Do I need to worry about brown outs with this TREX 500L setup?

[kirby_]

I've got a new T-REX 500L, with:
- The stock servos (3 of Align DS525M, 1 of DS515M). The specs say they will operate fro 4.8-6V, I was going to choose 5-5.5V for the BEC output from the ESC, with the idea that the the voltage drop wouldn't be more than 0.5V and I don't know if I really need 6V power yet.

- Frsky X8R RX. The specs say it'll operate from 4-10V, draws 150mA at 5V.

- Spirit FBL. The specs say it'll operate from 3-15V, draws 30mA at ???V.

- I was going to use the kit provided stock Align ESC w/ BEC (RCE-BL70G), but I smoked it on the bench. Not sure if it was me or a faulty part (probably me, I'm the newbie). So, I ended up with a CC Phoenix Edge 75. I haven't opened it yet, so I could return it if I discover I need something else.

Do I need to worry about brownouts with this setup? I don't do anything close to aggressive 3D. For the next several months, it's all hovering, circuits, working my way toward competent sport flying, maybe an occasional loop or barrel roll if my skill progresses.

I've read enough to understand how I would shore up the RX->FBL->Servo power system, I'm just looking to avoid the complexity for my first big build if I can avoid it. The stock Align ESC w/ BEC is capable of 5A, can I trust that the CC ESC w/ BEC will do the job as well? Does it matter what BEC voltage I choose (obviously not higher than the 6V the servos will take)?

In general, what is a good bench test for inducing brownouts so I can try to induce and detect the problem rather than discover it in the air?

[deebee]

I prefer to hook a voltmeter to the fbl controller (plug it into an empty plug that has power or hook it to a y cable) and monitor the voltage while I perform this standard test.
Once your heli is built and all electronics hooked up and installed,
Unhook 2 of your 3 motor leads from the esc (making sure they cant short),
Power up your transmitter, power up your heli.
Check reciever/bec voltage
Work pitch, Rudder and cyclic quickly and constantly for at least 30 seconds ( a minute is better)
Watch voltage level it should stay within +-.3 volts of idle reading
Many people who don't use the voltmeter will use one hand on top of the head to apply resistance to the grips moving and use the other hand to vigorously work the pitch, and basically just check to make sure the receiver doesn't brownout.

Some things to keep in mind servos use the most power when stalled, and for an instant when the motor quickly reverses direction.
Some Built in becs can be weaker when the esc is under heavy load (from the main motor)
Telemetry or built in receiver voltage logging is best,
I have substituted a cheap lipo alarm on 2s and set 3.6 volts per cell to monitor a bec set to 7.4 volts (it runs at 7.6-7.7volts idle) if it drops below 7.2v the alarm sounds. The trick to using a 3 dollar alarm is to split the voltage evenly to simulate 2 cells.

[Ron_R]

You *should* be okay, as the servos you have aren't HV, but if you want extra peace of mind, wire in an External BEC. The CC BEC Pro is an awesome unit and works very well. I use it on my Goblin 500.

[kirby_]

Ok, I'll wire up some sort of servo harness to my dmm. But it sounds like I can check things with the Phoenix edge, proceed with my build then think about a separate BEC later. Thanks!

Anyone have recommendations about running at 6V vs 5V for everything? I know the servos will be a little quicker, is there a downside?

[Ron_R]

No downside at all assuming the ESC's BEC can output the required amperage.

[Solmanbandit]

I ran my 500 ESP without a BEC for a while with a castle 75 with no issues and I like to throw it around. As a piece of mind, I went ahead and added a CC 10A BEC and haven't had a single issue. Any about a 500, I would go with the 20A BEC.

[jml79]

The cheapest insurance is a capacitor. Spektrum sells one with a servo plug already attached. Add it to an empty port on the FBL or RX and it will buffer out any quick current surges/voltage drops. Solved a lot of problems for me and cost $6. I add one to all my helis.