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Angel, I guess I will have to find myself a busted quark and do the mod and see if it can be done. Might be fun. It will only be illegal if I sold their software, which they only have. There is nothing they can do if you purchased the product and modified it, accept refusing to honor the warranty. Isn't that what you guys are doing with these things in the first place. Adding caps, heatsinks, new cases. Those are all hardware mods, software mods can be done too. Same thing with 1:1 scale cars and modifying/reprogramming the ecu for better performance. If a piggyback rom can be build for more features, then why not.
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I really think you have THE worst luck with RC I have ever heard! The only thing I can think of is the thermal pad inside isn't fully "stuck" so the FETs aren't making good contact. But three Quarks that have problems? Wow is all I have to say... |
Brian, "wow" wasn't the word that I used. LOL
I'm tired of messing with it. I put the MM back into the truck and will run it until my Neu gets back. Then I'll pull the Quark apart and do the mod. BTW, I did find the little note in the Quark manual saying that if you need finer low speed control, you should narrow the neutral range, so this is probably why zpb has such fine low speed control and I don't. They do warn that running a narrow neutral range can cause cogging. I'll have to try it. |
O.K. I've been out of town unexpectedly, so....
Zeropointbug- Do you still want the quark I killed???? I have read somewhere that having extra CAPS only works good if they are "on top of" the FETS- I also read somewhere that it is BAD to have the CAPS "very far from" the FETS. (something about extra resistance - I dont remember) These were posts from consumers, nothing official... I put 4 caps directly on my board where the other 2 caps connect. (1 next to and 3 across from. yes they stick out the side...) I replaced the sticky pads with thermal epoxy, and epoxied the case to the rcmonster heatsink (no fan but it is connected to the chassis and gets good air flow) I just set up my new NEU 1512 2.5D smooth can with a 6200 5S4P maxamps in my 8ight buggy with 13/46 - the quark setting are all hot (Its a bit jumpy, I'll probly soften the torque) I ran it HARD and FAST (faster then that buggy has ever been) for about 30 min - Motor = 165* or so, Batteries = 110*, Quark = 145* (it was 94* weather) Some tuning and a motor heatsink will only make it better!!:017: |
Hey guys, I hate to be the crying baby of the bunch, but...I ran the truck this morning. It's getting HOT down here now. I ran for about four minutes and it thermalled.
I had had enough so I pulled the Quark apart and guess what I found. The pcb was moving around in the case pretty easily, so I started to peel the heat spreader from the case and get this, the adhesive on the FET side of the spreader just let go. It came off completely in tact. Check out the pic... http://i154.photobucket.com/albums/s...r/DSCF0300.jpg Do you see the indentions in the thermal pad from the FETs? You don't because they're hardly there. It looks like fewer than a third of the FETs were actually stuck to the pad. Apparently, whatever lubricant it is that is used in the manufacturing process for the chips wasn't cleaned off. What is up with S&T? |
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Some pics of my mods...
the heatsink bolts into the frame at the engine mount holes (a bit of notching and it fits) the small piece of duct tape keeps the top cover from sliding forward...you can also see the CAPS are epoxied together (they are quite stable and fairly out of reach of the lid) Attachment 3046 here you can see the notch in the side extends halfway across the bottom, exposing the solder point for the positive side of the CAPS and power input (otherwise this is unaccesable after the epoxy sets...) (yes i need new diff) Attachment 3047 I like the low, centered COG with this install. The top 3 CAPS are along the center line and it all fits nicly under the top. Looks like I have a 'punk' Quark! (it has a mohawk) Handling is spot-on and balance is very close. (need to change reciever pack and location for spot-on balance) |
blipo, I like the sound of the way that your setup is running. I have a 1512 1.5Y coming in. It's very close to what you have. If I can get temps like that after 30 minutes of running, I'll be a happy camper.
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Geez, you're running the smooth can motor and getting temps like those. Great!! I have a finned motor coming so it should run even cooler.
I like your mod. The only thing that bugs me about it is that those caps could get knocked off. |
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About the floating PCB; I kinda figured. Makes sense that it wasn't cooling if the FETs weren't even attached to the case! I know it's kind of a crappy solution, but S&T probably uses the pad so that they can remove it easily for service. Unfortunately, it doesn't last long. Once you do the "internal mod", your heat problems should be over. I say "should" because with your luck, it won't work. ;) Adding caps should help even more... |
Yes, I had the narrow neutral range as well, that's why.
AAngel, my FET heat spreader was the very same as that! It was only touching half of the FET's, and the PCB moved around easy (slack). But I am thinking that the caps leads being GONE had something to do with it starting on fire. Are you sure you don't want to wait for my custom quark case for yours? If not, maybe you should epoxy the top FET heat spreader as well, to increase thermal conductivity (power spikes). I also received the 30 caps this morning, I have the day off so I will see what I can do for a cap bank.:) Let me know if you are going to do as far as the 'mod', or if you might want my case. |
Since we are on the topic of Quarks here...
I bought some 1000uf 35v 85c caps for my quark. Can I use these with out damage to my quark? Also I am putting a custom heatsink on it too. I'll post pics of it later... Thanks! Bye:018: |
I would have recommended 220-330uf 35v 105c; lots of smaller ones being better than one or two big ones. You would also want a cap capable of handling a higher temp- 105c or more ideally. Wait and see what the others say though.
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CG, I believe that the caps that we are using are rated to 105C. I suppose that whether that makes a difference to you depends on how hot your esc gets. Am I right? Someone else will have to pick this one up.
zpb, I'm glad that you finally got them. I was starting to get worried. I went ahead and did the mod with the stock case. I would be interested in a better case. What ever you do design, be sure that it holds the two pcbs together so that they don't separate during rough running. I wish I had my Neu motor. I emailed Neu with this... Quote:
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Sounds like Carol is a robot, only capable of basic replies to questions. At least they got it okay; with any luck they will get you out a new one by early next week- fingers firmly crossed...
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cemetary gates: They should work alright, if they are Low-esr, but I don't know of any, if any low-esr caps that have a running temp of only 85c. The more caps you add, the lower the operating temp they will have, as long as they are low-esr type.
BliPoRaceR: That is the ideal way to mount caps yes, but like AAngel said, it's too exposed for my tastes. The way AAngel mounted his caps on his MM, and Quark is more what I like, and the resistance from adding that little bit of wire is minimal. But you sure would want to keep the caps on the pcb (stock). Looks like it would work very well though. AAngel: If you do the mod, you won't likely be able to take it off the FET's again, maybe the case though. I am going to get a FET clamp machined first for now, until I get the case machined (and finalized). I'll use one of the heat sinks I have and mount it to it. |
Oh, yeah, I don't think those are low-esr caps. If I were you, I would not install them, they will most likely blow out and spill electrolyte all over your esc, and possibly damage it as well. sorry.
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I would ask Cartwheels if he has any of the ones he bought left- they are the realdeal good quality ones.
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zpb, I did do the mod, but it is reversible. I've gotten the AA loose before, even from smt chips.
I wonder if there is anything on the controller that would be hurt by acetone. If not, that would be a good way of weakening the bond of the AA. I've used it to separate parts before. A good soaking in acetone overnight should do the trick. The heat build up of the top set of FETs is still weighing on my mind. I'm going to have to wait and see how it runs. If the mod works as well for me as it has for everyone else, I should be OK. As far as the Neu goes, I was hoping to hear the good ole "we've shipped you a new one already." Or better yet, "we are out of 1512s, how about a 1515 1Y or 2.5D." LOL |
What epoxy did you use then?
The heat build up on the tep FET's... like I said, any power bursts will have a larger temp differential than the average temp difference, so higher thermal transfer the better. But it is harder to do the top set i guess. The best way would to just use the case I designed really. You just apply thermal paste, and slide in on and clamp her down, there goes all heat sources down the sink. :005: HEAT sink that is. |
LOL.
I used AA epoxy. |
Ahh!
Don't tell me I bought the wrong thing again!
I bought this to bond the heatsink to my quark and to do the thermal mod to it. Please don't tell me that this stuff wont dry! I'm not doing good today... Bye |
CG......... I'm so sorry. :002:
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So... since this stuff wont dry, can I just blast it off with circuit board cleaner?
Bye:002: |
You can just wipe it off and clean up with some denatured alchohol. I'd also stay away from anything with silver in it. The Arctic Alumina that many of us use is ceramic based and won't conduct or capacitate (is that a word? LOL).
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oh, you already applied it... then yes use 99% alcohol then with a cotton swab, or Q-tip, and get it clean, clean, clean. Keep rubbing until your cotton swab (keep replacing with clean one) is clear and NO sign of grey in it. Try and not get anything onto the FET's pins.
I am going to clean out my quark case and use it as the cap bank, and maybe use some AA i have to attach it to the case, if not CA glue. I can't find any copper buss bar or anything, and I guess you can't really solder to aluminum, I might have to use 12Ga wire then. I am going to use 6 caps. |
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But really, why would you take it off once you do it? |
Oh right, you did say you did that. That's nice to know then, I was just thinking if he ever wanted a case machined?
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Yeah, I guess that is a reason...
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zpb, I used 1/8" copper tubing that I flattened in a vice. It works really well and is available at most hobby shops/hardware stores.
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Oh yeah, I just thought of that actually. I have 1/4 inch here, but maybe I'll go tomorrow and get some, that should provide a low resistance, low inductance channel for the caps.
Hey, I just told my machinist to mill this up so I can try it out. I have emailed Mike a couple times, but he hasn't responded. He must be very busy, I won't bother him with anymore. The distance between it is 4.00mm, I squeezed the FET's with the caliper and that is that measurement I got with a good pressure, I thought. |
Yeah, I've emailed Mike a few times and never got a response. With all of the emails that he gets, I suppose that he has to prioritize his responses and what you are talking about having done is way beyond milling a motor mount. It's probably going to require a 3D machine of some sort or someone on a mill with a lot of patience.
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I removed the tape off my top FET heatsink and epoxied it hanging out to one side. (the FETS are a bit off to one side so this works well) Then I epoxied it to the side of the case when I did the bottom FETS. With no end caps I get air flow inside too.
My bottom Heat pad thingy looked the same off a NEW Quark, I thought my old one came apart, but looks like they are not 'seated in' right from the start. I just got back from racing, used smaller tires after a 15 min haul my motor was 180* in spots, my Quark was 120*, batts barely warm. I think I will try to gear up to try to equalize my temps a bit. The nitro guys really took notice this time.... My CAP mahowk is doing fine. Its quite sturdy and in a well protected spot. As for CAP placement, I dont think it was the extra wire that was a concern. I wish I could remember more, ( I cant find it now) but it was proximity to the FETS that was a concern. (I understand electronics and wiring, but this was something that didnt make sence at the time, and I just glanced over it.) |
They probably were talking about inductance? At higher frequencies that are present in these BL controllers, inductance must be noticed and accounted for.
Also, flat wire (or flattened copper pipe), buss bar, whatever has lower inductance, and resistance than round wire. This is because inside the wire (round), there are self induced eddy currents which turn into heat. But no doubt your setup should perform very well, i am going to have to use the same setup for a while with the clamp thing, until I get the case machined. |
I know on brushed ESCs you can get a cap that is too large. I had problems thermaling a G-10 until I put a cap on it and the thermaling went away. People were supposed to had problems damaging the ESC by putting too large of a cap on it. I am sure that these ESCs are very different so this may not apply.
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I wonder how too large a cap can cause problems?
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The only thing I can think of is the spark caused when you initailly plug the batts in, or maybe if the cap stores a voltage greater than the esc is rated for, that might cause the esc to go pop? Theory being that it would be like trying to run to many volts through the esc- more than its rated for. A theory anyway......
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