hmmm, all I can find on Digikey is surface mount type caps, but a good selection though.

Also, what is the difference between cut-tape (CT), and Tape and Reel (TR).

I would like to find out what the voltage ratings on the ceramic caps(Novak trans-cap), and the transient chip are. Then maybe I could just mount a higher voltage cap to it?

I'm sure ESC manufacturers could integrate these chips onto their boards, you would think. For example, the Quark, they could have soldered the FET's closer to each other, and added an extra capacitor, maybe a few more ceramics too, their is room after all.

It looks like three of the trans caps in series will provide the same ripple current as three 35v 330uF caps in parallel. Plus the hf ceramic caps, and the transients are a bonus. I think I can make a nice little package of three of these soldered together nicely.

Cut tape means just what it sound like. The SMT components come packaged on a plastic tape and they just cut the tape to fill your order. On the tape and reel, you get a whole reel of the components on the tape. For smaller quantities, you'll be getting cut tape. It's what I always get. It you've never bought any sort of quantity from digikey before, just be sure to check their quantity pricing. A lot of the times, buying 250 only costs a little bit more than buying 50.

Oh, the stuff I used to buy that came on cut tape were really small resistors; 0603 through 1210. I don't know that a component, as large as a capacitor used on an esc, would come in cut tape form. Make sure that what you are getting is the physical size that you want. I don't know.

ZPB: Just remember that caps in series calculate like resistors in parallel: Total capacitance = 1 / ( 1/C1 + 1/C2 +1/C3 )
So, if you get three 330uF caps and put them in series, the total capacitance is only 110uF, but the voltage rating is the sum of the voltage ratings of all three.

AAngel: Yeah, sometimes buying in quantity can save a bunch of $$$. So, if anyone wants to get some low-ESR 220uF/330uF 35v 105*F caps, I'm in for a group buy for 10-12 of them (plus shipping of course).

oh okay, after I typed the message, I kinda figured it out. I remember when I bought some resistors as well, they came on a line of tape, in the leads.

I know that, but if I get the 35v 330uF ones, I will use them in parallel. I was talking about the Novak trans-cap in series, which I don't really like doing, BUT IT'S SO DANG TEMPTING! :027:

What do you think about the trans-cap in series? three of them.

I also wouldn't mind getting a bunch of caps as well Brian. Have you found any radial type caps, all I have found is surface mount.

wait, don't you mean resistors in series as well? That's not a very good comparison still, IMO. :030:

Nope, with resistors it's just a simple sum.. (in series that is)

Here; this offers some help;

Resistors in series;
http://www.physchem.co.za/Current%20...ors.htm#Series
Parallel;
http://www.physchem.co.za/Current%20...s.htm#Parallel

Capacitors in series;
http://www.play-hookey.com/dc_theory...apacitors.html
Capacitors parallel;
http://www.play-hookey.com/dc_theory...apacitors.html

I know, resistors in parallel, you divide the Ohm value by how many you have, series, you multiply, but in each case, the power dissipation goes up by the total number you have.

is that what you mean? power dissipation?

I really like this trans-cap idea, I think it's worth it, $45 for three, and possibly the best protection for a $280 controller, and prob better performance. IMO

You have any idea why capacitors are on controllers? not to protect the controller. They protect the batteries from the fast pulses the BL controller uses to spin the rotor.

Batteries will get a high internal resistance on pulse loads.. (on both discharge and charge) (throttle/brake) voltage will drop, batteries will get hot. They just can't deliver the juice on the high frequency the controller works on. Not talking about acceleration peaks but the switching frequency. Not to mention the pollution it will cause in the HF region..

Best way to protect the controller is to use trancil diodes on the motor side.

Yes, they are to protect the controller, it would probably run cooler if you have more capacity, low-esr of course, slightly more power. Yes, they also protect the batts as well, they simply can't deliver the short pulses.

Read my post again, i am saying the opposite.

Why would they protect the controller?

Those Trancil diodes seem like they might help to clamp the back-emf pulses from getting to a really high value, especially with high-inductance motors. I just wonder how much power they can absorb. It's hard to see the underside of the board, but I don't think either Quark or the MM use them...

Personally, the only thing I'd want to do is add a little more capacitance on the input so the existing caps don't have to work as hard.

It's too bad these controllers pull so much current in a way, because I think a low turn coil on the battery lead would also help supply a bit of current boost as well as filter the ripple from the batteries. That in conjunction with the input caps would create an LC filter. Unfortunately, the wire would have to be quite thick (or even use Litz wound coil) and may even need a ferrite core to concentrate the flux, but then the controller would start getting kinda heavy.

I've seen them which are capable of killing 1500 watt spikes. And you can use them parralel to gain more power.

I meant protect the controller from heat from switching, better caps will provide faster switching? Is that right? And I thought they protect whole system from noise, spikes, voltage ripple?

What kind of voltage are talking here? Where have you seen them, on a controller, or just the part?

It's a transil diode instead of trancil. My bad.

http://www.st.com/stonline/products/...re/an/3568.pdf

they are available in several voltages (a LARGE variaty, from 6-600volt or so; found an 18V type, which can withstand 1500 watts during 1 milisecond.

Good thing about these transils is they work bidirectional.. (at least, that's what i thought)

http://www.ortodoxism.ro/datasheets/...onics/8694.pdf

here, the 25V type seems to be interesting;
SM2T27A

I don't know if their capacity has got negative influence on the EMF signal though..

I thought about the effects of the needed feedback for the controller, but I figure it would clean up the signal if anything. If the signal is not a perfect spike (noisy on the top), then these would effectively shop that noise off - kinda like how FM modulation works in RF. However, because there would be no actual "peak", the signal might resemble a square wave more than a spike...

Cool, would that part be something like what the Novak trans-cap uses then? In the little pic, they look very similar.

Wouldn't 25v not be enough though? Wouldn't we need something at least like 30 volts or more?

For any kind of clamping diode or device, you select the voltage that you want to clamp at. It's not like a capacitor where you choose one about 15% higher voltage than the voltage you plan to run at. Kinda like a regulator; you don't choose a 6v if you want 5v...

No, i know, it's just that 6s Lipo is 25.2 volts, I know no one runs it, and the controller is meant for 25v.... just a thought. I guess for most our setups, the 25v would work.

Brian, have you found some good low-esr caps on Digikey.com? I can't seem to find any, only a few surface mount types, which I don't want, as you prob as well I'm assuming?

No, I haven't really looked yet. And no, no surface mount caps for me...

Got yah...

I have looked and looked for a supplier good low-esr caps, I have given up. There are those ebay ones, which are 35v/1500uF for $19 for 25 caps (good deal), and the one 25v/2700uF Novak cap, which is enough voltage rating for up to 4s LiPo; the Novak one sells for $10, which all you are paying for is the Novak sticker, maybe they ARE good caps, but thats not the cost...

Here are some good options:

Novak 25v/2700uF low-esr (unknown manufacturer)

http://www.shopatron.com/product/pro....56.7400.0.0.0

Nichicon 35v/1500uF low-esr (better choice IMO)

http://cgi.ebay.com/25-Nichicon-35V-...QQcmdZViewItem

Or, if you want 200 capacitors, there are 330uF caps, like the ones IN the Quark . $26 for 200 caps.

http://cgi.ebay.com/200-Nichicon-35V...QQcmdZViewItem

Wow, 200! I was thinking of about 20, lol. But yeah, the ones they use in the Quark, just more of them would be nice to use.

HERE is the data sheet on those, they are Nichicon PM series caps. They are the best series that have 35v rated.

The 330uF has 0.06ohm (100khz), and the 1500uF has 0.024ohm (100khz). So five of the 330uF to get roughly the same capacity as the 1500uF will get you 0.012ohm, pretty good.

I am trying to decide between these. :024:

I still want to try those 140 farad Maxwell Ultra capacitors, it appears as thought they have better ESR than these low-ESR caps. Even factoring in the frequency coefficient for ESR

DC ESR: .0072ohm

1KHz ESR: .0036ohm

It looks like to me they would do a better job with such low esr, and very large capacitance available. Plus you would have extremely high power on tap. Batts would only deliver the average current draw. They are rated for 530 amps with a short circuit, and 15,000 watts/kg. $5 a cap, you would need 8 for 4s LiPo.

You guys are true electronics buffs, and I salute thee. You got me thinking too- what would be the effect of wiring another capacitor (of the same type it uses) to a HVMaxx esc? I know it only runs at 14.4-16.8v,but the capacitor is rated for 2700µF & 25v; would it be beneficial in terms of what you've been talking about- smoother/better performance & reduced back emf etc?....

ZPB: OK, but 140F will make one hell of an arc! Current would be theoretically infinite, only limited by the battery capacity and wire gauge. IIRC, last time this came up, I suggested that you permanently wire a cap to each pack to avoid arcing from the initial connection. Just use a resistor on initial charge to force a lower charge. This would definitely let you use much lower C-rate batteries since the cap will take care of just about all current pulses. And you'll get closer to the actual Ah of a battery since it won't be running as hard. However, will the price and weight increase be worth it? I say you try it and see - I'd MUCH rather spend your money ;)

Are you sure those are the ones that Quark uses? If so, I'll probably wire an extra two on the Quark and a couple on the MM.

suicideneil: Running a capacitor at lower voltage is perfectly fine, it will actually extend the life of the internal insulator since it's not running close to its max. The only downside is the slightly bigger physical size. It'll be better for your batteries, but not sure if you'll see a noticeable increase in performance. But it sure won't hurt - just make sure you hook it up right. :)

Did you read the whole thread back? The main reason why you should solder a few more caps on the input power leads of an esc is for reliability, number one, those caps take an electrical pounding, and stand back up for some more... well not always, like what happened to mine.

Having more capacitance/less impedance caps

-They make for more efficient FET switching, prob a cooler running controller, thus more reliable
-Take load off the stock caps in the esc (which they are limited by space)
-May or may not achieve more power, smoothness. depends.

You can go ahead and try using that Novak cap if you want, see how it works. Having more capacitance is like a heatsink for electricity, the more the better.

I wouldn't call myself a BUFF, but thanks! :027:

I understand more physics stuff, not electronics per say.

Yeah, of course Brian! That wouldn't be an arc, that would be critical mass occuring at contact! :005:

I would have them as part of the pack, but wired with little wire as possible, and shorten all wires between it and the esc. I can also set current levels of 0.01 amps with the power supply I use, as you might know.

About it being worth it, I really do think it would be worth it, not considering weight, just looking at performance, reliability, and much longer cycle life of the battery. I wouldn't doubt it would pay for itself even before the battery is at end of life. I can see it AT LEAST tripling the battery cycle life.

BTW, I made a mistake on price, they are $15 for the 120F U-cap, you need 8. They have a calender life of 10 years, cycle life of 500,000.

It looks as though they have a high energy version and a high power version. The 120F being power, and 140F being energy, the 120F has a lower ESR of 0.0025ohm, the 140F is 0.0035ohm.

I was just thinking, this really sucks. I mean, we are talking about what is arguably the best large scale esc on the market right now. First we have to accept that it won't do 6S as it should; now we are hearing that when used for its intended purpose, we should add caps. Well, why didn't they add them?

As for the Caps in the ebay link. Are those the ones that we need? If so, I'll grab 'em.

Just to be sure, all I'm doing with them is soldering one leg to the + input and one leg to the - input on the esc where the battery wires are soldered to the esc, right?

I've had such crap luck with escs lately, that if this Quark lets me down, I'm liable to start a bon fire with all of my r/c stuff.

Oh, and why not smt caps? Form factor? Performance?

OK, never mind. I found a pic of one and I see why not.

AAngel: You bet, you can cut a little insulation from each lead and stick each cap lead into the wire strands and solder that. That's the only way I can think of at the moment? And yes, those on eBay that i linked, they will work very well, they are very low-esr caps. Kinda nice if one could find a better supplier, so you wouldn't have to buy 200 caps when you only really need two!

I totally agree with you that an esc like this cost, and performance should be better able to handle these vehicles. But the reason they can't put larger caps on it, is simple, space. They should make a little kit, or a "Quark" aftermarket cap they can sell if you are using a large RC car. I would only benefit them, IMO. The other reason this esc fails, is the heatspreader problem, if they fixed that, it would be 100% better.

The smt caps are useless for this, just try making a connection with those little tabs on them! :024: Most smt caps are solid polymer caps, which at the lower voltages (<16v) they have really good esr ratings, and they are very durable. Motherboard manufacturers are using them lots now, video cards have used them for about 5 years now. Nothing that will work for this app. though, the low-esr electrolytic outperforms them at these voltages, or at least what I have seen.

I don't have my Quark yet, so I've never seen one up close yet. Aren't the battery leads just soldered to a pair of holes in a PCB?

Anyway, are those the caps that are needed? The 300uf 35v ones linked to on ebay. It would seem that the price isn't bad for 200 of them.

I have decided I am finally going to give Ultra-caps a whirl! :027:

I am going to get the 140 Farad (x10), I'm only using 8, but the quantity pricing is better for 10, only $14 more for 10. $150

I am figuring the voltage drop on a 100 amp load will be less than .4 volts.

HERE is a link to the Online Shop

17,500,000uF anyone?:018: :005:

You could also use these, if you are using 4s LiPo. They are 25v/820uF, your choice.

Yup, those are the caps you need, they are the 330uF/35v.

The wire leads go through a hole at the end of the case, which is plastic. The wire solders adjacent to the pcb board. HERE is a pic.

Thanks for the pic. The Quark looks like it'll be easy to work on. I suppose, the first thing I'll do is upgrade all of the leads to deans wet noodle and add the caps.