Badcaps Forums

Badcaps Forums (https://www.badcaps.net/forum/index.php)
-   General Electronics Technical Discussion (https://www.badcaps.net/forum/forumdisplay.php?f=29)
-   -   A 2200lm 7057 LED car lamp... (https://www.badcaps.net/forum/showthread.php?t=98970)

eccerr0r 09-13-2021 11:11 AM

A 2200lm 7057 LED car lamp...
 
1 Attachment(s)
I ended up finding one of these bulbs and tried lighting it...

WOAH yeah I think 2200lm is about right - it's blindingly bright. It's yellow unfortunately, but that's expected to be 7057 replacement.

From what I found it's 12V 1.75A so this thing is dissipating about 20W, though unsure how much is light vs heat. It does get hot fast - cannot hold onto it in about 20 seconds. Not sure how much of the metal frame is actually functioning as a heatsink or not.

I do wonder how long this thing will last if I run it 100% duty cycle, I suspect it was intended for blinkers with much lower duty cycle?

Note that at 2200lm, this is brighter than a 100W incandescent rated at 1600lm.

sam_sam_sam 09-13-2021 05:38 PM

Re: A 2200lm 7057 LED car lamp...
 
If you were to run it more than 50% of time then put a current limiting resistor or a PWM controller which would be my pick

petehall347 09-13-2021 06:23 PM

Re: A 2200lm 7057 LED car lamp...
 
have had to dispose of a few that look like that cos they end up falling to bits . then i replace with proper bulbs .

eccerr0r 09-13-2021 07:12 PM

Re: A 2200lm 7057 LED car lamp...
 
What was the failure mechanism when they "fall to bits"?

It looks like a lot of different bulbs are out there, would be nice to tell which specific ones.

I found out the metal base seems to be conducting part of the heat so it's definitely doing something to conducting heat around.

petehall347 09-14-2021 02:42 AM

Re: A 2200lm 7057 LED car lamp...
 
ones i had trouble with are sidelight bulbs inside the headlights . they turn to dust . maybe its the heat from the main and dip bulbs .

stj 09-14-2021 04:16 AM

Re: A 2200lm 7057 LED car lamp...
 
the chinese are now making led car lamps that look original using mini led filaments!!
i saw them on ali the other day - not sure how bright they are though.

eccerr0r 09-14-2021 08:39 AM

Re: A 2200lm 7057 LED car lamp...
 
wtf the "LED filaments" will not survive vibration.
Those "LED filaments" was entirely an aesthetic thing that will never be seen in an enclosure...

---

Ah interesting - they chose 1.75A so that the power consumption of the device matches the original incandescent 7507 bulb: 21 watts. So this abomination uses the same amount of power, gets (almost) equally as hot... but generates 8 to 10x the amount of light!

Another interesting characteristic...found that these LEDs seem to go down in power consumption slightly as it heats up - down to 1.5A when it becomes too hot to hold. Dimming slightly most likely... is it self limiting?

stj 09-14-2021 08:45 AM

Re: A 2200lm 7057 LED car lamp...
 
the filaments arent effected by vibration, and they allow much more leds resulting in lower power per led.

eccerr0r 09-14-2021 10:02 AM

Re: A 2200lm 7057 LED car lamp...
 
They sure are affected by vibration, it's not the LEDs themselves but the mounting onto the stalks, heavier the "filament" the more torque it supplies onto the stalk, potentially breaking welds when shaken.

Unless they use more supports which would cost more...

redwire 09-15-2021 06:39 PM

Re: A 2200lm 7057 LED car lamp...
 
It looks like 3 LED's in series strings and 16 groups of those, for 48 LED. It's to get ~9.6V LED and then resistors to drop the 12-14V down for that.
That looks like about 110mA/LED and dissipating maybe ~16W plus the resistors ~5W.
It's just the heat is too much if they were lit all the time, i.e. a brake light in a traffic jam.

sam_sam_sam 09-15-2021 06:58 PM

Re: A 2200lm 7057 LED car lamp...
 
It would probably be better if it had a PWM controller ic chip instead of a resistor for current limiting control

eccerr0r 09-16-2021 06:47 PM

Re: A 2200lm 7057 LED car lamp...
 
Since it's yellow, it was intended to be for turn signals.

There is one heck of a lot of LEDs on the cob: there's 78 total - 6 faces of 12 plus another 6 on the end - so 26 strings of 3.
Current limiting Resistor(s) is(are) probably in the core somewhere. Does not appear to be a PWM unfortunately.

sam_sam_sam 09-17-2021 12:25 AM

Re: A 2200lm 7057 LED car lamp...
 
You could do away with the current resistors and use a PWM controller the led module would last a lot longer doing it that way and you could adjust the brightness of the leds

eccerr0r 09-19-2021 09:35 AM

Re: A 2200lm 7057 LED car lamp...
 
How hot is too hot for LEDs..

Apparently commercial heatsinked LEDs fail the "if you can't put your finger on it you need a fan" test...

Then again it seems any LED lamp that produces more than about 100lm (1W) eventually gets hotter than you can leave your finger on.

stj 09-19-2021 09:43 AM

Re: A 2200lm 7057 LED car lamp...
 
these are designed for a 50/50 duty cycle remember

eccerr0r 09-19-2021 02:58 PM

Re: A 2200lm 7057 LED car lamp...
 
It was not written explicitly, not sure where you remembered that?

stj 09-19-2021 03:41 PM

Re: A 2200lm 7057 LED car lamp...
 
it's an indicator lamp for a car.

petehall347 09-19-2021 03:44 PM

Re: A 2200lm 7057 LED car lamp...
 
or brake or fog light

eccerr0r 09-19-2021 05:00 PM

Re: A 2200lm 7057 LED car lamp...
 
If there is no duty cycle listing written, 100% duty cycle must be assumed.
Fog, head, dome, courtesy, etc. lights might well be 100% duty cycle...

Aren't yellow lamps frequently used for fog lights too?

redwire 09-19-2021 06:43 PM

Re: A 2200lm 7057 LED car lamp...
 
I've found it's a heat-limited situation. An incandescent bulb can run quite hot, much hotter than electronics. So expecting to dissipate 20W of heat in an enclosed light fixture, well it's going to just be too hot. Especially on a hot summer day. The limit is melting the socket and reflector.
My limit for touch is around 160F/80C and LED's are run even to 100C in cheap crap.


All times are GMT -6. The time now is 02:57 PM.

Powered by vBulletin ®
Copyright ©2000 - 2021, Jelsoft Enterprises Ltd.