Brownout help!

[Stuart Watson]

Howdy - I'm pretty sure my problem is that I'm getting brownout: when moving servos quickly (or even not that quickly!), I lose receiver signal for a couple seconds, then it reboots. Here's the electronics stack:

• Motor: AEO C20 Pro 1550kv Long Shaft https://alofthobbies.com/aeo-c20-pro-1550kv.html
• Battery: Tattu 3S 450mAh 75C XT30
• ESC: DualSky XC12Lite https://alofthobbies.com/dualsky-lite-12a-esc-xc-12-lite.html
• Receiver: FrSky RX4R
• Servos: 2x Emax ES3352 Thin Digital Servos https://alofthobbies.com/emax-es3352-thin-digital-servo-2-8kg-39-oz-in-10-sec-12-4-grams.html

If the brownout prognosis is right - should I just get an ESC with a BEC of more than 1a? Get different servos? Add a capacitor to the receiver?

Thanks for your wisdom in advance!

Stuart

 

[Konrad]

The 1 amp BEC is far too weak for the use of digital servos. When looking at caps to drive a servo they need to be rather large to supply the joules of energy needed. Caps are used to filter clean the Vss of ripple noise, not drive the servo.

 

[HENNY]

The 1 amp BEC is far too weak for the use of digital servos. When looking at caps to drive a servo they need to be rather large to supply the joules of energy needed. Caps are used to filter clean the Vss of ripple noise, not drive the servo.

This is an area that many folks dont consider carefully enough. Even some of the cheap 5amp becs cannot supply enough current when multiple servos are connected to the receiver. Use a good quality bec with addiquat current output capability. Many becs don't have a good transient response meaning they cannot supply the instantaneous current demanded by the servos so the output voltage to the receiver drops, if it goes below 3 volts the receiver has to reboot and if the servo is still requiring more current the receiver can go into permanent reboot cycle. And that can mean good bye model.

 

[Wayne]

I'm always trying to get the ESC manufacturers to give us larger BECs.

 

[Stuart Watson]

OK - good feedback, thanks for the help everyone!

 

[Nigel]

Also - stall test your amperage. An unloaded servo will pull a fraction of what a stalled servo will. Some manufacturers list this spec on the box, sometimes not. Always useful though, and a good idea.

 

[Martin]

I agree. sounds like brownout for sure. Did you fix it? how? thanks
martin