Battery question for navigation lights.

[Stuart Linfoot]

I want to run some navigation lights on my electric airplane, and have it as light as I can get it.

I picked up a 5mm blinking red LED (anti collision beacon), and 3 - 5mm solid (non flashing) LED’s for the wing lights and tail light, these are 5 volt 80 mA LED’s, I also got a 5 volt voltage regulator (thinking that a regulator would be lighter then running a separate battery pack for the lighting system.)

I want to run the lighting system off of the two cell 1,500 mAh Li-Po battery pack that’s also going to be running the motor, speed control, receiver, and servos.

I’d like to set it up with a micro switch that is between the battery and voltage regulator, so I can turn the lights on and off.

I want to set this up so it will be plugged in and getting it's power through an empty port in the receiver.

Does anyone see anything wrong with this setup? Am I asking for trouble running the lighting system off the flight pack?

Thanks
Stuart

[Mr.RC-CAM]

...these are 5 volt 80 mA LED’s,Are you sure they are 80mA each? That is an unusually high current. Can you post a link to the data sheets?

I’d like to set it up with a micro switch that is between the battery and voltage regulator, so I can turn the lights on and off.Ok. Not hard to do.

I want to set this up so it will be plugged in and getting it's power through an empty port in the receiver. That conflicts with the previous requirement. Either run it off a spare Rx port, or run it directly off the battery (with or without a Vreg, your choice).

Am I asking for trouble running the lighting system off the flight pack?
My opinion is that if your ESC's BEC is not overloaded with the max allowed servo count, then you are in luck. Keep your total LED current under 125mA's.

More info: http://www.rc-cam.com/led_info.htm

[Stuart Linfoot]

the planes going to have 5 servos (4 hs55's, and one hs50) it will be a 4 channel plane, with the 5th channel for a drop box slung under the plane, after I posted I got to thinking that there's about 5 volts or so going to the receiver anyway, so no need for a voltage regulator, but then if the bec can't handle the extra power from the lights, then I could be blowing out the esc, so maybe going direct off the battery might be better, the esc is a Castle Creations Pixie 20p and the motor is a gws 350

[Mr.RC-CAM]

With five servos and 2-cell LiPO, I would not burden the BEC with any additional load. For simplicity, just connect the LED's directly to the battery with correctly chosen current limiting resistors.

As mentioned, the 80mA LED current spec sounds a bit odd. Be sure to determine the correct current draw before calculating the resistor values.

[Stuart Linfoot]

I got the led's at Radio Shack, I did mess up, their 20 mA each, or 80 mA total combined

[Mr.RC-CAM]

What are the Radio Shack Part numbers?

[Stuart Linfoot]

I forgot left everything at work tonight, I can let you know tomorrow what the part numbers are, I did check out your web page, and found the LED stuff very helpful, I even printed it up to bring home and read, and forgot that to.

I must have to many projects going because my brain is going in 6 different directions and once ... :eek:

[Stuart Linfoot]

ok here's the part numbers

Blinking red LED 276-036
20 asorted LED's 276-1622 (this is where I got the rest of the lights)
Voltage regulator 276-1770

[Mr.RC-CAM]

Those LED's will add some bling, but they will dissappoint if you intend to night fly. The 276-036 is only 9 mcd, so it will not be very bright. The others are generic parts, so they are standard brightness too. Things really do not shine until you go above a couple thousand mcd.

The blinker LED has an IC in it and should be supplied with a fixed voltage that does not exceed 5V or so. Your Vreg can be used for this, but since the blinker LED is intermittant duty, you can probably cheat and run it from the Rx's power.

The other LED's should be configured for 20mA to 30mA operation; Absolute voltage is not critical and they can be wired to the 2-cell LiPO with simple series resistors. This will eliminate the VReg.

If you do use the Vreg, be sure to install the two caps that the mfg recommends. Otherwise, the part may oscillate and cause rude problems.

RC-CAM

[Comatose]

From 2s you're probably okay with an extra 80mA in load running from the RX. If you ever go to 3s, then use a separate battery or a switching BEC powering everything.

[Stuart Linfoot]

the only night flying I do is under parking lot lights, and I can see the plane up to an altitude of about 100 feet AGL, so the lights would be for effects only, but on the other hand, if there not going to be very bright, then maybe I'm better off going some place other then Radio Shack to find what I need?

I'm just not sure where to go with out having to order off the internet, I'd like to find what I need locally.

Stuart