Powering onboard gear.

[Wmacky]

I'm looking for recommendations on how to power all my onboard UAV gear. I want to use Lippos, but I'm not sure about going with 2s, or 3s, and not sure how to regulate everything. the equipment is as follows:

500MW lawmate trans
RCAP
TinyTrac3
GPS OSD or "Blackbox"
Pico alt
MAHi

One possible issue is that I would like the option to use a 1W trnsmitter, that would require 12v. If not for this a 2s would seem to be the ticket. I'm also looking for herringbone free video!

I'd love to here about YOUR setups as examples!

[misfitsailor]

I have used lipos, even for video tx. The only downside of the li-poly cells is that you can not run them down all the way or you kill them. There are voltage cut-outs you can rig, but then the lipos can only be used for non-critical systems.

BTW, have you considered a brushless alternator setup?

[Unterhausen]

we use 2s and 3s which powers our plane for quite a while. I bought some cellphone adapters from a vendor on Ebay, and modified them to put out 5v @ 3A. We don't have anything that requires 12v. This powers a Stargate/micronav and the receiver/servos for 2-3 hours easy off of 2100mah batteries. Obviously you should go with switching power supplies/BEC instead of linear. There are some of the "simple switcher" type devices that will switch up -- you would have to design your own, but it isn't that hard.

[workshop]

Some switching power supplies create RF interference than can corrupt onboard electronics. The amount of RF is related to the switching frequency and general quality of the power supply. RF leakage into onboard components is related to RF shielding techniques, electrical isolation and space (good ole inverse square of the distance for EM falloff).

A more conservative approach would be to use linear power supplies that are not as efficient or cool running. The benefit, however, is that linear supplies do not create any RFI. I have a personal preference for the SmartFly brand of aircraft power supplies (linear regulators).

On my UAV systems, I usually parallel two lipolys on a SPDT switch using each switch side to carry the current of each battery. When the switch is closed the batteries are paralleled and fed to a power buss. The power buss is routed through the fuselage and tapped at three locations (GPS, telemetry and Nav/Control). Each tap leads to a linear regulator (3 on the Catalina Project – 5.5v, 1A for GPS, 5.5v, 3A for Cam/Vid TX and 6.0v, 3A for Nav/Control). Each regulator is adjusted UNDER LOAD until the desired voltage output is programmed into memory.

To help prevent running down the lipoly batteries, I installed a super bright red LED on the other side of the switch so when the UAV is OFF the LED is ON indicating a battery is still installed. On a more esoteric note, I fed the UNregulated power buss to my OSD so I could watch raw battery voltage on the screen as I fly.

I used 2 cells on my 5.5v camera system and 3 cells on my 12v camera system. To clean up your video, focus your efforts on improving the antenna(s) on your ground system rather than adding power to your transmitter. I’ve only flown 2 miles away from my GS so far but the video from my 600mW, 2.4GHz video system is crystal clear. I’m using a BW Diversity receiver and two 14dbi patch antennas.

Jeff