Too Much Current From A Battery Killed my Brushless Motor? I DON'T THINK SO!!

[MailManX]

Originally Posted by Warmntoasty

Oh man, this doesn't sound good for me! My truck always cogged a little too and it was doing it really badly before it died (see above post).

The LHS called me yesterday and said he thinks the ESC is gone or it's binding but they can't fix it until mid May when his technician returns from China. I don't recall any issues with binding but I do recall the brakes not working correctly towards the end there. I think its the ESC. The only question is, did I do it running it through that puddle or was it destined to fry like yours. Either way, I think they will look after me (this time).

Keep us or me posted if you can on what you upgrade it with. I'd like a waterproof 150 amp esc preferably but they look hard to find. And I can see now that a comparable motor will just slide into the heat sink....

Cheers

After my experience, and what I read from others with poor DHK electronics, I believe yours was destined to fail. The water may have sped that up, but it WAS going to happen, regardless.

You're right, larger waterproof ESC's are hard to find. However, 120A waterproof ESC's are easy to find and they are pretty small. I might go that route for the Maximus. I have decided not to move the motor and ESC from my Thunder Tiger. They are just too big and it wouldn't be worth the effort. I recently put a Hobbywing WP-SC8 (120a) waterproof ESC into my grandson's Traxxas Stampede 4x4 and it is very compact. It might be just the thing for the Maximus. Then I'll just have to find a reliable, strong motor with a can size of 3660.

I intend to start a new thread of the rebuild. It might be a little while before I get to that, but I promise it will happen.

[MailManX]

Hey Warmntoasty - It looks like Hobbywing "possibly" just released a waterproof 150a ESC, model number WP-8BL150. It is a Quicrun series which I am not familiar with. I know that the EZRun and XeRun series are very reliable, but I can't find much info on Quicrun. Also, I cannot find it directly through the Hobbywing website. Rather, I can find it on ebay, Amazon, Banggood, RCEcho, RCMart, etc. On quick first look, they all seem to be shipping from Hong Kong. I suppose it's possible that they are knockoff's and not legitimate Hobbywing products.

You wanna be a guinea pig again, or is dealing with the DHK Maximus torture enough for now?

Honestly, I think the WP 120a Hobbywing or Castle Mamba Monster 2 would be more than enough capability. I truly don't believe the Maximus should ever be run on 6s.

As for motors, any 36mm dia motor will work. Thankfully, there is plenty of excess length in the motor mount area. The Neu-Castle 1415 1y 2400Kv motor has a 3670 can. That is an awesome motor. Leopard and Tacon both make 3674 size motors that are well fitted to 1/8th scale power. Looks like we have some good options there.

[Warmntoasty]

Thanks so much for the advice MailManX,

I think 120a will be enough. Waterproof sounds the way to go and I think I can easily waterproof the existing receiver myself. And I don't ever intend to run it on anything more than 2s or 4s batteries.

I'm gonna ask you a couple more questions though ....

If the esc is the culprit, why should I upgrade the motor? Is this 'best practise' or could I leave this stock until it fails (if ever)?

If i purchase an aftermarket esc, does this affect my trim controls via the transmitter? I'm guessing not as the receiver remains the same.

Cheers

[losikid]

I've read page 1, I haven't read page 2 yet...

I do agree that the new batteries isn't pushing the power into your electronics. BUT it has the capability of supplying ALOT more current than the stock batteries. If that motor was under any sort of significant load it can easily overheat and take a shit on you if it has a good enough power source. The shitty stock batteries were limiting the power it could draw, so it wasn't overheating...but those bad ass batteries told the motor it could have as much power as it wanted, giving it the option to overheat.

The cause of the issue is probably drag in the drivetrain, improperly geared, or too small of a motor. As a motor shouldn't overheat unless it is being over worked (too much load). So you could think of the stock batteries as a band aid to the issue (not allowing the motor to overwork itself).

As for a equation to prove that a battery doesn't push current. Ohm's Law V=IR .

[MailManX]

Originally Posted by Warmntoasty

If the esc is the culprit, why should I upgrade the motor? Is this 'best practise' or could I leave this stock until it fails (if ever)?

If i purchase an aftermarket esc, does this affect my trim controls via the transmitter? I'm guessing not as the receiver remains the same.

I actually don't know if every failure was the ESC. In fact, the Hobby People manager was pretty sure the motor caused the problem at least two of the five times. To back that up, he found a "service bulletin" from DHK indicating that if a motor failed, there was a different part number that needed to be installed. Sadly, I cannot find that paperwork at the moment to see what the part number was. In my case, each time the motor failed, it caused the ESC to fail. Therefore, if you can afford it, I think the safe route is to replace both at the same time. Probably best not to mix dodgy electronics from DHK with good electronics from a reputable company.

Your trim controls will not be affected for steering. However, anytime you buy a new ESC, you have to calibrate it to your radio transmitter so it knows the neutral, max forward and max reverse points for the trigger. That calibration is very easy to do and comes with the instructions for the new ESC.

Originally Posted by losikid

I've read page 1, I haven't read page 2 yet...

Yeah, sorry! I do tend to get a bit verbose. I just really enjoy writing and I get carried away all too often.

Originally Posted by losikid

I do agree that the new batteries isn't pushing the power into your electronics. BUT it has the capability of supplying ALOT more current than the stock batteries. If that motor was under any sort of significant load it can easily overheat and take a shit on you if it has a good enough power source. The shitty stock batteries were limiting the power it could draw, so it wasn't overheating...but those bad ass batteries told the motor it could have as much power as it wanted, giving it the option to overheat.

The cause of the issue is probably drag in the drivetrain, improperly geared, or too small of a motor. As a motor shouldn't overheat unless it is being over worked (too much load). So you could think of the stock batteries as a band aid to the issue (not allowing the motor to overwork itself).

As for a equation to prove that a battery doesn't push current. Ohm's Law V=IR .

Definitely no binding in the drivetrain. That was checked and rechecked.

Thanks for the equation! I won't need it now since Hobby People Corporate apparently stepped in and authorized the warranty repair again. That new repair lasted less than 30-seconds, so I've given up on the DHK electronics. Hobby People was awesome to keep replacing the parts, but ultimately I have to give up on them, too, because their warranty repairs never got me anywhere except back to the store over and over and over.

I don't think I'll ever know for sure what the culprit was, or if it was even the same thing every time. At least two of the times, the Hobby People manager told me it was the motor.

I think it may have been the weak OEM batteries. Each time there was a failure, it was when using the stock batteries. Never once was there an issue with the newer batteries. They only became an issue when the store manager saw them and hoped to have an out for warranty service. Sad. Although I believe it was a poor design or low quality electronics from DHK causing the problem, Hobby People is the sole retailer for DHK in the US, so it ends up basically being a "store brand".

Anyway, I've moved on and am putting this behind me. I'm gonna gets some different electronics and find out what this truck can really do when it's able to run more than a couple of times without failure. I have a slew of other RC's and love doing my own work on them, so deciding to work on the Maximus myself will be the right choice for me.

Cheers!

[Warmntoasty]

OK, I'm gonna bug you just a little more because even though I might get this fixed under warranty, if it goes bad again, I'm jumping on ebay immediately. I'm gonna go the combo way and I've seen this:

EZRUN Latest product SC8 Combo 4700kv 3656 Brushless motor with waterproof 120A ESC

But the motor is 4700kv. Would that be ok? If I'm running the batteries in series, I assume I'm ok with up to 2x4s lipos?

ESC FEATURES
3 Features
3.1 Completely water-proof and dust-proof..
3.2 Powerful built-in switching mode BEC
3.3 Excellent start-up, acceleration and linearity features.
3.4 Plenty of programmable items, suitable for various of chassis's, tires and racing tracks
3.5 Electric brake function, also compatible with mechanical disc-brake system
3.6 Multiple protection features: Low voltage cut-off protection / Over-heat protection / Throttle signal loss protection
3.7 Internal timing can be changed easily to make the ESC suitable for various of motors
3.8 Easily programmed with the SET button, LED Program Box, Professional LCD Program Box(OPTIONAL)and USB Link Software(OPTIONAL)
3.9 Special program port for easily setting the ESC
3.10 ESC firmware can be updated through the USB adapter in the LCD Program box
3.11 Mounting stand for installing the ESC on chassis easily and firmly
3.12 Top quality motor
-Aluminium shell (case)
-High quality magnets
-Copper wires of high temperature endurance
-Good quality bearings
4. ESC Specification
4.1 Output: Continuous 120A, burst 760A.
4.2 Input: 6-12 cells NiMH/NiCd or 2-4S Lipo
4.3 BEC: 6V/3A (Switching mode)
4.4 Resistance: 0.0004 Ohm.
4.5 Motor Supported: Sensorless Brushless Motor.
4.6 Suitable Motor: * Note #1
With 6 cells NiMH/NiCd or 2S Lipo: KV≤6000;
With 7-9 cells NiMH/NiCd or 3S Lipo: KV≤4000;
With 10-12 cells NiMH/NiCd or 4S Lipo: KV≤3000
Suitable Car: 1/10 4WD SCT, 1/8 2WD and 4WD buggy/SCT (Include TRAXXAS 1/10 SCT);
4.8 Size: 59mm(L) * 38mm(W) * 34mm(H);
4.9 Weight: 113g(Without wires)
The cooling fan of EZRUN-WP-SC8 is powered by the built-in BEC

[MailManX]

Originally Posted by Warmntoasty

OK, I'm gonna bug you just a little more because even though I might get this fixed under warranty, if it goes bad again, I'm jumping on ebay immediately. I'm gonna go the combo way and I've seen this:

EZRUN Latest product SC8 Combo 4700kv 3656 Brushless motor with waterproof 120A ESC

But the motor is 4700kv. Would that be ok? If I'm running the batteries in series, I assume I'm ok with up to 2x4s lipos?

Combos can save you money, but only when they combine items you actually need. In this case, I would steer you away from the 4700Kv motor. Typically, an 8th-scale rig such as buggy, truggy or monster truck typically needs a motor closer to 2000Kv.

There are lots of places on the web to get info on what brushless motor KV means, but this is one of the clearest I've seen:

Understanding R/C Brushless Motor Ratings

To summarize, higher KV motors are "capable" of faster speeds, but do so by sacrificing torque. Lower KV motors have more torque to move bulkier trucks and get them up to speed more quickly. The lower KV motors also run cooler on a larger range of gear ratios. Lower KV doesn't have to mean the truck is slow. By giving you the option of running with different pinions, you can temporarily gear for very fast speeds to get speed runs, but you would not want to bash with that gearing.

I won't try to steer you to any brand. Just get what works for you. If you can't find a combo, then do your best with individual prices on the parts you really need.

Best of luck on that my friend!

[Warmntoasty]

Thanks again MailManX

Will keep looking around. Appreciate your feedback.

Will be interested to see how you go when you upgrade yours.

Cheers

[Dad,Canyoufix?]

Well, glad you have it figured out, Crappy electrics that are worth the time or money. So how much did this rig cost new? I would have took the truck back, with receipt, said I don't want it, hand over the refund. If they need to get it form the manufacturer, so be it. ill save the gas money from running to the LHS 5 times and just buy something else. I can understand wanting to keep a rig your attached to, or you really wanna make it work, but if the rig is failing with nothing I did to help it, I don't think it owns up to a space in my list of rigs, Plus that motor mounting system looks destined for failure. High torque brushless vs smooth steel to flat toothed aluminum heat sink as a mount? Don't know about that. Good luck with it though. Maybe post a additional video of it when you have worthwile electronics in it.

As for not trashing DHK, any company that doesn't address quality issues with there product and sells electronics that aren't worth 10 min of good run time, Deserves a good thrashing. The truck may be good as a roller, but make sure you review it as such, Good as a roller but not worth the money they make you pay for a rtr. (BLASPHAMY ALERT! Sounds like owning a nitro would be less hassle)

Just my $0.02

[MailManX]

Originally Posted by Dad,Canyoufix?

(BLASPHAMY ALERT! Sounds like owning a nitro would be less hassle)

That had me laughing out loud!!

The DHK is about $400 new. I never would have purchased it for that. However, I took a known risk when it was on a one-day sale for $250. I figured that was the price for a good roller. Since I am not a helpless novice, I was interested in experimenting and posting my results.

Truth be told, the only reason I went through all the hassles with Hobby People is I wanted to be able to document how well they and DHK support their product. It gives me something to write about when I review the truck. I pushed REALLY hard for a full refund more than once. I even asked the corporate office of Hobby People to intercede. They flat refused. In doing online research, that seems normal course for this brand and store to refuse refunds. The only instance I read about where Hobby People made the refund was where a DHK Optimus buggyy caught fire with the stock ESC and batteries. The guy plunked the melted hulk on the counter at Hobby People and asked for his money back. He's the only one I'm aware of that got it. Even then, they gave him store credit which he applied to a different rig.

Check out the third page of this thread for a picture of the melted buggy:
DHK Zombie, Maximus, Optimus, and Optimus XL - RC Industry News (moderated) @ URC Forums

Just a side note: The DHK brand seems to be selling better in countries outside the US. I'm hoping to use a couple of world-wide forums to post a review and share idea with other DHK owners.

[Dad,Canyoufix?]

Glad I could make you smile after all that. Well for 250 I guess you not out all that much. Good deities help those that paid full price. I can't believe they have that bad customer appreciation and respect. Glad you did all that writing so when someone looks up the brand this thread has a chance to make others wise to the game DHK and hobby people play before they place their chips. I think hearing how the hobby people shop handle the problem is the most disturbing thing. I remember my old LHS ceasing to sell a certain model of a buggy they had due to the amount of problems they had with the one they tested for the store, and offered full refunds to those that bought one and still had the receipt. Either way, let us know how the chassis,suspension, and drive line hold up when you get a power plant in there that will last more than 2 parking lot blasts.

[MailManX]

I started a new thread in the non-crawler section of this forum to report on the new motor and ESC that I purchased for the DKH Hobby Maximus Monster Truck:

REPORT: DHK Hobby Maximus Motor and ESC