led lighting and howto?

[shaggy2112]

I was surprised there is no led lighting tips and tricks stickied anywhere. I have done some searching the site and havent been able to find an all in one thread about led lighting...just bits and pieces here and there. Anyone know of a good one...Or can this thread be the start of one. Looking for howtos on various power sources...running lights from the receiver...volt and amp draw on different lights...mounting and plugin options...waterproofing...etc.

 

[4doorrt]

Re: led lighting howto?

Awesome idea for a STICKY! I bought a set to add to the wraith I have from a local hobby shop. The set had aporx. 10 3mm led that ea one pluged individually into a harness that was wired parallel ( all positive together and all negative together) and plugged into the receiver. Installed with ease and worked great, however there was a crap load of plugs everywhere.

I decided to clean up the install by running the lights in series (positive to negative) in groups of 4 based on info I read on a led website. NO LUCK! Only a few worked. I tried to test the each led with low voltage and a voltage meter and burned out several of the LEDs. Super bright then pop! The instantly quit and obviously were burned.

I know there of tons of LEDs with different voltages and there are calculators on the net that will design your setup based on load and resistance Nd number of LEDs but does anyone have a more simple solution?????

The stock wraith system only use 6 LEDs and and them seperated using a circuit board in series 2 for the back and 4 for the front. I tried to series into the stock harnes and no luck that way either.

Please someone ( electrical engineer ) HELP us lay people pimp our rides!!!

 

[AreCee]

Re: led lighting howto?

Use the calculators, someone has done all the math for you and all you need to do is plug in the values.

It's all about the voltage, parallel = same voltage, series = shared voltage.

Here's a very good one: LED series parallel array wizard

 

[shaggy2112]

Re: led lighting howto?

Awesome idea for a STICKY! I bought a set to add to the wraith I have from a local hobby shop. The set had aporx. 10 3mm led that ea one pluged individually into a harness that was wired parallel ( all positive together and all negative together) and plugged into the receiver. Installed with ease and worked great, however there was a crap load of plugs everywhere.

I decided to clean up the install by running the lights in series (positive to negative) in groups of 4 based on info I read on a led website. NO LUCK! Only a few worked. I tried to test the each led with low voltage and a voltage meter and burned out several of the LEDs. Super bright then pop! The instantly quit and obviously were burned.

I know there of tons of LEDs with different voltages and there are calculators on the net that will design your setup based on load and resistance Nd number of LEDs but does anyone have a more simple solution?????

The stock wraith system only use 6 LEDs and and them seperated using a circuit board in series 2 for the back and 4 for the front. I tried to series into the stock harnes and no luck that way either.

Please someone ( electrical engineer ) HELP us lay people pimp our rides!!!

Ya I thought the same thing...and have been going through the same problems burning up leds...my problem now is try to run two cree leds as headlights...not alot of info out there on howto make the cree leds work with the regular leds. Thats why I figured we could have it all in one place hopefully...even down to different lighting options, sizes, scale lighting, lighting can/bucket options, ect. Even vendor options for those that dont wanna diy. I know theres a ton of stuff out there and as many ways to make it work...putting it all in one spot seems to make sense.

 

[R/CMARK]

Re: led lighting howto?

I was supprised that there wasn't more info on here about LEDs as well. When I started to wire my lights, I serched all over the site and only found peices here and there. I got to tell you its super easy. Use the calculator in the link previously mentioned or co to superbrightleds.com.
There is a lot of good info there. You just need the info off the leds and decide on what power you want to use. Put info into the calculator and it will lay it out for you. The superbrightleds calculator will even give you a wiring diagram. I went to radio shack and picked up several leds and a 9v battery plug, entered in the calculator the info and done! really simple.

 

[ZippoMan]

Re: led lighting howto?

I have a Wraith kit and just bought the simple LED controller and 6 LEDs. I am going to liquid electrical tape the circuit board to waterproof it. I figure for the price and ease of installation it is well worth the $27.00CAD shipped to my door. Just use the stock light buckets in the kit and plug into channel 3 of the receiver!! Easy as pie!! Mmmmmmm pie...lol

 

[4doorrt]

Re: led lighting howto?

Ok the plug and play is easy but I want custom lighting on my wraith. Interior floor boards lights over the proline shocks and a few placed under to light what u are crawling over.

LEDs are dirt cheap I should be able to build this setup for about 5 bucks.

Used the wizard provided above but my layout shows a resistor on each led running all LEDs parallel. How do the over the counter 10 led kits like the one I had prior not use any resistors and plug straight into the receiver?

And what mcd lights are best. I know that the higher the mcd the brighter but really do u want 11k mcd white run with 600 mcd green? And so on.....

The wizard doesn't give u the option to use multiple LEDs with different variables. I just want the cleanest install possible without the rats nest of wires and resistors.

 

[Olle P]

Re: led lighting howto?

LEDs are very basic in the electronics skills required, assuming it's just for an on/off design. From there it's much easier to design your own circuitry than to provide a "one size fits all".
The tricky part is to know how much current you actually want for each LED, and then design the circuit accordingly. The LEDs come with a recommended current rating, but sometimes you want less intensity and therefore less current. Only practical testing will tell how much current (reduction) is required to get it right for you.

I did a semi-advanced circuit myself to have one single pole (manual) switch control a full/half light setting on my crawler.
There are four red rear LEDs. Four white front LEDs. One white rearward LED.
- At the "full" setting all LEDs shine at full brightness.
- At the "half" setting the red LEDs shine at full brightness, since they're weak anyway. The rear white is off. The outer front LEDs shine at a reduced intensity. The inner front LEDs just glow a little.

 

[ZippoMan]

Re: led lighting howto?

Yes I guess if you need to have custom lighting then doing it yourself can be good and possibly cheaper. I just like the convenience of pre-made stuff that works and you can easily fit in your RC. I have nothing against trying but my skills are not so good at making nice neat circuits...hahaha. Just one mans opinion.

 

[Charlie-III]

Re: LED lighting, how to?

LEDs are very basic in the electronics skills required, assuming it's just for an on/off design. From there it's much easier to design your own circuitry than to provide a "one size fits all".
The tricky part is to know how much current you actually want for each LED, and then design the circuit accordingly. The LEDs come with a recommended current rating, but sometimes you want less intensity and therefore less current. Only practical testing will tell how much current (reduction) is required to get it right for you.

I did a semi-advanced circuit myself to have one single pole (manual) switch control a full/half light setting on my crawler.
There are four red rear LEDs. Four white front LEDs. One white rearward LED.
- At the "full" setting all LEDs shine at full brightness.
- At the "half" setting the red LEDs shine at full brightness, since they're weak anyway. The rear white is off. The outer front LEDs shine at a reduced intensity. The inner front LEDs just glow a little.

Ummm....are you limiting current (not likely) or voltage (more likely)?

I will assume you're using resistors in front of the LED's, thus when you add enough resistance, you vary the voltage output, possibly turning off some LED's at lower voltage inputs (you drop below the minimum operating voltage required).

Not slamming, just asking/clarifying.8)

 

[Brainstain]

Re: LED lighting, how to?

Yeah.. This is why none of my trucks have lights. I have built buggies from scratch, scale chassis, real 1:1 stuff.. But I literally can not wrap my brain around lighting. My first attempt ended in almost no light, then a poof, then everything thrown on the other side of the garage.

 

[SMR 510RR]

Re: led lighting and howto diy

Its really not that hard guys.

Before you start you will need to know a couple pieces of information.

Source Voltage:
What will be powering these lights? You can run it off your RX (6v) or a battery of some sort (like a 9v battery).

The specs on your LED's:
You get these from whoever you got your LED's from. I get mine from LED Lights, Bulbs & Accessories - SUPER BRIGHT LEDS and for a 5mm white LED with a 30° viewing angle they list:

Continuous Forward Current: 30mA
Typical Forward Voltage: 3.4v

Now with that information we have everything we need to do the calculations to figure out the proper circuit to use (parallel or series) and what resistance needs to be added.

Lets say I was using these LED's as head lights so I want two of them. I am using this calculator LED series parallel array wizard as it not only calculates the required resistance but will also tell you if you can go to series vs. parallel and give you options, that can be helpful.

On 6v input I fill in my information and it gives me these results:

If you look at the diagram it says that I need to wire them in parallel with a 100 ohm resistor on each leg.

Now lets say we were using a 9v input, just input your specs and you get:

Now on this one we are able to wire them in series with one 82 ohm resistor.

So then just keep doing the calculations for all of your different lights, also I would separate them by location. If you have a total of 6 of these white LED's but 2 are headlights and 4 are going to be in a light bar on the roof do the calculations on each set.

Now just wire each set up and then wire up a feed, basically all of these individual circuits will be in parallel from a main feed coming from your power source. I bought a bunch of servo wire and just pull off the signal wire to give me a nice small power wire with 2 individual wires. Then I got some servo connectors that I can add so that I can separate the string into multiple sections if I need/want to be able to unhook portions and so that I can plug these directly into my RX or a RC switch if I am going to turn them on/off from my TX.

Also another for those who want to run your lights off of your RX at 6v...I got a little RX pack that holds 4 AA batteries that is roughly 6v fully charged to use for testing/building them up without having to plug my whole rig in and to get the power to the RX. You could also use an extra BEC to supply testing power to your lighting.

Also you do have to make sure that you wire the LED's in the correct direction as they will only turn on with "forward" voltage. Again, whoever you get your LED's from should have a diagram that shows what is + and - usually determined by a notch in the LED and one leg being longer than the other.

I think that should get you guys going on building your custom lighting setups!"thumbsup"

 

[Olle P]

Re: LED lighting, how to?

Ummm....are you limiting current (not likely) or voltage (more likely)?

It's principally the current that is influenced, since the feed voltage is fixed and the LED voltage drop vary only a little with the current.

... when you add enough resistance, you vary the voltage output, possibly turning off some LED's at lower voltage inputs...

As stated above; adding resistance reduce the current, not the voltage.
As the current decrease so does the light intensity.
To really turn the rear white LED off I use a regular diode in series with the limiting resistor, to add a further voltage drop when the voltage fed is about the same as the LED voltage.

 

[Olle P]

Re: led lighting and howto diy

Continuous Forward Current: 30mA
Typical Forward Voltage: 3.4v

Now with that information we have everything we need to do the calculations...

... provided you want full brightness, yes.
For reduced brightness you need to know how much the current has to be reduced.

When wiring the LEDs in parallel it's possible to use a single resistor, which is then going to be less resistive.
In the example above it's said to use a 100ohm resistor for each LED. Instead one can use one resistor of 86.7/(number of LEDs) ohms to feed them all.

Notable is also that the resistor used must be capable of handling the power it will use. (Usually not a problem.)

 

[Fowlboy]

Re: led lighting and howto diy

How do you calculate proper resistance when you have 4 LED's in 1 string each having different forward voltages and/or current specifications?

 

[SMR 510RR]

Re: led lighting and howto diy

... provided you want full brightness, yes.
For reduced brightness you need to know how much the current has to be reduced.

When wiring the LEDs in parallel it's possible to use a single resistor, which is then going to be less resistive.
In the example above it's said to use a 100ohm resistor for each LED. Instead one can use one resistor of 86.7/(number of LEDs) ohms to feed them all.

Notable is also that the resistor used must be capable of handling the power it will use. (Usually not a problem.)

In that situation there was not enough voltage to drive both LEDs at full power so wiring them in series was not possible if full power was desired.

How do you calculate proper resistance when you have 4 LED's in 1 string each having different forward voltages and/or current specifications?

The only way I know how to accomplish that is to calculate them individually and run them in parallel rather than series.

The problem with LEDs is that they work differently then other electronics. In most electronics, lets say a traditional light bulb, as heat increases resistance increases so they basically self limit how much current they can take. With LEDs as heat increases resistance decreases so you can get yourself into a runaway current situation where your LEDs are bound to let out the magic smoke.

With two or more leds with different specs if you put them in series the LEDs that allow more current through will take more than their share and eventually go poof, when they are in series if one fails then the rest are forced to take the extra current and are going to poof too. Running them in parallel is the best way to avoid this.

 

[norco kid]

There's a really sweet free program called calcrc (Google it) that has all sorts of rc calculations and amongst them an led calculator to tell you what resistors you need for any voltage & # of leds!

 

[jjlove]

I have done a bunch of led installs in RC cars and Slot cars. I have never had a problem with just matching the number of leds to the power voltage. What I mean by this is... like stated above, leds operate at 3.4v each. If you are using a 9v battery, you can hook up 3 leds in series and just be under the safe voltage. Now lets call each set of 3 a strand. You will now be able to hook up each strand in parallel and you can run as many strands as you want. My new TF2 is going to have 12 leds in total. So I will have 4 strands of 3 leds each.

I use the smallest wire I can find, like 22 gauge. Just solder the wires onto the leds and hot glue the wires along the body.

I solder 2 aa batteries together to get 3v and then solder wires on them and use it to test different leds to check polarity and brightness.

 

[SMR 510RR]

I have done a bunch of led installs in RC cars and Slot cars. I have never had a problem with just matching the number of leds to the power voltage. What I mean by this is... like stated above, leds operate at 3.4v each. If you are using a 9v battery, you can hook up 3 leds in series and just be under the safe voltage. Now lets call each set of 3 a strand. You will now be able to hook up each strand in parallel and you can run as many strands as you want. My new TF2 is going to have 12 leds in total. So I will have 4 strands of 3 leds each.

I use the smallest wire I can find, like 22 gauge. Just solder the wires onto the leds and hot glue the wires along the body.

I solder 2 aa batteries together to get 3v and then solder wires on them and use it to test different leds to check polarity and brightness.

Technically you should put a 1ohm resistor inline with each string to eliminate the chance that the LEDs will pass more current then they are rated for when they get up to temp.

 

[jjlove]

Technically you should put a 1ohm resistor inline with each string to eliminate the chance that the LEDs will pass more current then they are rated for when they get up to temp.

I agree that my method is crude and your are correct. But, I have never had an led fail using this method. I set up a bunch of on road 1/10th scale cars that were raced in endurance races. The races were a few hours long and the cars only stopped for a battery change.

Leds are cheap and to me it is worth the risk of keep it simple.