Quick question. Is a 4.7uF capacitor the same as a 470uF capacitor?

No. A 470uF capacitor is 100 times the capacitance of a 4.7uF capacitor.

However, I think you are referring to the 470pF cap shown in the diagram.
pF = picofarad, or 1x10E-12 Farads.
nF = nanofarad, or 1x10E-9 Farads.
uF = microfarad, or 1x10E-6 Farads.
4.7uf = 4,700nF = 4,700,000pF

Also, does it maker what voltage rating i get?

For this project, no. Anything over 3v is ok.

 

The duty-cycle and the current determine the brightness.
The duty-cycle is almost 50% so the brightness is the same as an LED lighted continuously with half the current.

The power from the battery is 1.25V x 8mA= 10mW. Ignoring circuit losses making heat, if seven 3.5V LEDs are used then each gets 10mW/3.5V= 2.9mA average which is not very bright.

 

The duty-cycle and the current determine the brightness.
The duty-cycle is almost 50% so the brightness is the same as an LED lighted continuously with half the current.

The power from the battery is 1.25V x 8mA= 10mW. Ignoring circuit losses making heat, if seven 3.5V LEDs are used then each gets 10mW/3.5V= 2.9mA average which is not very bright.

youre right there not that bright.

Is there any type of LED setup that well light up say 8-10 feet?

The end result with this project i want is. to be able to see at least 8 feet in front of the rc car, because im making a custom FPV (First Person View) system, So i can drive the RC car at night while wearing video goggles

 

Thats gonna be tough. you may want to see if there are "KC" lights for rc cars. Or use some superbrights. You will need another battery pack, however.

 

Thats gonna be tough. you may want to see if there are "KC" lights for rc cars. Or use some superbrights. You will need another battery pack, however.

This is were my idea came from, But it looks like he is just using a flash light

http://www.youtube.com/watch?v=TbCU46z3dcU&feature=watch_response_rev

But this is what i would like. These are WAY bright

http://www.youtube.com/watch?v=F1OO5OVnGM0&feature=related

 

Would it be esyier for e to just get a 11.1V 3S LiPo battery and try to run my lights off of that?, Because i can get 1 of those pretty cheap. Then recharge it when i need to.

I could also get a 4S LiPo witch is 14.8V. then do something to that if need be

 

Yes. Thats what I was getting at. Use a second battery pack for the lighting.

That way, you can do all you want with the lighting (within the battery boundries) and not effect the cars drive power.
you could get 1 or 2 LUX stars and they will give you a lot of light. These guys can get hot, so heat sinking should be considered, but because your moving, shouldnt be tough.

 

Yes. Thats what I was getting at. Use a second battery pack for the lighting.

That way, you can do all you want with the lighting (within the battery boundries) and not effect the cars drive power.
you could get 1 or 2 LUX stars and they will give you a lot of light. These guys can get hot, so heat sinking should be considered, but because your moving, shouldnt be tough.

yea im pretty sure i can find a spot for another battery.

can you link me some where i can buy LUX star lights?
I cant find any.

Also what battery should i get? the 11.1V or 14.8V?

 

did you mean FLUX lights?

 

http://www.luxeonstar.com/

Luxeon, sorry I should have been more clear.

 

http://www.luxeonstar.com/

Luxeon, sorry I should have been more clear.

Wow those thing are way bright.

So if i got 3 of each of these. I can run it off a 9V battery pack. by running them in series right?, Because it says the "Typical Forward Voltage : 3 Vf (@ 350mA)

http://www.luxeonstar.com/ANSI-White-3000K-20mm-Star-Rebel-77-lm-p/mr-3000-77-20s.htm

http://www.luxeonstar.com/Carclo-19-Deg-Rippled-20mm-Lens-No-Holder-p/10208.htm

http://www.luxeonstar.com/Carclo-20mm-Round-Lens-Holder-White-p/10236.htm

 

that would be cutting it close, but it should work..

What is the actual voltage of the pack? is it 9v or 9.6v?

 

LEDs work from a controlled current. Do not connect LEDs without proper current limiting or current regulation. The current control circuit needs extra voltage so three 3V LEDs in series with a current control circuit needs a supply of about 11V or 12V.

Cheap "ultra-bright" LEDs from E-Bay are bright only in a very narrow angle and can barely be seen off axis. Get name-brand modern wide-angle LEDs instead.

 

Audioguru speaks the truth.

I was only considering a resistor. You may want to consider using a 11.9 or around there, battery pack. I have seen them on RC cars before.

 

A battery has a fairly high voltage when fully charged so the LEDs will be bright. But the voltage from a battery drops as it is used then the LEDs will be dim or not lighted if a simple resistor limits the current.
If a regulated current circuit is used then the LEDs will always be at the same brightness as the battery voltage runs down.

 

On the Luxeon page you were looking at, take a look at the buckpucks, They are regulators for the LEDs. It will take the varying voltages from the battery pack and, well, regulate it.

 

Audioguru speaks the truth.

I was only considering a resistor. You may want to consider using a 11.9 or around there, battery pack. I have seen them on RC cars before.

I've never seen a 11.9v pack, i can get a few different packs. either a 3S LiPo 11.1V or 4S LiPo 14.8V or a 9 cell NiMh pack 10.8V or 10 cell pack 12V

What ever pack you think would be best. it only needs to run for 30-45min at a time

 

I may be thinking of the 11.1...

Here is a pack that should give you around an hour in safe range if you ran all three at 350ma.. I would consider just using 2 Luxeon stars... but, its your project.

You will be using 350mA * 3 LEDs = 1050mA or 1.05A

The pack I linked to is rated for 2600mAh So using only half of the rated spec, 1300mAh, You can run the 3 lights for ABOUT one hour before hitting the half point.

Then you recharge and do this over and over again.
Now temperatures and what current you ACTUALLY use on the LEDs will effect time and current draw. You may find that using 250mA or 300mA is plenty bright.

That will give you more run time and longer life for the LEDs and the batteries.

 

the link you mentioned didnt show up.

If you think 2 of the LUX LEDs well be plunty of light. Then ill go with 2.

Can you link the rest of the stuff off of the Luxeon site. That i need to run both LEDs safely. I dont wont to burn out a 11$ LED, Because i didnt get the right stuff

 

ok.. this 1 part will run BOTH stars, You have decided on 2,

Add this to your shopping list.

You will need A battery,
a buck puck:
http://www.luxeonstar.com/700mA-Non-Dimmable-PowerPuck-Driver-With-Leads-p/2008b-700.htm
a little switch to turn it on and off
and 2 LEDs (350ma)

the buck puck is small.. 1.5" long and .5" high

And the heat sinks for the LEDs
and some wire
That should be it.