Mamba Max and 5S?
 

Well, what are your thoughts on it. I'm thinking I am wanting a bit more top end out of my G2R (though gearing is light right now). I don't think I'll get the top speed I want no matter how I gear up, so I'm thinking of just going 5S to do the job.

I'm just wondering how the MM will fare? Just wanted some opinions.

Have you put in better caps? Back voltage is higher than input voltage so I think the 35v caps are a must.

If he does want to go with more caps, then he's lucky to know a guy who has a bunch :angel:

I do have a few caps (a couple of the Novak HV caps and also 4, 330uf, 35v caps that I got from suicideneil). And I'm sure MetalMan has a boatload like he already mentioned. :yes:

So if I just put on more caps you guys think I'll be ok?

I figure that more voltage will help reduce current loads and therefore will be less stress for the ESC, since the FETs are technically rated for 6S...

I melted some excess solder when I ran mine on 5s and it blew out a few fets.

This may have been due to a huge voltage spike casue b a rock in my spur gear. And the fact it was spinning a 7xl. Add a few caps and give it a try, just gear low and take it easy until you get some good temp readings.

I will say that a 7xl on 5s lipo in a 1/8 buggy is badass, never got a chance to get it hot, but i am sure that it would cook!

This is a 1940/7 in a G2R. Its pretty lightweight (~9.2lbs) and has a pretty smooth drivetrain.

I run a G2R with a 1950/7 and a MM. I usually run 2 2s2p 6000 mah. I put a 3s2p 8000 on with one of the 6000's and the truck moved. BUT the MM was hotter than it should have been. Dont:neutral: have a temp gun so can't give you a degree but it was cooking.

are you guys saying if you just add capacitors to an esc it can handle more volts???

the nice thing about the MM is that it'll only cost you 50 bucks if it doesn't handle it well. :smile:

Depends on how badly you overloading stock MambaMax, in some cases it helps in some it is just not enough.

ohh. does it work with any other escs?

No, most ESC's comes with correct caps inside to start.

you make bigger caps sound like a bad thing...

They do help battery but not much for ESC...
In MM case above 4S and with higher currents caps start to overheat and once their temp goes up all the good things they used to do for ESC vanishes away. Following with failures first and smoke second...
Also "bigger" caps are not always better then smaller ones, there are specific parameters and placement which makes them good.

not trying to be a pain but, what are the parameters?

ESR (L is hard to find in data)
Rated Current
Rated Voltage
Operational Temp

First parameter with can size will drive rated current, rated current with voltage will define rated power.

Well, if I'm not mistaken the caps I got from Neil are the same ones that were part of the RCM group buy, so to speak, and if I recall most are using them with great success...

But that aside...what is the general consensus? 5S on a Mamba Max ok or is that pushing it?

Read my post, check your caps, if they better or close then 41mOhms/1240mA/105C
Then you got a deal.

5S information useless, unless you specify motor/vehicle weight/gear ratio, or just power if you can.

They are 330uf each, 105C, 35V. I couldn't find ratings on resistance.

The vehicle is a G2R that weighs between 9 and 9.5lbs, running a Lehner 1940/7 currently geared at 51/16 with an old E-Maxx tranny locked in second gear. Running Traxxas Response tires all around (decently lightweight). Batteries right now are a pair of 2S FlightPower Evo30 4500mah packs wired in series to 4S. Was planning on getting a pair of 3S packs to make two pairs of 5S...

A lot of low-ESR caps I've looked up don't specify the resistance per se, but do list the AC ripple current they can handle without heating up unduly, or list the operating temperature. Generally, the 105*C temp rating is a good bet they're low-ESR...

Based on continuous run with ESC at 50C.
at 10A draw -> ~6.6W at 50C dump at ESC "Ok"
at 15A draw -> ~14.85W at 50C dump at ESC "Ok""
at 25A draw -> ~41.25W at 50C dump at ESC "Ok"
at 35A draw -> ~80.85W at 50C dump at ESC "Ok/No"
at 50A draw -> ~165.00W at 50C dump at ESC "No"

It is quite easy to check current draw with eagletree.

I have more pinions so I can gear down accordingly...

Unfortunately, I don't have an eagletree...

Do you know your run-time?

Thread moved to Castle Creations.

hiya all, sorry to ask this, sorta new to this and just try`n to read up as much info as i can before i go out and buy a truggy to convert. At the moment i have a crt .5 conversion, so its easy to run my MM on the 3s to keep that truck run`n along, but i was looking at get a thunder tiger st-1 and putting in a neu 1515/2.5 and get a 5s, but was wondering if i should get a new ESC as well or can i stick with the MM. was reading the post on this threads but some of the stuff sorta flew over my head. thanks for any of the help, like i say not in a big rush, just try`n to find out what i should save up for. hopefully by the time i decided to get all this, the MMM will be out.

Today I tried powering up the MM on 6s. It worked when I turned off the cutoff just like GriffinRU said. But from what i'm reading here it looks like I better forget about 6s if there is any question about 5s. GriffinRU also said his mod doesnt affect the MM's ability to handle 6s either, so I guess i'll just have to wait for the "MMM"?

It would handle 6S but it won't protect your LiPo batteries. If you want to be safe with LiPo then you can cheat, by monitoring only half of your 6S LiPo cells. To do that you need to unsolder...is it scary?
If not, than unsolder black wire (close to red power wire) from power switch.
Then split your 6S LiPo into 3+3 or 2+4 whatever combo, you can even tap into balancing taps...
Attach you full 6S voltage to regular MambaMax power tabs. Then attach black wire from switch to red wire from lower side battery. Something like black wire from battery one to negative tab of ESC, red wire from the same battery to the black wire of next battery and black wire of power switch then red wire from second battery to positive tab of ESC.
I will try to draw or publish picture later over the weekend...
Then set you MambaMax cutoff at number of cell corresponding to lower battery and you good to go!!!
<<< 6S LiPo under MambaMax >>>

MambaMax above 4S LiPo with LiPo support
 

Just to clarify, you have attached the switch negative wire to the blue wire? Have you done much testing with this setup already (like on 6s, to test reliability)?

Yes, that is correct.
I've tested it last week on the bench, right at this moment I am testing on E-Maxx.
Give me half an hour and I will update with real test info.

DON't TRY this setup!!!
 

DON't TRY this setup!!!

I encounted serious problems with this setup, not quite sure why. But I do need to investigate, it cogs like crazy at mid to high RPM...

Sorry, update will follow.