LED What?

[Bigjim]

I'm totally confused by LED bulbs. Perhaps someone can shed some light on the subject.

I've been swapping out incandescent bulbs for LED bulbs on my boat and RV. In most cases, the bulbs go in and work exactly as you might expect.

However, several times I put LED bulbs into the socket and nothing happens. At first, I thought I had been scammed by a supplier. Bad bulbs! But using some loose wires and my 12 volt battery, I tested the bulbs and they worked fine connected directly to the battery.

You might think: "Oh he's got a dead socket in that light." But the incandescent bulbs worked fine in the socket! Yes, the LEDs are supposed to be compatible with the bulb being replaced.

Here's the real stumper. I just ordered some new bulbs and when they arrived I tried them out in the stern light (a brand new fixture). The new bulb worked perfectly and was very bright. But it is a tall bulb with three LEDs.



The fixture only has clearance for bulbs with two LEDs. BUT, when I grabbed one of the 2 LED bulbs I bought previously, the bulb didn't light up.



I tried the same bulb in an interior light socket and it lights perfectly, but the 3 LED bulb doesn't! What?

Both sockets are 12 volts. BOTH sockets work with incandescent bulbs! BOTH LED bulbs are supposed to be compatible replacements! ALL the bulbs work fine connected directly to the battery!!!

So, why does one LED bulb work in one socket and not in another when all of the sockets on the boat are 12 volt and the ones I'm using are supposed to work with these bulbs! HELP! This is driving me crazy.

(FYI, the bulbs pictured are not the actual ones I used, but they give you the concept.)

[noelex 77]

The LED’s are polarity sensitive. Incandescent bulbs are not (although the polarity can affect the life of some globes).

Swap over the + and - wires on the fittings that do not work with the LED’s and the problem will be fixed.

[hoolie]

Don't forget LEDs are polarity sensitive. Try swapping over the connections, or at least putting a multi-meter on them to check the polarity is correct.

[Paul Elliott]

Polarity? Some LED bulbs are designed to operate with either polarity, but some require that the negative wire be connected to the socket shell, and the positive wire connected to the socket center contact. Use a voltmeter to check the voltage polarity at your sockets.

[jamhass]

Besides polarity, if you are using LEDs in colored nav lights, make sure you use LED bulbs rated for the specific nav light fixture. "white" LED bubs are not like incandescents and the colored lenses filter out too much of the light.

[hellosailor]

LEDs are polarity sensitive. But some LED "bulbs" are assembled with other tiny components that let them work regardless of polarity.

I notice the bulbs you show are bayonet base, 1156 automotive style. ALMOST all cars that use 1156 bulbs run the positive lead to the center contact, so for that style of bulb polarity can be "assumed" as center positive almost all the time.

But there are no rules that require that polarity, especially on a boat. So it is very possible that some of your bulbs are polarity sensitive, and that some of the sockets were wired up very casually--with the center negative instead of the normal positive.

Easy way to test those bad bulbs and sockets, just reverse the polarity, or buy bulbs that cost a little more and are "protected" so they don't require polarity matches.

[Bigjim]

The photos used above were used to show the difference in the height of the bulbs I was using. The actual bulbs are 1157 compatible with dual contacts at the bottom of the bulb, like this one.



Therefore, you should be able to remove, rotate and re-insert the bulb to reverse polarity. Some of my sockets are actually plastic so there is no ground function in the socket.

So, does anyone know why one such bulb will work in one socket but not another? And, yet the bulbs are all good and all work when connected directly to the battery!

[fox9988]

1157 automotive bulbs can not be rotated 180 degrees in the socket. The medal pins on the sides of the bulbs are at different heights.

[hellosailor]

Trust me, 1157 bulbs CAN be rotated 180 degrees the wrong way in a socket. Cheap sockets will just flex enough to allow that. It has been done and witnessed. Properly made sockets and bulbs can't do that--but that immediately puts anything from anonymous online vendors in question.

"Black cat, white cat, all same. Catch mice."
1157 bulbs, same as 1156 bulbs. The presumption is that the center leads are both positives and the case is negative. For all standard cars, which use negative grounds and *switched positive* lighting supplies. Toyota is a major exception, their headlights all use switched negative wiring instead, although their sockets are wired normally.


Answer to the OP is still the same: Whoever wired up your boat's sockets, did it the quick and fast way, ignored polarity, because that never mattered on boats until LED bulbs came along.

If you are using 1157 bulbs in 1157 sockets and only some of them work? Check the polarity. (You can use a cheap 1157 polarity sensitive LED bulb to do that.(G)

And why would they use 1157 bulbs and sockets on a boat anyway? Don't tell me, you have two-level lighting in the cabin lights? Or tail and brake lights on the transom?(G)

[Sailmonkey]

Originally Posted by Bigjim

The photos used above were used to show the difference in the height of the bulbs I was using. The actual bulbs are 1157 compatible with dual contacts at the bottom of the bulb, like this one.



Therefore, you should be able to remove, rotate and re-insert the bulb to reverse polarity. Some of my sockets are actually plastic so there is no ground function in the socket.

So, does anyone know why one such bulb will work in one socket but not another? And, yet the bulbs are all good and all work when connected directly to the battery!

I was under the impression that most if not all 1157 bulbs were dual “filament”. That each contact on the bottom was positive and the ground was the case.

[hellosailor]

"Some of my sockets are actually plastic so there is no ground function in the socket"
No, there still is a ground function. The outer case *must* be connected to the 12v negative lead for the bulb to work. Whether that is connected directly to ground, or indirectly and switched, it still has to go to ground. Unless the polarity was reversed and it goes to hot.

Earth ground, chassis ground, circuit ground, return, whatever you call it. Yes they are different but again "all catch mice".

[unluckycharms]

Originally Posted by Sailmonkey

I was under the impression that most if not all 1157 bulbs were dual “filament”. That each contact on the bottom was positive and the ground was the case.

They come in multiple flavors.....some dual + on the bottom and - on the case, some with single + and single - on the bottom contacts.

As for the bayonets, some have are on-level with each other, others are offset:


There are so many sellers out there, I simply skip over them if they don't provide clear information about the contact polarity and bayonets.

[StuM]

Originally Posted by unluckycharms

They come in multiple flavors.....some dual + on the bottom and - on the case, some with single + and single - on the bottom contacts.

As for the bayonets, some have are on-level with each other, others are offset:


There are so many sellers out there, I simply skip over them if they don't provide clear information about the contact polarity and bayonets.

I think you will find that BAY15D is the only 1157 there. The BA15S is commonly an 1156 or an 1141 an the BA15D doesn't have a 11xx equivalent number

[StuM]

Originally Posted by Bigjim

The photos used above were used to show the difference in the height of the bulbs I was using. The actual bulbs are 1157 compatible with dual contacts at the bottom of the bulb, like this one.



Therefore, you should be able to remove, rotate and re-insert the bulb to reverse polarity. Some of my sockets are actually plastic so there is no ground function in the socket.

So, does anyone know why one such bulb will work in one socket but not another? And, yet the bulbs are all good and all work when connected directly to the battery!

Interesting, the pictures in your gallery appear to show three different bulb formats. This one appears to be a BA15D bt another is of a BAY15D/1157 with offset lugs. SO you can't reverse it one. The thir is a BA15S which is reversible Which raises the question, how is it wired, almost certainly not the standard 1157 negative case and two separate positive circuits (one low wattage, one high wattage).


WIthout seeing side and end on views of the bulbs you are actually talking about, it's impossible to tell what is going on.

[dkenny64]

but..


an 1157 type uses the case as ground..
most boat fixtures don't use case as ground..
so you have to be careful in what you buy.


I bought some that are +- on the bottom pins with offset side pins(1157 style).
but no connection to the case..
make sure what you buy are for marine..auto types are different..


-dkenny64