Trex 700E DFC HV Super Combo

[jraydoran]

Hi Gents,

Sorry if this has been discussed before.

With the HV kit, you run a 2S lipo straight to the 3gx controller. The servos are powerd by the bus in the 3gx or any other controller.

These HV servos are rated 7.4 volt yet a 2S full charged lipo puts out 8.4 volts. How do these servos handle this increase in voltage?

Secondly is there any noticeable difference is servo speed as the RX pach get discharged to eg 3.6v per cell for example.

I am thinking about an HV kit but regulated power just seems more consistent or am I just overthinking it?

Any advise a comments will be appreciated.

Thanks in advance!

Kind regard
Jason

[Geardaddy]

Yup! You are overthinking it! The HV servos are designed to fly on a 2S lipo.. So they will be fine at 8.4V at the beginning of your flight..

Regulated power will probably be more consistent, although to us mortals I don't think you will ever notice a difference in servo speed, or how the heli flies from the beginning of the flight to the end.. And if you know what a lipo discharge curve looks like, it peaks at 4.2, then drops quickly to nominal voltage where it is stable for the most part until it really runs out of power.. The regulator is just another point of failure..

JMHO..

GD

[msallua]

Originally Posted by Geardaddy

Yup! You are overthinking it! The HV servos are designed to fly on a 2S lipo.. So they will be fine at 8.4V at the beginning of your flight..

Regulated power will probably be more consistent, although to us mortals I don't think you will ever notice a difference in servo speed, or how the heli flies from the beginning of the flight to the end.. And if you know what a lipo discharge curve looks like, it peaks at 4.2, then drops quickly to nominal voltage where it is stable for the most part until it really runs out of power.. The regulator is just another point of failure..

JMHO..

GD

+1

[jraydoran]

Thank you GD and msallua!

Appreciate the response. I thought I might be over thinking this. GD your explanation makes perfect sense.I plan to use a 3000mah gens ace 2s pack. Does anyone know it it will fit upfront on the tray without affecting the canopy!

Thank you!

Kind Regards
Jason

[dee cee]

Anyone running a life pack or would that be more for the regular servos?

[HFMan]

LiFe is better for servos rated for 6V. It's not enough voltage for true HV servos.

I really question whether it's wise to have all the HV servos drawing off the power bus of the Align 3GX (heck, ANY FBL controller for that matter.) I have a Western Robotics BEC, and it can't keep up with the HV servos (I get brownouts when I cycle the collective up and down really fast.)

I've read that the Align 700 HV servos can draw upwards of 30 amps, which is generally more than any power bus is capable of in a FBL controller. I plan to run straight LiPo pack with no BEC, with dedicated power to at least two of my servos to reduce the current draw on the VBar power bus.

[RCTada]

I ran a LIFE pack on my 700e DFC HV servos unregulated straight to the Beastx and had no problems.

Sent from my DROID BIONIC using Tapatalk 2

[dee cee]

Yeah I would have thought life are fine it would just mean the servos are run at a lesser voltage... Maybe not such a bad thing and they certainly seem to have enough power/speed according to the spec sheets when run at even 6 volts. Good to know.