Trying to make custom 5 LED light bar work

[Brickman]

I bought some warm white LEDs
5mm LED - Warm / Soft White - Ultra Bright Round Top

and a few 150 ohm resistors to make a custom LED string in series for my Axial 5 bucket light bar.
I want it powered by the Rx and controlled by a remote switch.

I knew it's not going to have enough voltage from the RX or my Lipo 2S 7.4v battery to power the lights. I pluged it into my Axial simple LED controller and only 4 of the lights work.

How can I get all 5 to work? I would need some sort of voltage up thing stronger than Axials one? It's my 1st LED wiring job so im a total Noob .

I've read on here about LEDs and used the calculator, but I want the lights in a series and not parallel. Too many wires in a parallel. Also im using 22 gauge wire.

[Awesome-Sauce RC]

if you are intent on series only wiring then you will need to get a voltage step up booster, i made and use one for my lighting needs but thats because i need it small and branded for my circuits, however you could probably get one from fleabay for a few dollars.

as they are only standard leds and max 20ma per led you dont need 22awg wire if you want something more flexible and thinner, i use 28/30 awg for my leds and they tend to be running up to 100ma per string and they have been reliable on that wire, and i have made a hell of alot of them lol.

also worth mentionong the leds may be rated 20 ma but when doing your resistor calcs you dont need to run them at 20ma, maybe 15 at most, an led is just as bright at 15ma or even 10ma as it would be at 20, but it is more efficient and produces less heat in the die, also as an led warms up from use its current draw increases slightly so if you run them at 20 ma and they get warm from use and start drawing more current than they are rated for then they will self destruct.

unlike most other components in circuits that only draw as much current as they need led's are different in the fact that they are greedy and suicidal, they will draw all the current they can until they kill themselves so 15ma max gives you a safety margin for when they have been on for a bit and warmed up and will probably be drawing more than the initial resistor calculation was set for.

this is my step up boost circuit, 6v in and 18v out or whatever i need upto 40v, it can allow me to do series strings pulling a few hundred milliamps which is good for my custom lightbar and other things and it can go up to 40v and still give me just over 100ma but it costs more than the cheap ebay offerings



also you may want to look at cool white led's instead of warm white, they will appear brighter than the warm white ones



tony

[Brickman]

Thanks for the input.
A step up converter like this will work?
XL6009 DC DC Adjustable Step Up Boost Power Converter Module 1pc | eBay

I'll defiantly get some 15ma resistors. Don't want to change out the LEDs anytime soon.

[Awesome-Sauce RC]

yep that would work, only downside to those is they are bigger than the castle bec's for example.

i use the alternative step down version of that for my breadboard circuits and its taken lots of abuse quite well lol


tony

[Brickman]

Finally had time to work on my lightbar. Got it 90% done.

Instead of using resistors I bought some LED drivers so no matter the input voltage the LEDs wont burn out.
20mA LED Driver - Never Worry About Resistors Again

Left the lights on for a half hour and only get 80 degrees and 75 in my room.


Just need to mount the bar on my Wraith, run the wires through the body, seal up the electronics box and ready for night driving

[Cammmo]

That current limiter looks very cool!

I put a nice bright light bar on top and was all stoked but when I got it in the dark I soon realized I was blind where it counted...on the rocks! Couldn't see jack to pick a line. Ended up putting LED strips of green rock lights on the horizontal side panels and another small green light bar up front aimed down for 270 deg of rock lighting. It is awesome!

[Brickman]

All done





Receiver and LED stuff in the radio shack project box. Blue thing is the step up voltage converter for the 5 bucket light bar.