|
MMM Explodes into FLAMES!
Sorry, no video. But here is what I posted in "another forum".
Was driving my Brushless ERevo around over the weekend at a family "camp out". My bro in law was driving around his Losi Ram and I my 3.3 (smoking him), and then my ERBE... which REALLY blew the boys away! I wasn't really doing anything spectacular. Just driving it around grass and asphalt, not fast like speed runs. Just driving it around, popping some wheelies, and landing some skateboard ramp jumps. I didn't feel like I was pushing it AT ALL compared to other times I drive it. After 20min of that, it stopped moving. I peeled the lid back (not the lid pictured fortunately!) to see if maybe a battery connection came loose (which can happen after a jump landing), and before my eyes....POOF! The ESC went up in flames. Literally! FLAMES! I ripped the body off and immediately pulled my $300 lipos out, not wanting them to explode and destroy the entire truck... and was able to get them out. My brother in law blew the ESC fire out. So it's charcoal, and I have NO idea why. Fortunately, Castle will cover it fully under warranty (I presume), but MAN was I bummed out!!! My batteries are Flightpower 3s 5000mah 30c lipos. My brakes are set at 30% and my punch at 100%. The batteries were fully charged and I had only been driving around for maybe 15min tops. And that includes some starting and stopping to do this and that, turn the veh over if it rolled, etc. I run the Lipos parallel of course. The motor is a Neu 1515 2.5d and I think it's ok. But I couldn't believe my eyes when that thing puffed into flames. It was like magic. I didn't see any smoke, nothing. Just POOF! with instant 4inch flames!!! I was determined to pull those lipos though, cuz I knew the ESC would be covered, but the Lipos? Nope. If the truck had exploded too, would I have gotten another one from Traxxas? Not likely. So, I had to save the batteries and the truck. Fortunately, I escaped with only a blistering burn on my finger, and a very small section of the chassis is melted. But I don't think enough to need to do anything about it. My body (not the one pictured) is fine too. A tad melted, but very minor. It's my basher body anyway. Took these about three hours before I drove the vehicle. Nothing changed.... http://i143.photobucket.com/albums/r...BE/ERBE_02.jpg http://i143.photobucket.com/albums/r...BE/ERBE_04.jpg http://i143.photobucket.com/albums/r...BE/ERBE_15.jpg http://i143.photobucket.com/albums/r...BE/ERBE_10.jpg http://i143.photobucket.com/albums/r...BE/ERBE_19.jpg The horror: http://i143.photobucket.com/albums/r...RBE-MMM_08.jpg http://i143.photobucket.com/albums/r...RBE-MMM_02.jpg http://i143.photobucket.com/albums/r...RBE-MMM_05.jpg The batteries: The only thing that was toast was the shrink wrap had melted. http://i143.photobucket.com/albums/r...RBE-MMM_09.jpg http://i143.photobucket.com/albums/r...RBE-MMM_10.jpg My voltmeter, which may not mean much... had them at 11.47 I think. Both packs. So, I'm pretty sure that they aren't toast. They aren't puffed at all, nor are they soft. I'm going to charge one and closely monitor the charge, and will reshrink them if all goes well! This could have been MUCH worse, but still....<shudder> P.S. - The Moabs? Yes.... I know! |
Hmmm, Thats really strange ?
I'm sorry I have nothing to add as to why you had the meltdown but you have my condolences for your loss. |
I have had two mmm fires and i hate the smell !!! its the worst chemical smell ever. Your bringing back bad memories........ sniff , sniff
|
Moabs are almost never good for a practical BL high torque beater. They look saweet though.
My condolenceses |
The setup should be run on at least 4s, but 5s would be better to yank around those big tires. I'll bet the ESC had enough and bit the dust. You really should look into a 5s setup...
|
Nasty. Motor and voltage choice is fine, only question is what gearing and esc settings were you running?
Seems like a random failure though rather than bad setup and/or being pushed too hard... |
Quote:
|
Quote:
|
Really? Says 6s in his sig, no mention in the opening post- unless he said 3s in 'the other forum'...
In which case = bad setup, unless it was geared for no more than ~20mph on that voltage with that motor. |
You can see in the pic it is wired for 6s... Schultz would say too long battery leads...
PS That is not as far gone as my MM's went - I sent back the few burnt fets I could find... |
Quote:
"I run the Lipos parallel of course." ?????????????????????????????????????????????? Unless he's mistaken and ment series ? |
Quote:
|
According to this pic he was running 6s:
http://i143.photobucket.com/albums/r...BE/ERBE_10.jpg Notice the batteries are in series. That could be the problem. Maybe hes was overgeared for 6s 'cause the thought he was running on 3s? Sorry about your MMM, CC will take care of ya. |
[QUOTE=What's_nitro?;302197]According to this pic he was running 6s:
http://i143.photobucket.com/albums/r...BE/ERBE_10.jpg Notice the batteries are in series. I didn't see this, good catch. The meltdown is still unexplainable till we know more about gearing and settings. Still could easly be a freak of nature. |
After reading the article from MGM regarding volt spikes and braking, this makes sense....
The MMM may be rated for 6s, but I wouldn't do anything silly like use your brakes in that set up. The batteries look adequate but what were you geared at? Hopefully Castle can sort this out for you and address the rising death count of MMM's on 6s Lipo |
Quote:
|
Quote:
There's the thread on it. My question is, if you run say a converted Revo and use mechanical brakes as opposed to motor brakes, can that go part of the way to eliminate this issue? |
what about the fact that he was at 30% braking; or does that not change the amperage spikes?
|
..another valid question, could the larger tyres have compounded the problem?
|
lol...yeah they designed the MMM to be run without brakes :no: I don't think theyd be much use that way...
Probably doesn't help that he was running a V2 - what firmware version was it? |
Where the hell is JPOPROCK ?
We need more info ! Tire size and weight a issue ? If gearing and recomended voltage is used, possibly but I don't think so. |
SERIES. SERIES! My mistake. I even went back and changed it from series to parallel after my proof reading my post before sending it! HA! Man.. what a tool. Sorry.
You know... it did cross my mind that the tires might be a touch big. But my Badlands weren't extremely far from it, but smaller yes. They gripped like mad too. Too much for certain things. I don't do a lot of high speed driving. Just medium speed bashing around the yard. So, I hadn't been really driving it around all that fast this day. 20min of it tops to be exact, and my very first time ever w/ these stupid tires! I'll have to think about my gearing because I can't remember. I think it might be 54/20. And given my temps were always good w/ the Badlands... I didn't think a thing about the tire switch. I realize that 54/20 is pushing it a bit for med speed bashing (i.e. not speed runs), but w/ that 1515 2.5d can always doing well before, and at WOT from time to time, it just didn't occur to me that the Moabs would cause a fire! I figured it would get bit hotter, but not to the point of failure! Gosh... I sure hope this wasn't a serious oversight on my end. I'm sick about it already. Do you think that 25C is too low, or ok in this case? W/ the Moabs, what gearing would you suggest? j |
The reason I was running 30% braking... was because I wasn't ever able to just "kiss the brakes" in the air to correct anything. A "kiss" resulted in an immediate FLOP on to the lid. They were at 50% when that was happening. So, reading the Castle Link explanation of it all, I thought that 30% of the strongest setting meant I'd be scaling full power braking back by 70%. And if 50% was still sending the truck on to it's lid...30% might be just right. No? Cuz on literally ALL my other veh's, a tap of the brake is always enuff to correct certain things. But a "tap" on my ERBE was like a whole new ballgame. I could never understand it either. It's my first MMM experience. So please pardon me when I display extraordinary ignorance to certain things! Also, I was CERTAIN this was a V3, not V2, and only a few months old. Is there some way to know for sure? Cuz I was sure it was V3, but could be wrong. When you say firmware... are you speaking of the Castle Link Firmware? If not, than I'm not sure. I was up to date as far as CL was concerned. Like... 1.20 or something like that. My MMM is a bit under the weather... so I can't check. LOL!
Man... that fire was the rottenest smell EVER too. My truck still smells like it, my Explorer, etc. Horrible smell that lingers! The ESC is already in the mail back to CC. So... do I need to weight these tires then and report back? I'll say this much... they certainly are bigger, but they aren't all that heavy really. |
The instant brakes thing sounds like one of two possibilities:
1: The ESC was not properly calibrated to the ESC, so it saw any brake action as WOB (wide open brake). 2: The ESC was somehow running in reverse when you applied forward throttle. I know that brakes in reverse are more touchy. This would be caused by having the servo reversing setting on the radio set wrong. You'd have to set it the other way and recalibrate the ESC to the radio again. I don't know if it's even possible to have the ESC arm if the throttle is reversed, but something to look into. |
AFAIK V3 ESCs have the battery wires soldered directly to the board, not sockets on the ESC on the battery side.
|
Both my V3's have socketed battery and motor leads. According to a previous post by Patrick (I think), it's the luck of the draw; some V3's are like what I have, some are like what you have.
|
My CRT.5 did the same thing with the breaks, even on the surface: tapping them locked up the wheels. You'll want to check the settings in the castle link and make sure you have forward w/ reverse lockout as the setting. If you're using it as just with reverse then I think the brakes lock as soon as you touch them (boat setting???). I'm not really sure if this is the problem, but it fixed my crt.5 brakes with the MM
|
Quote:
|
Quote:
Sounds like a problem with the brake setting though, I hadn't realised the lockup thing. What remote were you using? I was pretty stupid for overlooking this, but I had forgot to calibrate my futaba tx, and it was doing the locking up thing. Turned out that from the ESCs perspective, I was driving around in reverse (at 50%) and hitting the brakes on the tx was just sending the esc into full throttle forward. Certainly not a good idea. Make sure you reverse the throttle channel on futaba Tx, then recalibrate ESC. |
20/54 with those massive and heavy tires is probably part of it. You said the motor never got too hot though, so that makes me doubt the gearing a bit (if the motor is getting hot it's pulling enough amperage that the ESC is most likely getting hot as well.)
Looks to me like a FET couldn't handle it and it blew, Castle will definitely take care of you on this. I really hope they can get different FETs or maybe find a distributor that has better QC, it seems that they aren't quite up to snuff. Sure the failure rate is low but still too many are going IMO. |
Bad gearing, bad tyre choice, dodgy esc and/or radio settings (brake issue) = fail.
I thought this was RC-Monster, not the traxxas forum :neutral: Instant brakes sounds like either the throttle profile wasnt changed from the annoying default setting of 'forwards-brake-reverse' that engages reverse without you even letting off the brakes, or the throttle channel was reversed at some point before/ after programming to make it behave that way. You cant guess at these things, or scratch your head and say ' umm, not sure ' (like on the gearing question for example). If you dont pay attention to what you're doing, you WILL screw up stuff that costs alot of money to replace. Always set the throttle to the 'forwards-brake-reverse with lockout' option that will engage reverse once you have come to a complete stop, then release the trigger & re-enage it to go backwards. </rant> |
Gee... who could have seen that coming? A rant from Suicideneil? What a shock! Actually Neil... aside from your generally awful elitist attitude to those who are less your equal, I will acknowledge that you are a great source of information, and you really do know your stuff.
Anyway... I know for a fact that I had FBR w/ Lockout. I always use that. The only way that it could have changed... was by accident. Sometimes when in CastleLink... if you're not careful with the scroll wheel, it can change settings without you noticing. But I'm pretty sure that didn't happen. And I did not chance the throttle curve either. The reason I hesitated on my saying what gearing I used was because it's been a while since I've changed it, and I've got like 8 trucks. I would have to look to be sure. But I'm almost positive it's 54/20. I understand the notion of the bigger tires causing more heat. The Badlands ARE smaller, but come on. The Badlands weigh 9.1oz and the Moabs weigh 14.9oz each. So for 4 tires, that's: Badlands: 2lbs 4oz Moabs: 3lbs 11oz So the Moabs outweigh the Badlands by 1lb 7oz. My truck weighs 8lbs with no tires or lid, including Lipos. So the total truck weight with tires is: Badlands: 10lbs 4oz Moabs: 11lbs 11oz I understand the theory about size, rotation, gearing, etc. Or should I say....I understand that it matters. You can get all geeky with numbers and figures if you want. But the bottom line won't change for me anyway. Which is, the truck with Badlands geared 54/20 never got hot. The can was warm, but not hot. Easy to touch. Same for the batteries. So one would then have to assume that putting the Moabs on it would increase the heat a bit, but not to the point of a flaming ball of fire. It may be worth noting again that everything was hot after the fire. The can, the batteries, wires, etc. With Badlands, running like mad in near 100 degree weather, heat was never like this. This was the very first time I had ran these Moabs. It was maybe 85 degress that night. Not to mention, I hadn't pushed the truck hard at all. No speed runs, nothing. I was just driving around the asphalt driveway, and a freshly mowed yard, doing jumps off a 12-14" skateboard ramp. I wasn't even thinking "Watch out for supreme heat", when I could run like a mad dog with my 1lb lighter Badlands and not have a problem. It just wasn't something I expected. As far as my radio goes, It's been set up the same way for months. I'd have to look at it later to see what it is. And it's a shame that I can't check my ESC either. I'm almost sure I saved my Profile though. I don't think that I can load that profile using another ESC that's not a MMM. I only have a Sidewinder for now. I'll be checking that saved profile though when I get my new one, just to see. With the radio, the only way something could have changed would be if it had gotten bumped in my bag or in my hand. I should add that the radio is an Airtronics M3. Great radio. I like it anyway. I've never been around anyone else's ERBE, so I can't compare. But my brakes have ALWAYS been this way. Also, the truck would make an audible sound when braking. Sounded like semi truck stopping sorta, but on a much smaller level. I can't quite describe the sound. But sorta like a deep squeaking air brake type sound. Having no experience with a MMM, I thought it was the nature of the ESC. And with it flipping onto it's lid when tapping the brakes in the air... I also thought it was because it was a super powerful ESC that I was going to have to get used to. The reason I'm posting this stuff here is, to put it bluntly, a matter of respect. A "tip of the hat" per se to you guys here. You guys are on some other level of expertise.... and I figured out of all the places to post something regarding the MMM, this would be the place. I also posted the same thing in the Traxxas forum. And so far, there hasn't really been much "geek speak" about what could have happened. No slight to those guys though, because there are plenty there that know what they are talking about. Besides, my issue isn't with the ERBE or Traxxas. It's with Castle. And if it helps... the diff's in this truck are the RC Monster 1/8 hybrid's, my Hyperion was purchased from RC Monster, among many other things. So, I think I have every right posting here. But hey.... if it's a big deal, we can just drop it right now and I'll go about my merry way. It's no shirt off my back really. I'm not here to cause problems. J |
IMO this isn't a heat issue at all... MMM has thermal protection and will take care of shutting itself down when it gets too hot...
This is either bad fet, too much amp issue or a ripple issue or more likely a combination... The tires are 50% heavier and this does make a big difference to intertia especially as the mass is on the outside of the wheel: http://upload.wikimedia.org/math/3/0...9413414ddc.png where m is mass and r is the perpendicular distance to the axis of rotation. This would cause an increase in the amp draw of the overall system - Partial loads are also quite hard on an ESC as it is switching the current on and off to match your input. This switching and high amp draw could have caused ripple - This is worse still by the "longish" battery leads with the series connector across the whole chassis - If the ripple gets too much the caps can't cope and you get FET meltdown... My guess its a combination of the above - you could add an extra HV cap to the input leads to help... PS Neil just needed chocolate... |
Interesting point. I'll admit, that I'm not experienced enuff to even begin to argue. Sounds good to me though!
So, you think my leads were too long? If they were, they were only long by maybe an inch. I didn't have all that much slack if I remember right. Also, are you saying that they way I had it wired in series was incorrect? Or... where the wire was located? I'd have to see a picture of another suggestion. I'm a visual learner I guess. I don't want this to happen again that's for sure. And I'm going to have to make up some new lead anyway. So do you have a suggestion for gearing to try? I realize that you just have to experiment a little. But I don't want to go on a gear buying spree because they are expensive. I'd like to stick with these Moabs if I can, and speed isn't my thing really. It's nice to have on tap, but i'll trade speed runs for medium speed bashing any day. Thanks! |
Those lipos are in series no question about that.
I'm guessing bad fet's or ripple voltage killed the MMM along with running McD's super sized tires. |
When you get your ESC back from castle and you still want to run the Moabs thats fine, but I would seriously considering gearing down a bit when running
6s. Going buy what you wrote about gearing,motor etc your topping out at around 58mph, it's a bit much ? If you haven't seen this it's a very helpful tool thanks to BrianG. http://www.scriptasylum.com/rc_speed/index.html |
Yeah, Neil gets a little grouchy at times. I think he just needs a hug, but I'm too far away (it's a long swim), and it probably wouldn't be welcomed anyway. You just gotta read in between the rants to get to the "meat" of the post.
The tires do look rather large, but as long as you were geared to compensate, it shouldn't be a problem. Temps were ok, so thermaling was not a concern. Maybe something got caught in the drivetrain momentarity causing excessive overcurrent? Or maybe the MMM decided it had enough. As you know (and was said), wires should be kept as short as possible while retaining enough slack to reach their destination without stress. And, if you had it wired incorrectly (in parallel vs series, or series the wrong way), you'd definitely know it; the truck either wouldn't move at all, or be very slow. I personally still think the abrupt brakes issue was either caused by improper ESC/radio calibration, or the servo reversing was set wrong. The reason I say this is because you said you used the same radio and has been this way from day 1. The brakes should NOT be that touchy, especially since you turned down the brake force. Once you have it set up right, you'll see how they are really supposed to work. An indication (aside from heat) of overgearing is short runtime. What kind of runtime are you getting with what voltage/Ah battery? (You may have stated this previously, but I'm too lazy to look). 6s @ 5Ah of decent cells should get you at least 20 minutes. If you were getting 10-15 minutes, then gear down a bit. Good luck and let us know how things turn out! |
Yeah, I know about 'ol Neil. I can take it tho' :wink:
In fact... he went off on me in the TRX forum about something stupid. Which I didn't mind. I took it all with a grain of salt. But he was REALLY on one that day, and just brutal. I responded to his post and didn't back down one bit. But somehow or another the Traxxas Police Dept caught wind of the thread and banned him! HA! I felt so bad, because I didn't feel it was necc to do that. Those guys over there are the touchiest people in the world if you ask me. Any-hoo.... I'd like to stick w/ the Moabs, yes. But let's be clear on something... 58mph was not achieved using the Moabs! This run where the ESC smoke was the first time I'd ever ran them. And I SWEAR on my life that I was not running hard, or even close to hard. I didn't have a lot of room to do that. I mostly putted around the yard throwing wheelies while everyone there looked in amazement. I also let my Bro-in-Law drive it, and he almost crapped his pants. He could barely drive it, and he for sure never got on it because he was scared too. Then I took over and would do a jump, circle back, do a jump, circle back, repeat... then it stopped moving, and the rest is history. With the Badlands... I would run it WOT down the street over and over, flew around my giant yard in an oval, pull a jump, repeat. I drove it HARD and never with a problem. I will admit though, that occasionally after a jump, the landing would cause the red wire from the ESC to pull out of the right battery lead. I'd power off the ESC, reconnect it, turn the ESC back on and go. That's what I thought happened when the truck stopped running the other day. I had just landed a simple jump, started to drive it back to me, and it stopped. I thought the wire had came loose, but it hadn't. I'm going to try some different Spur gears for sure. But in trying new spurs, what would you suggest? Maybe leave the pinions and change the spur to something bigger? I don't want to smoke the new ESC "experimenting". I LIKE the Badlands though. Don't get me wrong. They are the bomb on dirt! And they literally RIP grass from the ground. But they are almost too grippy sometimes. I was digging the Moabs because they looked good and they weren't as grippy. I could do some drifting type turnarounds. Perhaps getting some Relux rims and some other kind of tire would be best though. Something the size of the Badlands, just a different tread. I'll say that the Traxxas Response Pro tires I have on my 3.3 Revo are probably the best tire I've yet to run, and I've run lots. They actually "sing" when running across whatever surface. But they are mounted on 17mm splined hexes, and I don't want to covert the ERBE over to that size. As far as runtime is concerned, I can't say for sure w/ the Moabs. But w/ the Badlands, same gearing, I was getting probably close to 30min runtime. Because I wasn't hell bent for speed the whole time. it would take about an hour to sync charge them both. It's so strange to me that perhaps the settings with my radio could have been off somehow. When I go home tonight to look, what specifically should I look for? But it's all moot since I can't verify anything on the ESC right? Also doesn't the fact that I have a Neu 1515 2.df come in to play? Wouldn't it's ability to slow the truck down have anything to do with the uber powerful braking? Heck, I was thinking of going from 30%, down from 50%, and taking it to 20% even! Plus, since I was running the RC Monster Hybrid 1/8 diff's, wouldn't that have actually lowered my gear ratio a bit more? One thing I failed to consider when putting the Moabs on I guess. |
When you get it running again, put some negative curve in your brake curve. This will help with your having to reduce the brakes so much to keep it from diving when you brake a little in the air.
|
So, are you saying then to pull the curve down a bit? If I could see what it looked like, I would do much better. Or, if you told me what range to adjust it to, and at what point to bring it up, I'd understand.
|
| All times are GMT -4. The time now is 11:29 PM. |
Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2025, vBulletin Solutions Inc.