the bulbs are 12V single contact 'push and twist' with lugs, but the transformer that runs it is 24V (in a garage outlet)

The lamp has 2 bulbs. After a recently replaced them, they burned very bright and then burned out within a very short time! The other odd thing is that this was daytime, and I had just installed a new electric eye.

My questions are:

Should the BULBS be rated for 24V since the transformer is 24V? That seems logical, but the bulbs we have here are 12V and are what another family member had been using, as far as I can tell!

I'm no electrician, but I didn't think you 'add' the bulb voltages (2 x 12V bulb=24V at the transformer)

Can someone clarify what size bulbs I SHOULD be using? Are 24V bulbs even available?

As most 'simple' projects go, this one is proving to be much more daunting than I ever expected.

Thanks

 

[pentavolvo]

Could be because the bulbs are wired in series or there could be a lot of voltage drop due to wire size

 

[MikeF2316]

24 volt is common on heavy vehicles and such. Automotive style bulbs for 24 volt applications are commonly available.

 

[nadogail]

A 12 volt bulb on a 24 volt circuit will burn very brightly for a very short time.

 

[malibu101]

A 12 volt bulb on a 24 volt circuit will burn very brightly for a very short time.

Correct.
The flipside is a 24V bulb (on 12V) will burn very dimly for a very long time.

 

[The Cobbler]

sounds like they were wired in series prior, then when you put the new post in they got wired parallel?
you can wire them in series, or as mentioned, you can get 24v bulbs , another option would be to get LEDs that are rated for 24 volts

 

[Shiftless]

sounds like they were wired in series prior, then when you put the new post in they got wired parallel?
you can wire them in series, or as mentioned, you can get 24v bulbs , another option would be to get LEDs that are rated for 24 volts

Yep!
That’s exactly what I was going to say. Burning bright for only a few seconds is exactly what indicates that the full 24 volts were going to both of those 12 volt rated bulbs.
Another option would be to change the transformer to 12 volts.

LED bulbs would be my choice. I changed all of my landscape lighting bulbs to LED.

 

[The Cobbler]

Yep!
....
Another option would be to change the transformer to 12 volts.

.

Duhh, that's sure another choice, and since most landscape transformers are 12 volt, it makes perfect sense