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-   -   Quark fried, blown capacitor... (https://www.rc-monster.com/forum/showthread.php?t=6608)

zeropointbug 04.30.2007 10:34 PM

no comment.....

Yeah, that might be a problem, you don't want to go too big because of arcing like you said, your plugs might just become vapor after a while. :005:

Other option, what do you think about making a plug literally soldered right onto the board and poke out of the case? And have a cap bank on the battery end of things, right next to the deans, so almost no wire length between the caps and the case. But do you think caps should be on the other side of a plug?

BTW, i've tried to find solid polymer caps, but only made up to 16v. The only place I have seen them is a PC motherboards, video cards, some new sound cards. I don't want to run them in series either, IMO.

I wonder if ultra caps would help. Do you remember our thread back in Dec.? They would simply be for more power and take load off batts, but if used right, could they function as a power stage cap?

BrianG 04.30.2007 10:49 PM

One way to help with the arc is to use a light bulb between the last contact you make. Once the caps equalize, no more arc.

I'd keep the wire coming out of the ESC. If anything, use larger 10GA wire.

Yeah, putting caps in series will add their voltages, but halve the capacitance (assuming you are using two of the same values). Ultracaps might help, but are too big and heavy IMO. Not enough bang for the buck weight-wise. You have to keep the caps as close to the ESC as possible.

I would just add the caps to the PCB or the wires right before the ESC.

If you decide to get some caps, you usually can get a better price if you buy bulk. I would be interested in ten 220uf 35v caps. If we can get more people on this, it can be a group buy...

zeropointbug 04.30.2007 11:12 PM

ICIC

Where are you thinking we can get these caps? I can't remember what caps Quark uses, but I don't think they are the best, IMO. They should use three at least too.

What size are the ones in the Quark? 350uF? I can't remember.

Do you think it would be worth it doing a group buy, i'm just thinking of the shipping cost too... you know?

I wouldn't mind buying a whole lot of these either, like 50 or so, just to have for what ever. Low-ESR caps are fun when playing with pulse discharge.... brass washers.... wire coils.....:005: :005: Sounds like a gun shot when you short the coil out on a bank, and many disappearing coils. lol i was using 300 volts though.

Serum 05.01.2007 01:40 AM

Quote:

no comment.....
Guys like you are the reason why the guarantee rules get tighter and tighter.. No need to explain this, i think?

You 'modified' it, you need to tell them honest what you did to it. as simple as that.

Cartwheels 05.01.2007 02:11 AM

Couple days ago I just bought 10 of the 220uf 35v caps that Brian recommended. The price was pretty cheap from Digi Key, only about 3-4 dollars for 10. The shipping and handling was was probably 2 times that though.

BrianG 05.01.2007 10:01 AM

Let us know how you used them and how they work. Pics are required of course. :)

jhautz 05.01.2007 11:53 AM

Quote:

Originally Posted by zeropointbug
BTW, he said when I get it back, I should solder a couple good caps on the input leads for preventative maintenance. He said it should be done with large 1/10, 1/8 scale vehicles.

So I am going to find a source for these 'NICC' NRSH caps and use them. I like the looks of the 35v 330uF caps, maybe get 4 of them...?

Anyone got a recomendation for caps to use across the battery leads? Id like to do this mod. I feel like I push my Quarks pretty hard and anything I can do to help them I am interested in doing. Unfortunatley i'm kind of an electronincs dummy. I know capacitors basically just store a charge and release it when the overall system voltages drop to keep the votages as even as possible. How does adding more capacitiors help? Make it more resistant to voltage drop therfore drawing less amps by keeping the voltages higher?

Did S&T recomend a capacitior to use? A link to a place to purchase and any instalation instructions would be great.

BrianG 05.01.2007 12:19 PM

Yes, adding caps will help supply a little extra current boost when the ESC pulls heavy current in bursts, but the capacitance value of those don't really provide much help there. They are there to help absorb the back-emf pulses, since they are really A/C pulses. So, they are used as storage to a small degree, but more like A/C filtering. Maybe GriffinRU can provide a little more insight since he seems to have more experience with ESC design.

zeropointbug 05.01.2007 12:22 PM

They are not really for voltage drop, they are for power conditioning and noise/spikes absorption. They take a crap load of abuse, obviously, and more of them spreads the load between each of them. They also provide more of a pulse when switching.

We should figure a good value for the capacity and use that, too much capacity, to much arcing will occur when plugging in batts.

About 'no comment', all I said was the cap had blown, I looked in, saw it... I mentioned I had a plate adhered to the case. He just kept telling me to send it in and they would replace it, he obviously didn't care, then he was talking to some guy in Switzerland? Who could that be? :005:

But yah, I'm thinking either 4 220, or 330uF caps right in next to the Quark input. I'll let you know what I decide

BrianG 05.01.2007 12:40 PM

IIRC, the Quark has two 330uF 35v caps. Adding 2 more 330uF caps would bring the total capacitance up to 1320uF. Better yet, use three 220uF caps - same overall value but should handle the current better and the increased overall surface area will help with heat. It might be difficult to add three more caps close to the input and still have short leads and not look like crap. Two should be fairly easy though.

zeropointbug 05.01.2007 12:54 PM

yah, 2 330's sound pretty good. Also, what do you think if one made a little cap bank of say 4-6 caps of 330 and made another input in the case right next to the batt input, and had the bank protected by shrink wrap? It would sit right up to the Quark, either they lay down on side, or 4 standing up in a square bank, do you know what I mean?

zeropointbug 05.01.2007 12:56 PM

what does IIRC mean?

BrianG 05.01.2007 01:31 PM

Yeah, a little "bank" should work ok. Just keep in mind that the more capacitance you add the more arcing on battery hookup.

IIRC=If I Remember Correctly. :)

zeropointbug 05.01.2007 07:05 PM

Quote:

Originally Posted by jhautz
Anyone got a recomendation for caps to use across the battery leads? Id like to do this mod. I feel like I push my Quarks pretty hard and anything I can do to help them I am interested in doing. Unfortunatley i'm kind of an electronincs dummy. I know capacitors basically just store a charge and release it when the overall system voltages drop to keep the votages as even as possible. How does adding more capacitiors help? Make it more resistant to voltage drop therfore drawing less amps by keeping the voltages higher?

Did S&T recomend a capacitior to use? A link to a place to purchase and any instalation instructions would be great.


Oh sorry didn't reply to you. The capacitor they recommend, sort of (easily available somewhat) is the Novak power capacitors. Just so they can say hey, here, this is the one we use, they work.... know what I mean.

Here is a LINK

They look good to me, should work great for the Quark, having 2 680uF caps.

zeropointbug 05.01.2007 07:22 PM

Forget that, that is the wrong capacitor for this, it's only 16v caps. They just mentioned Novak caps, so I searched it. But I can't seem to find 35v Novak ones, they seem to only have 25v caps, I don't think thats enough IMO.

I'll find something.


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