[TheSteve]

Long before the MambaMax was released I repeatedly bugged Castle(via Shawn Palmer) to build it with a 6 volt BEC. I've always been disappointed they didn't do it. High end brushed motor ESC's have been 6 volts for years now.

With that in mind I decided to upgrade a MambaMax to a 6 volt BEC. The easiest idea was to simply remove and replace the factory 5 volt regulators(the Max has two of them) with 6 volt units. There were two problems though - in the package style Castle decided to use there doesn't appear to a be a 6 volt variation of the regulator. I was also concerned about the BEC voltage being used internally in the MambaMax to power its own processor(which is limited to less then 6 volts) After ripping one apart to replace some fets I discovered there is a third 5 volt regulator which powers only the CPU and fet drive circuitry. This meant I could change the main BEC parts without fear of damaging anything else in the controller.
Since I couldn't find drop in replacements I decided to look for an alternate regulator. I decided to go with a regulator which has proven itself over and over again, the Micrel MIC29302(variable voltage output, 3 amp regulator) This is the same regulator Novak has used for years in its high end controllers. Reading online forums will show several ESC's with BEC dropouts and such but those problems never seem to happen to Novak controllers - this is an area where they got it right long ago(Excellent work Novak!)
I was given two blown up Novak Cyclone controllers from a friend and decided to "borrow" the regulators from them, along with the voltage output configuration resistors(why find my own when they are provided by the dead ESC's)

The regulator is configured for 6 volts and can handle a 3 amp load with the proper heatsinking. It was a bit of challlenge to fit in the controller simply because of the large metal tab on its back which had to be insulated from several other traces on the PCB. It also needed to have its ground tab soldered to the MambaMax pcb for heatsinking. There is lots of room in the MambaMax case for the thicker regulator, so that wasn't a problem. If Castle did someday decide to change/upgrade regulators they would just need to update the PCB layout. They would also have to decide to spend more money as the Micrel parts aren't as cheap as the generic 5 volt regulators they currently use.

I also discovered something else I think Castle could improve on - the existing on/off system has the BEC power running through the switch. I much prefer Novaks way of doing it, the regulator they use has a soft on/off option, the switch has next to no current going through it, it simply tells the regulator to turn on or off. This isn't a huge concern for me as I bypassed the on/off switch anyway, but its something they may want to consider in the future.
Obviously this will void the Castle warranty, I had to try it on atleast one controller though.
I have included a picture of the finished project.
To see what the original looked like refer to this link - http://forums.radiocontrolzone.com/a...id=72688&stc=1

[leomax001]

Originally Posted by TheSteve

Long before the MambaMax was released I repeatedly bugged Castle(via Shawn Palmer) to build it with a 6 volt BEC. I've always been disappointed they didn't do it. High end brushed motor ESC's have been 6 volts for years now.

..............................


..............................

I also discovered something else I think Castle could improve on - the existing on/off system has the BEC power running through the switch. I much prefer Novaks way of doing it, the regulator they use has a soft on/off option, the switch has next to no current going through it, it simply tells the regulator to turn on or off. This isn't a huge concern for me as I bypassed the on/off switch anyway, but its something they may want to consider in the future.
Obviously this will void the Castle warranty, I had to try it on atleast one controller though.
I have included a picture of the finished project.
To see what the original looked like refer to this link - http://forums.radiocontrolzone.com/a...id=72688&stc=1

.......... good job.......
but wasn't better to get another brand of esc...... ????

personally, I replaced my old mamba max with a Sphere competition TC Spec in my touring car, and it is way better, for sure......

http://www.lrp-electronic.de/e/lis/0...p_TC/80750.jpg

[Mr Mamba]

Great job!, thanks for sharing with us


Get another brand? Some of us are tired of seeing smoked Sphere's :P

[leomax001]

Originally Posted by Mr Mamba

Great job!, thanks for sharing with us


Get another brand? Some of us are tired of seeing smoked Sphere's :P

........and some of us are tired of "cogged" mamba in the track.... (especially when release and re-apply full throttle out of slow turn... ) or using fast digital servo at only 5 volt......

[Mr Mamba]

never have cogging, but I preffer have a little cogging than little quality

The bad thing is to have a 5v bec, the only thing I miss on the castle ESC, that why I use a 7.2 servo, much better an lrp with 5.5v bec ( does the TC one have 6v or stills on 5.5v?)

Dont get angry men, you ESC is great, lets hope that on third try of the sphere became much better that the castle one

[TheSteve]

Wow, comparing the LRP sphere to the MambaMax? The LRP is famous for BEC issues, falling apart and over heating, I'll pass on it.
Thats not to say I think sensored controllers are a bad thing, Novak is improving its brushless design with each ESC they release. The sensored setups are really geared towards the racers though, they don't offer the power and flexibility of a sensorless system from Castle or Schulze. I don't use nimh in any of my cars, I only use LiPo, and in touring I only use 3S LiPo, which means "poof" for most sensored controllers. I also don't have any cogging issues.
Anyway, this thread wasn't created to continue the endless debate over which is better, if thats what you want to do, start your own thread.
I simply wanted to show a "fix" for the only weakness I see in the MambaMax.

[Mr Mamba]

Hi Steve!

Could you please post a picture of the board to see how much taller is the new regulator compared with the usb ?? i mod to have less height my mamba case and I dont know if it will fit.

Many thanks again!

[TheSteve]

Sure, I can take a picture this evening. The new regulator is less then half a millimeter thicker then the usb port, so if you left even a little room for clearance you should be fine. Before you do try it though take a good look at the factory pcb, you have to insulate some pads on the pcb. I used kapton(polymide) tape to do this which is a high temperature/burn proof tape often used in electronics. Its also used in LiPo packs as insulation and looks reddish brown in color.

[CharlieS]

FOr anyone that doesn't want to go this route, you can also just use a our stand alone "NSR" (Nitro Servo Regulator). It would be wired to the ESC's power tabs then plugged into the RX. This is the same BEC/Regulator circuit we've been using for years. Remove the ESC's red wire from the harness and Voila, sure it's extra baggage in the car, but this is a mod I wouldn't be wanting to do myself..... BEC voltage and power make a big difference to how well everything runs, and how consistent your car works.

[TheSteve]

There are a good selection of external BECs thesedays. More then one of them is using the MIC29302. I am more then comfortable performing surgery on ESCs, receivers etc - I've been doing it since the Novak 4 ESC (not the T4) Adding it internally is also cheaper as the regulator can be had from Digikey for less then 5 dollars.

More then anything perhaps this is just a plea to Castle to consider updating the Max in the future.

[kufman]

much prefer Novaks way of doing it, the regulator they use has a soft on/off option, the switch has next to no current going through it, it simply tells the regulator to turn on or off.

This is bad for switches unless they are gold plated. Switches and relays need a little bit of current to clean the contacts when they are energized. Without this, the contacts tend to glaze over or corode and then they don't work very well. I personally don't believe in BEC switches at all since they don't disconnect the power from the drive FETs.

[TheSteve]

Having used Novak products for years I don't remember too many switch failures, I think they use good enough quality switches glazing isn't an issue.

I would totally support no on/off switches at all, especially with LiPo packs becoming more popular - its an absolute requirement to always unplug your battery when done.
Newer radios also make the switch less of a requirement - with 2.4ghz radio systems the radio won't come to life from the wrong transmitter.

[glassdoctor]

no offense Charlie, but as mentioned there are PLENTY of external bec devices out there, one of which is the Novak one. I have used several different ones myself and they all work fine.

Also... Castle has a nice bec device of their own soon to be released for about $20

This thread is obviously about a guy who likes a tinkering project, more so than a "need" for an external bec.

[CharlieS]

You're right sorry, all this Novak talk had me plugging away. I send My apologies sir.

[Joe Ford]

Noticed glassdoctor's post about our soon to be released UBEC so I thought I'd chime in. It'll be good for up to 6s lipo and you will be able to plug it into the Castle Link to set your cutoff voltage anywhere from 4.8v-9v. Approx dimensions 1" long, 1/2" wide, 1/4" thick...weighs about 4-5g. MSRP of $24.95...7A CONTINUOUS rating and 10A peak. We've also talked about integrating it onto the Max.

[JakeE]

Any idea on a release timeframe for the Castle BEC Joe?

[TheSteve]

Joe - I need one of the new BEC's to beta test, lol - sounds like it will really rock.

btw, look into the Micrel 29302 for a linear regulator

[mguebert]

Integrating it into the MAX speedo would be cool!

[rca]

yes integrating it would be good, but what about those of us who already bought the mamba max? can we send it in for the upgrade? I don't mind paying a nominal fee for it if it materialised

[kufman]

btw, look into the Micrel 29302 for a linear regulator

from the specs listed, I would be suprised if the Castle unit uses linear regulators. A linear regulator has to disipate all the power that it is dropping. That is, if the battery is at 12V and you want 6V at 3A, you have to disipate (12-6V)*3A=18W of power. On the Castle unit that would be (22.2-6)*7A=113.4W!! That must be a switching regulator.

Mr. Ford, Will the output be adjustable as well? Or will it be fixed at 5V? Cheap servo power is available with 6V.

[chilledoutuk]

i think that steve was hinting at the use of the Micrel 29302 in future mamba max's if they don't have other plans.

[TheSteve]

The Mamba Max absolutely uses regular linear regulators. Its rated for 3S maximum, any higher voltage and you need to disable the BEC - simply because of heat.
Hopefully the Monster Mamba max will use the new switching regulator Castle has designed.
I would like to see Castle use the Micrel 29302 in the regular Mamba Max as its a great part, its not likely to happen though simply because of tooling costs.(new PCB layout, new solder mask stencil, more cost and more testing etc etc) Hopefully they see this and consider it for the future though.
I think all experienced racers know how important the BEC is.

[Joe Ford]

kufman...the Castle BEC is a switching regulator, and the output is adjustable anywhere from 4.8v to 9v using the Castle Link software.

I'm not sure if we're going to integrate it onto the MM or the MMM...time will tell. I don't want to speculate, only give you gents hard data.

Castle BEC shouldn't be too much longer...fairly certain alpha testing is done, but haven't had time to catch up with the engineers...too much work and travelling to shows in a short period of time. Leaving Friday for the 1/18 NATS in CT...gotta get more work done. I'll check in when I get back.

[kufman]

Sounds good to me!!