Quark fried, blown capacitor...

[BrianG]

Most ESCs have them right near where the power wires are, so anywhere near there is fine. You could even solder them to the actual power wires too; just strip back a tiny bit of insulation as close to the board as possible, wrap the cap's legs around each wire, and solder in place. You probably should find a way to insulate that area a little to prevent shorts. If you use a wired cap (like Novak uses), keep it as short as possible; makes no sense to use a low ESR cap if you add wire resistance.

The caps are marked with a stripe or even a - symbol on the negative lead.

[jhautz]

the stripe is negative or positive?

The wire stripping thing is what I was thinking. Just wasnt sure if it mattered how close to the board it was.

Geez, I'm going to have to go back and re-read this whole thread. I've almost forgotten exactly why it is that we're doing all of this. Will this make things easier on the batteries?

OK, someone is going to have to post showing the most creative way of mounting these things.

[zeropointbug]

ah Geez, you forgot already?! :005: You were even 'Franked' today on the phone! :005:

jhautz, yes, the white strip will be the negative lead.

A good idea of mine to mount up to 6 caps, is to tap the input leads with short run of wire, say 6cm, long enough to mount 6 caps down the length. I would strip slots in the wire insulation for each caps leads to penetrate the wire, and solder each cap into each slot in the wire. Or you could make the half the length and mount two caps per slot (one on each side). I would then shrink wrap those caps, or use the packing tape (the strong stuff with fibers in it) to secure them. You will want to mount these in a way that they WILL NOT bounce around or get physical abuse, indeed they can't handle that $HIT.

Let me know if you don't understand what I meant.

ZPB

You're talking about having two strands of wire 6cm long with caps hanging off of them and then soldering these wires to the input leads, right? If you do that, how would you keep them from bumping around. Also, if you shrink wrap them, how is the heat going to get out?

Man, if I had a strip of anodized aluminum, I'd make a cap bank and epoxy that thing to the top of the quark.

What about this...

Make a cap bank using two strips of copper. Solder that all up. Then take the bank and use some sort of electrical insulator. Maybe just a piece of themal pad and stick it to a piece of thin aluminum. I mean really thin. Thin enough to bend with your hands. What I ultimately envision is an aluminum box with the caps inside. Before you make the last fold of the box, you could wrap the ends of the box with tape and fill the whole thing with thermal epoxy, leaving the two copper tabs sticking out for soldering a piece of wire to so that you can tap into the power leads. For the epoxy, you could just use some devcon two part. When you mix it, just add a generous portion of aluminum oxide power for home made thermal epoxy. Voila, encapsulated cap bank that will shed heat.

You should try this homemade thermal compound. It's a lot cheaper than AA, but it doesn't work quite as well. It does work though. You can get the aluminum oxide powder from hobby stores that cater to rock collectors. Lapidary polish I believe it is. It's just aluminum oxide and does not conduct current nor has any capacitance. You'd be surprised at how well this stuff moves heat.

Here are some caps I just installed on a couple of ESC's. I just put 2 on each ESC. The CRT with the with Quark and the MM is going to be for an 8ight buggy. I did have a chance to run the CRT. It was running really great, but I had changed the gearing all around. I put HPI Pro diffs in front and rear and changed the center diff to 46/12. The changes were all good.

[jhautz]

Did the caps make a difference? Was there any temperature benfits?

The Quark was running a lot cooler but I don't know if it was from the grearing changes or both. It was at least 90*F that day and the Quark was at 112* after 20 min and usually it is at 130-148*F. You can't really see it in the pics but I have the heat sink and 2 of the 40mm fans underneath the ESC. I wish I had more of a definite answer.

Btw those caps are the 270uf ones.

[zeropointbug]

AAngel: That does sound like another good idea. How thin of copper were you thinking? I can't even get copper buss bar where I live, as it's a smaller town.

About the heat, with 4 extra caps on it, the heat output from each one will be much lower than the two in the Quark. Even with shrink wrap on it, it will dissipate more than enough heat. The wire would only be two pieces, + and -, all of your caps solder to this, down the length.

Since you mentioned this, I would like to see an RC car controller with a 'spilled' housing. It's like a moderately thermalling conducive plastic that is pored into an esc housing with the board, and a heatsink is sealed onto the FET's and protrude out of it, also, with 5.5mm plugs (female) sticking out of the housing. No dirt, shocks, or water can enter the thing.

[zeropointbug]

Originally Posted by Cartwheels

The Quark was running a lot cooler but I don't know if it was from the grearing changes or both. It was at least 90*F that day and the Quark was at 112* after 20 min and usually it is at 130-148*F. You can't really see it in the pics but I have the heat sink and 2 of the 40mm fans underneath the ESC. I wish I had more of a definite answer.

Btw those caps are the 270uf ones.

That looks pretty good with the caps on the Quark there, the ones on the MM, the wires look a little small, IMO. How is your Quark mounted to your heatsink exactly?

Where did you get these caps? What brand are they? low-esr?

[zeropointbug]

I looks like a person would have to solder 24 caps on a controller to get an equivalent ESR as these ultra-caps I purchased. Also, the rating on the ultra caps is at 1khz (0.0025Ohm), and the caps are rated at a standard 100khz (0.06Ohm).

BrianG, or anyone: Do you know how this will compare? At the different frequencies?

hi like i said #7 before.
just use 470uF/35V u-Low esr cap x 4(P) to soldered power-line.

it's will pretty cool esc, i am try long time.


By the way, something my experience,
you maybe need re-soldered quark power-line wire and motor line wire,
better need use PB-free solder with silver 6% or more and 220c temperatue up good solder.
it make sure your quark has hi-temp do not melt your junction.
this my experience..
hope this help.

zpb, I want to use strips that are thick enough to be rigid. I want to mount (epoxy) the bank to the side of the case and bend the strips down to meet directly with the power leads to be soldered. I'll then put a coating of liquid electrical tape on the exposed connections. I'm going to try to find some copper strips. If I find myself in a pinch, I'll just go to the hardware store and buy a length of copper pipe and cut strips out of it. I don't know much about metallurgy, so I'll take a quick resistance reading with my Fluke before I go soldering stuff to the pipe strips.

As for the caps, personally, I have no idea what will be the best, but I know what I'll be using.

andy, thanks for the info. I'm glad to know that the addition of the caps does indeed help to keep the esc cooler. I've been using silver bearing roisin core solder for a long time now. I got it at Radio Shack and is supposed to be for electronics. I like it because it makes a strong mechanical bond. I've actually repaired copper and brass parts withit and it holds very well. Much better than epoxy.

[zeropointbug]

Cooler running, yes, i DO recall someone saying that? Do you remember who that was? :005: :005:

[MetalMan]

Originally Posted by zeropointbug

car controller with a 'spilled' housing. It's like a moderately thermalling conducive plastic that is pored into an esc housing with the board, and a heatsink is sealed onto the FET's and protrude out of it, also, with 5.5mm plugs (female) sticking out of the housing. No dirt, shocks, or water can enter the thing.

Have you seen the Mtroniks brushless ESCs? Those have the FETs mounted to the aluminum body/frame of the ESC, which also acts as a heatsink. There are solder posts (instead of your idea of using plugs). It is sealed in a semi-translucent epoxy filler-type stuff.