Two Led's On The Right Side?

[Squidge]

A single LED can kill a car battery in a month
Depends on the LED. I fail to see how a LED drawing 2mW (or even a bog standard, cheapo 40mW LED) can flatten a typical 360 Watt car battery that quickly, and don't forget you can PWM them, so you could run them at a 50% duty cycle... (Yes, I'm not counting the mW drawn through the limiting resistor, but thats hardly going to change things).

Of course, if you used a 3W LED, that can drain the battery much faster, but no one would put one of those in a portable device, as it would burn your retina out.

 

[Tor]

A single LED can kill a car battery in a month
Depends on the LED. I fail to see how a LED drawing 2mW (or even a bog standard, cheapo 40mW LED) can flatten a typical 360 Watt car battery that quickly, and don't forget you can PWM them, so you could run them at a 50% duty cycle... (Yes, I'm not counting the mW drawn through the limiting resistor, but thats hardly going to change things).

Of course, if you used a 3W LED, that can drain the battery much faster, but no one would put one of those in a portable device, as it would burn your retina out.

You're comparing the wrong units. Ampere and ampere hours are what you want to look at.

But as you say, it depends on the LED.

A good old round red LED (> 2mm diameter) draws 20mA. That's 14.4 ampere hours per month, and if you suck that out of, say, the 45Ah battery of my small Japanese car you'll notice it - if it's cold it's basically flat. If it's one of those 30Ah cottage batteries for you solar panel it's even worse (and yes, I became aware of this LED problem when a guy with just such a system told be about the insanity of the solar cell company - they had put a LED on the system. Everything was dead when he arrived after a month.)

Newer, smaller LEDs may draw 10mA, so you're a little better off, but we're still talking 7200 mAh/month. Then you have those tiny LEDs which may draw less, but it still adds up. The one in my Palm PDA killed the device over the weekend when I was stupid enough to install a program which turned on the LED (as a warning) when the battery dropped to 80%.

LEDs on an always-on, battery-powered (in the mAh, not Ah range) device like the Pandora is just wrong IMO. They're nice when you're plugged into the wall.

Do what you want with the LEDs, as long as I'm able to switch them off I'll be happy enough!

 

[Squidge]

You're comparing the wrong units. Ampere and ampere hours are what you want to look at.

Why? A typical LED doesn't use 12V, so it's mA rating would be useless for a 12V car battery.

You say a good old round red LED (> 2mm diameter) draws 20mA - at what voltage? If that's 3.3V (typical Pandora voltage), then thats 5mA from your car battery or 3.96A per month. A low power LED has a typical forward voltage however of more like 1.8V, which would give you 3mA or 2.16A per month.

 

[Curlyjs]

You say a good old round red LED (> 2mm diameter) draws 20mA - at what voltage? If that's 3.3V (typical Pandora voltage), then thats 5mA from your car battery or 3.96A per month. A low power LED has a typical forward voltage however of more like 1.8V, which would give you 3mA or 2.16A per month.

To complicate a bit things...

A typical LED draws 20mA with a voltage drop of lets say 2.5V (the voltage drop depends of many things mostly the material its made). If its driven by current LED driver the power drawn is only 20mA*2.5V*efficiency. If it's a passive method (simple resistor) then, the power used is 20mA*3.3V.

So Squidge, you right in most cases

JS

 

[bakawhite]

How about we put LEDs like, all around the edges, except with one of those pieces of plastic that makes it look like a bar of light, then when we turn the Pandora on it can, like make a spot of light travel around the case while it's booting

(haha i'd probably sit there for hours just turning it on and off to see the cool lights :lol: )

And then it says: 'I'm the Openpandora Inc. 3000' and you go nuts

Edit:
http://www.youtube.com/watch?v=Mlt4GQ45TXg

"open the bay doors, HAL"

I'll GTFO now...