Porch light - any ideas?

[dickschaak]

I am still having problems with my porch light. It will last about four or five hours. I have gone from 20 watt bulb down to 8, still won't last. Any ideas?

[bruceisla]

Originally Posted by dickschaak

I am still having problems with my porch light. It will last about four or five hours. I have gone from 20 watt bulb down to 8, still won't last. Any ideas?

Hey Dick, not familiar with what's been happening ... can you reiterate ... what does "won't last" mean? What happens after 4-5 hours?

[Brockx]

Originally Posted by dickschaak

I am still having problems with my porch light. It will last about four or five hours. I have gone from 20 watt bulb down to 8, still won't last. Any ideas?

I read thru your earlier thread. Does anything else come on when you turn your porch light on, inside step light, door handle light, etc.?

If yes, then perhaps your porch light is wired in series. If another light is wired in series then the excess current thru your porch light would blow the bulb prematurely.

[njs42]

Interesting. In ten years of intermittent usage, sometime leaving mine on all night I have only replaced the bulb once. I can only share what I would check in the same circumstance.

Check the voltage to the bulb socket. Too high too low, trace back to look for problem.

Intermittent shorting, in the bulb socket? Is the socket clean, free of rust, does the bulb fit correctly? Too loose or too tight?

Bulb quality, are you using a good bulb in the first place? Maybe just try a different brand.

Is the light being subjected to any abnormal vibration, is the receptacle tight, nothing loose.

Is there any reason for excess heat in the light fixture, weep holes if any plugged? Etc

Is the voltage constant any surging at the fixture?

[bruceisla]

Originally Posted by Brockx

I read thru your earlier thread. Does anything else come on when you turn your porch light on, inside step light, door handle light, etc.?

If yes, then perhaps your porch light is wired in series. If another light is wired in series then the excess current thru your porch light would blow the bulb prematurely.

That is odd ... I think it's time to get out the meter and check the voltage at the socket.

[94-Newmar]

More info would certainly help... What type of bulb? Bayonet style? If so 1156? 1142? I have not run across this very often on customer's coaches, but I've always been able to solve it by replacing the fixture itself. It is my understanding that as the sockets (if bayonet style) not only supply the 12v negative it also acts as a heat sink to draw heat away from the base of the bulb and to maintain a more even "cooling down" between the base and glass seal - as the glass cools substantially faster than the base which can cause the seal to be compromised, and poof, the filament breaks.

An older fixture or one that is exposed to the elements can oxidize enough to still pass the ground to the bulb but not make good enough physical contact to the base to help equalize the cooling down process.

[RoamingGnome]

I replaced all of the bulbs regularly used in my rig with LED equivelents a few years ago and havent had a single bulb fail since then. LEDs run much cooler than incandescent bulbs and conserve power when boondocking too. Just figure out the base type and search Amazon or your favorite RV parts supplier. If you want to venture into the more elaborate LED layouts such as flat panels then also measure the maximum dimensions that will fit in the fixture with cover installed.

[dickschaak]

Originally Posted by bruceisla

Hey Dick, not familiar with what's been happening ... can you reiterate ... what does "won't last" mean? What happens after 4-5 hours?

The bulb burns out. I just measured the voltage at about 11.6. It is on the low side so the current May be too high.

[dickschaak]

Originally Posted by Brockx

I read thru your earlier thread. Does anything else come on when you turn your porch light on, inside step light, door handle light, etc.?

If yes, then perhaps your porch light is wired in series. If another light is wired in series then the excess current thru your porch light would blow the bulb prematurely.

It must be wired in parallel because when the light is burned out the handle is still lit.

[dickschaak]

Originally Posted by njs42

Interesting. In ten years of intermittent usage, sometime leaving mine on all night I have only replaced the bulb once. I can only share what I would check in the same circumstance.

Check the voltage to the bulb socket. Too high too low, trace back to look for problem.

Intermittent shorting, in the bulb socket? Is the socket clean, free of rust, does the bulb fit correctly? Too loose or too tight?

Bulb quality, are you using a good bulb in the first place? Maybe just try a different brand.

Is the light being subjected to any abnormal vibration, is the receptacle tight, nothing loose.

Is there any reason for excess heat in the light fixture, weep holes if any plugged? Etc

Is the voltage constant any surging at the fixture?

Good ideas. I will try them.

[dickschaak]

I ordered some LED lights to see if that will solve it.

[Brockx]

Originally Posted by bruceisla

That is odd ... I think it's time to get out the meter and check the voltage at the socket.

If my theory holds any water the voltage would not be any greater, the extra load on the bulb filament would be what was blowing the bulb.

[njs42]

LED RV Porch light, Cool White - RV-LED.com

Motion Activated Security Light - 12v for RV - PPL Motor Homes

Could be time for one of these.

[sailor_lou]

On a D.C. incandescent bulb, low voltage will only result in a dim light and will have no impact on current (think about the dashboard dimmer in your car). Are you sure your using 12v bulbs? If so, the failure may be due to an overheating condition from either a higher wattage bulb being used or a condition like 94-Newmar described.

Lou
05 TS Envoy