RC-Monster Forums

RC-Monster Forums (https://www.rc-monster.com/forum/index.php)
-   Brushless (https://www.rc-monster.com/forum/forumdisplay.php?f=12)
-   -   Finally finished my buggy conversion!!! (https://www.rc-monster.com/forum/showthread.php?t=15134)

Mozzy 09.19.2008 12:59 PM

Finally finished my buggy conversion!!!
 
Well, I was at RC Garage (LHS) tonight after getting the buggy completed & running. :yipi:

We went out the front for some quick runs on the road & OMFG (!!!) it was like a rocket on just 60% EPA. :surprised:

Turned a brand new front set of crimefighters into pizza cutters & they have the centre of the tread removed.

Then Nick (the shop owner) had a burn & burn it did when the Quark ESC caught fire!!! A massive cloud of smoke came out as it burned away.
It was quite funny to watch actually.

I'll be having a little chat with Aiden from Ark Innovations on Monday after yet another unsuitable recommendation. :tongue:

Receiver, motor, battery & servo are ok. :yipi:

Here's some pics.

http://i55.photobucket.com/albums/g1...Readysetgo.jpg

http://i55.photobucket.com/albums/g1...gy/Closeup.jpg

http://i55.photobucket.com/albums/g1...buuurrrnnn.jpg

http://i55.photobucket.com/albums/g1...Mmmmtoasty.jpg

http://i55.photobucket.com/albums/g1...llfriedout.jpg

Suffice to say, I WILL NOT be putting another Quark in any of my 1/8 machines, they just can't cope. :diablo:

pullinteef 09.19.2008 02:35 PM

What gearing did you run? That 2779 KV on 5S is a ton of RPM (51411) and amp draw. Too bad, but I wouldn't be so quick to judge Quark on that. They make some very good products overall, and anything will fail if it's pushed too hard. I bet it was fun while it was working though!

lincpimp 09.19.2008 02:46 PM

A 6xl on 5s lipo!!! That setup can most likely pull 150 amps, if not more... No wonder the quark died. Try a 9 or 10xl next time. Conversion looks nice though, good job.

DRIFT_BUGGY 09.19.2008 03:08 PM

How long did it run for before going up in smoke?

Mozzy 09.19.2008 03:09 PM

I was using a 15t pinion & stock 46t spur.

The motor has a max draw of just 110A, & the ESC can cope with 120A, I thought I was doing ok with my choices. Also, had the throttle EPA at 60%.

Especially considering the Aust distributor recommended the ESC & had checked my motor (I sent it last time I toasted one of these) & said it should be good.

Bummer, guess not.

Well, I'll ask him what he'll do now after this.

I have a 2084kv sitting here will that be any better?

& oh yes, it was fun alright for about 10-15mins.

I guess, I still have a lot to learn about these things.

Just looked at these, http://www.impaktrc.com/product_info...oducts_id=2461 http://www.impaktrc.com/product_info...oducts_id=2681 would they be better suited?

pullinteef 09.19.2008 04:47 PM

I think you are overgeared also, especially for that setup. (I get 67.8mph theoretical / 62mph drag adjusted on the gearing calculator)

Just as a note, and I'm not saying you did this, but make sure to set the EPA after doing the ESC neutral/max calibration. If you set the EPA to 60% and then calibrate I think that 60% throttle will register as the 100% point as far as the ESC is concerned. Someone please correct me if I'm wrong. Also, how does reducing EPA affect temps? I remember reading that brushless motors don't like partial throttle so much, is this true?

lincpimp 09.19.2008 05:09 PM

Quote:

Originally Posted by Mozzy (Post 214242)
I was using a 15t pinion & stock 46t spur.

The motor has a max draw of just 110A, & the ESC can cope with 120A, I thought I was doing ok with my choices. Also, had the throttle EPA at 60%.

Especially considering the Aust distributor recommended the ESC & had checked my motor (I sent it last time I toasted one of these) & said it should be good.

Bummer, guess not.

Well, I'll ask him what he'll do now after this.

I have a 2084kv sitting here will that be any better?

& oh yes, it was fun alright for about 10-15mins.

I guess, I still have a lot to learn about these things.

Just looked at these, http://www.impaktrc.com/product_info...oducts_id=2461 http://www.impaktrc.com/product_info...oducts_id=2681 would they be better suited?

The 2084kv motor would be a much better choice with the gearing you have... The amp ratings of motors are not really viable with car use. They are based on some sort of prop testing.

tc3_racer_001 09.19.2008 06:28 PM

yep, i can confirm that. also, i run 4s with a 2550kv, and a 12t pinion, its stupid fast (for me) but i would definately be wary of that motor, its a 4s motor at max. (really i dont think its suitable for any application, its too hot to use and on 3s eficciency is out the window.)

try a neu :P

1512 2.5d seems popular on 4s and a bullet on 5s.

BL_RV0 09.20.2008 12:25 AM

The 2.5d is a 5s motor, and a rocket on 6s.

Mozzy 09.20.2008 01:32 AM

I always calibrate as per ESC manuals, which for this was everything at 100%. I remember having to readjust everything due to running nitro motors on the same model.

It was 60% of the maximum available power at WOT....I think that's how it works.


I might try the 2084kv on a 14t pinion to see what it's like & if temps are very low try the 15t pinion again.

I'm now wanting to shy away from high kv motors as I want long runtimes for racing.

Also, I'll be working at my mates LHS ( I called him today & he was trying to convince me to come down as they were busy. hehehe) & we're going to be making up complete BL conversion kits comprising of mount, motor, ESC, pinion, battery & tray for a lowish price.
So, I'm guinea pigging alot of things to see where I'm going wrong in order to be assured that if I/we convert a car or sell the kit with explicit instructions on what to do, that it won't come back fried.

Basically, make a dikhead proof conversion kit that can whip a nitro without the reliability issues.

Thanks for the help fellas.

tc3_racer_001 09.20.2008 04:21 AM

fool proof until you let them adjust the pinion mesh!!! lol. some people have such trouble with this i just dont get it

2084 (8xl right?) sounds better. im running a 12t and its pretty quick so according to brianG's calc, it should be close (11t on 2550 is the same as 14t on 2084) but yours may run hotter due to the build quality - going to try the MMM?

Sammus 09.20.2008 04:43 AM

running at 60% epa is no good either, esc's dont like running at constant part-throttle. I've blown several traxxas escs, every one of them was fine for high speed stuff with a lot of full throttle. use it on a tight track where your only around 1/2 most of the time and they melt. Something to do with how they control the power output (pwm), im not sure why it makes it heat up more.

Mozzy 09.20.2008 07:29 AM

Yeah, exactly! Meshing's not rocket science, but, some people just can't do it. I just don't get it.

Of course we'd offer the option of it being converted in house & handed back after a full pack of testing to make sure.


Tomorrow, I'll be trying the buggy again with a MM V1, 2084kv & the 5S. With a change to the 14t. Fingers crossed!!

So, Sammus, it's not good to cut down the EPA to restrict WOT? I need some clarification on this that is 100% certain.
No offence Sammus.

Thanks again.

Might have some pics of another toasted MM V1 after tomorrow! :lol:

Sammus 09.20.2008 07:34 AM

Yeah I'm not 100% on the tech behind it. I know castle tell you not to do it, but in response to a slightly different question. That and I've noticed that my ESC's run hotter at partial throttle than at wot.

Mozzy 09.20.2008 07:40 AM

I had a quick read & it's saying that the ESC is 25A & the motor can draw 45A, that's not comparative though.

My ESC's can all cope with more amps than the motors can draw, so, where does that leave CC's theory/explanation?

tc3_racer_001 09.20.2008 07:58 AM

ok, when u fire it up tomorrow, run at very low speed (barely moving, without cogging etc) for a few minutes. then take some temps. do it on grass if you can :)

the motor will be (SHOULD) be cool as well as the lipos. the ESC however will be warm. (harder to see on a V1 as the fan is ALWAYS running...) then do some top speed running (after everything is at ambient) and check again...

the motor should be warmer the lipos warm and the esc cool. it seems almost like a resistor, burning off the ecess current off but i know it doesnt work like that (i.e manual speed controls!!!) so how it works exactly im not sure... could it be to do with the variable timing that the escs use? *or is that only castle ones??*

id like to know too. hope this helps :)
ryan

btw, where do you live? im in brissy and if you were too (hobby garage is a name i am familiar with!) we could possibly meet up once youve got it all sorted to compare etc..

jhautz 09.20.2008 09:59 AM

It sucks that you burned up that quark. I was waiting for someone to do a review of using it in a 1/8. Based on the motor, voltage and gearing I don't blame the quark for failing. I think you would have burned up just about any esc with that setup. I still have hopes for the SSB being a viable 1/8 controller and based on the specs and the success of the predecessor the 125B I still expect that it should be a nice controller for 1/8, but they are virtually impossible to get here in the US at this point and it seems rather expensive everywhere else in the world.

If you are planning to run it on the track with 5s, the 1600kv Medusa motor you linked to would your best choice of the motors mentioned. the 8xl will still run hot for extended runs.

Nice conversion. Hope you have better luck with the next setup.

Mozzy 09.20.2008 11:09 PM

Well, I'm off to the park in a few minutes. As soon as my mates lipo charges.

I'll let you know what happens with the 2084kv & 14t pinion.

TC3, I'm in Melbourne.

Not only did I fry the Quark, I also fried a brand new BLS Futaba Servo!! Surprisingly enough, my Spektrum Pro recevier works exactly as it did before. WTF?

I have another issue.

I was working on my mates E Revo (converted) last night & mounted a brand new MM V2, but, then remembered I had to change the settings on the ESC to remove brakes, change the punch & LVC.
I plugged it in to the USB cable & the two greens came up on the screen & into the program I went.
Altered the required settings & when I went to update it, it constantly stopped with an error code saying that the ESC wouldn't respond & failed to update.

I tried 3 different USB cables for MM's & still no luck.

Broke out another brand new MM V2 from the same batch this morning & it worked without a problem.

Has anyone had this issue?

Sammus 09.21.2008 01:39 AM

The motor amp ratings are near useless when your running them in a car, don't listen to them its an air thing.

Just because a motor is rated to 100A or something doesnt mean it cant draw more. If you bind the shaft and floor it will effectively short the battery through the esc and destroy it.

Sorry I don't know the tech behind it, it has something to do with the switching of the fets in the esc. I'm not asking you to believe me, I just thought you'd like to know that it is very possibly the reason you killed your esc.

Mozzy 09.21.2008 01:59 AM

Well, I'm back!

Hehehe, MM V1 #2 just decided to not work anymore.

Powers the receiver ok & the fan's still working, buuuuut, the little green light flashes when I give throttle. Looks like another MM to be returned.

Now, back to the motor/ESC/batt's performance.

What can I say, but, thanks fellas!
It worked a treat, motor no hotter than 45C, ESC 35C & 5S batt 30C & the runtime with the 4000 must've been well over 20mins. Went onto the 5S 5000 & must've gotten about 8-10mins & it just stopped.

It was pretty fast too, loved it, I really need a torsen centre diff too!
My mate had a go & couldn't believe the power over his BL Revo with a 2382kv 7XL, 4S & MM V2 running quite reliably with 3 packs.

A couple of nitro buggy boys turned up, I had a tinker with his car for tune & what not & it really made me realise why I now run BL, soooo much easier to deal with once the combo is right.
Anyway, I gave him a go of my buggy & he couldn't believe it. I had a go of his with the .28 in it & couldn't believe how S-L-O-W it was!!! Not to even mention the absolute lack of punch!!

Over all, I'm very happy with the performance & reliability while it lasted. Now I really have to get my CRT properly completed!

BL_RV0 09.21.2008 01:06 PM

Your MM is fine. It's hitting overvoltage. If you have a 4s pack, try that. One of my MM's hits overvoltage, and I guess I'll just discharge it until it goes to a little lower voltage. Worth a try I suppose.

Mozzy 09.21.2008 11:50 PM

BL_RVO, I understand, but, I shouldn't have to go to a lower voltage.

I, like many others, bought these things to cope with higher voltage & I'm not going to use a crappy 14.8V source when I have 5 5S packs to allow me to run low kv & looooong runs.

CC just need to address these problems. ASAP, which I'm sure they are.

Please don't think I'm having a go at you as that's not the case, I'm just annoyed that I would have to restrict myslef with voltage when I shouldn't have to.

I'll be contacting CC on another matter & will get them to address this one as well.

pullinteef 09.22.2008 12:02 AM

It sounds like there is some MM / MMM confusion here. Which are you using?


All times are GMT -4. The time now is 07:55 AM.

Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2025, vBulletin Solutions Inc.