vasek

My Feedback: (4)

Hi,

I need a stepdown from 7.2v for a 6v servo (all other servos & Rx are HV)

Can I use the same stepdown as for 6v to 4.8v ? If not where can I get one?

Thanks V.

pilotpete2

For one servo you could put one or two diodes in the positive lead of the one non HV servo.
Just curious, but what type of servo is it?
Pete

BuschBarber

My Feedback: (2)

There are $5 voltage regulators that can be used, InLine, with an individual servo. I have seen them mentioned in other threads with web links posted.

I have some JR 791 Retract servos that cannot handle 6v. In my case, the aircraft is an H9 P47-150. I just use a 5v regulator between the Switch Harness and the Rx since I do not need the extra Speed and Torque for the servos on the other channels.

What type of Rx battery are you using? Is it a 2cell LiPo, 2cell LiFe, or a 5cell NiMh? 2cell LiPos charge to 8.6v. 2cell LiFe's charge to 7.2v but drop very quickly to 6.6v. I use 2cell LiFe or A123 Rx packs and I have never had any trouble with servos rated for 6v. HV servos should handle 8.6v but I realize that you have at least one non HV servo.

ByLoudDesign

Get a Smart Fly regulator!! http://www.smart-fly.com/Products/Re.../regulator.htm

vasek

My Feedback: (4)

It's a 2S lipo, so i guess it's 8.6v and the servo is HS-755MG for rudder

I do have a stepdown that is made for 7.2v (5cell) to 4 cell (5.6 ?) can I use that one on 2 lipo?

BuschBarber

My Feedback: (2)

I use voltage regulators with LiPo Rx batteries, but they were just labeled 5v or 6v, or adjustable. I don't recall whether they were rated for a maximum voltage. I have used the same 6v regulator with 2cell (8.4v) or 3cell (12.6v) lipo packs. The Nominal Voltage of a LiPo cell is 3.7v and the fully charged voltage is 4.2v.

vasek

My Feedback: (4)

Ok I think I've solved my problem, IF a 7.4 V rated servo can take 2 LiPo fully charged (?)

It's a HS-5765MH I had it for another project.

BuschBarber

My Feedback: (2)

Many times, manufacturers refer to the Nominal voltage, of a battery pack, rather than the fully charged voltage, when showing specs for a servo. We all know that a fully charged 4cell NiMh pack is well above 4.8v and a fully charged 5cell NiMh pack is well above 6v. I would bet that any servo rated for 7.4v is designed for a 2cell LiPo pack.

pilotpete2

+1,
Hitec HV servos list speed and torque ratings for 6V and 7.4V. The write up is very specific that the 7.4V rating is for 2S Lipo.[8D]
My current project needs a set of decent ball bearing standard servos. I decided to try the new Hitec HS-430BH HV servos, even though I use 2S A123's for my gas/glow receiver power.
A dual BB HV servo for 14.49, I'll give them a try[8D]
Pete

vasek

My Feedback: (4)

So I'm set then! Thanks guys. The 2S LiPo HV servos are still new(s) to me
V.