R/C Tech Forums

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

Reply
 
Thread Tools Search this Thread
Old 12-29-2011, 06:19 PM   #16351
Tech Adept
 
hunts3lehigh's Avatar
 
Join Date: Mar 2011
Location: South west Florida
Posts: 223
Trader Rating: 18 (100%+)
Default Caps

I've seen a lot of info about caps. I've worked with electronics for 23 years, on all sorts of things. Everyone has said things that are correct, but the main idea of caps is to smooth the spikes out. Not the large dips in voltage, as there is simply not enough storage space in the sizes we can use to proved any amperage. A 47 Micro farad cap will supply power to an L.E.D. for about 1 second thru a 500 ohm resistor drawing less than .1 amp. Our motors pull large amounts of amps, so any voltage stored in the cap is quickly gone with no benefit to the motor, but to the ESC. The cap will keep the esc collectors on the transistors flowing more amps since the input voltage will be just a few thousands higher and so the forward bias will keep the amps flowing just a tiny, tiny bit more. Caps cannot store more voltage than the battery, without a diode in series to block reverse flow, and that will take an even larger voltage drop and pull away from the battery voltage. In fact all devices connected to the batter will have a voltage drop, and take a little from the total peak voltage. Any cap will be installed on the ESC input leads and so will be in parellel with the battery, and so if the battery or the CAP are higher in voltage, a potential difference is created and the electrons flow to the other device and balance out. IE, if the cap was 8.4 volts and the battery was 8.2 there will be a difference of potential of .2 volts between positive charged devices, but still that electrically would allow electons to flow to the other device and even out until there was no potential difference. That is exactly why we balance charge our lipos, so that there is not current flowing internally from one cell to the other.......

Also, connecting any cap directly to the motor will Decrease performance. only the smallest fastest discharge type should be used to limit spikes created from the brush moving off the comm. Any large cap will take voltage from the battery to charge, and lower the overall voltage to the motor all the time, and since the cap is directly on the motor, it will discharge as fast as the voltage is reduced from the esc since it is a direct short across the motor windings. No performance gain with a larger cap on the motor at all. Only the ESC will perform smoother and supply a bit higher voltage under load to the motor. But then again, anything connected to the ESC/battery will have a load and pull voltage away, so bigger or more is not always better in this case.

By the way, gates are normally switched on and off via +5 or 0 volts. TTL transistor logic using gates called xor, nor, andor, etc.... in a or gate, either input can be +5 and the out put will turn on or off. Others require both on or off to change the output state. A cap will change the voltage curve, to a better square wave rather than a sort of rounded square wave. That will reach the +5 just a bit quicker and the gates will change state just that much faster.

So, anyway, blah blah, blah........... Remember anything added to the system electrically will take from the total power output, you cannot get something for nothing in electronics. Caps only smooth the flow and allow for more precise voltage output, which can be a bit higher than if no caps were installed. ( in fact caps tend to leak when they go bad and will have a constant current flowing thru them and take more power away than they can store!!) something to think about................

Last edited by hunts3lehigh; 12-29-2011 at 06:30 PM.
hunts3lehigh is offline   Reply With Quote
Old 12-29-2011, 11:30 PM   #16352
Tech Elite
 
tony gray's Avatar
R/C Tech Elite Subscriber
 
Join Date: Jun 2002
Location: Melbourne, Australia. Home of rc-mini.net
Posts: 3,210
Trader Rating: 4 (100%+)
Default

For those people entertaining the thought of splashing out their cash on an M Four, with the idea that 'Oh I'm sure you can fit a 540 in there somehow...'

Take note of these pictures of our car. There is literally no possible way to put a 540 motor into this car without machining new bulkheads and a new upper deck. That's what you'll need to do..

tony gray is offline   Reply With Quote
Old 12-29-2011, 11:44 PM   #16353
Tech Champion
 
monkeyracing's Avatar
R/C Tech Elite Subscriber
 
Join Date: Mar 2008
Location: SnowMexico
Posts: 5,836
Trader Rating: 10 (100%+)
Default

Awww, isn't that cute! Another little touring car. Yawn. Please, Gawd, let this car have it's own, separate thread and may people find that thread and stay off this one.

So, question for anyone who might own a Xevo. I've found that I'm breaking C hubs on a regular basis with mine. Since I'm not willing to get better at driving, I've thought about using the 3Racing aluminum C hubs. My question is: Will the outer damper mounts that attach to the plastic C hub also fit the 3Racing version? It looks like they made some cutouts there, but are they in the right spot?
__________________
Stab it and steer.
monkeyracing is offline   Reply With Quote
Old 12-29-2011, 11:51 PM   #16354
Tech Elite
 
tony gray's Avatar
R/C Tech Elite Subscriber
 
Join Date: Jun 2002
Location: Melbourne, Australia. Home of rc-mini.net
Posts: 3,210
Trader Rating: 4 (100%+)
Default

Gee you get bitter and twisted sometimes Jim.....

I reckon an argument can be put that the M Four is more relevant to this thread than Xevo questions!

However..I do share your lack of any real interest in the M Four...I wasn't the one that bought one I hasten to add!
tony gray is offline   Reply With Quote
Old 12-30-2011, 12:21 AM   #16355
Tech Champion
 
monkeyracing's Avatar
R/C Tech Elite Subscriber
 
Join Date: Mar 2008
Location: SnowMexico
Posts: 5,836
Trader Rating: 10 (100%+)
Default

Meh. I haven't slept for at least 36 hours, but I would've been bitter anyway. As for the relevance of the Xevo: Yeah, I know, but the Xevo thread is a barren wasteland and I'm so astoundingly cool that I figure I should be able to ask Xevo questions any old place. I posted the same question on a yak gelding forum, as well. They'll be sorry if they don't answer!

...so tired...zzzzzzz
__________________
Stab it and steer.
monkeyracing is offline   Reply With Quote
Old 12-30-2011, 12:45 AM   #16356
Tech Elite
 
tony gray's Avatar
R/C Tech Elite Subscriber
 
Join Date: Jun 2002
Location: Melbourne, Australia. Home of rc-mini.net
Posts: 3,210
Trader Rating: 4 (100%+)
Default

Yak gelding? Now you're talking. Boy do those guys know their sh*t... You made the right call there.

p.s. Do you think anyone else understands what the hell we're talking about?
tony gray is offline   Reply With Quote
Old 12-30-2011, 12:47 AM   #16357
Tech Adept
 
justchris's Avatar
 
Join Date: Aug 2010
Location: Gosport England
Posts: 145
Default

Hi monkey
Any idea where you can get the
xevo conversion ??????????
__________________
TC6 Savox ] TC6.1 Sanwa ]
XL 5.9 Optifuel] M11X 2.4G ] 6000 IP lipo
justchris is offline   Reply With Quote
Old 12-30-2011, 12:49 AM   #16358
Tech Elite
 
Join Date: Jan 2009
Posts: 2,005
Trader Rating: 10 (100%+)
Default

Quote:
Originally Posted by hunts3lehigh View Post
I've seen a lot of info about caps. I've worked with electronics for 23 years, on all sorts of things. Everyone has said things that are correct, but the main idea of caps is to smooth the spikes out. Not the large dips in voltage, as there is simply not enough storage space in the sizes we can use to proved any amperage. A 47 Micro farad cap will supply power to an L.E.D. for about 1 second thru a 500 ohm resistor drawing less than .1 amp. Our motors pull large amounts of amps, so any voltage stored in the cap is quickly gone with no benefit to the motor, but to the ESC. The cap will keep the esc collectors on the transistors flowing more amps since the input voltage will be just a few thousands higher and so the forward bias will keep the amps flowing just a tiny, tiny bit more. Caps cannot store more voltage than the battery, without a diode in series to block reverse flow, and that will take an even larger voltage drop and pull away from the battery voltage. In fact all devices connected to the batter will have a voltage drop, and take a little from the total peak voltage. Any cap will be installed on the ESC input leads and so will be in parellel with the battery, and so if the battery or the CAP are higher in voltage, a potential difference is created and the electrons flow to the other device and balance out. IE, if the cap was 8.4 volts and the battery was 8.2 there will be a difference of potential of .2 volts between positive charged devices, but still that electrically would allow electons to flow to the other device and even out until there was no potential difference. That is exactly why we balance charge our lipos, so that there is not current flowing internally from one cell to the other.......

Also, connecting any cap directly to the motor will Decrease performance. only the smallest fastest discharge type should be used to limit spikes created from the brush moving off the comm. Any large cap will take voltage from the battery to charge, and lower the overall voltage to the motor all the time, and since the cap is directly on the motor, it will discharge as fast as the voltage is reduced from the esc since it is a direct short across the motor windings. No performance gain with a larger cap on the motor at all. Only the ESC will perform smoother and supply a bit higher voltage under load to the motor. But then again, anything connected to the ESC/battery will have a load and pull voltage away, so bigger or more is not always better in this case.

By the way, gates are normally switched on and off via +5 or 0 volts. TTL transistor logic using gates called xor, nor, andor, etc.... in a or gate, either input can be +5 and the out put will turn on or off. Others require both on or off to change the output state. A cap will change the voltage curve, to a better square wave rather than a sort of rounded square wave. That will reach the +5 just a bit quicker and the gates will change state just that much faster.

So, anyway, blah blah, blah........... Remember anything added to the system electrically will take from the total power output, you cannot get something for nothing in electronics. Caps only smooth the flow and allow for more precise voltage output, which can be a bit higher than if no caps were installed. ( in fact caps tend to leak when they go bad and will have a constant current flowing thru them and take more power away than they can store!!) something to think about................
Nice one!
cheapskate.brok is offline   Reply With Quote
Old 12-30-2011, 12:54 AM   #16359
Tech Master
 
I)arkness's Avatar
 
Join Date: Jul 2006
Location: Victoria,Aus
Posts: 1,104
Trader Rating: 7 (100%+)
Default

Quote:
Originally Posted by tony gray View Post
Yak gelding? Now you're talking. Boy do those guys know their sh*t... You made the right call there.

p.s. Do you think anyone else understands what the hell we're talking about?
nope not a clue
__________________
B.Portelli
Hyper RC - Metro Hobbies - RAB Hobbies - Wild Turbo Fans
Off road - Schumacher - R1Wurks Australia (Coupon Code - R1BP5%)
On road - Race Opt - Team Powers
I)arkness is offline   Reply With Quote
Old 12-30-2011, 01:16 AM   #16360
Tech Elite
 
tony gray's Avatar
R/C Tech Elite Subscriber
 
Join Date: Jun 2002
Location: Melbourne, Australia. Home of rc-mini.net
Posts: 3,210
Trader Rating: 4 (100%+)
Default

Quote:
Originally Posted by justchris View Post
Hi monkey
Any idea where you can get the
xevo conversion ??????????
A few weeks ago it was being distributed/made by Spice.
But the page on their website has now mysteriously disappeared...

This is the original link

http://www.area52.cc/news/1511-desir...rsion-kit.html

which linked to here..

http://www.hgd-spice.jp/
tony gray is offline   Reply With Quote
Old 12-30-2011, 01:22 AM   #16361
Tech Fanatic
 
Join Date: Oct 2003
Location: downunder
Posts: 814
Trader Rating: 22 (100%+)
Default

Quote:
Originally Posted by tony gray View Post
Yak gelding? Now you're talking. Boy do those guys know their sh*t... You made the right call there.

p.s. Do you think anyone else understands what the hell we're talking about?
Gelding of Yak's, done so as they are better pack yak's.

Minimizes their urge to fight against other yaks in a sexually orientated show of power.

Also done to improve their concentration, maybe Mr Gray that is the answer to help with your driving...
Either that or we may have to grind your teeth down when you get aggresive.

Only joking mate have a happy New Year see you at the mini nats.
bjspinner is offline   Reply With Quote
Old 12-30-2011, 01:32 AM   #16362
Tech Elite
 
tony gray's Avatar
R/C Tech Elite Subscriber
 
Join Date: Jun 2002
Location: Melbourne, Australia. Home of rc-mini.net
Posts: 3,210
Trader Rating: 4 (100%+)
Default

Mate I think you've just confused everyone even more...except me of course.

Ahh Mini Nats...and this time I can actually RACE!!!
tony gray is offline   Reply With Quote
Old 12-30-2011, 01:45 AM   #16363
Tech Regular
 
lupin_au's Avatar
 
Join Date: Dec 2009
Location: Clifton Springs Vic
Posts: 252
Trader Rating: 2 (100%+)
Send a message via MSN to lupin_au
Default

So the real question is is a Yak Gelding forum about Yak's or the actual act of doing the gelding?
__________________
Exotek T2R | Schumacher Mission | M05 Mini | RC18R | X-Ray T2-007 EU | Tekin | Sprektrum | EDS

http://www.westcoastrccarracing.asn.au/
http://www.lupinzblog.com/
lupin_au is offline   Reply With Quote
Old 12-30-2011, 01:46 AM   #16364
Tech Elite
 
tony gray's Avatar
R/C Tech Elite Subscriber
 
Join Date: Jun 2002
Location: Melbourne, Australia. Home of rc-mini.net
Posts: 3,210
Trader Rating: 4 (100%+)
Default

First one, then the other ....
tony gray is offline   Reply With Quote
Old 12-30-2011, 01:57 AM   #16365
Tech Regular
 
Join Date: Jul 2009
Posts: 403
Default

Quote:
Originally Posted by tony gray View Post
For those people entertaining the thought of splashing out their cash on an M Four, with the idea that 'Oh I'm sure you can fit a 540 in there somehow...'

Take note of these pictures of our car. There is literally no possible way to put a 540 motor into this car without machining new bulkheads and a new upper deck. That's what you'll need to do..

You mean like this?

This is not recommended... The end lid is actually GLUED on. so it need so be welded back on again if you take out to much of the glued area.

Its a 9T. And yes it does get rather hot pushing my TL-01 around.
MatsNorway is offline   Reply With Quote
Reply

Similar Threads
Thread Thread Starter Forum Replies Last Post
Tamiya Mini Cooper M-03L Hop-ups mini71 R/C Items: Wanted to Buy 4 05-04-2016 11:07 AM
Tamiya Mini Cooper mach51 R/C Items: Wanted to Buy 10 09-02-2011 12:08 AM
FS:TAMIYA Mini Cooper, TA 04S rthmotorsports R/C Items: For Sale/Trade 4 10-20-2007 09:37 PM
Tamiya 415 MSX and M03 Mini Cooper F/S Racer X79 R/C Items: For Sale/Trade 14 12-22-2006 07:38 AM
Tamiya M01,02,03, or 04 Mini Cooper ccugolf.com R/C Items: Wanted to Buy 2 12-05-2004 08:55 PM


Tags
m03, m03r ules, m05, mini, tamiya


Currently Active Users Viewing This Thread: 2 (0 members and 2 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 11:15 PM.


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

SEO by vBSEO 3.5.0