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Wiring Setups and Connectors - High Amps and Voltage Problems

Old 01-23-2018, 01:39 AM
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Exclamation Wiring Setups and Connectors - High Amps and Voltage Problems

Hey guys, been away from the forums for a few years due to dropping out of the hobby for financial reasons. Now I am back, ready to purchase my first ever "pro style" 1/8th scale Truggy KIT rather than an RTR. Now I want to power this thing correctly, so of course I will be headed to Team Tekin for an ESC and motor, and to Protek RC for the 170SBL servo (450 oz-in at 0.08 sec on 6V wow!).

Last time I left the hobby was after major disappointment when my barely 3 month old Serpent Cobra 1/8th E-Truggy went up in flames when the RX8 Gen 1 ESC just decided "Nope, I'm Done". I had run the truck through maybe 5 charge cycles and the electronics showed no warning signs of issues at all. No studdering, no power loss, no smoke, no heat problems. Just driving along, maybe 30-40% throttle just to test out new tires, and it suddenly stops and erupts into flames. I didn't even jump it, at all, I was in an empty dirt parking lot trying out city-block tires! After this catastrophic failure and basically loosing $1000 in just 3 months, I parted ways with the hobby. I want my next RC to be bulletproof (and I mean .50 cal triple Kevlar type BULLETPROOF) as far as wiring, batteries, and connectors are concerned.

Ive heard that the Gen 1 RX8's went up in smoke alot, but I wanted to check with some more experienced members of the community to see if I may have done something incorrectly on my old rig before I continue and move on to build a new rig.

My old setup consisted of 10AWG wire and Deans Ultra Connectors from Amain Hobbies which I figured was plenty, but the fire started on just 4S LiPo power. This new setup will be capable of 6S power, and while I dont plan to run so much power, I would like to configure the wiring and connectors to support 6S power to have quite ample protection for my new RX8 Gen 3.

I am thinking of upgrading the wiring on this build to 8AWG and I want to run the biggest and most powerful connectors available to support the immense 300 Amps Per Phase that the RX8 is capable of, not to mention the added load of that insane ProTek Servo (My new favorite servo over all other servos including Savox!).

So tell me guys, what sort of connectors are you using on your 1/8th Scale 6S setups? What kind of wiring are you using? Should I go so far as to use even special solder to handle the high amperage? Should I have connectors between the ESC and motor for convenience? If so, what connectors? Are my Gens Ace 5000mah 40C 2S LiPos (I have 4 of them) good enough, or should I upgrade? What batteries would you recommend that are decent priced? Is there anything else that I should consider?

One final question, I still have the melted RX8 lying around in my toolbox. Do you think I could send it in? Im doubtful as its been in there for about 2 years and any warranty it had is almost certainly expired. Also, I wouldn't be interested in a straight swap, only if they gave me the new Gen 3 instead. Otherwise, I will simply purchase a new setup.
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Old 01-23-2018, 06:17 AM
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So researching for hours and hours and hours I finally found good reviews on connectors, on batteries, and recommendations for wire gauge and other information on other aspects of RC wiring and electrical draw. I have learned quite a few new things over the past 4 hours or so and wanted to share the information as the info was actually quite hard to find and required searches using very specific wording to find the information.

Firstly, Discharge ratings (40C for example) on Lithium-Polymer battery packs are completely USELESS. After finding a forum showing that they tested battery output using real, professional amp-loading electrical equipment, their results showed that NOT A SINGLE battery on the market today can actually output the C rating that they rated at, even the mighty Max Amps. I kind of always suspected this, as if you take C ratings seriously, then the 8200mAh, 110C battery listed at the end of this post would be capable of 902 Amps. 900 Amps, from an RC car battery??? Ya, I didn't think so. My full size Volkswagen GTI that I drive uses a battery that is rated at 450 Cold Cranking Amps. So no, your RC car battery will not deliver twice the power of your full size car's battery, absolutely impossible.

Now while I had this suspicion to begin with, what I did not realize was just how far manufactures claims are exaggerated. I found new batteries from a company I like, called SMC. I like these guys because I found over 10 review videos on YouTube ALL expressing just how amazing these batteries are. AND they outperform most mid-grade LiPos WHILE being less expensive than even Gens Ace! But the BEST thing about these guys is their honesty and integrity. On their own website, they have an article explaining how discharge C ratings are completely bogus, and they even list the proper amps output of each battery they are selling, and this is the TRUE output!

Now the battery I am interested in is linked at the end of this post. It is a 4S 7400mAh 90C rated battery, but right next to the C rating it says 149 Amps. This is the TRUE rating of the battery. If you used the standard mAh and C calculation, then it says this battery is capable of 666 Amps. So, which sounds more reasonable to you?

So the C rating claims 666 Amps, but the actual output is 149 Amps (Continuous). That is just 22.4% of the C rating claim. So the general rule then would be to take whatever C rating calculation result you got, and divide the amps by 4 to get much closer to the TRUE rating of your battery. Divide the amps by 5 to be really safe.

Now, while the RX8 Gen 3 states it is capable of requesting up to 300 amps of power, this will NEVER, EVER actually happen. Once again, the ratings are exaggerated, and once I found PROVEN, technical tests of scale brushless motors, I found that the REAL draw tends to hover around 50-60 Amps in most conditions, but the more powerful motors such as the Tekin T8 Gen 2 line can spike at 90-100 amps under hard acceleration. Therefore, the SMC battery I want is more than powerful enough, but my 5000 mAh/40C Gens Ace isn't; as its TRUE amperage limit is more towards 50 Amps rather than the claimed 200. This may explain why my Gen 1 RX8 went up in flames, despite the fact I hit full throttle several times with it with no issues during bashing sessions, but then decided to go up in flames at 30% throttle on a gentle testing run. Whatever, anyways...

Finally, I found technical information regarding AWG wiring and specific amperage loads for specific connectors. 12 AWG wiring is barely capable of 50-60 Amps continuous and 100 Amps burst, so a Tekin setup completely maxes out these wires, so if you are planning on running a Tekin RX8, then upgrade to 10 AWG. Deans Ultra plugs are also just BARELY capable of handling 50-60 Amps Continuous and 100 Amps burst for just a few seconds. So while my wiring was fine on my old rig, the connector was maxed out. Further research shows that connectors are the most restrictive part in wiring, and so going above and beyond your required rating is recommended, as the hottest part of the wiring tends to be at these connections. Therefore, I can come to a fairly certain conclusion that my Serpent Cobra Truggy went up in flames not because of the batteries (because I still have them and they didn't burn or puff at all and still function normally), but rather much more likely because of the Deans Ultra connector probably melting and causing a short-circuit.

So, what connectors should we be using on our Tekin RX8 setups? Well, browsing Amain hobbies connectors and misc. parts I came across the RCProPlus Pro-S6 connectors that use GIANT 6mm bullet connectors inside completely isolated housings. They are specifically designed for 8-10 AWG wire, and are rated at 240 continuous amps (probably exaggerated as well but probably good for 150-200 judging by their immense size)! They are also designed to allow two batteries to plug directly into each other on one side so you do NOT need a series adapter to connect 2 batteries to one ESC! As we know, as wire length increases and you add more connectors; the resistance, heat, and power loss all goes up, which is NOT GOOD. So eliminating the need for multiple battery adapters is a VERY GOOD THING! Watch the video in the link to the connectors and at the end you will see two 6S batteries being plugged into one another to create a 12S battery with NO adapters!

So using all this new information, I can now recommend a SAFE wiring setup for the RX8 and all other 1/8 scale ESCs and Brushless motors:

Most lower end 1/8th scale ESCs and motors (such as HobbyWing, Leopard,ect.) will be okay with 12 AWG wire and your typical Deans Ultra connections with average 5000mAh/40-50C batteries, as the motors draw less amperage than higher end 1/8th scale motors. However, if you want to run Tekin, Orion, LRP, Reedy, Castle Creations, or other higher end 1/8th scale electronics, then upgrading to the 10AWG wire and at LEAST the XT90 (90 Amp continuous) connectors is an absolute MUST. At this point you also want to upgrade your batteries to a MINIMUM 6000mAh/60C rating or equivalent.

The SMC battery below comes wired from the factory with 10AWG wire, so I will stick with 10AWG wire for my new setup, to keep everything nice and even. Different size wiring in different points of the electrical system is DANGEROUS and should be avoided at all costs (10AWG battery leads leading into 12AWG ESC wire means the power coming from the battery gets choked at the connector, leading to increased heat and possible fire!). Product Links Below:

902 Amp (Claimed, NOT TRUE) 2S LiPo: https://www.amainhobbies.com/reedy-z...c27320/p727177

149 Amp SMC True Rated 4S LiPo: https://www.smc-racing.net/index.php...product_id=491

200 Amp RCProPlus Connectors: https://www.amainhobbies.com/rcpropl...ros6p8/p492923

Hopefully this thread will help you prevent electrical problems in your RC vehicle! If this thread has helped you then please let me know!

Last edited by wallacengineeri; 01-23-2018 at 06:43 AM. Reason: Spelling Errors
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Old 01-29-2018, 02:49 PM
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Send that RX8 in. For about $120 Tekin will send you back a brand new Gen3.
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Old 01-29-2018, 03:10 PM
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Originally Posted by Krio
Send that RX8 in. For about $120 Tekin will send you back a brand new Gen3.
Even with how long the Tekin has been sitting around? Its been in a box, melted, for like a year now. Also, I didn't buy it. It came on a truggy that I purchased used. Honestly it may not be worth it regardless, as my new Truggy setup will also be getting the T8 2000Kv motor for more torque and less speed. So thats $160 for a new motor plus $120 for replacement RX8 plus shipping to Tekin for the replacement ESC. To be honest, $320 for a whole new setup is about the same cost, plus I cant do it right now, my new project will be taking place sometime later this summer after I move to Seattle.
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Old 01-29-2018, 04:08 PM
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Send the esc in the summer and have a spare for your box, or sell it, as for electronics it's hit or miss as you really never know when they will go up, I had 2 esc's go up back to back and blamed the battery, but I am not taking the chance on that battery, I also feel the gen 2 esc's where not better, and that's what I had go up flames, but my current E truggy has a gen 1 esc with a 2050 and a spare gen 3 with a brand new 2250
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Old 01-29-2018, 05:11 PM
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Originally Posted by Troubles Dad
Send the esc in the summer and have a spare for your box, or sell it, as for electronics it's hit or miss as you really never know when they will go up, I had 2 esc's go up back to back and blamed the battery, but I am not taking the chance on that battery, I also feel the gen 2 esc's where not better, and that's what I had go up flames, but my current E truggy has a gen 1 esc with a 2050 and a spare gen 3 with a brand new 2250
Super glad that the Gen 1 RX8 is working so well for you, it and the Gen 2 were well known for series issues including many fires, so you have quite a gem there
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Old 01-30-2018, 07:36 AM
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Originally Posted by wallacengineeri

The SMC battery below comes wired from the factory with 10AWG wire, so I will stick with 10AWG wire for my new setup, to keep everything nice and even. Different size wiring in different points of the electrical system is DANGEROUS and should be avoided at all costs (10AWG battery leads leading into 12AWG ESC wire means the power coming from the battery gets choked at the connector, leading to increased heat and possible fire!).
Just want to post that using different gauge wires doesn't cause a choke point. As long as both wires are adequate, like 10 awg battery wire and 12 awg motor wires in a car that only needs 12 awg, there isn't a problem.

Originally Posted by wallacengineeri
Even with how long the Tekin has been sitting around? Its been in a box, melted, for like a year now. Also, I didn't buy it. It came on a truggy that I purchased used. Honestly it may not be worth it regardless, as my new Truggy setup will also be getting the T8 2000Kv motor for more torque and less speed. So thats $160 for a new motor plus $120 for replacement RX8 plus shipping to Tekin for the replacement ESC. To be honest, $320 for a whole new setup is about the same cost, plus I cant do it right now, my new project will be taking place sometime later this summer after I move to Seattle.
If you don't want it, I bet someone would buy it off you for a few bucks to get a discounted Gen3. The esc/motor bundles do save a bunch of money, so if you already need a motor you won't save much.
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Old 01-30-2018, 08:00 AM
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Originally Posted by Krio
Just want to post that using different gauge wires doesn't cause a choke point. As long as both wires are adequate, like 10 awg battery wire and 12 awg motor wires in a car that only needs 12 awg, there isn't a problem.
This is true, but of course I was referring to the other way around (i.e. a Tekin T8 setup requiring 10AWG but having 12AWG on the battery or ESC leads or Motor, ect.

Originally Posted by Krio
If you don't want it, I bet someone would buy it off you for a few bucks to get a discounted Gen3. The esc/motor bundles do save a bunch of money, so if you already need a motor you won't save much.
That is a fairly good idea, but honestly I will just give it away, or at the most like $20. A melted ESC is worthless after all and there is no guarantee that Tekin will "play ball" if you know what I mean...

Regardless, this thread is incorrect. I learned quite a bit more about amperage since posting this thread. While C ratings are still useless, the actual SAFE amperage is not just 25% of the C rating. In fact, the percentage varies alot, like ALOT ALOT. So I will be creating a new thread on the subject, sometime today. Im hoping it will get the attention of many users and moderators, and hopefully get "stickied"
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Old 01-30-2018, 08:14 AM
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tekin is a solid company and stands behind there exchange program..I have been dealing with tekin since there rebirth and even products b4 the new tekin in the early 90's they replace..
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Old 01-30-2018, 08:15 AM
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Originally Posted by wallacengineeri
This is true, but of course I was referring to the other way around (i.e. a Tekin T8 setup requiring 10AWG but having 12AWG on the battery or ESC leads or Motor, ect.



That is a fairly good idea, but honestly I will just give it away, or at the most like $20. A melted ESC is worthless after all and there is no guarantee that Tekin will "play ball" if you know what I mean...

Regardless, this thread is incorrect. I learned quite a bit more about amperage since posting this thread. While C ratings are still useless, the actual SAFE amperage is not just 25% of the C rating. In fact, the percentage varies alot, like ALOT ALOT. So I will be creating a new thread on the subject, sometime today. Im hoping it will get the attention of many users and moderators, and hopefully get "stickied"
I figured that's what you meant, but just wanted to clarify for anyone else who was reading.

I guaranty Tekin will honor the exchange. Randy Pike (Tekin Employee/Team Manager) has posted here in this forum that they replace any busted RX8 with the Gen3. On their service form linked below, they note that all generations of the RX8 have a replacement cost of $123.

Randy's post: Tekin RX8 1/8 Scale Brushless ESC Thread

Tekin Service form: http://www.teamtekin.com/assets/tws_service_request.pdf
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Last edited by Krio; 01-30-2018 at 08:45 AM. Reason: spelling
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Old 01-30-2018, 09:49 AM
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Originally Posted by Krio
I figured that's what you meant, but just wanted to clarify for anyone else who was reading.

I guaranty Tekin will honor the exchange. Randy Pike (Tekin Employee/Team Manager) has posted here in this forum that they replace any busted RX8 with the Gen3. On their service form linked below, they note that all generations of the RX8 have a replacement cost of $123.

Randy's post: Tekin RX8 1/8 Scale Brushless ESC Thread

Tekin Service form: http://www.teamtekin.com/assets/tws_service_request.pdf
Hmmm, sounds good, I will let local racers know, there is no point selling the RX8 here since shipping costs would make the idea virtually pointless
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Old 01-30-2018, 03:43 PM
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Thread completed: WARNING - LiPo "C" Discharge Ratings are INVALID!
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Old 01-30-2018, 04:02 PM
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There's a lot of connectors out there. I run the Castle 6.5mm bullets and they work great in my 6S truggy. If I was starting over today I would run a connector that has an anti spark feature. This is an example of a nice one and will handle very heavy current loads, could be quite overkill for you though depending on what you're doing with the truck. https://www.offshoreelectrics.com/pr...d=ose-qs8-anti

If you're driving on the track you'll pull less than 100 amps and any decent connector on the market will be fine. You'll only pull 300 amps if you geared very high for speed runs.
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Old 01-30-2018, 04:06 PM
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Originally Posted by 0verkill
There's a lot of connectors out there. I run the Castle 6.5mm bullets and they work great in my 6S truggy. If I was starting over today I would run a connector that has an anti spark feature. This is an example of a nice one and will handle very heavy current loads, could be quite overkill for you though depending on what you're doing with the truck. https://www.offshoreelectrics.com/pr...d=ose-qs8-anti

If you're driving on the track you'll pull less than 100 amps and any decent connector on the market will be fine. You'll only pull 300 amps if you geared very high for speed runs.
Holy cow dude yea those things are way overkill! Holy moly... those things must be rated for like, 400-500 amps considering the 6mm connectors I want are rated for 200! Those 8mm connectors would be fantastic for 1/5 scale brushless conversions though. Any idea where I could find anti-spark 6mm versions?
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Old 01-30-2018, 06:07 PM
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XT90 5mm
https://hobbyking.com/en_us/xt90-s-a...___store=en_us

AS150 7mm
https://hobbyking.com/en_us/7mm-as15...___store=en_us
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