how many seconds will a bare P7 last direct drive 3.7v?

[waddup]

no heat sink, approx how long would it last b4 failure?

approximately.

2 seconds? 5 seconds? 15, 25?

 

[Greg G]

It'll go about 4-5 seconds before the beam turns angry blue, and then you had better cut power to it or you will kill it.

 

[CampingLED]

no heat sink, approx how long would it last b4 failure?

approximately.

2 seconds? 5 seconds? 15, 25?

Why do you ask? The Vf of the P7 does have an effect.

 

[qwertyydude]

Somebody should make a video of it frying itself then we can time it.

 

[waddup]

amazing (to me) :duh2: that life expectancy is changed from 4 seconds to 50,000 hours with a little epoxy and heat transfer.

 

[waddup]

Why do you ask? The Vf of the P7 does have an effect.

because im about to instal my first P7, and i was considering testing it 'free air' before fitting it into the light.:laughing:

im new to this :candle:

 

[spencer]

At 3A I drove one for at least 5 seconds. It got really hot but it wasn't to the blue stage.

 

[bshanahan14rulz]

if you're worried about it, just put it on some isolated or anodized metal and put a little pressure on it. Always keep an eye on it, though, as soon as it starts changing colors, remove the power. Even if you think its just your eyes playing tricks on you cause it's so bright, remove the power.

 

[MWClint]

why not just test it with 2xAA... I and J vf's will still light up on 2xAA and be dim enough not to cause damage without a heatsink for a short run.

 

[CampingLED]

why not just test it with 2xAA... I and J vf's will still light up on 2xAA and be dim enough not to cause damage without a heatsink for a short run.

+1. Alternatively you can connect it through a resistor when you test it.

 

[rizky_p]

i'll never try running P7 full power without heat-sinking, what is the point?

 

[Databyter]

I recommend use some protective glasses if your going to be looking at the LED directly. My understanding is that the p7 is bright enough and small enough to damage your eyes if looked at for too many seconds.

 

[IMSabbel]

Hm. My P7 here hava about 0.5g of mass, as an estimate, in a substrate and back metal.

At 3.7V, they pull about 4A.
This means about 14W or so, 12of them will be heat.

Going with a default average of a about 2J/gK, this will result in an temperature increase of about 50 Kelvin per second.

All very ballpark, but gives an idea about the shortlivenessless.

If the P7 is on a star, like those 2mm thick DX ones, it will last significantly longer.

 

[Linger]

just don't. Thermal past it to any metal sitting around - keep the contacts away from said metal (piece of electrical tape works) and no need to worry about electrical isolation - OR - use electrically isolating thermal paste and don't worry about it.
But really, you can put it on your stove, on a knife, on the side of a hammer,
on the bolt of a dead bolt.

I don't know about a toaster,
it's real thin,
but still better then nothin


Linger

 

[waddup]

ok understood thanks :thumbsup: