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410.3 Bashing on 3S and 4S capable

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jetdope

Member
Messages
15
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5
Location
IL & Upstate NY
Tekno RC's
  1. SCT410
Driving Style
Basher
The intent w/ my 410.3 build is to bash. No racing, just something faster than my crawler's top speed of 7.3MPH. I'll be running the SCT on baseball diamond hard packed clay w/ loose dirt and pebbles on top, and into the grassy areas. This will done through all four season - meaning precip of one form or another.

First, I have no clue what speeds for what ESC/motor/kv/battery combos will be. More importantly, what speed can I handle? I'm thinking 3S minimum since that is what I have, and definitely would try 4S, and maybe even tip-toe into faster/ depending on resulting speed. But is 5S or 6S likely, or is 4S plenty fast? Plus, higher speed = higher costs. Is it my ego thinking to go to fast? Budget is always a concern, but I'd rather, "buy once, cry once".

Bottom line as noob in bashing, what are your thoughts on going with a 4S max vs 6S max ESC/motor combo? I've researched threads and YouTube and made notes of suggestions and recommendations only to find my head spinning. A scenario such as mine seemed to end w/ a caveat of 'max 2S' or other (racing) restriction.

I am leaning towards the Hobbywing line; XR8 Plus or SCT with 3660 size sensored motor, but lost on what KV. Would it be best to base KV on 4S to begin with, figuring on a new different motor/KV if I step up to 5/6S? Is there a 'one-size' fits all motor/KV up to 6S? As you can see, I'm new to not only bashing, but brushless as well. The crawler is brushed since it's more for trailing than crawling. (BTW, it's been a blast!)

Oh - one more thing. What about installing a cap-pack? Is it a good idea?

Long, yes. Hopefully I made it clear in one post. I'm sure there will be more!

TIA, Dave
 
HobbyWing ESC's already come with "cap-packs" installed, their BEC's are very good quality.

I would recommend a sensorless setup for bashing, sensored electronics are more likely to fail.

You definitely want to stay with a 3660 sized can, although you can go larger, it isn't necessary and will only create more problems.

If you go 3S then I would recommend a motor in the 2500KV -3300KV range to get top speeds between 45mph-60mph depending on gearing.

If you go 4S then you want to go with a motor in the 1900KV-2500KV range to get similar speeds.

For 6S then go with a 1300KV motor.

More info here on my recent swap from 2S to 3S:
https://www.teknoforums.com/threads/build-review-sct410-3.1389/

I would recommend the 3300KV motor here for 3S with a 14T pinion:
https://www.hobbywingdirect.com/col...roducts/ezrun-max10-combo?variant=27757683921
 
Spot on...Thanks Bill!!!

45-60MPH - Yikes! 4S will likely be plenty. Think I'll stay w/ 6S capable ESC in case curiosity gets to me.

Re sensor/sensorless...the reason for sensored would be to avoid cogging at low speed. Is cogging something I would notice on a sensorless setup in a bashing scenario? In the crawler world everyone recommends sensored for smooth startup. Of course crawlers operate at the very low end most times. Plus I would dislike what I believe the cogging effect is (rachety startup).
 
For your stated intended use I wouldn't give cogging a second thought. I don't know what the SCT weighs but I bash another brand on 6S that weighs about 12lbs with batteries. I've never experienced any noticeable cogging. I run it at the track occasionally and even puttering past someone sideways in the middle of the lane is no issue. And yea, that 50-60MPH range is plenty fast and needs a good bit of space and does wonders when cartwheeled.
 
The KV you select will determine how many cells you can run.... i.e. if you ran that 3300KV motor on 6S, then chances are you'd overheat the motor in seconds, not minutes.

I once ran a 2350KV motor on 6S, but it was geared down and limited to 5 min races in the GT8e class.

Yes, a sensorless motor will have a very slight "ratchety startup" and will be problematic if you plan to go crawling with it, but general bashing around will be almost unnoticeable with 25%+ throttle applied.

Here is a demo of a HW sensorless combo with a 2000KV motor on 4S to give you an idea of what to expect:

 
Cogging is barely present from 4s and above. As stated by others, the one fits all motor does not exist. A Mamba X ESC would be 2s to 6s capable, but motors will have to be picked for purpose.

You seem to be wanting to go for decent speed and power. I would target 4s, it is really a nice balance of raw power (but not insane like 6s) and durability. Since you already have 3s batteries, they will give you a good first step with less performance (and damage) but still good thrill.

I would pick either one of the following options:
  • Mamba X (2s to 6s) with 4068 1900kv motor or 4074 2000kv motor
  • HW xr8 SCT (2s to 4s) with 4068 1900kv motor or 4074 2000kv motor
 
Thanks! Today has been full of learning. I've been reading and watching the tech side of brushless, sensor/sensorless, and how the ESC, motor size/Kv, batt, and gearing work together and their trade-offs. You guys have given me a good idea of real-world speed out of various combos.

Today I looked at Hobbywing because it's a more budget minded option. I like the idea of stepping up to the XR8 SCT for the option of 4S, programing, and data-logging. (Think I'll skip the idea of 6S.) Paired with a 3660 motor, I'm thinking 3600Kv on 3S w/ 14T pinion to start. Or would 3200Kv be better/lower temps for the electronics w/ 15T? Am I too high on the Kv? Am I in the ballpark on pinion? Thoughts?

Tomorrow I'll look at Castle and Tekin again. What are the pros/cons of the 4068/4074 motors w/ low Kv vs a 3660 size? Will the stock motor mount work w/ the larger can?

One other thing after watching the video with numerous wheelies. I was thinking I'd like more torque over raw speed. The video was on asphalt where I will run more on hard-pack w/ loose dirt/grit on top and/or grass. What is the trade-off to have a more planted front end? I'm guessing finger control to be most important to keep the front end either up or down.

Going w/ this much power and/or speed in brushless is way more complicated than on slow trail run w/ a brushed motor!

Oh - one other question. HW shows the XR8 SCT/3660 combo as, "product unavailable". Amain shows the same combo as backorder. Why would Amain expect it to be available when HW does not?
 
With 3s, I would go 3200kv over 3600kv. It will run cooler.

Loose dirt and grass are not gentle with motors, better be safe than sorry and pick on the lower kv range.

3660 motors are going to heat up quick. They are 1/10 mainly meant for 2s. You’ll need at least 3670 and 2400kv to run 4s. The larger can 40xx will pack more torque and create less heat. Something in the 2000kv will be perfect on 4s and still fun on 3s.

To save some dollars pick the xr8 SCT and a motor on ebay or juicerc.com. You can’t save much on the ESC and should stick to well known brands. On the other hand, it is harder to notice the difference between a $50 ebay motor and a $160 racing motor.
 
Main reason you don't want to go any larger than 36mm diameter can is the amount of torque generated, if you go with a larger can, then it would be okay to go with a 3674 can which offers a wide range of KV options to suit your needs, go with the KV range I listed in post #2 to suit the cell count you plan to run.

If you install a 4274 can in the truck, it will fit just fine, but you'll need to upgrade to the 17mm axles/hubs or you will risk damaging the drive train. The truck will have so much torque that it will be very difficult to control. A 3674 can will give the perfect amount of extra torque without going too far.

To keep things simple, I recommend you reconsider the option that I linked which is currently in stock. Inventory has been difficult due to COVID, Backorder and unavailable are synonymous, though HW typically does a good job of re-stocking product every 6 weeks, and not uncommon to see them sell out quickly since COVID.

Gearing can be tricky because there are many variables, just be sure to invest in a temp gun, more info here:
What gearing for upgraded electronics?
 
Good stuff! I like the fact you explain what and why of differences. Extremely helpful!

Bill...I prefer up to 4S capable, which is why I'm leaning towards the XR8 SCT. Does not have to be Hobbywing. Still need to take another look at Castle and Tekin. From the above, I feel a good starting point would be 3S, 36 can motor on the lower side of 2500-3300KV. Probably 2500KV to get used to speed. Once comfortable I could step up to 4S using the same motor more as a learning tool than anything. I'm guessing 2500KV on 4S would be approaching hot temps? In this 2500KV/3S/4S setup, I would expect to purchase another motor after becoming familiar on 4S for a more electronic-friendly lower KV - or stay 3S.

Re a temperature gun, I have yet to really look at any. I did stumble across one for $149 which I would think is more for the serious racer. Any recommendation on a more budget-friendly temp gauge?

I like the idea of manageable torque, so I will look into 3674 size 2500-3300KV. (FWIW, HW did say a shipment is expected in 4-7 days. I'm in no hurry w/ this build.) I'll check RCJuice as recommended. Still thinking of staying sensored since the sensor is more for low speed control and is cut out at higher speed. I can always run w/o the sensor to feel and understand BL better. Make sense?

Thanks again guys!
 
Sensorless motors will provide more power/torque for the same can size because a sensored motor loses space to fit the sensor board therefore having less magnet on the rotor, etc.

A sensor system is more likely to fail in a hard crash, it can't get wet and sensor wires tend to go bad and need periodic replacement. There is no good reason to justify a sensored motor for a basher other than spending extra money and increasing opportunity for things to go wrong.

A racer on the other hand is not interested in top speed, but having a sensored motor makes the throttle response smoother so it's easier for timing the jumps and increasing accuracy for landers, and in-flight control. A sensored motor will improve lap consistency and is necessary for a discriminating club racer.

If you will be switching from 3S to 4S then you will need to gear down and/or change to a different KV motor. It's best to decide how many cells you will run now.

So for example, if you want to run 4S, then I would get this 3674-1900KV sensorless motor here and start with a 16T pinion:
https://www.rcjuice.com/motor-esc/b...brushless-sensorless-motor-v2-waterproof.html

Depending on temps and desired speed, you might be able to gear up as high as 20T pinion, but these are variables that can only be determined after you start taking temp readings.

The temp gun I use is no longer sold, but this one here should work perfectly fine for your needs:
https://www.ebay.com/itm/Infrared-T...887798?hash=item3b493e43b6:g:b6YAAOSwoZle8BpH
 
Let me start w/ a request of thoughts on these...

Castle Mamba X (2S-6S) w/ Sensored -1415 - 2400KV (can do 3S/4S)(or 3800KV limited to 3S) $228

HW SCT Pro (2S-4S) w/ HW Sensored - 3660SD - 3200KV (motor limited to 3S) $174

HW SCT Pro w/ HobbyStar Pro4 SCT - 3000KV (limited to 3S) $162

HW SCT Pro w/Hobbystar Pro4 SCT-1800KV (limited to 4S)(I assume this means max 4S?) $162

Tekin is out. I don't want to spend that much at this point. Castle Sidewinder is out. On crawler forums I've heard it whines loudly. Might be in combination w/ specific motor. ???. Have yet to figure out Castle 1415 motor sizing.

Now, having looked at the above and previous posts; am I overthinking this? Feel I'd like to try 4S. It was mentioned 4S is the 'sweet spot'. Can that be explained further?

In part, I started by trying to find an 'all-in-one' solution. I now realize that simply does not exist. I feel going with a 4S (or more) capable ESC is where to start for me. Then find a 2500KV'ish motor to use on 3S and 4S, then upgrade to an appropriate KV once I find I want to expand in bashing, keep it simple in bashing by staying 3S, or completely drop bashing. And again...thoughts?
 
Your explanation makes perfect sense. Sensorless it is! Guess I need that push to get 'crawler low speed startup' out of my head. I'm diving in w/ your suggested motor. Motor done. For ESC...

Staying 3S would be simpler for crawler and 410, though not a deal-breaker. If staying 3S, I have it in my head, temps will increase if speed is increased. Is temp control more gearing than KV? Also in my head, is increasing speed, will 4S will relieve high temps? Maybe I'm looking at this wrong. Part of the difficult decision making is no experience in brushless/KV/ speed/torque/gearing/battery/temp tradeoffs, etc.. But I am getting there thanks to this forum.

Online, one can learn only so much. I did go to a local race a couple weekends back to talk w/ drivers. With zero social distancing, time was spent as a distanced spectator only. Classes ran didn't appeal to me; 2WD buggy, Euro-style Trucks, and Vintage Trans Am, all on-road.
 
That 3674-1900KV on 4S will be the "Sweet Spot" in terms of performance and efficiency. This will give you a far wider range of gearing options than a 3660-2500KV on 3S, though both setups will produce about the same top speed, the 4S setup will accelerate faster and provide lower temps as well as give slightly longer run times given batteries of equal work output in watt hours.

Castle makes a very good product, but I have never owned one so I can't say one way or the other about buying the brand.

HobbyWing (HW) has treated me very well over the years and has outlasted every other brand I have owned from close to a dozen brands of ESC's that I've tested over the years. The oldest HW I owned before it started gettng gremlins was about 4 years, I simply sent the ESC into HW for an RMA and they gave me a deep discount on a brand new ESC which was a newer version, the older ESC had been discontinued.

I used to run on-road many years ago, and I agree, off-road classes are way more fun! To be honest, I would still run on-road if there were no off-road tracks to race at ;)
 
Thanks Bill...you put in words the roundabout thoughts in my head. I am understanding better and headed in the right direction.

In the crawler forum, Castle is King. Few Tekin. Re HW, you're either for or against; no middle ground. The brushed crowd, if not Castle, is HW 1080 w/ Holmes Hobbies motor.

Just back from picking up 4mm files. Now to look into a temp gun.
 
Your explanation makes perfect sense. Sensorless it is! Guess I need that push to get 'crawler low speed startup' out of my head. I'm diving in w/ your suggested motor. Motor done. For ESC...

Staying 3S would be simpler for crawler and 410, though not a deal-breaker. If staying 3S, I have it in my head, temps will increase if speed is increased. Is temp control more gearing than KV? Also in my head, is increasing speed, will 4S will relieve high temps? Maybe I'm looking at this wrong. Part of the difficult decision making is no experience in brushless/KV/ speed/torque/gearing/battery/temp tradeoffs, etc.. But I am getting there thanks to this forum.

Online, one can learn only so much. I did go to a local race a couple weekends back to talk w/ drivers. With zero social distancing, time was spent as a distanced spectator only. Classes ran didn't appeal to me; 2WD buggy, Euro-style Trucks, and Vintage Trans Am, all on-road.

How many 3s packs do you own? Are they good quality? There is enough juice in a quality 3s pack to have fun.

If it was me, I would go straight to a 4068 1900kv/2100kv motor. Be 4s ready. Start running it on 3s with a larger pinion as suggested by Bill.
 
The 3S crawler batt's are inadequate for this build. It would work but for a very short distance!;)

Decided on a HW SCT Pro (w/ Programmer) and HS 3674-1900KV. I'll be picking up appropriate 3S and 4S later. As w/ the crawler build, I'll be taking my time w/ this too. I enjoy building and tend to stretch them out.

I do appreciate all the help here! I'm sure there will be more.
 
Due to potential unforeseen circumstances, I have cancelled this build. When the time is right, it will be revisited. I do want to thank those that helped in the decision-making of components. On the positive side, I did learn quite a bit on brushless.
Thanks again.
 
I build it. Tekno SCT410.3 with Ezrun Max8 Combo, and what should i say it is a little bit slow :). I guess i will go up to a 2600KV motor, maybe i'm more satisfied with the speed.
Guess a bigger Pinion would also do the trick. Running 15T Pinion in the moment and the motor isn't even handwarm after bashing a 4S 5500mah LiPo down in 13 minutes.
Parts you need. MT410 Motormount and MT410 Battery straps, i also exchanged the plastic crosses in the diffs against metal ones. Not sure if this was needed.
 

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