R/C Tech Forums

Go Back   R/C Tech Forums > General Forums > Electric On-Road

Reply
 
Thread Tools Search this Thread
Old 01-20-2015, 08:28 AM   #16
Tech Elite
 
mkiiina's Avatar
 
Join Date: Jul 2007
Location: Frisco TX
Posts: 2,316
Trader Rating: 69 (100%+)
Default

Quote:
Originally Posted by hairless_ape View Post
A HV servo doesn't perform any better at 8.4v than it does at 7.4v. The stated 7.4v numbers are it's peak.

Your argument is invalid.
Care to explain that? Are you trying to say that running a servo at anything over 7.4v doesn't result in different performance (higher torque/faster transit)?

Find that very hard to believe. (does that make your arguement invalid as well?)

I do thing that HV in a TC is overkill but to each their own.
mkiiina is offline   Reply With Quote
Old 01-20-2015, 08:45 AM   #17
Tech Master
 
Geezatec's Avatar
 
Join Date: Oct 2007
Posts: 1,455
Default

I don't think its the ESC determines the voltage, more on the RX that distributes the voltage. And don't think its the voltage, 6v/7.4 are onlt the min/max voltage servo can draw. Better to look at amperage the servo takes. RX is more of your voltage regulator. My opinion.
Geezatec is offline   Reply With Quote
Old 01-20-2015, 08:48 AM   #18
Tech Elite
 
mkiiina's Avatar
 
Join Date: Jul 2007
Location: Frisco TX
Posts: 2,316
Trader Rating: 69 (100%+)
Default

Quote:
Originally Posted by Geezatec View Post
I don't think its the ESC determines the voltage, more on the RX that distributes the voltage. And don't think its the voltage, 6v/7.4 are onlt the min/max voltage servo can draw. Better to look at amperage the servo takes. RX is more of your voltage regulator. My opinion.
That is not correct unfortunately. The ESC is what determines the voltage that is passed on to the rest of the systems (when running off the built in BEC). The RX just acts as a command and control module to pass along the input and voltage but doesn't hamper it in any way.
mkiiina is offline   Reply With Quote
Old 01-20-2015, 11:06 AM   #19
Tech Master
 
Geezatec's Avatar
 
Join Date: Oct 2007
Posts: 1,455
Default

Quote:
Originally Posted by mkiiina View Post
That is not correct unfortunately. The ESC is what determines the voltage that is passed on to the rest of the systems (when running off the built in BEC). The RX just acts as a command and control module to pass along the input and voltage but doesn't hamper it in any way.
Thank for clarification. ESC(electronic speed control) does what suppose to do, motor speed control. I still think the RX controls the servos. Then do away with the RX. Run with ESC only, don't think so!! They don't make a ESC/rx yet, do they!!!???
Geezatec is offline   Reply With Quote
Old 01-20-2015, 12:16 PM   #20
Tech Elite
 
mkiiina's Avatar
 
Join Date: Jul 2007
Location: Frisco TX
Posts: 2,316
Trader Rating: 69 (100%+)
Default

Quote:
Originally Posted by Geezatec View Post
Thank for clarification. ESC(electronic speed control) does what suppose to do, motor speed control. I still think the RX controls the servos. Then do away with the RX. Run with ESC only, don't think so!! They don't make a ESC/rx yet, do they!!!???
Common in smaller scales (look at the mini-z as a good example) and not as fun as you'd expect. Like futaba radios? Tough, this esc/rx combo only works with spektrum. Like savox servos? Ooops, can't use those as they need to have 4 wires to work with that esc that only works with Airtonics.

The current modular design is actually pretty good. The esc doesn't care what voltage it's fed (up to a point, some are only good up to a certain voltage and some will brown out below a certain point) or really where it's coming from.
mkiiina is offline   Reply With Quote
Old 01-20-2015, 12:56 PM   #21
Tech Elite
 
Odin544's Avatar
 
Join Date: Apr 2011
Location: Kennewick, Washington
Posts: 3,166
Trader Rating: 93 (100%+)
Default

Quote:
Originally Posted by Geezatec View Post
Thank for clarification. ESC(electronic speed control) does what suppose to do, motor speed control. I still think the RX controls the servos. Then do away with the RX. Run with ESC only, don't think so!! They don't make a ESC/rx yet, do they!!!???
The RX controls the signal to the servo (white wire). I do not believe it limits or controls in any way the voltage (red wire) to the servo however. It is a constant, limited by the BEC. This is why when you add an aftermarket BEC they have you disconnect the red wire from esc to rx.
__________________
Xray - ORCA - Avid RC - MaxFX Paint
TriCitiesRC.com
Odin544 is offline   Reply With Quote
Old 01-20-2015, 01:01 PM   #22
Tech Master
 
patorz31's Avatar
 
Join Date: Nov 2007
Location: Edmonton Ab
Posts: 1,236
Default

Quote:
Originally Posted by Geezatec View Post
Thank for clarification. ESC(electronic speed control) does what suppose to do, motor speed control. I still think the RX controls the servos. Then do away with the RX. Run with ESC only, don't think so!! They don't make a ESC/rx yet, do they!!!???
Umm the ESC puts out the voltage the BEC is set to give the RX. It passes threw the reciever and goes to the Servos. The RX doesn't control the voltage to the servos it just passes on what it gets. My 1/12th scale only passes on 3.7v to the servo cause that is all the battery will deliver (SANWA Super Vortex Zero with 3.7v Sanwa Servo) . My older 1/12th scale the ESC bumped up the voltage to 5.5 volts and that is what went the servo. There is no regulator in the RX.
__________________
Northern Alberta Scale Car Auto Racers Pres. and Promotions
TEAM POWERS, RACE-OPT, SCHUMACHER RACING,VBC RACING
patorz31 is offline   Reply With Quote
Old 01-20-2015, 01:30 PM   #23
Tech Elite
 
Join Date: Jul 2010
Posts: 2,030
Trader Rating: 8 (100%+)
Default

Quote:
Originally Posted by hairless_ape View Post
A HV servo doesn't perform any better at 8.4v than it does at 7.4v. The stated 7.4v numbers are it's peak.

Your argument is invalid.
physics says its not invalid.

Some servos can't handle more than 7.4V but those than can will perform better at higher voltages. Its a relatively simple relationship.

Feed a motor higher voltage it will either go faster or die. Simple as that. You can approximate it for the same motor (ideally) as apply double the voltage you'll double the no-load speed, double the torque, and quadruple the power.

Go do some testing of your own with a stop watch and a battery if you don't believe me. Report back the findings.

Quote:
Originally Posted by Geezatec View Post
I don't think its the ESC determines the voltage, more on the RX that distributes the voltage. And don't think its the voltage, 6v/7.4 are onlt the min/max voltage servo can draw. Better to look at amperage the servo takes. RX is more of your voltage regulator. My opinion.
If the ESC has a BEC then yes, it determine the voltage. The rx just passes it through along with the servo signal. It's not a voltage regulator.

On my 1/5th scale set up, I feed the receiver off the battery pack (to power it up) but pass out signal only. My servos are fed direct from the battery receiving the full 8.4V.

Not all receivers can handle the higher voltage though.

Last edited by cplus; 01-20-2015 at 02:13 PM.
cplus is offline   Reply With Quote
Old 01-20-2015, 01:58 PM   #24
Tech Addict
 
Airwave's Avatar
 
Join Date: Jul 2007
Posts: 633
Trader Rating: 1 (100%+)
Default

SkyRc/Toro/Gforce TS120 is able to provide a 7.4V BEC... You also need the connection to a computer to activate it...

Check your RX before doing that...
Airwave is offline   Reply With Quote
Reply



Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are Off



All times are GMT -7. It is currently 06:55 AM.


Powered By: vBulletin v3.9.2.1
Privacy Policy | Terms of Use | Advertise Content © 2001-2011 RCTech.net

SEO by vBSEO 3.5.0