My brushless HPI Nitro MT Project - Page 4 - RC-Monster Forums

GeeReg · 07.03.2006, 02:07 PM

This hobby is supposed to be fun, right? I went to run my 1/8 buggy today and put in the new FM radio I was using on the MT. I get there and guess what...it starts glitching. Son of a ________!. I say to myself, "This can't be the problem. I tried the other PCM radio in it and it glitched before." So I get home, switch to the PCM radio in the MT and guess what, IT DOESN't GLITCH. Ugh, great so the problem is my brand new FM radio. I tried another receiver so it's not that. I think I'm going to try a different frequency set of crystals. If that doesn't fix it then I'm in trouble.

Cart: At least I know I'm not alone. It must be a software thing then.

GeeReg · 10:57 PM

Just got back from a top speed run. GPS says 46mph with 52/15 gearing and Dirt Hawgs. I also only got about 7 min of runtime. Does that sound right for a 6L? It is overgeared though so that might have something to do with it. Got some high temps also. It's about 90 out right now and the motor got to ~140, ESC ~ 145 and batteries ~160 in some places :026: . I think I'm gonna need fans. Again it could be because it was overgeared also.

*edit* Hmm. Out of curiosity I checked the voltage on the pack and it was at 10.25. Seems a bit high for a dead 8 cell pack. So I hook it up again and it's still fine. Does the Mtroniks have a thermal throttling where it will cut the voltage down or something and not just stop? Would it do it at only ~145 deg?

*edit 2* Or not....I just charged the pack and it took 3800 mah.

SpEEdyBL · 07.05.2006, 06:11 PM

Those temps are fine for the motor and esc. Over 165 is when you should start to worry. For the batteries, yeah, that's a little hot. Do you have good solder joints and connections? Who knows, maybe any ni-mh batteries will heat up on such an amp hungry motor.

GeeReg · 07.05.2006, 10:57 PM

I'm not sure why the batteries get so hot. I thought the 6L was mild as far as amp draw ~69A? It's only the third pack I've assembled but I've been soldering forever so the joints should be all right. Oh well.

07.06.2006, 03:54 AM

15 tooth, that's way to big. I use a 9 tooth on my 540 9s and I'm sure you would benefit from a smaller pinion also.

GeeReg · 07.06.2006, 07:44 AM

I know it's too big for the dirt hawgs, I really bought it to use with the Road Rages. The 13t seems better but I haven't gotten temps for it yet.

cart213 · 07.06.2006, 01:50 PM

Hmm. I use 52/14 gearing with big ole M2K's, and I haven't thermalled anything...yet. I haven't run in the hot summer sun yet, though. I usually do it early in the morning. I still need to go to the lhs to pick up a few replacement parts to get it running again.

GeeReg · 07.06.2006, 03:27 PM

Hmm that's odd Cart. Maybe because you have a 540 and mine is a 380? 9t seems kindof low combat. I'll see how the 13 does but it already has enough torque with that so I'd hate to sacrifice the speed by going even lower. Even with the 15t it has a decent amount, enough to spin all 4 tires for a while.

SpEEdyBL · 07.07.2006, 02:28 PM

Like I said you motor and esc temps are fine. You could even gear up get higher speeds. It's your batteries that you need to worry about. Buying another motor wont solve the problem off maintaining top speeds and reducing battery temperatures.

GeeReg · 04:47 PM

I wasn't going to switch motors, I was just wondering. I don't really know what to do about the batteries. Cart's thread on emolis got me thinking so I may try them anyway, or LiPo, but probably not for a while.

GeeReg · 07.07.2006, 07:43 PM

Is anyone else this unlucky, or is it just me who can barely get through a pack without breaking something?

Ran it with the Road Rages and geared 52/15.

ESC ~150
Motor ~168 great
Batteries ~ 140

Maybe it's because the high traction on-road causes so much amp draw? I don't know. Every time I have a little "accident" also, the right battery pack smashes into the pinion, which is my fault by design. Still, my patience grows thin with you Mr. Brushless MT.

cart213 · 07.08.2006, 08:31 AM

Ouch! You should get some GPM aluminum c-hubs and uprights to replace the broken plastic c-hub. I got some, and they've held up well so far.

Don't give up yet!

Mike.L · 09:15 AM

Ouch thats pritty crazy man, i know that pinions are pritty pricy but you might have to get new pinions and try out different combations. And then see how the temps are.

Just to verify my rs4 Mt here, is the gearing fine on 51/13? on a brushed 18t motor?

GeeReg · 07.08.2006, 10:51 AM

I keep looking at the aluminum but I keep telling myself that if I'm going to buy the knuckle and c-hub, I might as well get the arms, then I might as well get the arm mount and then I can't just have it in the front so I need the rears. And that adds up to $200 or so. Then I go on tower and see the knuckles and hubs for $4.70 or whatever and I don't know.

When I get it fixed I'm going to try the 52/13 with the Road Rages and see what happens. It's seems really low to me but at least then I'd know if it's over or undergeared. It could be that it's undergeared right now and that plus the high traction is getting it hot? The cooler temps from the first run with the Dirt Hawgs were in the dirt/grass but geared pretty high 52/15, so I'm unsure.

Hmm also now that I think about it, this run was with the body on, so maybe that has a lot to do with it.

GeeReg · 07.17.2006, 08:17 PM

Well, I got some aluminum knuckles and the hub carriers, so they should hold up nicely. Got some more temps also. Just playing around in my yard with bursts of full throttle and a crappy fan on the motor:

Ambient: 90

After 6 min of running:

ESC: 160
Motor: 150
Batteries: 140

After 11 min of running:

ESC: 185 (eek...I think it thermalled so that's when I temped it and quit)
Motor: 167 (eek again)
Batteries: 145 (ok)

I need some really decent fans for the ESC and motor if I'm going to run this thing when it's 90 out. Unless it's gearing, but it's hard to test gearing at $12 a pinion.