Mamba Max in a Savage?

[Rtsbasic]

Hi guys, I'm looking to purchase a new speed controller for my BL Savage to replace my 9920 (not smooth, non existant tech support, only wrapped in heatshrink, etc), as some of you are already aware :) I'm thinking of the Quark 125, but it sounds like it thermals easy, other than that a good esc.

Then someone mentioned to me his testing one in a Twin Force, and it might work in my Savage as well (weighs 5.6KG or 12.5lb RTR with 12 cells). Which got me thinking, a couple of people have used them in 1/8 buggies..which are lighter than trucks, but have heavy drivetrains, so why not? I'd like to get some other peoples opinion on this, if you think it'll work or just thermal after 5 mins hard running. Espically from any of the guys using them in 1/8's or that sort of thing.

The rest of my setup will be, 540C 8XL motor, 14 cells GP3700 (mostly 14), and of course an external UBEC. Geared for around 40mph on 14 cells. My 9920 works fine but does get hot, its not thermalled yet though. Without fans. I have been given the green light by Mr Palmer= for the extra voltage btw upto 16 cells.

Cheers.

[crazyjr]

Wow, I was told not to do it with a 7XL and 12 cells, by MR Palmer. Must be they think it can do it now.

[Serum]

You got a green light for the mamba-maxx up to 16 cells?! how about 5S?

[neweuser]

I'm also intereseted......my quark is sucking the big aXX!!!

[Serum]

I just emailed Shawn too, he told me it was on your own risk, it is good to go to 4S though.

[BrianG]

Just my $0.02: I wouldn't do 5s. At full charge, 5s=21v. The caps alone on it are rated for 25v - who knows what the rest of the components are rated for. That's a bit close to the ratings. It should work as manufacturers figure in some tolerance levels, but you might decrease the life expectancy.

[Serum]

5S is pushing it too much IMO, 4S is tested and proved to work.

[Finnster]

The 7xl draws more amps, I beleive the spec sheet is ~103A or so, too much for a 100A ESC. The 8xl draws ~10A below that, so its ok. A 9xl would be even safer.

I too read somewhere a while back that the MM could do 16, but that is getting really high. The lg caps are 25V, so... Personally I've ran mine /w an 8xl on 15 GP3700 cells and it did great, and did mid 40s. This is only a rare occation I found the 14 cells speed more than enough.

Running on 14 well used GP3300 packs The revo does a touch under 40, so 40 in your heavier savage may not be possible on only 14 cells, tho fresher batts may do it. Dunno. The ESC was fine, but the motor starts getting pretty warm, over 150F, so that's more of the stumbling block.

You will need a fan tho. The esc quickly got upto 140-150F on a single pack of the 14 cells w/o fan. On even a small 25mm fan, temps stayed below 130, even after 4 pairs of packs and hard bashing.

Cliffs:

Yeah w/ the 8xl, but care has to be taken as its pushing the limits of the esc.

[Serum]

Bullocks.

the 7XL is okay in a buggy on a 100A controller.

The currents you are talking about are vehicle and gearing dependant, and it are peaks.

a 100A esc can handle higher peaks than the 100A as well.

[Rtsbasic]

Just to clarify a bit, I was given the green light for extra voltage when I was discussing using one in my RC10GT with him, and under the conditions that I inform him of any odd things or problems they might have missed in testing, and he'll cover the warranty as long as I explain the exact circumstances to him if anything bad happens.

Finnster, am I reading that right, your using a MambaMax in your Revo on 14-15 cells with an 8XL? And 130F running with simply a small fan on it? If thats the case I'm ordering one asap, sod the Quark.

[Finnster]

Originally Posted by Serum

Bullocks.

the 7XL is okay in a buggy on a 100A controller.

The currents you are talking about are vehicle and gearing dependant, and it are peaks.

a 100A esc can handle higher peaks than the 100A as well.

Well true, but the point I was trying to make is that the 7xl will draw more current, and we are talking about a heavy Savage and not a light buggy. It may work, but IMO given the app, its too hot a motor.

I would think you would really begin to fight heat issues with the esc which already requires a fan to run a higher turn motor in a lighter truck. Who really knows, AFAIK no one has tried it. Is it worth the $ to risk it? I can't recc it.


EDIT: N/M, my reading was off.. I would think a 7xl on a MM in a buggy may work. May still need a fan tho.

@RTS:

Most of the driving has been on 14 cells, 15 was done as an experiment on a speed run, but the tranny case was damaged during (the bearing hole for output shaft got loose and wobbly) and I haven't got it fixed yet. Outside was ~68F and the esc was ~115, but only ran ~10-15min before breakage.

I used a 40mm and now a 25mm and the temps have stayed low on me. I was using the 40mm fan driving hard in 80-90F weather in Aug and temps stayed low. Gen no higher than 125F, usually less, so I put on a smaller 25mm fan. Temps went up ~10F, but a still very safe range. Caps got to ~135F as a fan no longer blows on them. I'm certainly satisfied with the MM for mine, but YMMV.

[Serum]

I use the 7XL on 5S lipo, which is taking quite some juice on it. (120A-130A) this is still with a relative tall geared maxx, and this is with the warrior 9920, which isn't getting too hot either. again, the 7XL is only taking it on peaks. On 14 cells it's more than fine. It gets hot. But not too hot.

Using the mamba maxx on 14 cells isn't something i would recommend either to a user, and you have it in your signature.. LOL

[Finnster]

Originally Posted by Serum

I use the 7XL on 5S lipo, which is taking quite some juice on it. (120A-130A) this is still with a relative tall geared maxx, and this is with the warrior 9920, which isn't getting too hot either. again, the 7XL is only taking it on peaks. On 14 cells it's more than fine. It gets hot. But not too hot.

Using the mamba maxx on 14 cells isn't something i would recommend either to a user, and you have it in your signature.. LOL

:P


I like pushing the envelope, :) that's why I say YMMV (your milage may vary.) Works for me, but much of this is untested, unsupported so evreyone is a pioneer. Reminds me of the early days of overclocking cpus and how much fun that was.

I'd love to see some more people push it and see what it can do, but I'm quite content with my setup. The only bother I have is motor heat, and it may not be so bad as I'm just very cautious when it comes to heat. A Neu would go great.

[Rtsbasic]

I'm trying to avoid smoke coming out hence staying with the 8XL :)

Them temps are very impressive, can't be anymore than what my 9920 gets at the moment with my 9XL. How much does your Revo weigh?

I'm aware I'm riding the limits of the controller..but I think its a safe gamble based on input from your and other people. Never hurts to push the limits a little does it. Well till it actually blows and your $140 out of pocket! :D

[aqwut]

Maybe it's your gearing.. because I'm using the 9920 on the LST which is heavier I run on 12 and 18 cells with no problems..... and a 7XL... But maybe the 8XL or 9XL if you wanna be safe....