Adding capacitors to a Quark 125B

[zeropointbug]

Here is what I did to my 'Quark', if you want to call it that anymore. I used some flattened copper tube as buss bar and soldered 6 extra caps directly to the board. After I did that, I got magic-Mike the make me a FET clamp to squeeze the FETs with thermal paste (AS-5), and mounted it to a large heatsink for great cooling.... a little overkill, yes.... do I regret it, never!

Anyways, it runs even better now with these mods to it, smoother (if that's possible), I can't even try to make it cog, it seems like a sensored brushless system now. It stays super cool running 7s2p A123 (equal 6s lipo) on a Neu 1512 3D (1700Kv.), and it has got awesome power with power readings on Eagletree of 2100 watt spikes. The motor gets up to 160F at the end of a 30 min runtime.

EDIT: I also got my caps from AAngel. A group purchase sorta.

Originally Posted by zeropointbug

Here is what I did to my 'Quark', if you want to call it that anymore. I used some flattened copper tube as buss bar and soldered 6 extra caps directly to the board. After I did that, I got magic-Mike the make me a FET clamp to squeeze the FETs with thermal paste (AS-5), and mounted it to a large heatsink for great cooling.... a little overkill, yes.... do I regret it, never!

Anyways, it runs even better now with these mods to it, smoother (if that's possible), I can't even try to make it cog, it seems like a sensored brushless system now. It stays super cool running 7s2p A123 (equal 6s lipo) on a Neu 1512 3D (1700Kv.), and it has got awesome power with power readings on Eagletree of 2100 watt spikes. The motor gets up to 160F at the end of a 30 min runtime.

EDIT: I also got my caps from AAngel. A group purchase sorta.

I'm trying to copy this mod. How the capacitors are attached to the copper tube, + and - cords?

Also, how are the FET clamp + heatsink and Quark put together to get correct pressure between copper and fets?

[zeropointbug]

HERE is the link to more pics on the MOD.

"How the capacitors are attached to the copper tube, + and - cords?"

-What I did was lay the cap down, trim the leads on them, wrap tape around it once to make sure they don't move... then lay the +, or - leads onto one of the copper bars, then using a decently powered soldering iron, use alot of solder to bond them to the copper bars. I kinda slid the iron along while applying the solder behind it as the copper had alot of thermal capacity to do this.


"Also, how are the FET clamp + heatsink and Quark put together to get correct pressure between copper and fets?"

-The FET clamp is aluminum, Mike made it for me, so if you want one you could ask him if he still has the CAD file to machine it again? But, I just took the maximum thickness (can't remember exactly), something around 5mm from FET surface to FET surface, IIRC... then used that. The clamp was quite tight yes, I felt like it was going to crack something, but it was fine. It was perfect pressure on the FETs, it sucked every lat bit of heat from them and efficiently transfered it to the large heatsink (overkill) I got from a PC video card that died. How the FET clamp is attached is by thermal adhesive paste (arctic silver brand)... and that worked great!

In the end though, the Quark ended being killed... because it was mounted in a stupid spot, and when doing a wheelie, the truck flipped over and put alot of pressure on the body shell, and the Quark was right underneath, and pushed on the 'brains' board and shorted soemthing out, killing the brains board, the power board on it is fine however! I am going to redo this mod with the Quark I have now, as summer heat is on the way...

Hope this helps! Any other questions?

Originally Posted by zeropointbug

HERE is the link to more pics on the MOD.

"How the capacitors are attached to the copper tube, + and - cords?"

-What I did was lay the cap down, trim the leads on them, wrap tape around it once to make sure they don't move... then lay the +, or - leads onto one of the copper bars, then using a decently powered soldering iron, use alot of solder to bond them to the copper bars. I kinda slid the iron along while applying the solder behind it as the copper had alot of thermal capacity to do this.


"Also, how are the FET clamp + heatsink and Quark put together to get correct pressure between copper and fets?"

-The FET clamp is aluminum, Mike made it for me, so if you want one you could ask him if he still has the CAD file to machine it again? But, I just took the maximum thickness (can't remember exactly), something around 5mm from FET surface to FET surface, IIRC... then used that. The clamp was quite tight yes, I felt like it was going to crack something, but it was fine. It was perfect pressure on the FETs, it sucked every lat bit of heat from them and efficiently transfered it to the large heatsink (overkill) I got from a PC video card that died. How the FET clamp is attached is by thermal adhesive paste (arctic silver brand)... and that worked great!

In the end though, the Quark ended being killed... because it was mounted in a stupid spot, and when doing a wheelie, the truck flipped over and put alot of pressure on the body shell, and the Quark was right underneath, and pushed on the 'brains' board and shorted soemthing out, killing the brains board, the power board on it is fine however! I am going to redo this mod with the Quark I have now, as summer heat is on the way...

Hope this helps! Any other questions?

Thank you VERY much for your excellent pictures of the details and other information aswell. Now I understand the structure. Sorry to hear that your Quark died, are you going to make exactly the same kind of FET clamp and capacitor system for your new Quark too? Or is it a new evo model?

I just received Nichicon 35V 330uF low esr capacitors for this mod and I got a processor heatsink (copper+aluminum) which have to be cut a little smaller due to it's weight.

Otherwise Quark 125B is very good esc but it allows only 10 mins driving with 6s2p A123, then it needs couple of minutes to proceed.

[zeropointbug]

Oh for sure! My pleasure!

Yes, I am going to use the same clamp, as it's just thermal paste (not adhesive) on the FET clamp between the FETs, so you can transfer any Quark onto the setup as you wish.

Just for information, my ESC temps when running 7s2p geared a hair under 50mph (and big battery...) were I think never more than 10 degrees F over ambient, IIRC. You couldn't tell it had been running even, VERY nice. I could push the truck as hard as I wanted... and plus it seemed to have ran smoother, especially on startup, never cogged, ever. With my new Quark, it's annoying when I cogs, always at the wrong moment. Which only happens to me on 7s2p though, which was the same problem ppl have on 6s lipo.

[GriffinRU]

If you want it compact check this:
http://forum.rcdesign.ru/index.php?a...ntry&id=119589
http://forum.rcdesign.ru/index.php?a...ntry&id=119590
http://forum.rcdesign.ru/index.php?a...ntry&id=119591
http://forum.rcdesign.ru/index.php?a...ntry&id=119592
http://forum.rcdesign.ru/index.php?a...ntry&id=119593

[zeropointbug]

Yeah, to be honest, yours should work just fine with even the most high end setups. What were the temps on that thing anyways? The only benefit my FET clamp has is the cap bank on the esc, which will make it that much more durable, although, overkill I might add, but none the less.

Originally Posted by GriffinRU

If you want it compact check this:
http://forum.rcdesign.ru/index.php?a...ntry&id=119589
http://forum.rcdesign.ru/index.php?a...ntry&id=119590
http://forum.rcdesign.ru/index.php?a...ntry&id=119591
http://forum.rcdesign.ru/index.php?a...ntry&id=119592
http://forum.rcdesign.ru/index.php?a...ntry&id=119593

Do you have dimensions of these parts? It would be easier to find suitable copper piece. Is there thermal paste between copper and outer aluminum case, too? Or is it good enough with just copper against aluminum?

Both mods here are excellent, I can't decide which one to choose...