grosbeak

The Question:
Straight up: Is it or is it not okay to power servos rated for 6 volts with an unregulated 6.6V LiFEPO4? Here are the servos I'm using:

Channel 1
Port aileron
Hitec HS-5625MG
Rated for 4.8V and 6.0V

Channel 2
Port elevator
Hitec HS-5945MG
Rated for 4.8V and 6.0V

Starboard elevator
Hitec HS-5945MG
Rated for 4.8V and 6.0V

Channel 3
Throttle
Hitec HS-625MG
Rated for 4.8V and 6.0V

Channel 4
Rudder
Hitec HS-5945MG
Rated for 4.8V and 6.0V

Channel 6
Starboard aileron
Hitec HS-5625MG
Ratings for 4.8V and 6.0V


This is related to an ongoing issue I'm having with fried throttle servos (Throttle servos frying - cause unknown) but I want to ask this question in a separate thread.

LonnieMcc

Hello Grosbeak,

While I don't know much about the Hitec servos, I can tell you that YES it is safe to use a LifePO4 6.6 battery for servos rated to 6v.

Reason is, when a NiXX 5 cell pack is fully charged, it's voltage is close to 7.2v. When a Life pack is charged, it is 7.2v but quickly drops down to 6.6 and will stay there for awhile.

I have just recently switched over to Life pack's and I have alot of older style Futaba servo's. I also have one or two Hitech's in my cub and I have not had any issues with any of mine.

Hopefully somebody else that has more experience with those Hitec's will chime in about those.

radfordc

My Feedback: (14)

I run 2 cell LiFe packs in all my planes. But, I install a diode in the switch harness...the diode drops the voltage going to the RX down below 6v. I'm using 3 amp diodes (1N5402) from Radio Shack.

scale only 4 me

My Feedback: (158)

I've flown 5 different planes with A123 LIFE 6.6 volt packs in the last 3 years, like many others, I've never had a servo issue using many of the same servos you've listed.

Most Throttle servo issue come down to a mechanical binding problem,, I'd double check your linkages

good luck

grosbeak

Hi radfordc,

For someone with very little electronics knowledge, could you please explain exactly which wire that would be soldered into?

Thanks!

radfordc

My Feedback: (14)

The diode is installed in the positive lead (usually the red wire) of the switch harness. The diode has a band at one end and this band is installed away from the battery + terminal. Also, it doesn't matter which side of the switch the diode goes as long as the polarity is correct.

daveopam

My Feedback: (9)

Check your end points on the throttle servo. Is the servo putting pressure on the arm when the throttle is wide open?

david