I have some 12-volt outdoor lighting that is quickly blowing through light bulbs (couple weeks at a time.) I just measured the voltage and it read 13.4 volts. Could this be the culprit?

The other potential issue could be that the bulbs are running too hot for the enclosure. This used to be a 120-volt system, but we had some landscaping lighting work done and they decided to convert it to a 12-volt system. The problem is that the sockets are still standard home style sockets and the only light bulbs that are easy to find are 50-watt marine light bulbs.

What is more likely the blame for the short light bulb life?

I'm looking into purchasing some 12-volt led lights from Amazon but I'd like to solve this problem before spending more money on bulbs.


Both the voltage and temperature could be culprits here - many bulbs are sensitive to overvoltage.

If you are going with LED bulbs, you usually have a wider acceptable voltage range, but you should be able to get the max-voltage info before you buy.

Additionally, LED's have very low heat output, so will be just fine in the enclosures.

So I'd say the problem will be solved by getting LED bulbs (just check that max-voltage on the spec first) - these will last so much longer.

Alternatively, If you are handy with electrics, have a look at the power supply circuit and see if you can reduce the voltage. Are all the bulbs in series? If so, adding a power resistor will drop the voltage (at the expense of some heat generated across the resistor). If the bulbs are in parallel, you'd need to see if there is a voltage control on the power supply itself.

  • Thanks Rory, I'll purchase the bulbs and let you know how it goes. – Chris Feb 11 '13 at 4:18
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    This fixed it! The new LED bulbs have been going strong ever since. – Chris May 28 '13 at 21:47
  • Can you be more specific about what the fix was? was it adding a resistor, or changing over to led bulbs? – Tom H Nov 25 '14 at 13:43
  • @Tom H: I replaced the incandescent bulbs with 12-volt LED ones. None have burned out since I've replaced them. – Chris Apr 20 '15 at 4:02

With incandescent bulbs I suspect vibration can damage the filaments. LED bulbs might not be as susceptible.

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