Hitec 5995TG/JR 8711 max operating voltage

[rcflyer]

Hi guys, what is the maximum operating voltage for the Hitec 5995TG and JR 8711 servos? Thanks!

[adrian]

i have tried both on 7.4v(8.4) and they get very hot!!!! i use them on 6.5 regulated - no problems

[DKjens]

I have run 5995 on unregulated 2-cell Li-Ions. I burned one up in a 3-servo aileron set-up. On another 2-servo aileron set-up it started acting weird. I put a regulator in and it took care of the problem.

I do know of somebody though, who have run them like that for several years without any problems. He pointed out to me, that when running ganged together servos, he said the deadband as high as 6-8. I did not do that, so maybe that's the secret behind running them on this high voltage.

I presently run them on 6.5V regulated.

My new SX is getting 8711 and 8611 servos, and they will run on unregulated A123 batteries (6.6V).

[rcflyer]

Hi DKjens, the A123 is 3.65V at full charge, so for 2s packs, the voltage will be about 7.3V. What will be the maximum safe operating voltage for the servos?

[MomoBrut]

	Quote: Originally Posted by rcflyer
	Hi DKjens, the A123 is 3.65V at full charge, so for 2s packs, the voltage will be about 7.3V. What will be the maximum safe operating voltage for the servos?

That is not true. I am using 2sA123 about one year in my 33% Velox Revolution II.



Fully charged 2sA123 (with FMA CellPro) has 7.05V after disconnecting from charger. When they are connected to receiver and servos, the voltage quickly drops to 6.8V. The voltage drops to 6.65V after first flight and this voltage remains the same during 2/3 - 3/4 of discharged capacity.

I am using two 2sA123 packs connected in parallel through Schotky diodes. Schotky diode drops voltage about 0.2 - 0.3 V.

The picture of my self designed battery sharing "system" ...





The result voltage is 6.4-6.5V for receiver and servos. Sweet ...

[rcflyer]

Momo, that's pretty neat and thanks for the great info. What will the "no fly" voltage be for the 2s A123 packs? Thx

[MomoBrut]

To say the truth I do not know ... I test the remaining capacity after 14 flights (my typical set in one afternoon, each flight aprox. 8 min.) by discharging to 3V per cell and I get about 800mAh (in each battery). So 2200-800 is about 1400 mAh per one 2sA123, so all together from both batteries ... 2800mAh in 14 flights.

JR RS10DS, 8x HS-5625MG and 1x HS-5955TG

The absolute value of voltage makes no sense, because it do not change significantly. It is necessary to test remaining capacity in "defined" number of flights and set the "rule" for number of safety flights for current installation.

[martin18152]

Just bought a the Hitec 5995TG these are the specs:

Operating Voltage Range: 4.8-7.4 Volts
Operating Temperature Range: -20 to +60 Degree C (-68F to +140F)
Operating Speed (6.0V): 0.15 sec/60° at no load
Operating Speed (7.4V): 0.12sec/60° at no load
Stall Torque (6.0V): 333.29 oz-in. (24kg.cm)
Stall Torque (7.4V): 416.61 oz-in. (30kg.cm)
Standing Torque (6.0V): 433.27 oz-in. (31.2kg.cm) 5 degree deflection
Standing Torque (7.4V): 541.59 oz-in. (39kg.cm

I was thinking of bumping up my regulator voltage to 7 volts to get closer the 416 stall torque. I'm using the single servo in a 35% plane. Any opinions on how the other Hitec servos and futaba reciever with stand up to 7 volts. I rember using 5 cell Nicad packs with old futaba system back in the day, and they would provide 7 volts for awhile, never had a problem.

[Mike Mayberry]

Hey guys,

Please note that the 5995TG robot servo is only rating at 7.4v because it is intended for use in robots. In fact, you should be using the 5955TG servo not the 5995 for R/C usage as the robot servo has a smaller pulse width and does not come with the motor heatsink.

While the 5955TG can handle 7.4v, it is not recommended for R/C usage as it will reduce the life of the servo by approximately 30%.

Mike Mayberry
Hitec RCD USA.

[rcflyer]

Thanks for the clarifications Mike

[thewrap]

I think the max voltage that alot of servos are rated for is like 6 volts. I run mine at 5.5 for safety but around that you should be fine.

[drbyrnes]

I am new to this site, and new to giant RC planes. This winter I hope to start with building a Lanier Yak 54 (87",16-17 lbs.,50-80 cc. gas), and then hopefully a Hangar 9, 35% Extra 260 (105",27-30 lbs., 100-116 cc. gas). However I am having difficulty deciding on servos for these projects. There are so many out there, prices vary, brands vary, analogue vs. digital,etc. Can anyone give me some guidance on servos for big planes? The Yak requires a minimum 100 oz/in torque servo, and the Extra requires at least 180 oz./in. I know digitals with metal gears, high torque, and high speed are best. Which servos fit these specs, but give the best bang for the buck? Can I get away with analogues? (I'm not into competition.) I'd also like to narrow it down to either JR, Futaba, or Hi Tec brands. Some of the ones I've looked at are the Hi Tec 5955, and the JR 8611 or 8711. Thanks for your input.

Dick Byrnes
Sellersville, PA
drbyrnes@comcast.net

[main_gears_bent]

5955's, they are all you will ever need.

[jonkoppisch]

	Quote: Originally Posted by martin18152
	Just bought a the Hitec 5995TG these are the specs: Operating Voltage Range: 4.8-7.4 Volts Operating Temperature Range: -20 to +60 Degree C (-68F to +140F) Operating Speed (6.0V): 0.15 sec/60° at no load Operating Speed (7.4V): 0.12sec/60° at no load Stall Torque (6.0V): 333.29 oz-in. (24kg.cm) Stall Torque (7.4V): 416.61 oz-in. (30kg.cm) Standing Torque (6.0V): 433.27 oz-in. (31.2kg.cm) 5 degree deflection Standing Torque (7.4V): 541.59 oz-in. (39kg.cm I was thinking of bumping up my regulator voltage to 7 volts to get closer the 416 stall torque. I'm using the single servo in a 35% plane. Any opinions on how the other Hitec servos and futaba reciever with stand up to 7 volts. I rember using 5 cell Nicad packs with old futaba system back in the day, and they would provide 7 volts for awhile, never had a problem.

Don't hold your breath on getting that kind of torque or even half of that... They're a good servo but don't come anywhere close to the torque ratings.. No use burning up a servo over imaginary torque :22a:

[Extra260]

	Quote: Originally Posted by jonkoppisch
	Don't hold your breath on getting that kind of torque or even half of that... They're a good servo but don't come anywhere close to the torque ratings.. No use burning up a servo over imaginary torque :22a:

I think you kind of got brain washed in that new hitec servo thread on how some people believe the hitec only gets 150 oz of torque. The truth is I have one on the rudder of my 33% yak and I can do knife edge sqaure loops with it at the beggining and the very end of the flight with rigerous use of the rudder throughout. It is not a weak servo and I dont care how much torque people say it has it can power my plane around and the gears are tighter than when I bought it.lol