Options for powering my lights

[MrGravey]

My club is preparing for HHAEFI 2013 and anything happening at Hodges during the day is just because people are waiting for the sun to set. Night flying is the main attraction for a large chunk of the people that will go to this fly in. I have had A few 3S Bloddy Wonders set up for night flying, but I want to jump to the 4S set up they recommend for combat and such to get the extra power. I have always run my lights off the main flight battery in the past, and I can't do that with 4S that I know of so what is the best way to do this?

My first thought was to put a 3S 450mah pack in the plane just for the lights, and I am ok with that, but there has to be a better way. I will be thankful for any advice.

 

[Craftydan]

Are we talking night combat?

If no, then just leave the lights disconnected in combat then fly 3s at night.

If so, then Cool! Higher weight is on your side, so having a seperate pack might be ok, but space will get tight in there. You can get a 7812 regulator chip and a pair of capacitors to create a step-down voltage regulator and run it off the 4s pack.

http://www.radioshack.com/product/index.jsp?productId=2062600#

Biggest thing you need to know is how much current your LEDs are drawing. One of these can supply up to 1A per leg of LEDs.

For capacitors, anything in the neighborhood of 0.1uF caps will do (possibly less, but more won't hurt it). Connect one cap between the input pin and the common (ground) pin, and the other cap between the output pin and the commpn pin. Be careful if you get polarized caps -- the marked end *must* be connected to ground (unless they marked it with a plus, then, well . . . ).

your power connections should have the black wires (ground) all go to the common pin, the red battery (+) to the input pin, the red LED (+) wire to the output pin. there are diagrams floating around the net, unfortunatly I don't have any on hand.

The chips can be bought at any radioshack or similar electronics parts store, and built on a piece of perf board easily. make sure the part looks like the one linked -- they sell smaller packages, but they supply much less current.

 

[MrGravey]

I thought something like that would work, and I have some experience building things like this, but none designing them. I normally have to use someone else's plans to get there. I really wish I had taken some of those electronics classes I could have taken in college now. Live and learn I guess.

I have plunty of room, I don't use the swappable pod anymore for these planes. I never swap them anyway so it just worked out that I could do a little more with the same room without the extra pod involved. The room isn't a big deal at this point. I'll look into building this step down unit some more when I get home tonight. The plane flies on 3S but I like the 4S set up a lot better. Unlimited verticle is a must for me and my 3S set up just wasn't giving me that.

Thanks for the advice.

EDIT: Oh, and that I know of there is no night combat, but anything is possible out there. It wouldn't shock me to find it happening out there.

 

[Craftydan]

Night combat would be frikken cool, and I wouldn't put it past the folks at HHAEFFI to sneak it in.

but night bowling is cool enough . . .

 

[MrGravey]

I don't know that night bowling happens at HHAEFI. I know they do it at SEFF and I have been working on a special plan just for that on and off since I left SEFF this year getting ready for next year. A very cool game to play indeed. I'm going to email Crash now and see if night bowling is already planned, or if it can be added. Its my first HHAEFI but where there is Crash there is always something of interest.

 

[tw-ryder]

Hello MrGravey We recently had a similar problem, but coming from 2S voltage rather than the 4S you're using. I think the solution that worked for me will apply to your situation, as well:

Ebay Boost/Buck SEPIC Converter

Using about 3' worth of LEDs, I pull about 300ma at 12V, so nowhere near the 25W limit of the Step Up Converter I bought from the same vendor. No need for a heatsink, even. Since your setup is 4S though, this one can step down too. I've been pleasantly surprised so far, maybe this would work for you?

 

[xuzme720]

Just to tell you how my mind works, when I read the thread title, my immediate thought was "either batteries or a really long cord!".
Sometimes I wonder what is wrong with me....

 

[MrGravey]

A really long cord would be funny, but I'm not sure it would work so well.

I am putting the finishing touches on a few Wonders for HHAEFI now and I decided to go 3S with the night flier. I have more of those packs and I can go to a little larger motor to make the power difference. My flight times will suffer a little, but they were already much longer than I normally fly in one setting anyway.

Thanks for the advice guys. I do have plans for a 4S night flier but it will have to wait for November at the least and I'll be looking into the SEPIC converter then. If nothing else it will make something interesting to talk about with other pilots.

 

[Tritium]

Sometimes I wonder what is wrong with me....

Your a Texan, don't sweat it!

Thurmond

 

[jweather]

You could use this to go from 4S to 3S voltage: http://www.amazon.com/gp/product/B00CYX78HY/ref=oh_aui_detailpage_o05_s00?ie=UTF8&psc=1 $5.60 on Amazon with Prime shipping. I'm using one to run 5V LEDs off a 3S, and it works great, no heat issues like the linear regulators. Just turn the little brass knob with a screwdriver to get it to the output voltage you want.