In DC applications, such as Automotive, there is no circuitry, just a bulb. I'm afraid that the underlying cause is that like most repro parts nowadays, all of the LED bulbs are Chineseum.........

 

Those look nice. I need to convert the 70 to those. The Olds powered 4x4 was all LED except the headlights. As Joe said the conversion flasher is needed or they flash really fast, at least mine did till put one in. Man I miss that truck.

 

Most of the lights available on Summit have awful reviews. What brand are those Joe? My Princess Auto specials worked OK.

 

Read the package they come in. Most will state you cannot use them in enclosed fixtures. They do produce heat just in a different way. Energy will always produce heat. Manufacture recommendations are important with any installation.

Oddball there could be several reasons for the flicker. One is a low quality lamp, such as one's purchased at Cheepo (home) Depot or other bulk stores. Like anything else there are better quality lamps than others. Years ago I would use nothing but Phillips or Sylvania lamps, lately not so much. I would constantly do service calls for old lady's that thought something was wrong with there electric because there lamps wouldn't last. Almost every time it was supermarket bought GE bulbs. Told them to try a better brand and the problem went away. Coincidently, I never charged them and they would recommended me to others. Another reason could be the switching device. If you installed them on a dimmer the lamps might not be dimmable or the dimmer could not be rated for LED's. These lamps require special dimmers same as the flashing device JP recommended.

 

somewhat on topic...5 years ago, or was it 6? the wife and I got our motor home and since we boondock a lot (we live aside the ANF) we converted all the interior and exterior lights to LED replacements with the BA15 sockets (which are the size the 1157 and 1156 1041 etc bulbs take. The skinny is, we can run every light in and out of the coach for the same wattage of any 2 bulbs previously, so they do save on juice and hence heat. Such that we can go 3 days without a recharge from the 2 group 24's. (we got them all from Dan at LED4RV and he does sell taillight and marker festoons as well)

however, watts is watts and any current consumed - no matter how small - is dissipated as heat. In the incandescent the heat is produced in the filament which is essentially inside a dyson sphere and it transmits the heat to the glass envelope. this actually keeps the filament safe and it will burn darn near forever if you never turned it off. HOWEVER, the Leds have no such luxury and the heat transmits down the leads to the solder paste.

What I have found, and this is similar to chinese made electronics - stereos, tvs et al - the heat eventually desolders the SMD device from the board and off it goes. On the DC only applications the driver - as it were - is typically a 5v zener diode with Iz set at 500ma and the load current set at 25ma per device - max. Because of this they tend to have wide range ratings like 9-24v.

When ours started failing I called up Dan because we paid from $8-$12 EACH depending on the festoon size and he wanted me to return them for checkout and a credit. Surely I could not be the only one with a problem? AT first they asked what kind of voltage problems we have, well 2 lead acid 24DCs are pretty stable and the converter is dead on solid at 13.8v - but they never believe you, even when you have an oscilloscope hooked up....

So looking into it, if you have steady hands, a good eye and the right equipment you can re-solder the joints. How they are built is a picker places the SMDs on the board and a tiny trace amount of solder paste is applied and the bulb is on a conveyor thru what is essentially a pizza oven, which melts the paste in a half assed fashion.

THAT is how they are failing. every one of my trailers is LED now - either from the factory or myself - cargo (factory), boat, beavertail and dolly (me) and I have yet to have a failure on them - knock on wood, so the technology is sound, but the assembly is not.

Of note, at spring I likely talked to the same guy Joe did, as I am looking for better RV interior bulbs - we just got 2 60 device 'panels' that put out over 800 lumens at 100ma for the main lights in 2700K and they work NICE. when I asked him how much current vs how much lumens etc his bulbs were rated, he had no idea. It seems to me, that if you spent all the $$ on tents, displays, trailers, gas, show admission, labor, hotels etc as your career, simple facts about the devices would not be out of the question. I might have been rude to him, I didnt mean to be, but seriously?

 

Really? LEDs run straight on battery/alternator V+?

There may not be a rectifier, but there sure is circuitry in there, which should be somewhat sophisticated for high wattage applications.

 

there is a little bit. each LED will have a bias voltage, and a max current. For most of the stuff I insert into my stereo restores, its 3.2v and 25ma max.

while an led is a diode, it is not a rectifying diode and will break down quickly so I usually take the 6-12v ac lighting circuits, use a single 1n4001 style diode and a 100uF cap, this gives me from 7.5-15v dc (divide the ac voltage by RMS, or sqrt(2) over 2) from there its a read of the DMM and feed it into this equation:

Vss-Vb/Imax = R

so if I had a fixed 12v supply (which a car is not, and never will be) and I wanted say 20ma max current (I always slightly underdrive) it means I need 440ohms. Coincidentally when I order my LEDs in bulk from parts express they come with 100 ohm and 470 ohm resistors so you can hook up to 5v or 12v supplies - two of the most popular today. The only other x-factor is current, most of the resistors Parts Express send me are 1/4 watt.

well lets say this was for a car, who sees 14.4v at full alternator output. the same 20ma requires....560 ohms. Easy, green, blue, brown.

But power(wattage) is I squared times R so .... pluggin in = .224 watts, or REAL close to the 1/4 watt rating, here, Id go up to half watt.

so there is circuitry inside the DC only stuff. Not a lot, and not a lot of math either, but it is there.

 

Since you clearly know your stuff, I'll just call out this one oversight, to avoid confusing others.

The current consumed is dissipated as two things: heat and light.

In the incandescent bulb, most of it is converted to heat, and some to light (sometimes some to movement - ie: sound, as well, if the light hums a tiny bit).

In the LED more of the current is converted to light, and a smaller amount to heat.

The point is that LEDs waste less current as heat, and use more of it for what you want: light, but both are created from the current of electrons.

- Eric

 

My statement was with regard to the bulb itself, and is correct.

 

Im not sure what you mean 'the bulb itself' if you mean the item you buy that has the BA15 (or other) base and includes all the smds, well I guarantee you that the circuitry I described is present in the bulb 'assembly'

Cheap version? narrow voltage operating range and resistors only, better quality? then input voltage regulated by a zener as described.

trust me on this, you plug an led into any dc source that is above its bias voltage and it will flash once and be gone for good. You MUST limit the current. Youse gots no choice.

 

I think he means "the junction."

- Eric

 

I am very familiar with LED's, as are you. I am not referring to an automotive tail light bulb, I am referring to the individual LED's themselves (i.e. the bulb). Whether they be SMD or thru hole, they have no circuitry ........

 

ok gotcha, but Im not convinced that they are failing. Im of the mindset it is the solder joints as I have repaired some of the 'bulbs' I got. Its a PITA, but doable.

 

You are right. Having a Hot Air Station makes it much easier to work on SMD parts. Having old eyes makes it harder though.........

 

Looking forward to hearing an update on how well these bulbs work and how long they last. My previous experience wasn't the greatest with the large open taillights on my '83 Delta 88.

 

Do you have a mfg and part number for the bulbs you bought? I might get me a set to test out.

 

I bought some LED replacement 1157 bulbs. However they are loose and not making good contact. Without replacing the sockets, is there anything I can do like wrap some electrical tape near the base of the bulb?

 

Try one wrap of tape at the TOP of the connector (closest to the bulb element). This probably won't help.

Usually a poor connection means the connector is corroded, or there is a problem with the pin springs and wiring boot. You can rub a wire brush in there to clean up the sides a little, and hit the pins with sand paper or whatever you can use that reaches.

A "secure" connection is established by little springs under the pins in the base. The bulb pushes the pins down, you turn, and the springs push the bulb into the notches and holds it there. Once the boot dries up and doesn't allow the wires to slide, or a spring under the pins breaks, then you're in trouble. I'm not aware of a reliable way to fix this other than replacing the socket. That can be an entertaining challenge as well.

 

The problem with many of the LED replacement bulbs is that the little tips that hold the bulb in place are not long enough, and/or the diameter of the base is not large enough to fit properly in the socket. Return em and try some other ones.

 

i did all interior bulbs in my maurauder and only used Phillips. as for exterior bulbs everyone that used them on their marauders had terrible experiences, mostly the bulbs being too dim. i left the stock bulbs in the tails and went with 4300k HIDs for the headlights and foglights.