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Date: 12 July 2015. Change of Light Bulbs (LED versus cheap)


There are times when it is best to opt for the more expensive product. Often experts will tell you that switching out all your standard light bulbs for LED is a great power saver. It is, however there are options to spending all that money right away. Let me show you what I have done on Seaweed so you can judge if this method would work aboard your boat.

LED (Light Emitting Diode) bulbs are power savers.

The LED light by my bunk is perfect for reading. My bulb does not emit heat. That is important in the summertime.

Standard 12-volt light bulbs use approximately one amp per hour. LED's often are 1/10th that amount. Specifically they use .1 amps meaning you can have a LED on for ten hours and equal the power required for one hour of the standard bulbs.

These are two nearly identical standard 12v light bulbs. Please notice the ends differ.
It is always best to have the bulb needing replacement in hand when shopping.

That said, if your light is on only occasionally and for brief periods of time I would not immediately spend big bucks on a LED replacement. Especially if the light is seldom on, wait until it burns out or you find a bargain on LED bulbs.

Most yachtsmen will want to have the LED bulbs. They use less power. There is always a balance between power generation and usage. Still, it is seldom necessary to replace every bulb in the boat your first week of ownership. Of course if your budget can handle it...

Prioritize, swapping out bulbs in lights used the most often first.


Now reading lights are another matter entirely. By my pillow I have a small LED that perfectly lights my book. That light is on several hours per night so having a low power draw was essential for my happiness quotient and my batteries.


In my head and bunk area I have two overhead lights. They are turned on for such short time frames I opted to keep the inexpensive bulbs in them. And too, they are far brighter than my little reading light.

On our 40'er, I grew up reading by oil lantern. Thus I am more used to dimmer lights than many others might be. I prefer a soft glow versus a brilliant glare.

This is one of our old lanterns:


There are a variety of bulb bases, and knowing what you have is essential. But first you need to remove the glass piece from the front of the light housing. Mine are like those found on tons of older boats.

Three small easy to lose screws hold the glass in place. Remove two of the screws. Then lift out the glass and you are all set. The glass will slip out with ease.

Next, remove the bulb. There are several types of light bulbs with various bases. Twist to remove. There are nubs on the sides that prevent you from pulling straight out.

Mine happen to have two positives at the base whereas the ones I had in my ship stores had one. Thus I was off to the local marine hardware store for a new set of bulbs. The bulbs came two in a package and the price was $3.

If you opt for LED bulbs, be aware that polarity matters. Therefore if you've inserted the bulb 180 degrees off, it won't work, OR it will be dim/yellow versus white. Remove and twist the bulb one half turn to make it work perfectly. Also verify your 12v power is correct. Positive and ground matter in some LEDs.

The "easy" way to see if the power is correct is to stick your pointy red multimeter lead gizmo in the center at the base where the bulb fits. The black tester would go on the inside of the tube that holds the bulb. Check your reading. If it's a positive number the power is correctly fed to the light fixture.

If you opt to dismantle your light fixture, the next box offers a synopsis of what you need to know.



Brief note on 12-volt light wiring:


Blue wire is often power (positive side) for 12-volt DC lights and the white wire is ground. "Often" or "customary" means nothing if the previous owner has tweaked things improperly. Verify all with your
digital multimeter
 aka volt meter. (Amazon affiliate link provided)

How to check with your volt meter: Put the positive (red) wire from your volt meter on the blue wire. Attach the black volt meter wire to the white wire on the light. Your numbers should be positive.

If the number is -12.xx then you know your polarity is switched.

Nigel Calder has a whole book on electrical fixes. It is not hard but it is complicated. Your best bet is to have someone come aboard and give you a primer, helping you check one line from panel to outlet. From there practice and soon you will get it too.



More on wiring is in an upcoming article. In the meantime and always you should refer to Calder's Boatowners Mechanical and Electrical Manual 4the Edition. He's the expert. I'm just an in-the-field make-it-work boater.

Definitely opt to follow Calder's advice.
He understands the whys whereas I do not!

And if your vessel doesn't have an up-to-date (Third Edition) of Calder's then rectify that immediately. It's a necessity, and worth retail prices.


After swapping out the bulbs I once again have light in my forward cabin and the head. There are two other identical light fixtures in Seaweed. All currently use standard rather than LED bulbs. Someday I may change them all for LED versions presuming I can find some at a great price. If not I'll continue to opt for the $1.50 power-hungry bulbs for those lights used infrequently or for short durations.

When you buy a used boat often there are things you want to fix or change. For me, replacing perfectly good and rarely used light bulbs with LEDs is not a high priority item.

Do you have LEDs in all your light fixtures or is it a mixture?
And, what is your favorite LED supplier and brand?

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2015, 2023

Categories: Boat Talk, Books, Gear, Money, Recommendations

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A favorite aphorism:  How many boaters does it take to change a light bulb? None, because the right size bulb isn't on board, the local marine-supply store doesn't carry that brand, and the mail-order house has them on back-order.

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