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Successful 5S LIPO run on Mamba Max
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Finnster
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Successful 5S LIPO run on Mamba Max - 11.01.2006, 04:35 PM

Serendipidously I got my 5S (2+3S) lipos yesterday and got them charged and took my Evo out to lunch today to do a run. One word...WOW!

This is the 1st lipo pack if used, previously the highest I ran it was 16 GP3700s. Damn, lipos are really nice. The truck is truely wheelie on demand, even in loose dirt/sand.

Quick specs:

Mamba Max w/ 25mm 5v fan, 8XL, Rx pack, 5s2p 8000mah TrueRC cells. Emaxx tranny, 16/51 gearing, stock everything else (inc tires.) RTR weight of 5.0 kg.

Had the radar run out as well and did some speed runs on a long paved walkway after I drove in thru a sandy dirt track for ~10min. Did several back to back runs. Speeds were repeatedly (7-8x) 48 mph, with one run of 49.

The thing sounds like and absolute beast. Nitro people talk about the sound as a big reason to enjoy nitro... this thing sounded fierce and frightening as well at WOT. Like Satan's P'd off blender drawing your hand in, looking to liquify it. The spool up is amazing.

I was constantly checking temps. Even after all my speed runs the ESC was at 124, caps were @ 141 and the motor was 150. Ambient temps is ~68 (really nice day. :) ) I did run thru the grass for a while (~3-4min @ WOT) and the temps did climb, the motor got to 176 while the ESC went to 135, and the caps were ~146.

I normally run at a 15/51 gearing, so a little overheating was expected. My best speeds to date (at least repeatable, not all time best) was 44mph for 16 cells @16/51. I did do that once w/ 15 cells, but haven't had a chance to repeat it. The lipos are noticebly faster, punchier and vicious.

Last edited by Finnster; 11.02.2006 at 12:26 AM.
   
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Finnster
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11.01.2006, 04:40 PM

For Daf's sake,

Tthe MMax is still on factory settings and is using the elec brake. I have the brake turned down to 10% IIRC, and its still a bit harsh. Wants to just front flip w/ more than a feather touch on any higher setting. Consequently braking was fairly light, else flippies.
   
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sleebus.jones
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11.01.2006, 05:39 PM

I've had good luck with reducing motor temps by setting the start power to "high". Might want to give that a shot.

But yea, LiPo's are just flat out vicious. They make cells seem kinda silly! :)

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Nick
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11.01.2006, 06:03 PM

Woah, this is real good. To think how cheap the MM ESC is to!

So can it be pushed to 6s?


~ Nick.
   
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BrianG
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11.01.2006, 06:36 PM

Quote:
Originally Posted by Nick
So can it be pushed to 6s?
I'm thinking "yes": http://www.rc-monster.com/forum/showthread.php?t=4497 :)
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cart213
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11.01.2006, 07:08 PM

As long as you read the fine print. That's 6s LI-ION, not lipo. ;)
   
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BrianG
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11.01.2006, 07:17 PM

But it IS more than 5s Lipo. Not to mention M1 cells since they are the only Li_ion I know of with 3.3v nominal voltage. Normally, they have 3.6 or 3.7v nominal voltage.
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Nick
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11.01.2006, 08:18 PM

If the Mambamax can take 6s I will be kicking myself laughing... I mean. What a bargain! 5s is just insane enough for what it can give.

I will buy another one for my E-Maxx to replace the 9920 if that's the case, get some nice fans on it to.


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Finnster
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11.01.2006, 08:38 PM

I don't think I would do 6S, full charged would be 25.2V, and the caps are 25V rated.

Not that I think I would just die or go up in flames, but it would be asking alot if it. You'd be looking at a decreased lifespan prolly, but... if someone wants to try... :)
   
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BrianG
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11.01.2006, 08:53 PM

I agree with Finnster; even though manufacturers factor in a safety margin when rating components, running them so close to their max ratings will only shorten their life. Besides, the only hint for voltage rating we have is the rating on the caps. Those are electrolytic caps and are typically rated at 1v, 10v, 25v, 35v, 50v, and so on. Just because they are rated for 25v doesn't mean the rest of the components are.

Also keep in mind that the potential to draw more current than the rated 100A is MUCH easier with higher voltage.

Personally, 5s is pushing it. Just the fact that the CC rep said not to use the ESC as a brake at that voltage tells me that we are approaching the usable limit.
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Finnster
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11.02.2006, 12:13 AM

Quote:
Originally Posted by BrianG
I agree with Finnster; even though manufacturers factor in a safety margin when rating components, running them so close to their max ratings will only shorten their life. Besides, the only hint for voltage rating we have is the rating on the caps. Those are electrolytic caps and are typically rated at 1v, 10v, 25v, 35v, 50v, and so on. Just because they are rated for 25v doesn't mean the rest of the components are.

Also keep in mind that the potential to draw more current than the rated 100A is MUCH easier with higher voltage.

Personally, 5s is pushing it. Just the fact that the CC rep said not to use the ESC as a brake at that voltage tells me that we are approaching the usable limit.
Yeah, the power output @ 5S is tremendous, and this is with just a Feigao motor. I think this setup is really close to what the ESC can handle thermally, and may even be a bit much if you just wanted to drive thru grass, or other extremely challenging driving. I don't really do that, so it works for me. A Neu would help the situation. Its actually asking alot from the chassis as well I think as well to some degree. :)

What this ESC is doing is really remarkable, and is making even more excited for the monster maxx. I really hope to see a 6-8s controller, and the hints that Shaun P drops make it seem this is not unreasonable. If you are looking to go above this (and even up to this) you need to be careful and really watch your setup. It's not for everybody, but I am smiling. :017:
   
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captain harlock
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11.02.2006, 10:30 AM

Now, I believe Shculze might be crying on their mother's shoulder:

A Schulze controller: " MAMA..MAMA..Maba Max is kicking my *ss..waaaaahahaha..".

Schulze's mother: " See! I told you that you've to be nice to people. Shame on you Schulze my dear".


The name is Alawi. You can call me Al.
Nice to meet you!
   
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Finnster
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11.14.2006, 12:20 AM

YouTube
Google Vid

Last edited by Finnster; 11.14.2006 at 12:46 AM.
   
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Finnster
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11.14.2006, 12:47 AM

I made another quick vid of my brushless Revo in action. This time I have it running on 5S lipo, and its literally wheelies on demand. Its so much more powerful than on 14 cells. I've radared it @ 48 reliably w/ stock tires. Put new mashers on for the vid and they were balloning so bad I couldn't ever get to top speed, they just turn to pancakes. 35-40 mph is about the limit for mashers, so they should be Ok w/ a Hv 6.5
Keyword is throttle control, I'd rather have my finger holding me back than the motor. Enjoy!


Specs:

Mamba Max Esc
Feigao 8XL motor
Emaxx tranny, 1st gear removed
custom batt trays and rollbar
17mm Maxximizer beadlocks w/ Maxx Mashers
Rx Pack


Youtube


Google Vid

Last edited by Finnster; 11.14.2006 at 12:49 AM.
   
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riceman
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11.14.2006, 04:23 AM

Thanks for posting up those vids. Did you do any special proramming of the Mamba Max? I've tried out different battery combinations myself. My LST2 conversion does fine with 4s 8000mah and also with 5s 4000mah. However it is not too happy with 5s 8000mah. With the 5s 8Ah it will run only if I ease the throttle up but once it reaches half throttle it shuts down. I haven't quite figured that one out yet.
   
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