What “C” rating is safe???

[av8ersteve1]

Hey all. I never thought of this before but after getting all digital servos, my mind went there and I can’t seem to find any info on it so, I thought I’d ask. For a Rx (receiver) battery, in a 600 class nitro helicopter, what should the discharge rate in “C” (min/max) be when your using all High Volt, digital servos and a stand alone tail gyro?
I’m using 4 Hitec HS-8360TH servos, 1 Hitec HS-8315BH tail rotor servo, and a Spartan Quark gyro in my Raptor 30V2. The receiver is a AR7100R with rpm sensor for the rev limiter and I just want to be on the safe side when choosing the battery. Thanks for the info!

[ticedoff8]

For a Rx (receiver) battery, in a 600 class nitro helicopter, what should the discharge rate in “C” (min/max) be when your using all High Volt, digital servos and a stand alone tail gyro?

A "stand alone tail gyro" implies you are still using a flybar. The flybar does all the work and the servos are very lightly loaded.
And, "HV" servos will draw less current for the same load vs 6v (or 4.8v) servos.

Since the flybar equipped Trex 600N used 6v digital servos (Align DS-610) when it came out, I would expect the HV servo to be loafing and draw almost no power compared to the old 6V servos.

In that case, it really doesn't matter what the C-rating is for the receiver battery.
A simple, 5S NiCad pack would work fine.

As a gauge, if you fly FBL, then most of the larger BEC top out at 10A to 15A continuous and 20A peak.
But, batteries have a capacitance / impedance factor to them that allow for larger spikes without stressing.

Most of my 2S 2200mAh / 3500mAh LiPo's have internal resistances in the 5mΩ range, so I would estimate they are "really" 2C to 4C maximum anyway (even though the label says 20C) and they are working fine on my 700 size nitros

[AllanNg]

Get something that wiill give you 20a or more continuous and you should be ok.

[FlaFlyer52]

More specific to this line of comments, given a 700 nitro FBL and HV servos, what is the common size 2s pack[s] to run and what is flight time/number of flights per charge? I was considering running the Jeti dual redundant switching setup but looking for a sweet spot of light weight and flight times, perhaps four flights per charge may be too greedy?

[fastflyer20]

Ticedoff8 handled the pack C rating. A 2200 pack is one of the more common RX packs and will allow you to fly many flights as a starting point. You can go smaller for lighter weight if you wish. Since each combo of heli and pilot have different amp draws, fly three normal length flights, charge and note mah consumed. You can now determine how many flights you can get on your receiver pack. I tend to be conservative and only discharge receiver packs to 40% of capacity. Spare packs are not expensive, so I take an extra pack if I plan on many flights.