LED light problem

[jayem]

This is weird. We have a built-in banquette in the kitchen with 2 pendant light fixtures over the table. I've been using 60W, G16½ bulbs. Which is a small, globe-shaped bulb with a medium base. See photo. Standard sized bulbs are too long--they extend below the shades and produce glare. We leave the lights on at least 12-16hrs/day, and I wanted to install LEDs that I wouldn't have to change for a long time. I found LED bulbs in exactly that style, with an equivalent light output. But when I installed them, the bulbs emitted a low level of light even when the wall switch was off. And when I turned the switch on, the bulbs glowed at normal output for a second or two, and then went off completely. Both bulbs behaved the same way. The lights are on a dimmer switch, but the bulbs I used are rated as dimmable. Thinking the problem might be the switch, I screwed in a 100W equivalent, standard shape LED bulb that I use in my nightstand lamp. This worked perfectly. For some reason, these small LED bulbs act crazy, while larger LEDs work fine.

I'll mention that these pendants date from the 90s. They're contemporary in style, and made for the US market by a European manufacturer. They're very sleek and cool. I want to keep them. I'm thinking the fixtures just don't work with these particular bulbs. Any ideas? Should I replace the wall switch? 60W CFLs are all too big and stick out below the bottom of the shades. Should I try G16½ LEDs from a different manufacturer? Or just live with replacing the bulbs regularly?

 

[NothingIsImpossible]

As a tech geek I find LED bulbs confusing. There are all kinds like the ones above, then twisted ones, then weird cone ones. And despite some saying the same wattage, some appear darker, some brighter...etc. Then they have words like "Indoor brightness" or "Natural color". Its so very confusing. I just buy a bulb and if it is white I keep it, if yellowish or to dark I return it.

 

[chevyontheriver]

This is weird. We have a built-in banquette in the kitchen with 2 pendant light fixtures over the table. I've been using 60W, G16½ bulbs. Which is a small, globe-shaped bulb with a medium base. See photo. Standard sized bulbs are too long--they extend below the shades and produce glare. We leave the lights on at least 12-16hrs/day, and I wanted to install LEDs that I wouldn't have to change for a long time. I found LED bulbs in exactly that style, with an equivalent light output. But when I installed them, the bulbs emitted a low level of light even when the wall switch was off. And when I turned the switch on, the bulbs glowed at normal output for a second or two, and then went off completely. Both bulbs behaved the same way. The lights are on a dimmer switch, but the bulbs I used are rated as dimmable. Thinking the problem might be the switch, I screwed in a 100W equivalent, standard shape LED bulb that I use in my nightstand lamp. This worked perfectly. For some reason, these small LED bulbs act crazy, while larger LEDs work fine.

I'll mention that these pendants date from the 90s. They're contemporary in style, and made for the US market by a European manufacturer. They're very sleek and cool. I want to keep them. I'm thinking the fixtures just don't work with these particular bulbs. Any ideas? Should I replace the wall switch? 60W CFLs are all too big and stick out below the bottom of the shades. Should I try G16½ LEDs from a different manufacturer? Or just live with replacing the bulbs regularly?

Do these new bulbs work just fine in other fixtures? If not, it's goofy bulbs that should be returned. If so, you have an oddity worthy of an electrician's attention.

 

[Dave-W]

I would think the problem lies in the dimmer switches. Most LEDs do not work well with dimmers, and those that do usually need a specific type of dimmer. (not just a rheostat)

As Chevy said, try them in other fixtures WITHOUT dimmers and see how well they work there.

 

[Dave-W]

And despite some saying the same wattage, some appear darker, some brighter...etc. Then they have words like "Indoor brightness" or "Natural color".

LEDs usually will say what the actual Lumen output is (so you have a better comparison with incandescents) and a "temperature." 2500°K is a yellowish color similar to incandescents. A higher number (5000°K) will be a more pure white.

 

[RDKirk]

Dave-W is correct that some LEDs require modern technically advanced dimmers (old school rheostats need not apply).

However, "off" should still be off.

I'm wondering if that circuit was properly switched with the switch on the hot leg rather than the neutral leg. The switch can be on either leg and a regular incandescent will shut off, but if it's on the neutral leg, there will still be power to the socket (which is considered a bad thing in electrician circles). That can be checked with a circuit tester at a socket when it's switched off.

Or those dimmers are not properly shutting the current completely off at their lowest position. They may get close enough to zero current flow that an incandescent filament doesn't glow, but LEDs are far more active at lower current levels...which is why they operate with such low wattage.

Again, test those sockets for current when they are supposedly "off."

 

[Dave-W]

I'm wondering if that circuit was properly switched with the switch on the hot leg rather than the neutral leg.

Yeah - the same thought crossed my mind.

Again, test those sockets for current when they are supposedly "off."

Agreed. Old school rheostat dimmers often just took the current down to a small trickle. But that will still light up LEDs.

 

[chevyontheriver]

Yeah - the same thought crossed my mind.

Agreed. Old school rheostat dimmers often just took the current down to a small trickle. But that will still light up LEDs.

I think it's most likely that the dimmer is the problem. Old school dimmer maybe, or just worn out. Might be a do-it-yourself or it might require an electrician. Don't get zapped over this.

 

[jayem]

I did exchange the LEDs for regular incandescent bulbs. (I could buy 8 regular bulbs for what 2 LEDs cost.) But I found some small print instructions on the LED's packaging that I hadn't noticed before. It stated that the bulbs should only be used in upright or horizontal installations. There was even a small image of the bulb base-up with a diagonal line through it. And in my pendant fixtures, the bulb is base-up. Why would a bulb not be suitable if it's used upside down? But I kinda doubt this was the problem. I tested a 100W, standard shape LED in the same fixture and it worked fine in an upside down orientation. It's just strange.

 

[chevyontheriver]

I did exchange the LEDs for regular incandescent bulbs. (I could buy 8 regular bulbs for what 2 LEDs cost.) But I found some small print instructions on the LED's packaging that I hadn't noticed before. It stated that the bulbs should only be used in upright or horizontal installations. There was even a small image of the bulb base-up with a diagonal line through it. And in my pendant fixtures, the bulb is base-up. Why would a bulb not be suitable if it's used upside down?

I would get it if an incandescent bulb, which generates a LOT of heat, might only fit some orientations in a fixture. The LED should be very low heat, so I'm surprised it matters. Don't know what to say. But if you have LEDs now that work, you're probably happy but you might want to return those original LEDs.

 

[RDKirk]

I did exchange the LEDs for regular incandescent bulbs. (I could buy 8 regular bulbs for what 2 LEDs cost.) But I found some small print instructions on the LED's packaging that I hadn't noticed before. It stated that the bulbs should only be used in upright or horizontal installations. There was even a small image of the bulb base-up with a diagonal line through it. And in my pendant fixtures, the bulb is base-up. Why would a bulb not be suitable if it's used upside down? But I kinda doubt this was the problem. I tested a 100W, standard shape LED in the same fixture and it worked fine in an upside down orientation. It's just strange.

It is because of heat. The LED base circuitry does generate internal heat, especially as they go up in wattage. I've got some 100 and 200 real wattage high intensity LED video lights that need desktop-computer type active cooling systems.

With smaller lights, the light position can be critical in making sure air heated by the circuitry goes in the right direction away from the light. The penalty will probably be a shorter lifespan.

 

[prodromos]

Do you have 2 way switching on the circuit? If you do then it is likely that the neutral is being switched instead of the active. Alternatively, your switch might be faulty and isn't turning off completely but going to high resistance instead.
There are a few different types of dimmers, and dimmable globes need to be matched to the appropriate dimmer.

Leading edge dimmers (or triac dimmers) work by chopping the leading edge of the sine wave after it passed through zero. They work well with the old incandescant globes but also tend to need a minimum load, which LED globes usually don't provide.

Trailing edge dimmers work by chopping the tail of the sine wave before it passes through zero. They work well with low loads and are usually necessary for dimmable LED globes.