Making an esc better?

[Dafni]

GriffinRU, just want to let you know that this double-stacked MM still holds up great!

[GriffinRU]

Originally Posted by lutach

Artur,

On the Schulze controller, I see the small SMT resistors next to were the MOSFET goes. If I wanted to make extra powerboars, would thee work with the same resistance or would I have to use different resistance for everything to work ok? The reason I'm asking is because I see a few controllers that stack powerboards to up the AMP rating.

If you noticed, I'm not using them because I have them on my power board. If you stack power boards (identical) there is no need to change resistors (but they need to be tuned if you happen to replace stock fets with newer/better ones).

So if you have two schulze controllers then you can make a double decker, like mambamax with minimum effort. But do not exceed the current ratings of the fet drivers, do the math with# of Fets, # of resistors in parallel, Rg and switching frequency. But with 2 boards you should be Ok, otherwise start sharing resistors and fight with ringing.

What's the current limit on these proto-types?

Probably PCB limited to 75A, Fets are 330W rated up to 160A at 100C

[GriffinRU]

Originally Posted by Dafni

GriffinRU, just want to let you know that this double-stacked MM still holds up great!

Hi Dafni,
Great, did you build one?

[suicideneil]

I think Dafni is using the one you sent to Mike for testing.

[Dafni]

Yes, must have been one of the first you did. Mike got it back in september. We put it on my XT8

[GriffinRU]

New boards are very well done, hard to take them apart. But heatsink attachment was very poor on 2 units out of 3 :( This one fall off by itself...

So first step is take 2 ESC's apart and prepare them for future assembly.

Remove:
- wires
- capacitors
- separate boards
- remove header from FET's boards
- clean holes from solder

At the end you should have this.

Further steps will follow...

[suicideneil]

At least if the heatsinks fall off by themselves, there's no risk of damaging the fets by prising them off.... :/

Anyway, I had another crazy thought the other night: since it is simple enough to synchronise two motors of the same type & connect them to on esc, do you think it could be done with two HvMaxx motors and the HvMaxx esc? Im thinking if you just wire up one motor to the esc with the 3 main power wires & sensor wires, then wire the 2nd motor to the 1st (in sync), could the esc handle it with a few simple mods? I've seen how you (GriffinRU) beefed up the pcb traces with copper wire & extra solder to increase amp handling, so do you think it the could handle the amp draw of two 6.5 motors (since they are less demanding of the esc than the 4.5s), or would better fets be required than those fitted as standard?.... just another crazy idea, since twin HvMaxxes would be as good as the Twin VXL setup almost, but having to use two escs, two motors and 28 sub-c cells sounds a bit mad, and 2x 4s is abit expensive for my pocket....

Originally Posted by suicideneil

At least if the heatsinks fall off by themselves, there's no risk of damaging the fets by prising them off.... :/

Anyway, I had another crazy thought the other night: since it is simple enough to synchronise two motors of the same type & connect them to on esc, do you think it could be done with two HvMaxx motors and the HvMaxx esc? Im thinking if you just wire up one motor to the esc with the 3 main power wires & sensor wires, then wire the 2nd motor to the 1st (in sync), could the esc handle it with a few simple mods? I've seen how you (GriffinRU) beefed up the pcb traces with copper wire & extra solder to increase amp handling, so do you think it the could handle the amp draw of two 6.5 motors (since they are less demanding of the esc than the 4.5s), or would better fets be required than those fitted as standard?.... just another crazy idea, since twin HvMaxxes would be as good as the Twin VXL setup almost, but having to use two escs, two motors and 28 sub-c cells sounds a bit mad, and 2x 4s is abit expensive for my pocket....

For what it's worth, I had an e-maxx with 2 hv-maxx 4400's (2 esc's). I ran 24 and 28 cells. It was pretty fun, my Neu 1515 1y on 4s is better though
Pic:


Bye

[suicideneil]

Thats the good stuff right there. It does seem much more viable with smaller/lighter Lipo batteries, but then again a good motor like a Neu or Lehner etc will still beat it. Oh, apparently the techs at Novak said the new HV system they are working on wont be ready until the later half of next year, which sucks a bit, but I can wait & experiment in the mean time...

[GriffinRU]

• Sanding FET's for better adhesion and flatness
• Silver epoxy Top side of middle Fet's board
• Silver epoxy Bottom side of middle Fet's board
• Attach brass heatsink to top and bottom (Remove LED's)
• Solder Header to Top Fet's Board
• Solder new Caps to Top Fet's Board
• Check alignment of top and middle boards
• Apply heatsink grease to bottom Fet's of Top Fet's board
• Solder headers and caps, trim caps leads
• Attach brains pcb, trim header
• Prefinal view

Further steps will follow...


To suicideneil:
Why using bad motor when you can utilize better one, have you checked my thread about 7XL running on sensored mode, borrowing sensors from HV-Maxx motor?

[Serum]

my Neu 1515 1y on 4s is better though

I am not surprised by the useless cells you used on your hvmaxx!!!!

are they updated with the sintered rotor? i guess not?

I'll shoot a movie of my hvmaxx 4400 powered maxx on 4S lipo.. You will be surprised.



@griffinru;

Thanks for the write-up.!

[suicideneil]

Man, you make it look so easy. As for motor choices... well, there are plenty of better, more powerful & more efficient ones that could work with the HvMaxx esc via your clever mod (I've read that several times- impressive doesnt come close to describing it). I just feel that I like the sensored smoothness of the HvMaxx esc, so if there was a way to improve its amp handling capabilites -IE: so you could use two motors as I described, then that would be a rather nice route to try; the HvMaxx motors are only about $110 or so, which isnt too bad. I'd like to see the video Serum, you've got me all excited and interested!....

[GriffinRU]

You Welcome, Rene!

Originally Posted by suicideneil

Man, you make it look so easy. As for motor choices... well, there are plenty of better, more powerful & more efficient ones that could work with the HvMaxx esc via your clever mod (I've read that several times- impressive doesnt come close to describing it). I just feel that I like the sensored smoothness of the HvMaxx esc, so if there was a way to improve its amp handling capabilites -IE: so you could use two motors as I described, then that would be a rather nice route to try; the HvMaxx motors are only about $110 or so, which isnt too bad. I'd like to see the video Serum, you've got me all excited and interested!....

It won't be cheap to double current capacity of HV-MAXX ESC, but you can try to increase heatsinks surface area by replacing stock heatsinks with something custom (Just make sure not to short them).

Have you tried VXL ESC with sensored motor?
And I'm pretty sure Feigao has a 60A sensored car controller.

[suicideneil]

Interesting ideas. If only the VXL esc was 4s and not 3s, I would jump at it! Hopefully traxxas will bring out a higher voltage esc sooner or later, then I could run almost any sensored & sensorles motors (within reason). Hurry up traxxas.

EDIT: Is this you?

http://forum.rcdesign.ru/uploads/photo-4415.jpg

I dunno what I was expecting, but... that wasnt it!

[DrKnow65]

Very nice Artur! (you do make it look easy having done a little modding myself now) I see you are using the 3rd generation MM boards, any problems running 6S? I seem to remember some guys having problems going above 4S, someone said they thought it was voltage protection for the new fet's...

Also on the new fet's do you have a link to the fet spec's? I've seen the part number but I can't seem to find the specific fet.

I know with the lower fet count there appearse to be "open" spots for fet's, any chance one could add the extra 8 fet's to each board and esentially be tripling the capacity?

Lastly do you think it would work to do the extended buss/dual heatsink setup like I did with mine while using doubled up power boards? (mine is working GREAT and actually feels colder than ambient after a good hard run- of course I'm running a very light load setup with the XXXT/5700KV 2S lipo)

P.S. I found carefully using a wire gauge drill bit the same size as the 22awg buss wires to "clean out" the pcb holes made assembly much easier.

Will post pic's of my completed mod as soon as I find out what you guys are using to post your HUGE pic's (wink,wink, what service /how do you do that???)