A rant about the Tekin RX8

[8000ft]

First off I will say this, maybe this esc is better left to the racers on dry ground.

When I built my Yeti I decided to save a few bucks by purchasing some lower grade aluminum parts because I wanted the best ESC and motor by popular recommendation and it was unanimously the Tekin HD PRO 4 and RX8.

Pricy to say the least but what the heck it is the heart of the beast right? I knew that it was not waterproof but I will be running in the snow. I did a lot of reading and took great care in doing it right with silicone conformal coating.

Everything was alright for a week or two then on hard acceleration it began to stutter and buck off the line on hard launches. I went so far as to get into a personal correspondence with a Team Tekin tech. He and I tried to sort things out but no real luck. After a few more trial runs and replacing the sensor wire we could not get it to run smoothly again so he sent me a return RMA for out of warranty service. I still haven't sent it back with the only reason being that I had ordered a new RX8 and I figured that I could send it back when I get a few extra dollars.



The new RX8 was waterproofed with even greater care figuring that maybe water was the culprit, I still don't have an answer and at this point I don't see how my waterproofing could be any different than the way others have done it with great success.

Last night everything was running normally when quite suddenly (and I should say that everything was dry) the Yeti started shuddering and bucking violently on acceleration. After 2 or 3 times it just shut down. Strange I thought and when I got to it I found the both of the battery connections at the ECS Deans plug had become unsoldered and were still very warm.

I took the bottom of the ESC off just to verify the everything was dry and it was so I thought that maybe the battery was at fault.

I put the Turnegy battery on the charger and an error message came up that said something like 'main connection port error'. after a couple of tries I did get it to start charging but the number one cell was acting really weird. It started out at a lower voltage than the other two but gained voltage very rapidly and went over 4.22.

I shut it down and took it to our local fire station for their training exercises.

I put my other battery in it today and it ran fine for about 3 minutes and the it started to shudder again. I shut it down, took it home and opened up the ESC. Again it's dry, but this battery is now giving me the same error code.

In summary this has cost me 2 top of the line ESC's, 2 batteries, and the total loss of confidence in Tekin products.

I will now be looking for a new, factory waterproofed, modestly priced, bashers ESC.

If anyone is interested in 2 RX8 paperweights just send me a PM.

I am extremely upset about the situation. I can not fully blame Tekin but at the same time I find the situation a bit questionable and how their product may have caused a dead short going back to the battery and the potential of a fire and losing a $1900.00 vehicle.

How difficult would a fail-safe of some sort be to design?

 

[8000ft]

Just ordered a Mamba Max Pro W/ smart sense and a pair of Floureon 11.1V 4500mAh 30C Li-Po,

There went a quick $200 plus the 2 other ESC at $200 each and another $100 in toasted batteries brings it up to,$700. That hurts.

 

[Dwill]

I'm going to take a wild guess and say the coating is causing the heat build up. If it's getting hot enough to de-solder wires it's likely solder traces on the boards are also flowing and shorting.

That world be the end of the RX8. I've run RX8 Gen 2's in both my Tekno 1/8 buggy and my Tekno SC 4X4 for over a year with no problems at all. I'm running a RSX in my crawler and have not had a issue with it at all so far.

 

[WHITE-TRASH]

I beat the cap out of my gen 1 rx8 but not once did I run it through a puddle so yea... :lol:


If you wanted a real waterproof esc the mamba monster x is where it's at. That is one bad bitch and it's not a whole lot more money than the little mmp.

 

[8000ft]

No it desoldered at the Deans plug, a massive power draw heated up the supply wires and that's what heated up not the RX.

I'm going to take a wild guess and say the coating is causing the heat build up. If it's getting hot enough to de-solder wires it's likely solder traces on the boards are also flowing and shorting.

That world be the end of the RX8. I've run RX8 Gen 2's in both my Tekno 1/8 buggy and my Tekno SC 4X4 for over a year with no problems at all. I'm running a RSX in my crawler and have not had a issue with it at all so far.

 

[8000ft]

Okay, sell me on why the X over the other?

I beat the cap out of my gen 1 rx8 but not once did I run it through a puddle so yea... :lol:


If you wanted a real waterproof esc the mamba monster x is where it's at. That is one bad bitch and it's not a whole lot more money than the little mmp.

 

[WHITE-TRASH]

Okay, sell me on why the X over the other?

More amperage to the motor, no need for an external bec since its 8 amp directly from the esc and it's waterproof from the factory.

I still don't know why they haven't come out with an mmp 2 thats waterproof like they have with the rest of the line. It'd sell like crack in Harlem if they did.

 

[JohnRobHolmes]

This sounds like a plug issue. It would be impossible for the ESC to be faulty and not also overheat itself and/or the motor, while having enough current to desolder a plug. Solder heats up liquid around 250 amps by itself. Your system just couldn't do that. But a poor plug connection is not much different than a soldering iron.


Deans plugs just don't take much current. Fake deans plugs are hit and miss on quality, some are actually better than deans and some are absolute junk. You should be running compression bullet connectors like the XT60.

 

[JohnRobHolmes]

I still don't know why they haven't come out with an mmp 2 thats waterproof like they have with the rest of the line. It'd sell like crack in Harlem if they did.

Engineering time and board space. They spend more time engineering the most popular items. They can refine concepts and manufacturing processes on the micro and monster size, then apply that learning to the 10th scale for an even better product release.

 

[8000ft]

don't tell me that the whole problem could be the type of plug?! Why would the ESC run great for a few weeks and then start to shudder on hard acceleration and then soon after fail completely (no lights, no BEC)? I will take your advise and switch plugs on my new set up. But I don't see any signs of arcing or heat discoloration on the brass???

This sounds like a plug issue. It would be impossible for the ESC to be faulty and not also overheat itself and/or the motor, while having enough current to desolder a plug. Solder heats up liquid around 250 amps by itself. Your system just couldn't do that. But a poor plug connection is not much different than a soldering iron.


Deans plugs just don't take much current. Fake deans plugs are hit and miss on quality, some are actually better than deans and some are absolute junk. You should be running compression bullet connectors like the XT60.

 

[8000ft]

I must say that after getting off of the phone with a tech at Castle I will now say that I now believe that the combination of cold temps and batteries that were on the boarder line of capacity may have been the downfall of the RX8's.

I was running 4000mah batts with 60C and although these would be fine for summer, at the colder temps they may have been starving the ESC's capacitors and slowly killed them.

According to Castle, with the Pro 4 HD 3500kv and 3s I should be looking just a bit higher. Something in a 5000mah or higher and at least a 50C. Which by mathematics comes out almost even, 240 amp vs 250 amp, but sense the "C" ratings are a bit ambiguous I should be concentrating on the mah capacity.

I will be keeping the batteries that I just ordered for the summer time and for use in my son's Slash and I will now be looking for a bigger set batteries for the heavy Yeti. I will also be ordering the Mamaba X with it's sensor wire. converter.

Hind sight...could of saved $200 on the second RX8 if I had known this 4 months ago but I would have spent it on bigger batteries so in the long run it would have been a wash however knowing all of this now I am still in the hole with a big lesson learned.

 

[JatoTheRipper]

Deans plugs just don't take much current. Fake deans plugs are hit and miss on quality, some are actually better than deans and some are absolute junk. You should be running compression bullet connectors like the XT60.

I wish that comment would be a sticky. I often tell people that Deans are outdated and only used by many because we're "grandfathered in" with tons of electronics with Deans ends. The work well for a lot of applications, but they're no longer the "best". I also state that some T-connectors are much better than Deans. And I also say how XT60 is a much better connector. But of course people laugh at me because of XT60's origin and being one of HobbyKing's default connectors.

 

[JohnRobHolmes]

don't tell me that the whole problem could be the type of plug?! Why would the ESC run great for a few weeks and then start to shudder on hard acceleration and then soon after fail completely (no lights, no BEC)? I will take your advise and switch plugs on my new set up. But I don't see any signs of arcing or heat discoloration on the brass???

Plugs wear out, and deans wear out fastest compared to other styles. Gold plated plugs won't discolor, otherwise they would be discolored from initial soldering. It may have been your battery being weak too, but plugs desoldering themselves only happens when the ESCs fail in a dead short or when the plug connection fails. If your ESC is still operational, it points to the plug as the culprit. Either the plug itself or the solder joint.


Your intermittent shudder was probably the plug having poor wire connection, held on by heat shrink. You hit a bump and it studders. Accelerate hard and the G force pulls the wires around.

 

[Highmark]

I'd like to see your solder joints on the plugs as well. By the sound of it you had a low quality joint with enough resistance to melt the solder. I've beat the shit out of a de-fanned RX8 and never had any issues.

Here's a good comparison of the different plugs and what they can handle:
https://www.youtube.com/watch?v=QeTTw9i8WEc

Either way I don't see how you could blame Tekin for this one. Just because you threw a bunch of money at a problem doesn't mean it's their fault.

 

[Sneetches]

I'm gonna jump in and say your problem may be a plug issue too. This:

Everything was alright for a week or two then on hard acceleration it began to stutter and buck off the line on hard launches

Is exactly what my ARRMA Kraton did until I replaced the crap fake Deans plugs they used on the ESC. After replacing/resoldering myself with genuine Deans, the stuttering was gone. It was to the point where sometimes it wouldn't even launch on quick throttle pull, it would just sit there and cog terribly.

I've also had a bad solder joint on my Stampede 4x4's motor bullet break loose after weeks of abuse, causing the motor to only do a very bad stutter. Resoldered it and good to go.

 

[8000ft]

Not blaming Tekin, just the wrong choice for my application, basic bashing and in wet environments.

I'd like to see your solder joints on the plugs as well. By the sound of it you had a low quality joint with enough resistance to melt the solder. I've beat the shit out of a de-fanned RX8 and never had any issues.

Here's a good comparison of the different plugs and what they can handle:
https://www.youtube.com/watch?v=QeTTw9i8WEc

Either way I don't see how you could blame Tekin for this one. Just because you threw a bunch of money at a problem doesn't mean it's their fault.

 

[JatoTheRipper]

Not blaming Tekin, just the wrong choice for my application, basic bashing and in wet environments.

Your title stating "A rant about the Tekin RX8" indicates, to me, that you're placing the blame on the ESC. I believe that's why Highmark stated that.

 

[Alexander_0_1]

Lol...my first RX8 went up in smoke, it only took me a day and a half. I sent it in for warranty, and tekin replaced it, they never told me what I did though. I then wanted another RX8 much like you, only I had Holmes Hobbies do all the work for me (...connectors, water proofing), it still going strong today, I don't drive through puddles, but it quite common for me to find damp grass.

Disclaimer:
For anyone else considering getting holmeshobbies to water proof you a new RX8, be prepared to say so long to tekins warranty.

 

[8000ft]

True, in some respects I guess that I was and maybe to some extent still am finding some fault in the RX8 design. I mean being able to self destruct due to under powered battery supply seems to be something that could be prevented. I mean it shuts down to prevent the batteries from over discharging. Why can't it tell if it's getting damaged by low supply under demand?

Your title stating "A rant about the Tekin RX8" indicates, to me, that you're placing the blame on the ESC. I believe that's why Highmark stated that.

 

[8000ft]

so I just ordered a Vant Battery, 11.1V 6500mAh 3S Cell 75C-150C HardCase LiPo. = 487amp/975amp

I know it's not a name brand but it should have enough to power the Pro 4 HD 3500kv thru the mamba X.