RCCrawler Forums

shelljeep · 01-19-2010, 06:10 PM

Losi Night Crawler, basically stock besides 9 oz in the fronts and 142 oz steering servo.
I run LiPo Dynamite 6000 2S, and 4200 2S for batteries.
Today, I was only able to crawl for a few minutes, mebbe 5, before the LNC would act like it was bound up in very simple traction situations, not bound up or wedge type situations.
The battery still had 8.1V afterwards, coming off a full charge, usually around 8.38 or so. So the battery is still full.
The motor heat is something Ive asked around about and gotten different answers. It gets hot enough that I can't hold my finger on it longer than 3-4 seconds. It has also produced a light burnt odor before, actually a few times.
And I have noticed lately that it lurches at lowlow speeds rather than smoot transition it used to have when first purchased.
No loose wires that I can find.
Think the stock motor is already on it's last legs?
I've had this thing since 1-7, ran maybe 20 batteries thru it at most. I do run back to back sometimes, and I don't show it much mercy since I didn't think I needed to. I make sure to lift whenever I see it's wedged, but other than that, I just run it. Slooow technical crawls, to full throttle bumps, extended burnouts trying to make wheelbase type climbs. Am I running it too hard?
Thanks, Shell

shelljeep · 01-20-2010, 08:50 AM

I wanted to rule out worm bind, so I took the rearend apart.
I think the worms look good, but I have never seen these before. Nothing metallic in the old grease, nothing that would make me nervous about a 1:1 R&P.
How can I test the motor, esc, etc? I need to learn how to diagnose this stuff.
Pics of the spool follow, pinion was absolutely perfect, only the faintest hint of a wear pattern so I didn't bother snapping pix of it.

shelljeep · 01-20-2010, 09:00 AM

Also, I assume my hitemp disc brake bearing grease that I use for my real vehicles will be ok for this app?
edit- I have lithium grease also if more appropriate.
Are you guys tapping these diffs right behind the ring gear, under the pinion support, in order to make maintenance easier?

JeremyH · 01-20-2010, 09:12 AM

It could be that the motor brushes are getting worn. When they get some runtime on them and wear down a bit, they can stick and cause the motor to appear to bind. You might pick up a few new brushes and springs for that motor and swap them in. And yes, it does sound like that motor is getting too hot...

BTW, is this the same Shelljeep from Cowtown? If so, I've liked your 1:1 for quite some time....nice work.

shelljeep · 01-20-2010, 09:23 AM

I've got a hand wound 35T coming from CKRC, do you think I'll get more runtime out of it before it needs the brushes replaced?
How do you guys keep the motors from getting hot so fast?
Yeah, that's me man! Thanks for the compliment. I wish I hadn't cut it apart to buggy it. I'm building a 1ton YJ now. Here's a pic-

JeremyH · 01-20-2010, 09:32 AM

Looking good! I like that cage. I can still see the shelljeep in the background...

As for the motor, that really depends on the brushes and the contruction of the motor. Some brushes are made from a harder material and will last longer than others. Also, if you are running extremely stiff springs, they will wear out the brushes a bit faster. I believe that the stock LNC motor is a 55T, so that 35T will give you more wheelspeed which will produce more heat. I run 35T motors on my Bully rig and replace the brushes and springs about every month. It gets quite a bit of use and sees a LOT of digs...so the rear brushes wear faster than the fronts.

Zimm98 · 01-20-2010, 09:41 AM

I am having a similar probelm with my LNC bindnig when it should not bind. I hooked my amp/watt meter up to my truck and drove it and wached the display. When it would bind in easy situations the amps would not spike (if I got a spike it would indicate a mechanical bind). My crawler is under a month old too, I kinda wish they would ship it with a better motor. I am torn between spending the money to get brushless or just getting a brused to get me by.

shelljeep · 01-20-2010, 09:50 AM

I also have a 12 and a 16 tooth pinion coming so I can adjust the wheel speed if I need. Gearing it down like this should help take some of the load off the motor, right? Less load=less heat? I guess I'll probably push it just as hard though, once I get used to the new motor. So gearing is a moot point re: heat?
Thanks for all the input Jeremy.
This cage was about halfway built when I guy saw it online and bought it from me. LOL. I'm gonna finish it as far as I can in my YJ, than swap it into his next week. Working on the details now, and frame tie-ins.
Here's a logo plate I built for it, mocked up, still need to clean it, center it up.

shelljeep · 01-20-2010, 09:56 AM

Quote:

Originally Posted by Zimm98

I am having a similar probelm with my LNC bindnig when it should not bind. I hooked my amp/watt meter up to my truck and drove it and wached the display. When it would bind in easy situations the amps would not spike (if I got a spike it would indicate a mechanical bind). My crawler is under a month old too, I kinda wish they would ship it with a better motor. I am torn between spending the money to get brushless or just getting a brused to get me by.

That's good relevant info, thanks.
I guess I will either get good at replacing brushes or go brushless also.
Jeremy, I take it that you are MOA? So, you dig the rear more than front? Or are digs harder on the motor that holds the tires still?

JeremyH · 01-20-2010, 09:58 AM

Quote:

Originally Posted by shelljeep

I also have a 12 and a 16 tooth pinion coming so I can adjust the wheel speed if I need. Gearing it down like this should help take some of the load off the motor, right? Less load=less heat? I guess I'll probably push it just as hard though, once I get used to the new motor. So gearing is a moot point re: heat?

Nope, gearing will directly affect the heat of the motor. You are correct in thinking that if you slow the truck down (either using a lower tooth pinion or a larger spur) that you will reduce the heat in the motor. It's all a balance....find the right motor and gearing that wont overheat yet still give you the speed that you want. Just from looking around in the Losi Comp Crawler forum, it seems that there are quite a few folks running the 35 and 45T motors....so you are probably on the right track.

BTW, that logo looks cool! Waterjet?

Quote:

Originally Posted by shelljeep

Jeremy, I take it that you are MOA? So, you dig the rear more than front? Or are digs harder on the motor that holds the tires still?

Yeah, I tend to use the rear dig a bit more than the front, but I still use front quite often to swing the rear around when the front is wedged against a rock or something. Yeah, I will burn out brushes faster on a motor that I dig with more.

shelljeep · 01-20-2010, 10:03 AM

Good to know I'm getting the hang of this stuff. This forum is great. Thanks again, and that was cut out on my PlasmaCam table.

JeremyH · 01-20-2010, 10:06 AM

No problem. Yeah, lots of info here.

That cut looks MUCH better than anything I've ever made with a handheld Plasma cutter. I had not heard of that device before, but it looks like people are making some really cool stuff using them...

derangboy · 01-20-2010, 11:27 AM

I'm no expert, but it looks like your spool might be cut wrong. The teeth should be slanted but yours look to be fairly straight across. Easier to tell when it's next to a proper one. The top one in the picture is good. The bottom one is not. Sorry I didn't clean 'em up before I took the picture. Couldn't figure out why only the rear axle got hot! There's more info on this in the Losi Comp Crawler section as well.

shelljeep · 01-20-2010, 11:38 AM

I think it's the cam angle on my pic. My spool does have slanted teeth, meshes well at a right angle when I put them together.
Do the mis-cut spools have teeth that are absolutely straight? If so, mine is definitely ok, as there is a noticeable slant to them.
Thank you though!
I'll go search around in the LCC section, I have a used one that should be coming today by FedEx.

indiana mudcat · 01-20-2010, 12:23 PM

I think you deff need to gear down to control the heat, but the weight in your tires and stronger servo could be overloading your internal bec causing the rx to shut down. Might be time to add a CC BEC.

shelljeep · 01-20-2010, 01:29 PM

Whoa... Easy there fella.

What's a BEC?
I know ESC is electronic speed control, I assume this part of that? What are the other parts of an ESC?
Thanks!

JeremyH · 01-20-2010, 01:35 PM

BEC = Battery Eliminator Circuit

Your ESC has a built in BEC. The BEC provides power to your steering servo. However, an internal BEC can be sucked dry when the motor draws a lot of current. This is accentuated when you run lipos.

An external BEC, like the Castle Creations BEC, draws its power directly from the battery (bypassing the ESC) and provides constant current to the servo.

shelljeep · 01-20-2010, 02:00 PM

Just deleted a big batch of questions I had typed, lol. I'll search on this later, but yeah, sounds like it would help cure some of my steering lag too.

shelljeep · 01-21-2010, 07:24 AM

To wrap this up, so future searchers can find it, the motor was the issue. The new motor has plenty of power, no issues with lugging after the swap. I know a 35T has more power, turns faster than a 55T(stock), but I think that if there was a problem with anything else in the system, it would have shown up after the motor swap as well.
This car now has plenty o'power, and turns well too, since I added a Hobbico CS170 steering servo at the same time. I can steer the tires anywhere, at anytime, with no matter what the motor is doing. So this leads me to think the ESC w/internal BEC is ok.
These two upgrades made a night and day difference.
I wish Losi would have put a better quality motor in it from the start. I know I'm using big batteries that give me a fairly long runtime(30-45 minutes), but it should have lasted longer than 13 days. I was very careful not to keep forcing it to move when in an obvious bind. It ran on carpet, maybe, 5 minutes. The rest of the time was outside in the rock garden or cement.
Anyway, just be aware that you will be wanting to upgrade your motor and steering servo when you buy this crawler. 300 oz servos and 35T motors make it a whole new rig. All bitching aside, it still makes me grin like an idiot, even with it's flaws.

Zimm98 · 01-21-2010, 08:31 AM

I too had to change my steering servo, it is nice to have the truck drive where you want it to go. The cheap electronics keep the cost down which is nice but it would be nice just to run it. Did you look to see where your stock motor failed? It looks like on mine it brunt where the brushes contact the rotor making a dead spot (must of bound it up a little much).

01-19-2010, 06:10 PM	#1
shelljeep RCC Addict Join Date: Jan 2010 Location: Lafayette Posts: 1,077	LNC loses power after a few minutes... Losi Night Crawler, basically stock besides 9 oz in the fronts and 142 oz steering servo. I run LiPo Dynamite 6000 2S, and 4200 2S for batteries. Today, I was only able to crawl for a few minutes, mebbe 5, before the LNC would act like it was bound up in very simple traction situations, not bound up or wedge type situations. The battery still had 8.1V afterwards, coming off a full charge, usually around 8.38 or so. So the battery is still full. The motor heat is something Ive asked around about and gotten different answers. It gets hot enough that I can't hold my finger on it longer than 3-4 seconds. It has also produced a light burnt odor before, actually a few times. And I have noticed lately that it lurches at lowlow speeds rather than smoot transition it used to have when first purchased. No loose wires that I can find. Think the stock motor is already on it's last legs? I've had this thing since 1-7, ran maybe 20 batteries thru it at most. I do run back to back sometimes, and I don't show it much mercy since I didn't think I needed to. I make sure to lift whenever I see it's wedged, but other than that, I just run it. Slooow technical crawls, to full throttle bumps, extended burnouts trying to make wheelbase type climbs. Am I running it too hard? Thanks, Shell

01-20-2010, 08:50 AM	#2
shelljeep RCC Addict Join Date: Jan 2010 Location: Lafayette Posts: 1,077	Axle Inspection I wanted to rule out worm bind, so I took the rearend apart. I think the worms look good, but I have never seen these before. Nothing metallic in the old grease, nothing that would make me nervous about a 1:1 R&P. How can I test the motor, esc, etc? I need to learn how to diagnose this stuff. Pics of the spool follow, pinion was absolutely perfect, only the faintest hint of a wear pattern so I didn't bother snapping pix of it.

01-20-2010, 09:00 AM	#3
shelljeep RCC Addict Join Date: Jan 2010 Location: Lafayette Posts: 1,077	Also, I assume my hitemp disc brake bearing grease that I use for my real vehicles will be ok for this app? edit- I have lithium grease also if more appropriate. Are you guys tapping these diffs right behind the ring gear, under the pinion support, in order to make maintenance easier? Last edited by shelljeep; 01-20-2010 at 09:13 AM.

01-20-2010, 02:00 PM	#18
shelljeep RCC Addict Join Date: Jan 2010 Location: Lafayette Posts: 1,077	Just deleted a big batch of questions I had typed, lol. I'll search on this later, but yeah, sounds like it would help cure some of my steering lag too. Last edited by shelljeep; 01-20-2010 at 02:41 PM. Reason: sp.

01-20-2010, 09:12 AM	#4
JeremyH I wanna be Dave Join Date: Sep 2005 Location: Houston, TX Posts: 16,952	It could be that the motor brushes are getting worn. When they get some runtime on them and wear down a bit, they can stick and cause the motor to appear to bind. You might pick up a few new brushes and springs for that motor and swap them in. And yes, it does sound like that motor is getting too hot... BTW, is this the same Shelljeep from Cowtown? If so, I've liked your 1:1 for quite some time....nice work.

01-20-2010, 09:23 AM	#5
shelljeep RCC Addict Join Date: Jan 2010 Location: Lafayette Posts: 1,077	I've got a hand wound 35T coming from CKRC, do you think I'll get more runtime out of it before it needs the brushes replaced? How do you guys keep the motors from getting hot so fast? Yeah, that's me man! Thanks for the compliment. I wish I hadn't cut it apart to buggy it. I'm building a 1ton YJ now. Here's a pic-

01-20-2010, 09:32 AM	#6
JeremyH I wanna be Dave Join Date: Sep 2005 Location: Houston, TX Posts: 16,952	Looking good! I like that cage. I can still see the shelljeep in the background... As for the motor, that really depends on the brushes and the contruction of the motor. Some brushes are made from a harder material and will last longer than others. Also, if you are running extremely stiff springs, they will wear out the brushes a bit faster. I believe that the stock LNC motor is a 55T, so that 35T will give you more wheelspeed which will produce more heat. I run 35T motors on my Bully rig and replace the brushes and springs about every month. It gets quite a bit of use and sees a LOT of digs...so the rear brushes wear faster than the fronts.

01-20-2010, 09:41 AM	#7
Zimm98 Pebble Pounder Join Date: Oct 2009 Location: Rapid City Posts: 147	I am having a similar probelm with my LNC bindnig when it should not bind. I hooked my amp/watt meter up to my truck and drove it and wached the display. When it would bind in easy situations the amps would not spike (if I got a spike it would indicate a mechanical bind). My crawler is under a month old too, I kinda wish they would ship it with a better motor. I am torn between spending the money to get brushless or just getting a brused to get me by.

01-20-2010, 09:50 AM	#8
shelljeep RCC Addict Join Date: Jan 2010 Location: Lafayette Posts: 1,077	I also have a 12 and a 16 tooth pinion coming so I can adjust the wheel speed if I need. Gearing it down like this should help take some of the load off the motor, right? Less load=less heat? I guess I'll probably push it just as hard though, once I get used to the new motor. So gearing is a moot point re: heat? Thanks for all the input Jeremy. This cage was about halfway built when I guy saw it online and bought it from me. LOL. I'm gonna finish it as far as I can in my YJ, than swap it into his next week. Working on the details now, and frame tie-ins. Here's a logo plate I built for it, mocked up, still need to clean it, center it up.

01-20-2010, 10:03 AM	#11
shelljeep RCC Addict Join Date: Jan 2010 Location: Lafayette Posts: 1,077	Good to know I'm getting the hang of this stuff. This forum is great. Thanks again, and that was cut out on my PlasmaCam table.

01-20-2010, 10:06 AM	#12
JeremyH I wanna be Dave Join Date: Sep 2005 Location: Houston, TX Posts: 16,952	No problem. Yeah, lots of info here. That cut looks MUCH better than anything I've ever made with a handheld Plasma cutter. I had not heard of that device before, but it looks like people are making some really cool stuff using them...

01-20-2010, 11:27 AM	#13
derangboy Newbie Join Date: May 2008 Location: Canada Posts: 44	I'm no expert, but it looks like your spool might be cut wrong. The teeth should be slanted but yours look to be fairly straight across. Easier to tell when it's next to a proper one. The top one in the picture is good. The bottom one is not. Sorry I didn't clean 'em up before I took the picture. Couldn't figure out why only the rear axle got hot! There's more info on this in the Losi Comp Crawler section as well.

01-20-2010, 11:38 AM	#14
shelljeep RCC Addict Join Date: Jan 2010 Location: Lafayette Posts: 1,077	I think it's the cam angle on my pic. My spool does have slanted teeth, meshes well at a right angle when I put them together. Do the mis-cut spools have teeth that are absolutely straight? If so, mine is definitely ok, as there is a noticeable slant to them. Thank you though! I'll go search around in the LCC section, I have a used one that should be coming today by FedEx.

01-20-2010, 12:23 PM	#15
indiana mudcat RCC Addict Join Date: Jul 2009 Location: reelsville Posts: 1,871	I think you deff need to gear down to control the heat, but the weight in your tires and stronger servo could be overloading your internal bec causing the rx to shut down. Might be time to add a CC BEC.

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01-20-2010, 01:29 PM	#16
shelljeep RCC Addict Join Date: Jan 2010 Location: Lafayette Posts: 1,077	Whoa... Easy there fella. What's a BEC? I know ESC is electronic speed control, I assume this part of that? What are the other parts of an ESC? Thanks!

01-20-2010, 01:35 PM	#17
JeremyH I wanna be Dave Join Date: Sep 2005 Location: Houston, TX Posts: 16,952	BEC = Battery Eliminator Circuit Your ESC has a built in BEC. The BEC provides power to your steering servo. However, an internal BEC can be sucked dry when the motor draws a lot of current. This is accentuated when you run lipos. An external BEC, like the Castle Creations BEC, draws its power directly from the battery (bypassing the ESC) and provides constant current to the servo.

01-21-2010, 07:24 AM	#19
shelljeep RCC Addict Join Date: Jan 2010 Location: Lafayette Posts: 1,077	To wrap this up, so future searchers can find it, the motor was the issue. The new motor has plenty of power, no issues with lugging after the swap. I know a 35T has more power, turns faster than a 55T(stock), but I think that if there was a problem with anything else in the system, it would have shown up after the motor swap as well. This car now has plenty o'power, and turns well too, since I added a Hobbico CS170 steering servo at the same time. I can steer the tires anywhere, at anytime, with no matter what the motor is doing. So this leads me to think the ESC w/internal BEC is ok. These two upgrades made a night and day difference. I wish Losi would have put a better quality motor in it from the start. I know I'm using big batteries that give me a fairly long runtime(30-45 minutes), but it should have lasted longer than 13 days. I was very careful not to keep forcing it to move when in an obvious bind. It ran on carpet, maybe, 5 minutes. The rest of the time was outside in the rock garden or cement. Anyway, just be aware that you will be wanting to upgrade your motor and steering servo when you buy this crawler. 300 oz servos and 35T motors make it a whole new rig. All bitching aside, it still makes me grin like an idiot, even with it's flaws.

01-21-2010, 08:31 AM	#20
Zimm98 Pebble Pounder Join Date: Oct 2009 Location: Rapid City Posts: 147	I too had to change my steering servo, it is nice to have the truck drive where you want it to go. The cheap electronics keep the cost down which is nice but it would be nice just to run it. Did you look to see where your stock motor failed? It looks like on mine it brunt where the brushes contact the rotor making a dead spot (must of bound it up a little much).

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