HobbyKing.com New Products Flash Sale
Reply
Thread Tools
Old Feb 03, 2013, 07:25 PM
Dixie Sky Devils AMA# 1015548
tupeloflyer's Avatar
United States, MS, Tupelo
Joined Oct 2012
1,125 Posts
Discussion
capacitor on the ORx?

Been seeing these little capacitors on ebay and they say it will keep voltage stable in the event you have alot of amp draw preventing a brownout. does it really work? 3 to 5 bucks is cheaper than a new airframe.
tupeloflyer is offline Find More Posts by tupeloflyer
RCG Plus Member
Latest blog entry: Sig New ARF 4 Star 64
Reply With Quote
Sign up now
to remove ads between posts
Old Feb 03, 2013, 07:59 PM
Registered User
E-Challenged's Avatar
United States, CA, Garden Grove
Joined Oct 2000
11,752 Posts
Spektrum advertises these for 4-cell race cars, not recommended for aircraft use. I use $20 add-on switch-mode Park BEC's for my speed controls that have linear BEC's to prevent brownouts when using 3S lipos and four or more servos.

http://www.spektrumrc.com/Products/D...ProdID=SPM1600
E-Challenged is offline Find More Posts by E-Challenged
Last edited by E-Challenged; Feb 03, 2013 at 08:07 PM.
Reply With Quote
Old Feb 03, 2013, 09:07 PM
Registered User
Joensuu, Finland
Joined Mar 2002
1,435 Posts
Those little capacitors are useful only to smooth out any high-frequency ripple in the input voltage. They might be able to buffer a current surge that lasts less than a millisecond or thereabouts. If you want a capacitor that is useful as a power source buffer, it would need to be the size of a soda can.
jkettu is offline Find More Posts by jkettu
Reply With Quote
Old Feb 03, 2013, 09:56 PM
Registered User
Evan D's Avatar
Charlotte, NC
Joined Jan 2004
5,557 Posts
Waste of money.
Evan D is online now Find More Posts by Evan D
Reply With Quote
Old Feb 03, 2013, 10:20 PM
Wake up, feel pulse, be happy!
C₄H₁₀'s Avatar
United States, AK, Fairbanks
Joined Aug 2009
12,379 Posts
Spend the money on a BEC unit that can provide plenty of overhead power to run your servos. Instead of using a band-aid, just fix the problem at the source... Of course, the "problem" isn't really a problem for the vast majority of planes, so you don't need to worry about it anyway.
C₄H₁₀ is offline Find More Posts by C₄H₁₀
Reply With Quote
Old Feb 04, 2013, 12:50 AM
Registered User
United States, OR, Canby
Joined Aug 2011
2,137 Posts
Quote:
Originally Posted by jkettu View Post
If you want a capacitor that is useful as a power source buffer, it would need to be the size of a soda can.
Not true, this will run the RX and 4-5 HS 645mg servos, on the ground, for about 5 sec. after the power is turned off. At least it took that long before the RX would power down while moving all the servos before I could turn of my TX. And it is a lot smaller than a soda can.

http://www.fromeco.org/categories/Su...Equipment/DCUP
600Bob is online now Find More Posts by 600Bob
Reply With Quote
Old Feb 04, 2013, 09:48 AM
Registered User
Wintr's Avatar
USA, MO, Florissant
Joined Nov 2010
1,631 Posts
While it doesn't appear as large as a soda can, it does look as big as a 2 or 3 cell LiPo (and probably weighs as much). A good BEC is usually no larger than a receiver.
Wintr is offline Find More Posts by Wintr
Reply With Quote
Old Feb 04, 2013, 11:07 AM
Registered User
Florida
Joined Aug 2004
4,062 Posts
In all but the briefest (a few microseconds) of voltage depression, such capacitors are a total waste of your money, time and space. Do a simple energy calculation of what size a capacitor you would have to have to provide any reasonable time of protection. You will find it is much to large to be of any practical use.
Rodney is offline Find More Posts by Rodney
Reply With Quote
Old Feb 04, 2013, 11:15 AM
Registered User
E-Challenged's Avatar
United States, CA, Garden Grove
Joined Oct 2000
11,752 Posts
Go to Dimension Engineering's Website and read the FAQ's and installation guides. I use their $20 Park BEC's, switch-mode 1.5 amps, for all my small to medium 3S lipo-powered, 4 or more servo models. These BEC's as small and weigh almost nothing, easy to install, no need to disconnect red wire from ESC due to "bypass" feature.
E-Challenged is offline Find More Posts by E-Challenged
Reply With Quote
Old Feb 04, 2013, 07:52 PM
Registered User
United States, OR, Canby
Joined Aug 2011
2,137 Posts
Quote:
Originally Posted by Wintr View Post
While it doesn't appear as large as a soda can, it does look as big as a 2 or 3 cell LiPo (and probably weighs as much). A good BEC is usually no larger than a receiver.
It is about 2.5"x1"x1/2". Not something I would use on a small foamy but my 1/4 scale Tiger Moth doesn't know it's there, size is relative.
600Bob is online now Find More Posts by 600Bob
Reply With Quote
Old Feb 04, 2013, 10:40 PM
Co-heir with Christ
Dcope17's Avatar
United States, CA, San Juan Capistrano
Joined Feb 2013
130 Posts
Why not install a 5 cell AAA NiMh pack? On its own switch and usually 1000mAh. Will last longer than any capacitor will...
Running it parallel to the BEC, they might fight each other a bit unless you install a diode so that one won't try to charge the other...
Dcope17 is online now Find More Posts by Dcope17
Reply With Quote
Reply


Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Help! Burned out tantalum capacitor - RMRC 480 - help? Mochaboy FPV Talk 4 Aug 30, 2013 12:49 AM
Discussion Lightweight covering for rubber or capacitor power dayhead Free Flight 18 Jan 19, 2013 07:27 PM
Discussion Capacitors for Spektrum aircraft Rx Daytonarc Radios 10 Jan 19, 2013 12:41 PM
Discussion 9XR + ORx Module + E-flite BNF = No Prob harrye Radios 3 Jan 02, 2013 05:59 PM