LED's not hot enough to melt snow while driving!!??

[Titan2727]

Engine or driver one in the same nothing more than a transformer regardless that is where most of the heat is generated

Still say heated bezels was a no brainer for designers. More useful than heated mirrors imo

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[viper88]

Thank you. I edited my reply with a link to Amazon. Not cheap, but I’ll have it in my hands by Monday!

Plexus is also great for cleaning and protecting the soft top windows. I used it all the time on my TJ soft top.

 

[NavyVet1959]

Engine or driver one in the same nothing more than a transformer regardless that is where most of the heat is generated

Transformers are for either isolation, stepping up, or stepping down AC voltages. They are not for DC voltages. I seriously doubt that they would convert the DC voltages in the car's electrical system to AC, step them up / down to some other point, and then convert them back to DC for the LEDs. LEDs use DC voltages and in fact, if you exceed the maximum reverse bias on the particular LEDs that you are using, you will burn them out. Incandescent bulbs don't care how you plug them in -- they'll still work. LEDs though are a bit more picky. If you plug them in the right way, you get a LIGHT emitting diode, but if you plug them in the wrong way, you get a DARK emitting diode (and it will continue to produce DARK even if you subsequently plug it in the right way.

LEDs are more concerned with having the proper *current* sent to them, so the drivers limit the current. Whereas with an incandescent bulb, it doesn't matter if you have excess current since the bulb will only take what it needs, with LEDs, if you provide it with excess current and the voltage goes over some threshold point, it will burn out the LED very quickly. LEDs are not linear in how they respond to increases in voltage. Depending upon the design, you might have something as simple as a current limiting resistor or you might have a constant current driver. Current limiting resistors are easy and cheap for single LEDs or even a long string of single LEDs, but when you start talking about 5W or higher LED modules, you probably should be looking at proper drivers for the LEDs. You use Ohm's Law to determine the proper size of the current limiting resistor.

Let's say that you have a single LED with a 3.1V forward voltage and you want to run it off a 12V battery.
This type of LED is probably looking for around 20 mA of current, but your 12V car battery could provide hundreds of amps if it needed to. You need to add a resistor in series with the LED and that resistor needs to drop 8.9V.

Ohm's Law states that V = I * R, where V=voltage, I=amperage(current), and R=resistance(ohms). Solving for R, you get R = V / I.

So, this gives us R = 9V / 0.020A = 450 ohms

But, we also need to ensure that we have the correct wattage resistor.

Since P = I * E, where P=power(watts), I=current(amps), and E=volts, that means the P = 0.020 * 8.9 = 178 mW. The smallest wattage resistors that you will likely find in bulk on eBay are 1/4W (250 mW), so that would be acceptable.

Of course, this is pretty wasteful since more energy is being dissipated by the resistor than by the LED, so you might as well put 3 LEDs in series. That will give you 9.3V dropped across the LEDS and your resistor would only heed to handle 2.7V. Plugging that into Ohm's Law gives you R = 2.7V / 0.020A = 135 ohms with a power dissipated of 0.020 * 2.7 = 54 mW.

Hope I didn't confuse too many people with this... Just trying to point out that LEDs are not as simple as incandescent and you can't just go swapping things around like you could with incandescent. You need to pay attention to what voltage the LED assembly was designed to operate with. And with some cars, the CAN-BUS makes things even more inconvenient since if you don't add a load resistor to the LED bulb, the lights will flicker or it will thrown error codes on your display.

 

[sigsegv]

Hope I didn't confuse too many people with this... Just trying to point out that LEDs are not as simple and incandescent and you can't just go swapping things around like you could with incandescent. You need to pay attention to what voltage the LED assembly was designed to operate with. And with some cars, the CAN-BUS makes things even more inconvenient since if you don't add a load resistor to the LED bulb, the lights will flicker or it will thrown error codes on your display.

Very good description of how LEDs aren't a linear resistive load.

Our cars probably use a much more complicated constant current switching power supply for the LED headlights though. The variable alternator and ESS systems mean that the voltage fluctuates between 12V and 14V pretty frequently, making a purely resistive approach unworkable, I think.

Maybe they can get away with a linear regulator if the forward voltage of the headlights is reasonably close to 12v.

 

[viper88]

I think it's a combination of not enough omitted heat and the deep dish headlight bezel. Most cars(that have led's) have flush mounted lights.

Also, a lot of people haven't had snow yet.

Was fluffy snow nothing major, 31° out.

If happens to a few will happen to everyone else, do we not all drive the same design with the same parts?

There is always someone trying to make a buck. I bet some aftermarket company will make clear lens to mount flush with the headlight bezel. Or worse, dark shaded covers. lol.

 

[Majestic]

It’s no different than any other $60k SUV with LEDs.

 

[brow]

This is a major issue, noticed it when I bought my JL in April and we had a snow storm. Forgot about it up until last month when it started snowing. Definitely a safety concern. Has anyone spoken with their dealership or FCA?

On a sort of related note: I find the highbeams not all that effective, like they're pointing too high and don't do a great job lighting up the road. I typically just leave my low beam on with fogs when i need better lighting. As well, if it is snowing and I do hit the high beams, wow it lights up the snow so bright it's almost blinding.

 

[Biscuit]

if it is snowing and I do hit the high beams, wow it lights up the snow so bright it's almost blinding.

High beam is useless - and dangerous - in snow and fog. That goes for any vehicle, LEDs or not.

 

[Majestic]

This is a major issue, noticed it when I bought my JL in April and we had a snow storm. Forgot about it up until last month when it started snowing. Definitely a safety concern. Has anyone spoken with their dealership or FCA?

On a sort of related note: I find the highbeams not all that effective, like they're pointing too high and don't do a great job lighting up the road. I typically just leave my low beam on with fogs when i need better lighting. As well, if it is snowing and I do hit the high beams, wow it lights up the snow so bright it's almost blinding.

It’s not Jeep’s problem. LED’s are an option, no different than buying a car with performance summer tires or not choosing a cold weather package that heats the windshield washer nozzles.
Halogens putting out heat is an inadvertent side benefit to poorly efficient technology. “Self heating” halogens come standard, it’s you that made the choice to go with LED’s.

Even half caked with snow, LED’s are probably twice as bright as everybody else’s halogens with no snow.

 

[Capt-Zoom]

Gee, if it really is a problem on a moving vehicle (doubtful), maybe you should rethink spending a ridiculous $900 on LEDs.

I have much better things to spend my money on than led headlights. Just saying this would piss me off if it was happening to me.

 

[Titan2727]

It’s not Jeep’s problem. LED’s are an option, no different than buying a car with performance summer tires or not choosing a cold weather package that heats the windshield washer nozzles.
Halogens putting out heat is an inadvertent side benefit to poorly efficient technology. “Self heating” halogens come standard, it’s you that made the choice to go with LED’s.

Even half caked with snow, LED’s are probably twice as bright as everybody else’s halogens with no snow.

Of course its Jeeps flaw...led package=heated bezels. No excuse

 

[Titan2727]

I have much better things to spend my money on than led headlights. Just saying this would piss me off if it was happening to me.

Dont get me wrong the LEDs are worth every penny. Just the snow thing is annoying

 

[Majestic]

Of course its Jeeps flaw...led package=heated bezels. No excuse

It clearly didn't state that in your option sheet so that fail is on you.

 

[viper88]

I had headlamp washers on other cars. Headlamp washers would be useful with the LEDs. I guess this is another excuse to add the tow package for the AUX switches if anyone wants to add extra lighting. lol.

 

[Titan2727]

It clearly didn't state that in your option sheet so that fail is on you.

Let me correct myself, should be part of cold weather package. Sorry fail is not on me or anybody else who got leds. Leds are an UPGRADE not cheap halogen lights for people to cheap to pay for leds.

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