R/C Tech Forums

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

Reply
 
Thread Tools Search this Thread
Old 04-07-2011, 02:45 PM   #16
Tech Elite
 
Join Date: Aug 2001
Posts: 2,583
Default

Quote:
Originally Posted by daleburr View Post
A motor will only draw the current it needs. If a motor needs 80A and the battery can only provide 60A, then going to an 80A battery will provide more power. However going from there to a 120A battery would provide no increase in power, as the motor won't use the extra current the battery could supply.

Thats why some people see a difference when they go for a bigger C rating, and others dont. It all depends on what your motor needs (which in turn depends on the class, gearing, ESC settings and driving style).

For my 10.5TC I tried going from 40C to 60C and saw no difference in power. The data logger shows I never pull more than 70A, which the 40C packs are more than capable of providing.
You always have one of the most sound answers. Thank you.
Sydewynder is offline   Reply With Quote
Old 04-10-2011, 06:47 AM   #17
Tech Elite
 
Join Date: Jun 2003
Posts: 4,002
Trader Rating: 3 (100%+)
Default

I run 50c on silvercan. Makes a big difference.

It's not the amp draw.

It's simply the newer 50c packs have higher average discharge voltage than older 25c/30c packs.

Example:

Orion 25c = 7.2v
HiEnergy 50c = 7.8v

That is 0.6v difference or around 8% difference in battery voltage.

In silvercan, 8% advantage in power is huge.

Hope this helps.
__________________
www.rccartips.com
www.f1rccars.com
www.f1rcclub.com
http://www.youtube.com/user/rccartips/
http://www.facebook.com/RCCarTipsFan
rccartips is offline   Reply With Quote
Old 04-10-2011, 06:57 AM   #18
Tech Master
 
heretic's Avatar
 
Join Date: Aug 2006
Location: europe
Posts: 1,104
Default

The way I understand it, for stock racing there's jsut no way anything over 25C could give any advantage, all other things being equal.

But the latest " crazy Cs " batteries have a way lower inner resistance and that makes a huge difference no matter what motor you run, wherehas " big Cs " can be appreciated only in mod- someone correct me if needed.

Not sure I understand the last comment about Voltage, though. All my batteries are charged up to 8,4V.
__________________
I love wedge bodies. I love dish wheels.
heretic is offline   Reply With Quote
Old 04-10-2011, 07:42 AM   #19
Tech Elite
 
Join Date: Jun 2003
Posts: 4,002
Trader Rating: 3 (100%+)
Default

Hi,

Yes, we charge lipos to peak at 8.4volts.

But as soon as you connect a load (e.g. motor), some batteries will supply an average of only 7.2volts, some 7.8v, etc.

From my experience, the newer batteries supply higher voltage under load. Which might explain why people prefer 50c (i.e. newer battery technology) than old 25c.

You can do a simple test. Connect your race motor to a slave motor. Put a voltmeter at the output of the slave motor.

Then put a 25c battery to your race motor, take the voltage reading at the output of the slave motor.

Then do the same test with a 50c. Chances are you will get higher voltage reading at the output of the slave motor with a 50c, meaning the slave motor is spinning faster with a 50c.

__________________
www.rccartips.com
www.f1rccars.com
www.f1rcclub.com
http://www.youtube.com/user/rccartips/
http://www.facebook.com/RCCarTipsFan
rccartips is offline   Reply With Quote
Old 04-10-2011, 08:02 AM   #20
Tech Apprentice
 
SCTom's Avatar
 
Join Date: Oct 2010
Posts: 94
Default

rccartips, Thanks for shedding some light on this subject. Stock motors need all the help they can get (more voltage under load). I believe most people on here that say they feel no difference in higher C batteries are running low turn Mod. motors and are already blisstering fast.
Tom
SCTom is offline   Reply With Quote
Reply

Similar Threads
Thread Thread Starter Forum Replies Last Post
1/10 R/C F1's...Pics, Discussions, Whatever... Vyger Electric On-Road 13771 Today 06:13 AM
Daves R/C Tracks Hubbard,OR 8man72 Northwest Racers 6445 11-16-2017 10:59 PM
40C, 30C, 25C How much do I need? lusifur Electric Off-Road 13 11-15-2009 03:24 PM
The Politics of R/C Racing Alex Lopez Electric On-Road 285 03-13-2007 01:38 PM



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 08:22 PM.


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