LED question

[NinerBikes]

I want to install a Red LED in Rudolphs nose. Should I go with a 3mm or 5mm LED and if it draws 700 mw, how much AH of lithium ion battery do I need to go a week between recharges?

Oh yeah, and BTW, Happy Holidays to my Woodall's/ RVNUT interwebz tekkie friends.

Correction , should be 700 ma.

[NinerBikes]

SCVJeff wrote:

NinerBikes wrote:

tenbear wrote:
OP said his lamp was 700 milli WATTS. That would be about 58 ma. It would last about 12 times longer than was forecast.

Good catch, my bad, should be 700 mA

a 700ma red LED is gonna be blinding. Call the FAA to issue a NOTAM

Well, look what a good troll dragged out of the river! Get well soon, Jeff, we missed ya. Don't be so shy, now that your fingers work on a Mac again.

You're just the guy I'd hire to build up a flying LED Zeppelin as a spoof or a joke, but I suppose photoshop would be a lot less expensive, LI batteries are too heavy to fly and go "boom' in the storage area of jets, no?

[SCVJeff]

NinerBikes wrote:

tenbear wrote:
OP said his lamp was 700 milli WATTS. That would be about 58 ma. It would last about 12 times longer than was forecast.

Good catch, my bad, should be 700 mA

a 700ma red LED is gonna be blinding. Call the FAA to issue a NOTAM

[MEXICOWANDERER]

Remember that ridiculous parody?

Rudolph The Red, Knows Rain, Dear

Just got an order of 20ma Osram red 3.2 vf 5mm 120o 1 Hz devices. Very bright - way brighter than conventional chips. But maybe Rudolph's nose isn't supposed to be astable.

[tenbear]

Several mind readers on this forum :h :B.

[NinerBikes]

tenbear wrote:
OP said his lamp was 700 milli WATTS. That would be about 58 ma. It would last about 12 times longer than was forecast.

Good catch, my bad, should be 700 mA

[NinerBikes]

Sam Spade wrote:

WyoTraveler wrote:
700 ma is .7 amps.

And that's a LOT for a single LED.

Not at 3.5 to 3.7V, standard LiIon battery voltage. Rudolph's nose needs to be bright.

[tenbear]

OP said his lamp was 700 milli WATTS. That would be about 58 ma. It would last about 12 times longer than was forecast.

[Sam_Spade]

WyoTraveler wrote:
700 ma is .7 amps.

And that's a LOT for a single LED.

[red31]

I use a $20 12v 7ah sealed batt, 3hrs/night of a few landscape lights.

1 watt x 12hrs/12v ~ 1ah, x 7 days ~ 7ah

[WyoTraveler]

700 ma is .7 amps. Leave it on for 1 hour and you will have .7 ah. Therefore 1 divided by .7 equals 1.42 hours to consume 1 ah of battery. Looks like if you leave it on for 6 hours a night it will consume about 4.22 ah for the 6 hours.