RCCrawler Forums

Bray D · 03-02-2010, 03:34 PM

I've got a cc bec, and am powering the servo directly with it. I've got it programmed now at 6v. Just curious what the max voltage limit of the servo is. I don't really need the extra power, but it'd be neat to see what it's got.

Rockcrawler · 03-02-2010, 03:47 PM

http://www.hitecrcd.com/servos/show?name=HS-7955TG

Rated at 6V but some run them higher. I dont see the need for it though.

Zimm98 · 03-02-2010, 05:48 PM

I run these on my airplanes on a unregulated 2s lipo, and on my crawler I have it set to 7.5v. You get more speed and power at the higher voltages.

Bray D · 03-02-2010, 06:00 PM

holy cow. That's pretty serious. I may bump it up just to see what the performance is, but I doubt I leave it there. I've already seen a decrease in run time by adding the bec and running it at 6v.

Cycleeric · 03-02-2010, 06:03 PM

I've found that anything over 6v to a 7955tg causes alot of heat to build in the servo which will shorten servo life. If you need more power I guess you could step up the power and when the servo dies buy yourself a 7950 and go with big voltage and power to boot

AlmstEvil665 · 03-02-2010, 06:05 PM

Don't run a 7955 at more then 6v!!!! I ran mine at 7 and fried it in about 5 minutes. I had the BEC wired directly to the servo just like you. I think you can get away with a little more than 6v if you run it to your reciever but down time in sending the servo back is not worth the risk. If you want more power buy a 7950 that is made to handle 7.4.

P.S. At the Motorama comp one of the guys in our club bumped his up to 6.5v and burnt it up going through the start gate. I reset it to 6 and he swapped servos and was good to go.

Also get yourself a servo prgrammer. You can set the fail safe on it that will keep you from overloading the servo.

AlmstEvil665 · 03-02-2010, 06:10 PM

Quote:

Originally Posted by Zimm98

I run these on my airplanes on a unregulated 2s lipo, and on my crawler I have it set to 7.5v. You get more speed and power at the higher voltages.

If you are running these through your receiver than it's internal BEC will keep the servo in the safe range.

Just curious how you have the servo wired on your crawler to not burn it up at 7.5v? The 7955 is only rated for 6v. Maybe you have the 7950? I have seen more than one of the 7955's burn up when set over 6v when wired directly to the BEC. I have seen guys get away with 7.2v when they wire the BEC to Castles specs but I never wanted to risk it especially while running a 225 mini off of the receiver as well.

Bray D · 03-02-2010, 06:21 PM

OK maybe I won't bump it up lol. Like I said, I was just curious. Thanks for the words of wisdom guys.

Zimm98 · 03-02-2010, 07:03 PM

I am running the bec through the reciver, running them on unregulated 2 cell is commom pratice in the air world and they have a lot more to loose if a servo goes bad. I have run my servo this way for 2 months with no problems it gets warm but not hott. I guess I am willing to take the risk but when I have 2 put 5he 7955 back into my airplane I will replace it with a 7950.

corkysk8 · 03-02-2010, 08:04 PM

[QUOTE=AlmstEvil665;2333710]If you are running these through your receiver than it's internal BEC will keep the servo in the safe range.

I did not know a receiver had an internal BEC. If so, what does it do? I ask because I have my 7955 on 7v through the reciever and have ran it like this for two 45 minute runs without problems.

Bray D · 03-02-2010, 09:29 PM

I wouldn't call it an internal BEC, but more of an internal voltage regulator. I've heard you can bypass it if you power the receiver from a terminal OTHER than the "batt" terminal. ie - another channel that you're not using.

corkysk8 · 03-02-2010, 11:26 PM

Quote:

Originally Posted by Bray D

I wouldn't call it an internal BEC, but more of an internal voltage regulator. I've heard you can bypass it if you power the receiver from a terminal OTHER than the "batt" terminal. ie - another channel that you're not using.

I have a Spektrum SR 3100. It list the voltage input range as 3.5v - 9.6v. In the specs for the receiver it does not mention a regulator or anything like it.

If any body knows the answer for how running more than the recommended voltage to a Hitec 7955 through the receiver is better for the servo than running it straight from a BEC please help?

run2jeepn · 03-02-2010, 11:58 PM

The amount of Power you get buy just .5 to 1v isn't worth it. You only talking 30oz difference. If I remember right. So 330oz to 360oz. Your not going to notice it much if it last long enough.

Sharkey · 03-03-2010, 12:08 AM

i run my 6 volt servos at 6.6 volts, no issues. gotta remember, in a nitro car you have a 5 cell receiver pack, nominal 6 volts but fully charged its as high as 7 volts. receivers and servos dont burn up in nitro cars with that sort of voltage. also remember that a 7.4 volt servo is designed for 2s lipo direct power, meaning itll handle 8.4 volts.

liverkiller1 · 03-03-2010, 02:05 AM

im running the hitec 7954sh at 7v with my ccbec and have had no problems i think it handles up to 403oz torque at 7.4v

Zimm98 · 03-03-2010, 08:23 AM

Running voltage of servos is covered in detail here. Is the Hitec rep states the 7955tg is not oficially rated for unregulated for lipo it will handle it with out reduction of servo life. I think at 7+ volts EPA are important and also not forcing the servo to move in a bad bind.

http://www.rctech.net/forum/ask-hite...regulator.html

corkysk8 · 03-03-2010, 09:26 AM

Quote:

Originally Posted by Zimm98

Running voltage of servos is covered in detail here. Is the Hitec rep states the 7955tg is not oficially rated for unregulated for lipo it will handle it with out reduction of servo life. I think at 7+ volts EPA are important and also not forcing the servo to move in a bad bind.

http://www.rctech.net/forum/ask-hite...regulator.html

Thanks for the link.

SACCO · 03-03-2010, 09:36 AM

I've got a dead 7955 that was run at 6.5 volts. If you want one too, turn up that bec

prophetz · 03-03-2010, 09:47 AM

What he said!!

Quote:

Originally Posted by SACCO

I've got a dead 7955 that was run at 6.5 volts. If you want one too, turn up that bec

corkysk8 · 03-03-2010, 11:28 AM

Quote:

Originally Posted by SACCO

I've got a dead 7955 that was run at 6.5 volts. If you want one too, turn up that bec

How long did it last at that voltage?

03-02-2010, 03:34 PM	#1
Bray D Quarry Creeper Join Date: Dec 2009 Location: Central IL Posts: 282	hi tec 7955 max voltage I've got a cc bec, and am powering the servo directly with it. I've got it programmed now at 6v. Just curious what the max voltage limit of the servo is. I don't really need the extra power, but it'd be neat to see what it's got.

03-02-2010, 03:47 PM	#2
Rockcrawler I wanna be Dave Join Date: Jan 2005 Location: Hueytown, Alabama Posts: 6,777	http://www.hitecrcd.com/servos/show?name=HS-7955TG Rated at 6V but some run them higher. I dont see the need for it though.

03-02-2010, 05:48 PM	#3
Zimm98 Pebble Pounder Join Date: Oct 2009 Location: Rapid City Posts: 147	I run these on my airplanes on a unregulated 2s lipo, and on my crawler I have it set to 7.5v. You get more speed and power at the higher voltages.

03-02-2010, 06:00 PM	#4
Bray D Quarry Creeper Join Date: Dec 2009 Location: Central IL Posts: 282	holy cow. That's pretty serious. I may bump it up just to see what the performance is, but I doubt I leave it there. I've already seen a decrease in run time by adding the bec and running it at 6v.

03-02-2010, 06:03 PM	#5
Cycleeric Quarry Creeper Join Date: Oct 2008 Location: A little town called Dallas Posts: 434	I've found that anything over 6v to a 7955tg causes alot of heat to build in the servo which will shorten servo life. If you need more power I guess you could step up the power and when the servo dies buy yourself a 7950 and go with big voltage and power to boot

03-02-2010, 06:05 PM	#6
AlmstEvil665 Quarry Creeper Join Date: Jan 2009 Location: Hagerstown Posts: 369	Don't run a 7955 at more then 6v!!!! I ran mine at 7 and fried it in about 5 minutes. I had the BEC wired directly to the servo just like you. I think you can get away with a little more than 6v if you run it to your reciever but down time in sending the servo back is not worth the risk. If you want more power buy a 7950 that is made to handle 7.4. P.S. At the Motorama comp one of the guys in our club bumped his up to 6.5v and burnt it up going through the start gate. I reset it to 6 and he swapped servos and was good to go. Also get yourself a servo prgrammer. You can set the fail safe on it that will keep you from overloading the servo.

03-02-2010, 06:21 PM	#8
Bray D Quarry Creeper Join Date: Dec 2009 Location: Central IL Posts: 282	OK maybe I won't bump it up lol. Like I said, I was just curious. Thanks for the words of wisdom guys.

03-02-2010, 07:03 PM	#9
Zimm98 Pebble Pounder Join Date: Oct 2009 Location: Rapid City Posts: 147	I am running the bec through the reciver, running them on unregulated 2 cell is commom pratice in the air world and they have a lot more to loose if a servo goes bad. I have run my servo this way for 2 months with no problems it gets warm but not hott. I guess I am willing to take the risk but when I have 2 put 5he 7955 back into my airplane I will replace it with a 7950.

03-02-2010, 08:04 PM	#10
corkysk8 Rock Crawler Join Date: Apr 2005 Location: Monroe, Louisiana Posts: 550	[QUOTE=AlmstEvil665;2333710]If you are running these through your receiver than it's internal BEC will keep the servo in the safe range. I did not know a receiver had an internal BEC. If so, what does it do? I ask because I have my 7955 on 7v through the reciever and have ran it like this for two 45 minute runs without problems.

03-02-2010, 09:29 PM	#11
Bray D Quarry Creeper Join Date: Dec 2009 Location: Central IL Posts: 282	I wouldn't call it an internal BEC, but more of an internal voltage regulator. I've heard you can bypass it if you power the receiver from a terminal OTHER than the "batt" terminal. ie - another channel that you're not using.

03-02-2010, 11:58 PM	#13
run2jeepn I wanna be Dave Join Date: Sep 2005 Location: USA Posts: 11,196	The amount of Power you get buy just .5 to 1v isn't worth it. You only talking 30oz difference. If I remember right. So 330oz to 360oz. Your not going to notice it much if it last long enough.

Sponsored Links

03-03-2010, 12:08 AM	#14
Sharkey Rock Crawler Join Date: Sep 2009 Location: Abbotsford BC Posts: 563	i run my 6 volt servos at 6.6 volts, no issues. gotta remember, in a nitro car you have a 5 cell receiver pack, nominal 6 volts but fully charged its as high as 7 volts. receivers and servos dont burn up in nitro cars with that sort of voltage. also remember that a 7.4 volt servo is designed for 2s lipo direct power, meaning itll handle 8.4 volts.

03-03-2010, 02:05 AM	#15
liverkiller1 Rock Crawler Join Date: Dec 2009 Location: Lynnwood Posts: 569	im running the hitec 7954sh at 7v with my ccbec and have had no problems i think it handles up to 403oz torque at 7.4v

03-03-2010, 08:23 AM	#16
Zimm98 Pebble Pounder Join Date: Oct 2009 Location: Rapid City Posts: 147	Running voltage of servos is covered in detail here. Is the Hitec rep states the 7955tg is not oficially rated for unregulated for lipo it will handle it with out reduction of servo life. I think at 7+ volts EPA are important and also not forcing the servo to move in a bad bind. http://www.rctech.net/forum/ask-hite...regulator.html

03-03-2010, 09:36 AM	#18
SACCO I wanna be Dave Join Date: Jul 2006 Location: Moscow Mills MO Posts: 2,204	I've got a dead 7955 that was run at 6.5 volts. If you want one too, turn up that bec

RCCrawler Forums

Thread: hi tec 7955 max voltage