KITE LIGHTS LED'S 9 VOLT?

[zax]

I have this kite about 82"w 41"H i'm installing led's of all sizes ABOUT 30 LED'S BLUE mcd 2600 yellow mcd 1200 and some red jumbo's mcds @ 5000 and some smaller ones. WHAT should i use for power? 2 AAA BATTERIES AT 3 volts or 9 volt SHOULD i use both 2 or 3 nine volts what should I use the 4060 COMOS & resisters and capasiters? or should I only use 10 led's ? please help

 

[mechie]

Kite LEDs

What do you want the LEDs to do ... ?
If you just require night lighting then a 3 volt battery would be OK as there will be minimum volts drop across series resistors
As you mention CMOS are you creating some flashing display ? a higher voltage may be required for the logic.

I doubt that a couple of AAA cells will give much life, maybe a few minutes. You should consider something bigger - 20 square feet of sail should carry 3 or 4 'D' cells without too much difficulty :wink:

 

[bogdanfirst]

how about making them flash like the ones on a plane, red and green?

 

[zax]

led 's and a 9v

I'm I able to run 17-20 LED'S ON A 9 VOLT BATTRY?

 

[mechie]

LEDs in series

If you connect the LEDs in strings of four (assuming each drops about 2 volts) then five strings will allow 20 LEDs to run with a total current of about 100mA - this sounds OK for a little PP3 style 9 volt battery.
You should get maybe an hour from a battery.

Each of these strings of LEDs will require a resistor to limit the current - about 50 ohms should do it.

 

[daviddoria]

mechie, how did you determine the time the battery would last??

 

[Mosfet]

I DONT ADVISE THIS but it's interesting, no?

Teather your kite with thin two conductor wire.

If long enough wouldn't it create it's own current?

 

[bogdanfirst]

i doubt it....
in one instance you could add solar panels but then you dont need the leds....
for a 9V batery that has about 100-150mAh so you have 3 rows of leds -about 30-40mA eacg total current 90-120mA so the batt will last a little bit more then 1 hour......
how about using 6 AA batteries distributed around the edge of it...but it think that the weight will be the problem.....

 

[mechie]

Battery Capacity

daviddoria
I just looked up the amp-hour capacity of a PP3 this is a bit vague but...
A NiCad (the one I looked up) is 150mAh so this should last 1.5 hours at 100mA discharge rate (if you are lucky)
A Duracell "Procell" claims 550mAh - 5 hours ?
More realistically I reckon you should expect half this life and count the rest as a bonus (especially if you need to rely on the battery) :wink:

A Procell weighs about 50g so the LEDs and wiring will weigh more than the battery?

A kite of this size can lift quite a weight (at least a hefty camera rig) in a reasonable wind so a PP3 will be of no consequence. I allowed 20mA for the LED current as this seems typical - 100mA for FIVE parallel rows (I only drew three as I figured the rest was obvious)
I suppose zax will be flying this kite on a single line of about 300lb breaking strain? (~130kg) or more.
The weight is best concentrated in the centre of the kite - wingtip mass slows its response too much.

 

[bogdanfirst]

i think that the current might be bigger, because he has high brightness leds