The leds are getting hot. Help.?

I made this led array as a temporary solution to electricity outage but the leds get quite hot. Is that normal? Is there any better way to make such an array? I have attached pictures. The resistor is 100ohm.

Picture of The leds are getting hot. Help.?
24092011030.jpg
24092011031.jpg
24092011032.jpg
24092011038.jpg
sort by: active | newest | oldest
12 V and 100 Ohm resistor, and 3 white LEDs should be about right. How hot is hot ? Can you keep you fingers on them ?

Steve
+1

...unless the battery is ridiculous
@14v and 4v leds it makes sense
@14v and 3.7v leds it needs 150 ohm
@16v and 3.7v (worst case I can imagine) 245 ohm

@author. Is it the leds getting hot or the resistors?
Its not going to STAY at 14V for long though, once its off charge.

Steve
Shariq92 (author)  steveastrouk6 years ago
Sorry i was out of country and out of available systems. The leds are hot enough that i am unable to touch them for longer than maybe 5,10 seconds. The resistors are also hot but i thought that was normal.
No, its not really normal, with that size of LED, can you measure the voltage across your resistor and the voltage across you LEDs

Steve
Shariq92 (author)  steveastrouk6 years ago
sorry cant at the moment. cause i am not at home for another week or so but from what i remember the voltage on the leds was around 3.2. around cause each led had different voltage. I think thats because i am using cheap leds. i dont remember the exact voltage on the resistor though i think it was also around 3.
There's something odd going on, because your numbers make perfect sense, but the overheating does not !

Steve
Shariq92 (author)  steveastrouk6 years ago
|Its not melting or anything so i guess i will just continue to use it as it is. thanks for your help. any advice if i decide to remake such a lamp??
Shariq,
I look very closely at your board. Did you CUT all the tracks between LEDs on the board ???

Steve
Shariq92 (author)  steveastrouk6 years ago
yes, otherwise it wouldnt work.
I checked the voltages today. With the battery at 12.2V the resistor is 2.2V and the leds at 3.3V.
Just that, in the picture, I can't see any track cuts.

Steve