Question for the Mamba Max experts
 

I just ordered a mamba max and a wander 9XL for my G2R revo, I need to know if i really need a UBEC or reciever pack for 12 cells, thats all i intend to run on itand don't see a problem with running the bec off the esc. If anybody sees a problem let me know. Thank you.

Yes, you do need a UBEC. and you need to take out the red wire of the plug to the receiver to disable the internal bec

If your looking for a cheap UBEC. I have been running this one for a few months now and for $15 its pretty nice. Works perfectly. For that price you cant afford not totake the load off of the MM.

http://www.helidirect.com/product_in...oducts_id=1158

If the esc is rated for 12 cells, should the bec be rated for that as well? Like i said i'll be running 12 cells and no more, all my cars and trucks run on 6 cell packs so 12 cells in the G2R is easy to do. If i do need an external power supply, i'll go with a reciever pack, as i have a lot of them and i hear of the occasional interference problems with UBEC. I still don't see why i could run 12 cells on my 5700 without problems and need an external PS with a bigger motor. Thanks a lot and will keep this under advisment

You may not be actually voiding the warr then.. :) But still I would highly recc a UBEC or Rx pack. They are not that much and saves alot of heat at a high cell count. You've seen this in other threads that the BEC sheds the voltage (from 14.4V to 6V) as heat, so the higher the V, more heat is created. Couple this with a big motor, and you may get a toaster. If you really want, try it, just keep an eye on temps.

Even at a relatively low 12 cell count, the internal ESC BEC (being just a linear regulator) will still heat up quite a bit. At 12 cells (14.4v) and 3A load, that's over 25W of power the little heatsink has to dissipate, along with the heat from the drive FETs. Even a quarter of that value is quite a bit for that little heatsink. Personally, I'd use a seperate BEC for anything higher than 6 cells (or 2s for lipos).

The MM BEC is rated to 12 cells max so sure it'll work fine like it does with your 5700..but honestly why put the extra strain on it and waste the extra energy via heat? A $15 UBEC from here or starluckrc or some random HK company will work fine and deliver 6v to the reciever. More important when running the bigger motor because the esc is working harder and producing more heat anyway.

Thank you for the advise, much appreciated. I just got an email from Joe Ford of castle saying that the esc would probably fry with the setup i want to try, but the BEC is able to handle 12 cells. May try it, may not, Depends on how i feel when the esc and motor arrives. If i do try it i will put a fan on for better airflow. Once again, thank you for the advise and info, and for the reasons for the advise, some good info there.

If it doesn't fry with there 7700 motor, then a miniscule 9XL would never fry that ESC.

To be honest Mr Ford has to say that, a) because they didn't build it with large scale in mind so hasn't been extensively tested and Q/A'd for that application, b) an XL motor is a lot of motor to put on a 1:10 controller, I mean its 1.5x the size for one thing, and c) if it became commonplace for Mamba Max's to be used in Emaxx's and the like, wheres the target audience for the Monster Max, which no doubt will cost more and they will very likely make a bigger profit from.

Trust me mate it will work in your Revo as long as you use common sense and follow the advice that people have posted here. Finnster is running one in his Revo on 14 cells, and reports no problems. I have one in my Savage (heavier than a Revo), again no problems, with a fan over it, the hottest it got after a full pack today was 122F. That to me is damned impressive.

I'm going to put my 5700 in a touring car, because the t4 its in right now breaks everytine i run it (no gearbox issues, mostly chassis and suspension stuff). You're right, the mamba max is very impressive and delivered what everybody else couldn't, Top notch performance at a killer price.

Shawn is pretty much the only one at Castle that will green light using the Mamba as many of us are doing in big apps. But that is always with the understanding that the user knows what he is doing and that they are exceeding the intended use of hte controller. Warranty really doesn't cover these setups... but I can say they are very good to their customers so I personally don't worry about it.

I'm sure we can understand that they can't just ok such use publicly because many would end up smoking them due to poor setup/gearing, too many cells, etc

Shawn would strongly recomend using an effecient motor and of course gearing properly and monitoring gearing/temps. The Mamba has built in protection so it should not self destruct as some controllers tend to do... it will just shut down it you push it past the limits.

The bec is not a poor design and it has built in protection too... but what they say will happen when at it's limits is that it will shut off to protect itself and turn back on. It can do this many times per second if neccessary and this will be seen as at least a serious glitch if not complete shut off.

I would just run a separate bec... it's proven to be a solid setup. I don't recall anyone NOT using one is 12+ cell 1/8 setups. And they are only $15...

I have a couple from Dan at truerc.com... they were $15 and shipping was only a couple bucks.

I tried running the Mamba Max 4600 system in my Rustler on 4s Lipo with the internal BEC enabled. Let's just say it was terrible... That was definitely too much heat for the little BEC chip, and using the UBEC again fixed that.

I never worry about warrantees, if i do something stupid and it breaks, oh well. Thank you glass doctor and Metalman for your experiences and will keep them under advisment, as well as the others on this thread. I will probably try it as its within the parameters of what the esc can handle but will probably have to do a pack or UBEC eventually.
Will let you know what happens

I've been driving my revo with 12 3300GP cells, Mamba Max, and 8L and didnt disable the bec. It got hot (real hot)once when I went up like 6 teeth on the pinion and drove it in the basement(my ankle is still bloody:012: :012: :012: :012: ). But at 12/66 gearing on it, it wasnt really that warm and it was pretty fast. Mind you I do live right off lake Michigan and its freakin' cold out. Im going to test it today at the 16/66 gearing with a receiver pack and bec disabled. This is a budget setup. So far so good! I think I will make a video when the wife gets home also.

~john