Primer on electrics for Nitro Heads! Also: Why Electric?

This forum is dedicated to discussion regarding the HPI Savage Flux HP Brushless Electric Vehicle.

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KiZ
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Re: Primer on electrics for Nitro Heads! Also: Why Electric?

Post by KiZ » Sun Jan 11, 2009 3:13 pm

No, sorry xtreme, nobody to take vids for me  :(
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Post by kpj313 » Sun Jan 11, 2009 6:00 pm

Nice write up Kiz!
I'm on the verge of pouncing on the flux when available, but looking for advice on lipos.
I have the charger being shipped already, I went with the Hyperion EOS 0606i. I was looking at the Elite 35C High output, Elite 5000mah 3S to be exact and looking for some input.

-Karl

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Post by KiZ » Sun Jan 11, 2009 6:08 pm

Good choices. I would wait till the Flux is out before buying packs though, we need the exact dimensions of the battery boxes before anyone can decide on pack size.
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Post by xtremesavage » Sun Jan 11, 2009 6:23 pm

has antone heard of a release date yet?
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Post by igazzi » Sun Jan 11, 2009 11:02 pm

mate, that was an awesome write up!
answered basically all my lipo/brushless questions, as i to am looking at getting the flux.
however i do have one more question.. how do you find out the max amp draw from a motor/esc on the battery?

i figure you need this info to make sure your batteries are adequate and do not fall short thus killing the esc?
cheers

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Post by andrew12 » Sun Jan 11, 2009 11:31 pm

Just another question on the run time for this truck.  Is it true that a guy can only expect around 30 min using this setup.

http://www.maxamps.com/MA-5250-SAVAGE-Pair.

What is the charge time for these batteries as well.  Thanks

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Post by wolfsbain » Mon Jan 12, 2009 12:48 am

nice write up.  it is helping alot.  i just bought a team associated rc10b4 and a tamiya baja king and am going to be needing batteries.  i have decided on a novak havack 10.5 for the rc10b4.  but any recommendation on batteries will be great

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Post by KiZ » Mon Jan 12, 2009 6:01 am

[quote="igazzi";p="695938"]mate, that was an awesome write up!
answered basically all my lipo/brushless questions, as i to am looking at getting the flux.
however i do have one more question.. how do you find out the max amp draw from a motor/esc on the battery?

i figure you need this info to make sure your batteries are adequate and do not fall short thus killing the esc?
cheers[/quote]
[s]Well first off, an inadequate battery won't kill the ESC.[/s] (EDIT: So apparently some high power ESCs like the Flux/Mamba Monster don't like under-specced batteries. I am not entirely sure of the reason, but it has been said that they can cause damage. I believe this is unlikely with smaller ESCs) That only happens if the motor draws too much current. On the savage, that won't really be a problem to worry about. An inadequate battery will only make it "cog". As for the max draw from a motor/esc, well thats not always easy to work out. ESCs have a maximum continuous draw before they pop, but it usually isn't specified. The stock esc is 120A, which is plenty for the savage. Don't concern yourself with that too much, just look for batteries over 20c, higher the better. For ~5000mAh batts, that will be enough.


[quote="andrew12";p="695941"]Just another question on the run time for this truck. ?Is it true that a guy can only expect around 30 min using this setup.

http://www.maxamps.com/MA-5250-SAVAGE-Pair.

What is the charge time for these batteries as well. ?Thanks[/quote]
Yup, 30 minutes is probably a high estimate.

[quote="wolfsbain";p="695951"]nice write up. ?it is helping alot. ?i just bought a team associated rc10b4 and a tamiya baja king and am going to be needing batteries. ?i have decided on a novak havack 10.5 for the rc10b4. ?but any recommendation on batteries will be great[/quote]

Check out these batts: http://www.maxamps.com/products.php?cat=94
Any of the NiMH or 2S batteries will work with your Novak system. (the first four batteries)
Last edited by KiZ on Mon Dec 20, 2010 11:18 am, edited 3 times in total.
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Post by BLRunner » Mon Jan 12, 2009 6:09 am

The editor reviewing the Flux at RCU has listed the box size at 30mm x 50mm x 203mm (8 inches).
RCU Flux Review

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Post by wolfsbain » Mon Jan 12, 2009 11:25 pm

thanks kiz.  i am still fairly green to nitros but really green to electrics.

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Post by simonbelmont » Thu Apr 02, 2009 1:34 pm

FANTASTIC!!!!!!!!!!  Thank you.

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Post by arisking » Tue Nov 10, 2009 10:17 am

Yeah this article kicked *censored*.  Thanks KiZ.
This is my Savage:

|--o--|
 .|.
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|--o--|

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Post by abarth » Fri Jan 29, 2010 10:39 am

another big difference between lipo and nimh is the voltage drop under load, while fully charged a 6-cell nimh or 2-cell lipo will both have a voltage around 8.4V, under load the nimh will easily drop to 6 volts, while the lipo will keep it around 7 volts.
I run both in my Asso T4, and while the nimh gets very hot after a run, the lipo stays almost as cold as when I start.
exept for boats, I will never run an ICE again, lipo + brushless = insane
my garage is called area 31, strange things happen there

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Post by AlsSickness » Sat Jul 30, 2011 8:59 pm

Awesome thread, perfect for me today, just bought a Flux HP, totally sick, need a better wheelie bar and a more controlled trigger finger.

Thanks Kiz
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Post by SATANZ31 » Sat Aug 20, 2011 10:39 pm

[quote="KiZ";p="694485"]
Now, if that didn't convince you, maybe this will:
Image
(EV = electric vehicle, ICE = internal combustion engine)
Look at the light blue line. That's right. Instant torque starting from 1RPM, and a power curve to die for.
This, gentlemen is why electric is not just for kids. :twisted:

[/quote]

First off, I would like to say that I think Brushless RC cars PWN Nitro cars all day long.


That being said... What the *censored* is this graph even comparing? What engine and what motor? Further more why do the HP and TQ numbers NOT cross at 5252rpms? I mean after all, everyone knows that HP=TORQUE X RPM / 5252. Even saying that, why do the EV and ICE engines not even cross at the same rpm points on that graph? One crosses at like 5500rpm and the other at like 5800rpm.

That graph looks like somebody just made it on their computer.

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Post by rokie1432 » Sat Aug 20, 2011 11:40 pm

Would u prefer some hand drawn graphs?

We apprec ur view and preference on brushless over nitro.
However, your non constructive post is not going to help anyone.
If u have better understanding of how the graph should look like, then perhaps better use of hands (or computer) might prove better than mouth?
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Post by SATANZ31 » Sun Aug 21, 2011 10:47 am

[quote="rokie1432";p="804960"]Would u prefer some hand drawn graphs?

We apprec ur view and preference on brushless over nitro.
However, your non constructive post is not going to help anyone.
If u have better understanding of how the graph should look like, then perhaps better use of hands (or computer) might prove better than mouth?[/quote]

Well, I guess my post came off as mouthy sort of. It probably doesn't help that people probably think I said F#%$ instead of H E L L. Auto censor FTW...

But, that's just it... Me using the computer or hands to draw a graph is not proving anything. It is me making up my own results which seems to have been done on that graph already. On a real dyno graph, your horsepower and torque will always cross at 5252rpm. It if does not, then the graph has either been manipulated, or is reading speed instead of rpm.

Like I said, I am all about brushless. However the OP said... "Now, if that didn't convince you, maybe this will:" Then he showed the graph. How is that going to convince anyone who actually knows what a dyno graph looks like? If anything, it will just confirm their suspicion of brushless power.

I was actually going to post that graph on one of my car forums. We are having a debate over there about Nitro VS. Brushless. I am defending brushless. I almost posted it without taking the time to actually look at it. Had I done that, I would have been made fun of by real car guys for posting a fake graph that is comparing two completely unknown power sources.

So while my post seemed to be "mouthy", it was not intended to be insulting, just informative I guess. The OP took the time to put out a MASSIVE amount of information. Some of which actually helped me too! I thank him/her for that.

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Post by Logg » Tue Sep 04, 2012 8:29 pm

I have been searching for information while waiting on my XS Flux. Your post Kiz was what I needed to read.
It is also a relief since I have already ordered by battery's and upgrades. Its been 20 years since I had my last rc car and it was nitro..... A royal pain in the arse for messing about!
I guess both have come a long way since then, can't wait to get it!

Cheers

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Post by KiZ » Thu Jul 04, 2013 1:21 pm

[quote="SATANZ31";p="805019"][quote="rokie1432";p="804960"]Would u prefer some hand drawn graphs?

We apprec ur view and preference on brushless over nitro.
However, your non constructive post is not going to help anyone.
If u have better understanding of how the graph should look like, then perhaps better use of hands (or computer) might prove better than mouth?[/quote]

Well, I guess my post came off as mouthy sort of. It probably doesn't help that people probably think I said F#%$ instead of H E L L. Auto censor FTW...

But, that's just it... Me using the computer or hands to draw a graph is not proving anything. It is me making up my own results which seems to have been done on that graph already. On a real dyno graph, your horsepower and torque will always cross at 5252rpm. It if does not, then the graph has either been manipulated, or is reading speed instead of rpm.

Like I said, I am all about brushless. However the OP said... "Now, if that didn't convince you, maybe this will:" Then he showed the graph. How is that going to convince anyone who actually knows what a dyno graph looks like? If anything, it will just confirm their suspicion of brushless power.

I was actually going to post that graph on one of my car forums. We are having a debate over there about Nitro VS. Brushless. I am defending brushless. I almost posted it without taking the time to actually look at it. Had I done that, I would have been made fun of by real car guys for posting a fake graph that is comparing two completely unknown power sources.

So while my post seemed to be "mouthy", it was not intended to be insulting, just informative I guess. The OP took the time to put out a MASSIVE amount of information. Some of which actually helped me too! I thank him/her for that.[/quote]

I'm 2 years too late to answer this post, but you are right, SATANZ31, the graph is something that I randomly grabbed from google image search. I did not make it myself, nor was I attempting to claim it is a real dyno graph. The point I was attempting (perhaps badly) to make was the early availability of torque from an electric motor. The graph is probably not even about a brushless motor. Please ignore it.
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