what do I need to make LED lights

[Shodog]

I want to outfit my High lift with led's until the MFU comes out.  Other than the LED's, what do I need to run them off the battery voltage.  Is it a diode?

[OCD]

No, you need a resistor.  The value depends on voltage and what color bulb you're using. I like to use the receiver voltage tap, as it's a much more stable 6V, which is easier on the LEDs. (They can be 'burned out' if subjected to spikes in current)

I think that the new TLU-1 light unit that is out now has built in resistors so the guesswork is already done for you. Pretty cool considering how much time it takes soldering up individual resistors for each and every bulb.

I have a chart at home that gives all the values/voltages for common LEDs, but unfortunately I'm out of town right now so I don't have access to it.  Might want to check your local mom & pop electronics store to see if they have any advice or charts to offer (where I got mine from) Forget about radio shack unless you want to see some sales kid's head melt[] Most good shops have experience withthis stuff since LEDs are such a hot item now days.

I've soldered up a number lighting harnesses for projects and none of them have ever turned out as nice looking as the tamiya units, so it may be worth just waiting for the MFU anyhow.  I wouldn't be suprised if it too had built in resistors.[H]

 

-Steve

[Shodog]

I figured the Tamiya light kit would be the easiest way out but I don't know if the plug is an industry standard one.  I don't want to have to buy several additional lights just to get the plugs.

[OCD]

Buy the TLU light kit now, and when the MFU is released you can just pull the old stuff out and put in your new 934[] 

[Shodog]

Buy the TLU light kit stuff now, and when the MFU is released you can just pulll the old stuff out and put in you're new 934[] 

 Hey I like your thinking

Jim

[OCD]

Unless the 934 includes them, which it might like the new Skyline kit.

[Shodog]

Unless the 934 includes them, which it might like the new Skyline kit.

For the price I would hope it also includes a tube of KY Jelly

 

[OCD]

Unless the 934 includes them, which it might like the new Skyline kit.

For the price I would hope it also includes a tube of KY Jelly

 

 

Hear Here!

 And maybe sack of crack, since you'll need it if you plan on actually running it.

 -Steve

[DeeMiller]

If you want cheap LEDs, buy a flashlight or a lightning set for bicycles.

They are mostly already on 3V so you don't have to hassle with the resistors.

In case you want to connect them to 6-7.2V just connect them in line.(2x3V=6V).

Not sure if that works...just an idea.

You have to connect the + to the - of the other one otherwise a LED doesn't work.

When connecting parralel, just all + and - together to the + and - of the resistor/battery.

 

Grtz Dee.

[DJTheo]

True, you can always connect 2 same ones in series to half the voltage going to each, this way you don't need resistors and waste battery energy on them, but all energy goes to the lights.

Cheers 

[Dephcon5]

Be careful here, the current is what is most important as LED's dont dissapate heat so well. 3 to 4 volts is nominal for most LED's and 20mA to 30mA typical and max respectively. Some can go to 40mA.

The more LED's you have the higher the voltage requirement. Each hyper bright LED will drop about 1.9 volts across it. If you run them in series you could easially light 4 from a 9V battery, but you will still need a resistor to limit the current. Most LEDs have their characteristics specified at a current of 20 mA. Sometimes you can push it to 35mA or 40mA to get a brighter glow but you shorten the life.

My Lancia has the 6 LED's in the front and 2 more for tail lights running off a single 9V battery. On continuous use a duracell 9V lasted 38 hours before going dead.

The 6 across the front of the lancia are all wired in series so I only had to run a pair of wires from the 9V battery instead of 6 pair of wires. However wiring them in series means the total voltage drop would excede the source voltage since 1.9 X 6 is over 11 volts droped and my source is only 9V. But it worked as the LED's were happy with only 1.5V,  so I left it alone. The rear lights on the Lancia are in their own circuit off the same 9V and both front and rear circuits have current limiter resistors.

Jim, if you count up the total number of LED's you want to put in your F350, I will lay out a simple circuit, all you would need to do is source the parts. I can help with that too if you need it.  Just let me know if you prefer a 9V battery source or something else like 6V from the RX.

[DeeMiller]

Why a 9V battery?

I would use 2 NiMH rechargables as they are 1.2V (total 2.4V) and last a lifetime as LEDs use very small amounts of current.

That's why I would use the flashlight or bicycle lightning set.

Can you adjust the lightning capacity of a LED? I thought it was a fixed value...

How do I raise the current from a battery to get a brighter glow?

 Thanks in advance.

 

Grtz Dee.

 

[Shodog]

Jim, if you count up the total number of LED's you want to put in your F350, I will lay out a simple circuit, all you would need to do is source the parts. I can help with that too if you need it.  Just let me know if you prefer a 9V battery source or something else like 6V from the RX.

I am just thinking something simple 2 white 5MM for the headlights, 5 white 5mm for the roll cage. 4 yellow 3mm for the front and rear running lights. Once the MFU comes I will get one.  I would like to have lights in the mean time

[Dephcon5]

I recommend a 9V because they are small, easy to locate most anywhere on any RC, give hours of lighting fun, easy to hookup with a 9V battery connector and supply a high enough voltage to reduce the number of wires by allowing a series circuit.

You could use 2 NiMH at 2.4 volts and yes they would last nearly forever. But the voltage drop of the LED's means you would basically have to home run every LED back to the voltage source. For the High Lift roll bar alone thats 10 wires. Plus headlights and tail lights, its gets messy fast. But then again, you could run a pair o wires up the roll bar and then chain the pair to each LED lead. As long as the wire used is heavy enough to carry ~100 mA, which would not be a heavy wire at all.

You are basically correct as you can not adjust the light output of an LED. However because LED's have a window of operation like everything else you can "push it" so to speak. Most LED's specs are given at 20 mA. The older LED's would self destruct at 25 mA but many of the newer LED's can go to 30 or 35mA and live a healthy life. When the current applied to an LED goes up the light output goes up. Im splitting hairs on that point though, since the light output gain of a 18000 mcd LED from 20mA to 30mA is noticeable but its not earth shattering. More a matter of choce than anything. I run mine at 35mA and man do they glow! But one must be careful as LED's dont dissapate heat very well. I found 35mA to be a safe limit for the hyper whites. Also, for what its worth, I found out from experimentation that the hyper white LED's I use fail at 42mA

Ya dont raise the current output of the battery to get a brighter glow, you adjust the resistance value to raise or lower the current draw of the circuit. Since the voltage is fixed by the source (2.4 volts with 2 cells or a 9V battery) , the only variable is the resistance. Ohms law says if the voltage is constant then the current must go up if the resistance goes down (and visa versa). Sorry for the confusion on that one. Reading back, I didn't make that too clear I guess.

At the end of the day, its all a matter of preference. If your prefer to use 2 cells, you certainly will benefit from the fact that they will last a very long time as well it is a cheep solution since most of us can dig up 2 spare cells from the junk drawer. You could also use 2 AA cells which would also be easy in most any chassis and last a long time also. I just prefer the 9V way of doing things because it simplify's the wiring, ads a minimum of weight, is small and easy to place on most any chassis, and cheep as dirt. Space was more an issue on the TA03 lancia chassis than the F350 would be, so you could go with either option. There is definately more than one way to skin this cat and if you ask 5 different people your likely to get 5 different answers.

I was just trying to help.

 

[Guest joelvardy]

LEDs (super bright, normal, flashes, UV's) they cost pennies for the normal ones<em>(15p).</em> and a bit more for the super bright/flashes and more for ultra violet ones.

1k resistors - 20p (ish)

wire single modelling core 1a max - 25p (per meter)

batteries - if you are wiring up in parallel:

Then you only need to have the voltage of the LEDs so if each LED is 3v then you only need a 3v power source

REMEMBER YOU DO NED TO WIRE IN RESTORES. (sorry not on pic)

here is to wire it up in series (NOT RECOMMENDED):

[necronomicon]

I have made several LED wiring kits, and use a 9 volt battery to supply the power, adds weight, but i like to keep the power source totally seperate from the chassis battery etc, so its all enclosed on the body shell. LEDs can be purchased along with suitable resistors really cheaply in the UK on ebay (2 pounds for 10 ultra bright white LEDS, for example), for heavens sake dont buy the ones from maplins or radio shack, where an ultra bright white led cost 2.50 GBP EACH!. The chap i use supplies the resistors for your specified voltage free as well, ideal!. I would agree the proper tamiya unit is probably neater, as you do have lots of wires to tidy up, but if your on a budget, the DIY route is ideal if you can use a soldering iron and know ohms law!--I have fitted lights to 5 shells at a total cost of 10 pounds (not including the 9 volt batteries)

check out my tamiya web page for a few pics:

http://www.neilandannettec.co.uk/RC%20cars.htm

Neil

[necronomicon]

Heres some pics anyway!

 

[necronomicon]

and the rear ends!

 

[Guest joelvardy]

for heavens sake dont buy the ones from maplins or radio shack, where an ultra bright white led cost 2.50 GBP EACH!.

my local shop (NA Bardwells) are really good and cheep. they offer a lot of help also.

but for the quote above don't use maplins, how come on your site you have a link to them on your homepage

[necronomicon]

Joel, they are good for components other than LEDs, also great when seeing what components are about. Mail ordered from them loads till I found out ebay usually cheaper

cheers

Neil

[Guest joelvardy]

I do agree you can find it all there it is just expensive.

there is a really big one not far away

[petris]

I have a company that would make a kit for $115 ready to install.  2 head lights (wht), 2 tail lights(RED), 5 light bar (white), 2 fog/turning lights(amber). I haven't decided if thats the way to go or not - Jason at rclights.com is who I dealt with.

[Guest joelvardy]

this is for an RC mate

unless you meant $15 not $115

[petris]

Yes for an R/C High Lift - switches-batterybox - precut/soldered/shrink wrapped high intensity LED's -- the Tamiya Multi function Unit when it comes out is going to be in excess of $240US, I thought $115 for the full light set wasn't that bad, all professionally setup.

[InetRC]

My Lancia has the 6 LED's in the front and 2 more for tail lights running off a single 9V battery. On continuous use a duracell 9V lasted 38 hours before going dead.

If you wanted to get fancy, you can add a small CMOS IC to the lights. You can flash a small LED for close to a year on one small 1.5v battery. (I may have an MBA, but my undergrad is Elec. Engr.) []

Anyway... as someone else pointed out, there are many ways to skin this cat. I'd go with the least expensive of the bunch if I was going to replace the lights with the MFU down the road anyway.

Here's another reference site for RC lights: http://www.ramrcandramtrack.com/

Or if you want to really rack your brain type in "LED Circuits" on Google. [] 

-Alex