Modded Mamba Max Testing!!
 

I recently sent Griffinru a MM and had him do his "stage 1" mods to it. Upon receiving it from him I had a good look at it. His workmanship is very nice and clean, all mods are stock appearing and well executed. Basically the intent of the mods is to keep the esc cooler and help it to handle higher voltage. My first tests are with 4s lipo, I will try 5s lipo as well.

Test vehicle is an OFNA MBX R2
http://www2.towerhobbies.com/cgi-bin...?&I=LXAXV2&P=7

The buggy has a feigao 7xl, RCM heatsink/clamp, 15/51 gearing, and 50k traxxas diff fluid in the center diff to assist in motor braking. I am running a UBEC(of course) and have the MM bec disabled. My testing are is blacktop, cement, cut grass and dirt. I ran it for 10mins and then used an IR temp gun to determine the temp of the batteries, motor and esc.

Round 1:
Stock MM with Integy fan spaced 1/4 inch off heatsink, Maxamps 10000 4s lipo. After 10mins, battery 105f, motor 140f, esc 130f

Round 2:
Same setup as above without the fan. Ran for about 5 mins and the esc was up to 160f, everything else the same temp.

Round 3:
Swaped the stock MM with the modded MM. No fan used this time. Ran this setup for 15 min battery 110f, motor, 150f, esc 135f.
I would say that my "seat of the pants" feel was better with the modded MM. It started from a standstill on ful throttle well, no cogging and seemed a little faster accel than the stock MM. The temps were great, the upsized caps did not get anywhere near as hot as the stock caps do. I will say that I am not impressed with the maxamps 10000mah battery. I did not get the run time that I had expected from it. All three tests were done on the sme pack, without charging it, si about 30 min runtime. It is new, 2nd charge, so I will run it more and see if it improves with a few cycles.

Round 4:
Tried some different batterys. Used the milwaukee lipo cells, arranged in 2s2p packs and ran 2 of those packs in series for a 4s pack at 6000mah. Got around 20mins out of that setup and the temps were good until I hit the lipo cutoff and tried to keep it going. Temps of the batteries went up a bit, but still acceptable. Motor got to about 160f,but the esc stayed right at 140f, caps at 110f.

Conclusion:
The modded mamba max worked very well. It remained a good 30f cooler than a stock MM and did it for alot longer than the stock one could have. No glitching, thermaling, and did not heat up as the batteries drained. I would highly recommend this mod to anyone wishing to use a MM at 4s in a buggy/similar sized wehicle. My buggy is heavy, especially with the 10000 maxamps pack in it.

I will continue to test this esc, and will run a 9xl and 5s on it soon to see how it copes with the higher voltage.

Heres pics, cause I know you guys will ask:wink:

http://i206.photobucket.com/albums/b...p/DSCF1447.jpg

http://i206.photobucket.com/albums/b...p/DSCF1449.jpg

Thanks for the Review. Really great to know about a small mod like that made such a big difference in temps.

That's great news lincpimp. :yes:

What exactly did Artur do to it again? The cap mod and what else?

IIRC, it was Artur that said have the cap right on the esc board, or don't bother? :whistle:

Thanks for the great info. Please post when you test w/ 5s or 14 NiMh. My OE MM wouldn't run these as being overvoltage. It ran 4s.

Thanks for the info. I think I'll try to send him my MM ESC as well soon. Those temperatures with the modded ESC are without a fan, correct?

Without fan, yes. :mdr:

Why oh why, can't a Quark run that cool! But I guess the benefits of having a Quark require some 'sacrifices'. :(

He did upgrade the three caps on the board, they are almost twice the stock size. The really big cap (1800) has short leads and is soldered on where the power wires meet the board. The also added a heat spreader to the backside fets and a heatsink to the cpu/brains. I was very impressed with the cooling, especially that it ran cool for so long without a fan. I have a few other stock MM and they do not run that cool with fans and in lighter vehicles than the buggy. Definately worth doing on a 4s setup, made a noticeable improvement on startup too.

Updated 5s testing!!!
 

Ok tried 5s with the above setup. Yes 5s on a 7xl, I figured that I would give the MM a workout. Well it works and worked well until a small piece of steel/metal found its way into the spur and locked the pinion to it. The buggy was probally doing 40 at that moment and it stopped very quickly. The MM let out some smoke and is dead:cry:

Took it out of the buggy and had a look at it. Nothing looked obviously burned so I plugged it into the castle link. Programming worked fine so I guess that a fet crapped out, or something else let go in the power supply dept. I had the throttle pegged when it locked up. I talked to Artur and have shipped it back to him to inspect. I will post again when he gets back to me.

This really sucks cause the 5s setup was working very well. No cogging from a standstill, great low speed control, no hestitation either. I only got a minute of running, but nothing was even warm at that point. If he can fix it I will retry with 5s on a 9xl with the same gearing. That should put it at about the same speed as the 7xl/4s combo. I will also set the mesh a little looser and keep away from my shop parking lot as there is all manner of crap there.

I was really impressed at the improvement these mods made on a 4s, high draw setup like mine, I really hope that it can handle the 5s setup as well.

Sucks to hear that your new modded mamba smoked. Lets hope that it's not a total loss and that Arthur can fix it.

I'm sure that he can fix it. He knows his stuff!!!

I am impressed with Mamba built-in protection!
It was a very short high current spike, which took out one phase, check the melted solder :) but didn't destroy the rest.

As for fixing I sent you e-mail with details.

Thought I might throw in an update.

Talked to Artur this morning and he will try to fix it for me. I f not he says that he might have another use for the "brain" PCB section of the MM. Should be interseting. I will be sending him another MM soon to do the stage 1 mod to. It worked so well for 4s that I may have all of my MMs that I use on 4s done. Also heard that Mike is having some 5s success with the stage 2 modded MM that Artur sent him. I am waiting eagerly for some posts from Mike:tongue:

Thats fantastic news. All hail 'King' Arthur and his mighty esc mods!

Just for reference does anyone know where you can get compatible replacement fets just in case i need to repair a mamba max when they get out of warranty?

Part number BSC022N03 from Infineon Technologies, you can get them from Digi-key.

lincpimp, any updates on 5s testing??

where do you send it to get that done?

PM griffinru and he can do the mods for you. He does excellent work, looks like factory.

I have not tried it on 5s yet. I am currently building a few different vehicles that will give me the chance to try it out. It worked well on 4s, so I am optimistic on 5s.

Someone help me out on this one...

I recieved my Mamba Max today and besides having to dremel cut a screwdriver slot in a case screw because the head was stripped from the factory, I was satisfied.

Now I bought 3 35V 330 micro farad caps, a 1800 micro farad cap, 1 zener diode as linked to in that one post from digi-key. I also bought a small sheet of brass, artic alum thermal compound and epoxy, all added up quickly! I was planning on doing the stage one mod outlined in another post myself since I'm fairly good with building circuits.

-Now the stock MM has 3 330 25V caps, will I gain anything by switching to the 35V caps?

-Is it worth cracking it open to replace to diode or do all of the greasing and backing with brass?

-Also, are the stock motor leads (13 AWG) fine with the Feigao and the stock connectors as well?

-I was checking out that wiring diagram link n the forum, is it best to tap the UBEC off of the ESC or battery connector(ESC side of course). Next, it shows an optional 1000 micro farad cap in the 3rd channel of the rx, I'm running a CC UBEC, is that needed? I don't see how though, also my transponder goes there.

I am running this in a truggy on 4s with a Feigao 9XL, the only reason I was planning on doing this was to keep temps low on 15 minute mains. My whole goal with the mod was to keep temps LOW. I am going to run dual novak fans I bought as well (they look cool to which is always a plus).

Thanks!

The 35v caps are to help it run 6S, also I've noticed they do not heat up like the 25v ones, even on 3S.

I'd tap the ubec on the ESC, connector to the battery. This is a more stable voltage since the cap on the power supply at the esc keeps the spikes close to the esc (versus tapping it at the same place as the cap).

There is no original diode on the back of the power board. It's an add on to stop voltage spikes. I would recomend doing the brass on the back side, any additional cooling couldn't be a bad thing.

Extra cap in the reciever is not necessary if you are running 2.4ghz radio but you could always make a jumper for 3rd channel with the cap in it to keep a supply for the transponder if you want.

The "whole" mod will help with temps.

Or you could go overboard like me and put heatsinks on both sides of the power board with pusher/puller fans ;) You just have to put longer buss leads from one board to the other. I also put some scrap aluminum on the usb side of the brain board to cool the fet drivers and the bec the esc still uses to power itself.

Good luck, my best advice is to remove all the plastic wires and preheat the boards in the oven at 250* before attempting to solder or desolder.

hey DR. did you do the modding yourself? have you did any testing with higher voltage?lmk
phil

Thanks for the info, I have seen the cap tapped on the esc, should I extend a set of wire off of the esc for the 1800 cap? So that would make three sets of wires on the (+) (-) taps on the esc(1800 cap, UBEC, Battery)? Or should I tap the 1800 cap in just before the ESC off of the battery leads?

-Any pics of adding that diode install?

Thanks!

I am guessing that you are trying to perform griffinru's stage 1 mod. If so the need for fans may not be necessary. I ran my 1/8 buggy with a feigal 7xl, geared for 40mph, and a 10000mah 4s lipo (=very heavy) with a modded mm and a regular mm. The unmodded mm did need a fan and temps were still a little on the high side. With the modded mm I did not need the fan and the overall performance was much better. Since you are running a truggy, the added tire weight will put more strain on the motor and cause more heat at the motor, that may be of more concern than the esc, however the hotter motor will cause the esc to heat up due to higher current draw for wasted power production (heat).

Like what was said, a little more voltage headroom. You should size a cap to have at least 25% more voltage than what you plan to use. Can't forget that the back-EMF pulses will be higher than the battery voltage too. The only thing you lose with larger voltage caps (assuming you keep the same capacitance) is physical room.

Larger wire is always better for less v-drop at high current (less resistance). If you are gonna be pulling higher currents, either direct-solder the wires, or use larger connectors for the same reason.

Not sure it makes much difference since they are the same point electrically. Maybe a little less noise if tapped closer to the battery, but think the difference is negligible IMO.

The 1000uF cap is there to help smoothen out any UBEC switching noise from entering on the power line and to help with the current bursts the servos can pull. Helps to make for a more constant current flow.

I personally HATE fans, especially if you are counting on them to keep things cool. They can break, get dirty (which wears the bearings), and just adds wiring complexity. I also hate temps over 130*F, so I always simply add a little more heatsinking, but if gearing is optimal, there shouldn't be excessive heat.

Thanks for all of the help, does anyone have pics or info of where to put that Zener Diode? I should probably wait to ask until I open the MM, but I wanted to be prepared for when I do.

Have you seen my posts?

I have, they are actually the mamba max mods and tweaks and the making an esc better thread is in my favorites. I probably not seeing something on the post. I will try and reread, but if anyone has a link to it or knows where it is at, let me know. Thanks!

:)
No problem
http://forum.rcdesign.ru/index.php?a...ntry&id=110929

I start working on English version in my Russian forum blog. Should be under "Making an esc better (ESC Mods) English" on the right...

NICE! Thats what i thought. THANKS!

wondering how much you charge for this modification ...nice work by the way!!


thanks

Brian

Is anyone running this mod on 6s? Is it holding up?

@ GriffenRU, I've seen two different post's on people having problems running the MM with a reciever pack. I have seen the same thing in testing different configurations on my stuff.

I've just been thinking it's a difference between the voltage of the reciever pack/radio and the internal bec voltage of the MM. Say a 1.5ms signal at 6.0volts and a MM brain board voltage of 5.

Is there a way to disconnect the internal BEC in the mamba max and back feed the circuit? I.E. the ubec/reciever pack powering the brain board?

Can you provide links to threads with problems?<?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" /><o:p></o:p>
And what problems do you have running separate BEC?<o:p></o:p>
<o:p></o:p>
In general, "brains" have their own power supply and you do not want to mess with it and providing it externally won't be good thing either.<o:p></o:p>
What you can do, is completely take BEC part out, but if you do not use "RED" wire it is already out...<o:p></o:p>
<o:p></o:p>
6S is under development, but nobody asked for it either...<o:p></o:p>
I won't recommend running 6S with my mod1 and mod2 with 27V TVS, but I cannot stop you either. (check for TVS temp with good battery packs)

http://www.rc-monster.com/forum/showthread.php?t=9368 and mabey I can find the other tonight.

No problems with a ubec (@5v), just with reciever packs.

When you disconnect the red wire and run a ubec, isn't the "brain" potentially looking for a certain 5-0v, 1-2ms signal? What if your radio was over 5 volts, couldn't the brain not see a proper 0 volts on the bottom of the square wave?

As long as signals TTL-compatible - no problems, referenced via ground.

Well, I just did the stage one myself and the Mamba went BOOM! I plugged in the battery, everything was fine, turned on and everything is fine. I then turned off, pull full throttle on the controller to program, turned it on and the two FETS just above the negative pole went POP! I think I blew a good Mamba due to me wanting to putz with it myself, trial by error.

I am willing to sell the three sheets of brass (4"X6") about and about .050" thick(paid $14.00 from Mc carr 1.5"x1" piece cut out), mamba with salvageable parts(paid $112.00 Starluck R/C), CPU heatsink thermal epoxy(Unopened paid $13 from Mc Carr), artic silver thermal compound(Barely used any, paid $10), 10 pack zener diodes as linked to in this thread(paid $2 Digikey). Make any offer and I probably will take. I'm going to buy a new mamba and add the 1800 micro farad cap and not go any further.

Sorry about the MM. I've thought about buying an MM and doing these mods myself then I remember that I have no soldering capabilities and would probably end up smoking something.:lol:

I've got the fet's mustbnitro, I could replace them for you (read free plus shipping). Do you know why it shorted? Arctic silver is conductive, any chance you got some where it should not have been? You can use arctic alumina it's not conductive.

If you don't want to fix the MM let me know and I'll make you an offer.