LED issue...

[Duuuuuuuude]

Not really rc related, but it kinda falls into that realm.


I bought a led light strip, cut it up into little chunks, and made a work light for my mill. All of the little strips are wired in parallel, and powered by a 15v switching type wall-wart transformer.

It makes awesome light for about 5 minutes, then it begins to blink off at an ever increasing frequency.

Would rewiring them all into a single series circuit help? Is there something else I need to do to better accommodate my power source?

[JohnRobHolmes]

Is the transformer getting hot? Model? Is the blink at 60hz or starts as a wink and becomes a longer flicker?


You need to see what the amp draw is, and what your transformer is rated for. If the LEDs aren't pulling enough power to get the wall wart out of discontinuous mode it will make it run really hot and go into "limp". If they are pulling too much power and the transformer is amp mode, it will start skipping steps as the LEDs warm up.


Pulling too much power, you will need to take a strip out or reduce the sectional length. Pulling too little power, you can put a parallel resistor with them to up the current until the PS is happy.

[Duuuuuuuude]

It gets warm.

It starts as a single blink every 10-20 seconds, then slowly blinks at increasingly smaller intervals.

Transformer is rated at 1.6a.

[JohnRobHolmes]

Meter those amps, see whats up. Since it gets worse I would guess overamping.

[Duuuuuuuude]

Would an unpowered reading be sufficient, or do I need to go for operating current?

[JohnRobHolmes]

Need the operating current.

[Duuuuuuuude]

You are no fun at all.



Here is the setup in question...

[JohnRobHolmes]

You could guesstimate from the led spec sheet. Got it handy, or a link to what you have?

[Duuuuuuuude]

From what is on the packaging...

input - 12v
power - 14.4w/m
IP rating - ip55


Got them running now, meter set to the 200m scale, and its reading 24.2. This isn't a meter I use very much, so I'm not clear on the amp settings.

Actually, with the meter inline, they haven't started to blink yet.

[Charlie-III]

Originally Posted by Duuuuuuuude

From what is on the packaging...

input - 12v
power - 14.4w/m
IP rating - ip55


Got them running now, meter set to the 200m scale, and its reading 24.2. This isn't a meter I use very much, so I'm not clear on the amp settings.

Actually, with the meter inline, they haven't started to blink yet.

"200m" or "200ma"? Not sure what "m" is on a meter, "ma" would be milliamps.

The meter load "may" be enough to "resolve" your issue, but sorta bulky in the long term.

[Duuuuuuuude]

Just "m". I assume it means milliamps.

Further up there is also the funky "u".

I normally use a Fluke that does not have those settings, this is a cheap-o meter I keep on the bench for checking lipos and such.


The panel just now started to switch off, and I noticed a couple of the led's have a slight flicker to them.

[Charlie-III]

Originally Posted by Duuuuuuuude

Just "m". I assume it means milliamps.

Further up there is also the funky "u".

I normally use a Fluke that does not have those settings, this is a cheap-o meter I keep on the bench for checking lipos and such.


The panel just now started to switch off, and I noticed a couple of the led's have a slight flicker to them.

OK, I guess since you're in the "amps settings" area, they assume you understand the "a" is to be there.

So "m" is "milliamps" and the "funky u" is microamps.

So, 12VDC @ 24.2milliamps for a load on a PS that supplies 15V @ 1.6A.

Stupid question, is the PS output DC or AC?

[Duuuuuuuude]

Dc.

[ik632]

You try running them off a 3s pack directly? They look similar to a light I sell. With that many strips, you're under an amp easy. My guess is it's the power supply.

[Duuuuuuuude]

Yeah, they do fine on 3s.

[JohnRobHolmes]

You probably need more load. Or the ps is bad.

[Duuuuuuuude]

I'm such a doofus.


I completely forgot that there is a PC power suppy bolted to the underside of my workbench to run the stereo in the shop.

Still, I'm going to get this to work with the 15v source, partially for the wee bit more light output, and to keep from having another wire strung along the wall.

I'll hit RadioShack tommorow. Any particular size/type resistors I need to buy?

[Olle P]

Seems you have the LED strips mounted on a plate made of plastic.
Perhaps they overheat due to poor cooling? (May or may not contribute to your problem...)

[JohnRobHolmes]

300ohm 1 watt resistors if they have em, each one will pull 50mah. Or a 30 ohm 10 watt.