Should a battery powered LED get hot?

glunark

Sr Member

• Nov 18, 2014

• #1

Been getting a bunch of cheap LEDs, usually ten of the same colour powered by two AA batteries.

Most have been fine, but one of the ones I tested today had a few dull ones not lit as well as the rest, when I touched them they felt a lot hotter than I would expect.

Obviously I don't want to be burying these inside a plastic model if they are going to be getting red hot.

Just wondered if any of you had experience with this sort of thing.

 

Teddz

Sr Member

RPF PREMIUM MEMBER

• Nov 18, 2014

• #2

what kind of resistors do you have on them? How do you have them connected (series/parallel)?

What's the forward voltage the LED's can handle? Maybe too much voltage since they're getting 6v??

Is there a color change (other than the lack of brightness)?

I would toss the offending LED's as they could be flawed from the manufacturer.

 

glunark

Sr Member

• Nov 18, 2014

• #3

They were bought as a unit, one battery box connected to a wire with ten lights on, its kind of academic now, as both the lights that were heating have failed completely, so taking both back for a refund.

These aren't the ones, but they are very similar.

 

VOODOOFX

Well-Known Member

• Nov 19, 2014

• #4

If you want some electronics for a model I can always build a custom one for you... PM if your interested? fxshop@yahoo.com or call...

 

kruleworld

Well-Known Member

• Nov 19, 2014

• #5

fwiw, no they should NOT get hot. neither should the battery (unless you're charging it). I'd say Teddz is correct in that they were being over powered. the fact that they burnt out all but confirms it.

 

TazMan2000

Master Member

• Nov 20, 2014

• #6

LEDs will generate some heat, however if the heat is enough to be considered "hot" you have thermal runaway and the LEDs will fail quickly.
Its best to design the circuit properly. If you google it you should be able to find several resources online to do so.

TazMan2000

glunark said:

Been getting a bunch of cheap LEDs, usually ten of the same colour powered by two AA batteries.

Most have been fine, but one of the ones I tested today had a few dull ones not lit as well as the rest, when I touched them they felt a lot hotter than I would expect.

Obviously I don't want to be burying these inside a plastic model if they are going to be getting red hot.

Just wondered if any of you had experience with this sort of thing.

Click to expand...

 

glunark

Sr Member

• Nov 20, 2014

• #7

I think designing circuit boards is a bit beyond my skills.

I consider joining two wires quite the achievement.

 

Philly

Sr Member

RPF PREMIUM MEMBER

• Nov 20, 2014

• #8

glunark said:

I think designing circuit boards is a bit beyond my skills.

I consider joining two wires quite the achievement.

Click to expand...

If you need any help mate, let me know. I have LEDs knocking around too if you need any.

 

glunark

Sr Member

• Nov 20, 2014

• #9

Thanks, appreciate the offer!

 

TazMan2000

Master Member

• Nov 20, 2014

• #10

glunark said:

I think designing circuit boards is a bit beyond my skills.

I consider joining two wires quite the achievement.

Click to expand...

:lol Sure. Why reinvent the wheel? There are lighting kits out there for all kinds of models that are specifically made to each model, however, they can be modified to suit your own needs.

TazMan2000

 

W

Wes R

Legendary Member

• Nov 20, 2014

• #11

You can even get LEDs with resistors built into them that are pretty much ready to go as soon as you get them. You think LEDs are bad try capacitors that explode if you aren't' paying attention to wiring them lol

 

Lear60man

Master Member

RPF PREMIUM MEMBER

• Nov 20, 2014

• #12

Wes R said:

You can even get LEDs with resistors built into them that are pretty much ready to go as soon as you get them. You think LEDs are bad try capacitors that explode if you aren't' paying attention to wiring them lol

Click to expand...

My definition of an electric success if I dont let the smoke out. But I did learn about capaciters and leds. Yo gotta have them on the pos side or they last a nano second. Like WES said...they now sell them with capacitors already built in.

The easy way to an electronic success is to gut an existing toy and use its innards.

 

HughB

Active Member

• Nov 20, 2014

• #13

Lear60man said:

My definition of an electric success if I dont let the smoke out.

Click to expand...

The important thing to remember is that the blue smoke is what makes the electronics work. If you let the smoke out, they won't work any more, and it's a real pain trying to put it back in again.