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Old Jan 12, 2013, 09:43 PM
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Help!
1/10 car cogging.. ESC or MOTOR?

I bought this (http://www.hobbyking.com/hobbyking/s...w_Reverse.html) ESC to my HSP Tyrannosaurus (self made electric conversion) and a BL motor from ebay as well.

Car/system works but I can't drive normally because it runs and stops whenever it wants - still on my control over Tx.

Problem poll which I wrote on HK:
"Ordered a 3000kv sensorless motor to it. Everything was connected right, tryed it on 3S, ESC was factory default - car runed but with constant cogging. Sometimes it bursted with full throttle for 3-4 seconds and then stopped. And then again - sometimes the car just don't move when I hit throttle. I thought it was the ESC so I ordered the HK programming card. Changed few settings (timing to 1 and 4, startup to 0%, and other minor adjustments) and runed it today in -15C (about 5F) snow. Same thing - lot of cogging and throttle responds badly. // I tryed a different Tx/Rx and got the same problem. Tryed different battery - same thing. I'm using 21T pinion. Maybe it's the motor which I ordered from ebay?? Help.. can anyone give me advice. "

I don't know where to search the problem. And when I tryed it outside (-15C) the ESC started constantly beeping after 10min of testing, car didn't moved at all. Later back at indoors it came alive again.

Help, appreciated.
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Old Jan 13, 2013, 01:15 AM
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You do have the programming card? What motor do you have? What car, what battery? The more details, the better the chance for a "tailor made" answer.
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Old Jan 13, 2013, 02:00 AM
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Yes, I have the programming card which I ordered after 1st failure. All the information is written in my first post too but here's my setup again:

Car: HSP Tyrannosaurus 4WD (nitro converted to electric) It's basically like HSP Brontosaurus now which IS electric in stock.
3000kv bl inrunner (I guess it's 12T)
60A HK ESC / sensorless
3S 11,1v LiPo, 3000mAh, 20C
21T pinion



The Tx/Rx set can't be the problem because the servo works 100% when I turn the steering.

Actually it's my first car so I am not very certain how to manage with prog card.
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Old Jan 13, 2013, 03:38 AM
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Quote:
Originally Posted by piito View Post
All the information is written in my first post too but here's my setup again:
I'm still not reading any details about used battery, brand, type. 20C isn't very powerful though. That means you can only draw 60A continously, and burst perhaps just a little higher. This seems like a heavy and big truck, I tend to think the battery is underpowered for it. Also, at temps below 0 degrees centigrade, batteries tend to loose their power quickly.

Also only the KV rating of the motor doesn't say much, if you are not even fully sure of the number of turns. Can you post a picture of the motor or provide more details about it? Did you try a different pinion?
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Old Jan 13, 2013, 04:41 AM
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Well, I'm not sure if the battery brand name help to figure out the problem but I used HK Zippy series. Also I tryed with some 2200mAh battery which gave same results.

I don't have any more pinions but maybe I should order. I got this motor by really great price so you may never know what the chinese guys send to you in the end.

It's something like this (same i guess):
http://www.ebay.com/itm/13T-3000KV-S...c34ea5&vxp=mtr

As I wrote, my truck is actually a converted nitro. It has almost full aluminium body so it's quite heavy. I wouldn't say it's a 1/10th scale truck because it looks more like a 1/12 when I compare it to my friends Losi. So this 1/10 motor should still do the job.
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Old Jan 13, 2013, 05:45 AM
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I could be wrong but this sentence: "This 3650M sized motor has a core of 380 class motor but the outside appearance is as same as 540 class motor, so its size is suitable for all 1/10 class" seems to tell that it's basically a 380 class motor but in the housing of a 540 class, so it fits 1:10 scale vehicles better. I'm beginning to suspect this motor is not up to the job at all. How heavy is your converted truck? Most nitro stuff is 1:10 scale or bigger.

Btw, some stuff in the description is downright funny: "With the help of it, you will have mystery feeling and enjoy yourself"


Anyway, back on topic, apart from the possibility the motor is too weak, it could also be either your speed control or motor is faulty from the start. No one that lives near you and can help you with testing stuff like hooking up a different motor to this ESC etc? Or a local hobby shop willing to lend a hand?
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Old Jan 13, 2013, 06:13 AM
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Yeah, I was a bit surprised myself when I got the motor - it really is a 380-size motor with wide heat-ribs round it. But the car seems to have a lot of power - still! When I manage to hit the throttle for 2-3 seconds, it really is like a beast.

Body weighs 2000g with motor installed (without ESC, battery).

I don't know... I should order a bigger/quality motor then. I don't have any other options. My friend upgraded his Losi HighRoller a month ago... Leopard setup- works like a dream. But he won't lend it to test. I'm pretty sure.

Before BL setup I had a 7,2 25C LiPo system on it, 540-size brushed motor. It seemed quite underpowered if I compared it to my friends Losi. I won the 10m dragrace but it was way slower and had problems running up to hill. So... maybe it's chassis is heavy after all.

Helipal says it's "plastic origin" with BL system weighs 2500g. If I add my 270g battery and 60g ESC to my car the overallweight is kind of the same. According to this info I'd say it's not that heavy.
http://www.helipal.com/hsp-brontosau...ruck-1-10.html
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Old Jan 13, 2013, 06:22 AM
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2000 g is a little heavy for 1:10. Compared to racing class buggies, those are around 1600 g or so. No doubt the 8 shocks and massive tyres contribute to that as well. Then again, without these it wouldn't be a truck.

Still it's odd that when all is working fine, the motor seems to have ample power, as you say.

7.2 volt lipo? You mean 7.4 volt or was the previous battery a NiMh? Did you also test the current setup with the 25C battery (if this is indeed a lipo)?
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Old Jan 13, 2013, 04:52 PM
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I think the problem is that it's either over heating, or your battery can't supply enough amperage. How hot is the motor or ESC when it's not running right?

A 3000mah 20c 3s pack is really under sized in a 1/10th scale truck. Do you have any 2s packs to try in it? Ideally you want 5000mah 30c or higher packs, regardless of cell count.

Are you running the same gearing you were using with a 2s pack and 540 brushed motor?
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Old Jan 14, 2013, 04:54 AM
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Quote:
Originally Posted by wparsons View Post
I think the problem is that it's either over heating, or your battery can't supply enough amperage. How hot is the motor or ESC when it's not running right?
A 3000mah 20c 3s pack is really under sized in a 1/10th scale truck. Do you have any 2s packs to try in it? Ideally you want 5000mah 30c or higher packs, regardless of cell count.
Are you running the same gearing you were using with a 2s pack and 540 brushed motor?
Overheating is not the case because after every testing motor, ESC and battery are always slightly warm... I can't even say theyre warm because they can't be better.

I'm running the same gearing, yes.

Just came from another test-ride. I tryed it with 3S 6000mAh (2x3000 packs), 20C, and it had even more power than last time. This small motor looks like a really powerful thing actually. But the cogging problem exists :mad

And then I tryed it with 1800mAh, 2S, 25C LiPo... at start when I turned on the ESC, it went crazy, servo moved to one extreme position and stayed, throttle wasn't responding. Then I crumpled the power plugs a bit and it slowly came alive - I did had a bit control over throttle. But on 2S it's really slow and weak- totally pointless to drive. Still had the cogging issue.

So - could it be that I've made some bad soldering somewhere?? Or is it the ESC because this ESC sucks in my opinion. Even if the cogging is not influenced by the ESC it still sucks because it dyes out in the cold. And it was only about -5C today!
If it were bad soldering issue then the ESC would restart constantly - right? But it stays ON all the time...

Now I can't even test it anymore because the following week will be coldddd... -15 to -20 at least. Total discrimination by the HK!
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Old Jan 14, 2013, 05:21 AM
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It could be the connector between battery and ESC can't handle the current and it gets so hot the solder starts melting. No joke, I've seen it happen. What type connector is on the ESC?

As for the cold, it could also be your lipos are affected. With low temps the voltage under load crashes down.
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Old Jan 14, 2013, 08:48 AM
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Lipo packs have huge voltage sag when cold.

I would try a smaller pinion gear before blaming the ESC. How frequent is the cogging? Was it better with the bigger pack? Do you have a 2s ~5000mah pack to try it with?
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Old Jan 14, 2013, 10:34 AM
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Ok guys, I finally found the problem - it was the Tx/rx!!!

I was using so-called hidden antenna, a 3inch/10cm long antenna which should do the work so there won't be need for long wire. I am still using the "old technology", lower frequenzis.
I was really mad at it and when I was indoors I started to test the range of it. So yeah... when I removed the super-hidden antenna and pulled out the long wire again it seemed to work. And then I tested it outside (-15C) and I finally saw this beast running. I'm amazed how much power this little motor can produce

So I have to take my words back - not all chinese people are stupid! Some of them are - those who claim that the hidden antenna work... it's a bugger, I can't figure out why it's not working properly.

I ended my testing with one broken wheel because of the crash against ice-block. Plastic gets brittle and it happens. Need to order more aluminium.

Some day I will make a video how it performs on snow/ice. ESC seemed to work when it got constant action.

Thanks for helping. Your help lead me to the conclusion!

BTW, car overallweight with 6000mAh LiPo's is 2700g.
And it will be heavier when I build the aluminium cage to protect ESC and batterys.
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Old Jan 14, 2013, 10:56 AM
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Going by what you said in the first post, it couldn't have been the TX/RX because you said you still had full control of the steering. It wouldn't selectively pick a channel to be glitchy on.

Did you have the short antenna on it with the old brushed motor/esc? Switching to brushless shouldn't have changed the range at all.

Be careful with too much aluminum, it won't rebound after a crash (stays bent) and will just move the damage further along to the next weakest part.
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Old Jan 14, 2013, 01:12 PM
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So it was the TX/RX connection after all. If the problem was not present with the old brushed setup, perhaps the ESC puts out some high frequency interference? As brushless has no comm/brush contact that can cause spikes that require suppression.

Anyway, MHz transmitters require a long antenna for decent range, or at least an antenna that's as high above the ground as possible. If you dislike an antenna sticking out of your car, you should switch to 2.4 GHz systems, these have a far shorter antenna, that can usually even provide good range when it stays under the body shell.

Here you can see the antenna installed in my Twister 2WD buggy:



It's the little light gray wire, running from shock tower in a small arch to the front, to the right of the lipo. Range is perfect with this setup.
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