What the newest cheap servo hotness?

[TheLetterJ]

Originally Posted by Rekreant

You have a 2075 that hasnt burnt itself out yet? Lucky dog! Every 2075 ive had blew its fuse during normal 2s SCT use. 4 for 4.

Yep. This one has to be 5 years old and I just replaced the $4 gears for the first time a month or two ago. Running the sloppy Traxxas servo saver the whole time on a 2wd Slash with a 65mm motor on 3 and 4s with 5.5" tall tires. As much as I hate the term, this car definitely qualifies as my basher... it gets hucked off the top of sand dunes, skateparks, mx tracks, and drainage ditches with little mechanical sympathy. My son's slash was built out of mostly used/take-off parts, and his 2075 of unknown history is still doing its job, so at least I've got some spare parts for his now.

Honestly, a 20kg servo is overkill in this application since I intend to keep running the servo saver, which surely breaks away long before it sees 20kg. Still, for <$13, it's better in just about every way than the $40 2075 it's replacing. Horses for courses.

[Rekreant]

I think it has to do with you having an older 2075, all mine were less than 6 months old. I think they had a bad production run or something.

[JohnRobHolmes]

I can confirm that my v1 gears are compatible with many of the JX servos.

Since I had my v1 SHV 12v servo knocked off by JX (ex employee of my OEM that stole a lot of files), I was interested to see how much it was just a visual knockoff, and how much was 100% copy. One vendor is using JX for his "14v" servos, so I picked up one as well. It has a little higher torque output, which tells me they probably upped the PWM output a little. Hook them up to my programmer, not a surprise that they connect right up. Yep, just a little higher PWM. Not just a knockoff, a complete ripoff of my v1 housing, motor, gearset, and control board.

What I don't understand is why a vendor would put their entire reputation on the line by claiming that the product is completely new and original, when it is more than obvious that neither the product or the concept is. I know this isn't new in the hobby (especially china vendors), but I won't be upset to watch them have all the same problems I did with my v1. Good luck buddy, you got into bed with a business partner that will steal your work too. Too bad they left my OEM right before I made the v2, lol!


https://holmeshobbies.com/electronic...0v2-servo.html

[Natedog]

Originally Posted by durok

I recently found some new info on my favorite cheap servo ( the DS3218 ) and thought I'd post an update.

(BTW - I noticed this thread was slipping deeper into the forum - in dire need of a bump, considering how many new "cheap", or "newbie", or even "budget waterproof" servo threads we get...)

The oft-discussed DS3218 has been recommended many times for an under $20 servo, you flat CANNOT beat it for the money.

I bring it up again because I found a listing that included an exploded view of the internals - so you can see both why it is inexpensive, yet why it works fine for so many people - basically if you are running roughly 4.5" or smaller diameter tires on a typical scaler/trail rig/basher, it is likely to be all you would need.

To repeat the product info:

For less than $18 (currently), you get (quoted from mfg, of course...) JUST shy of 300oz-in of torque and quicker than .15sec/60deg of speed at 6.8v.

Waterproof (hmm... let's say "water-resistant", but we have had people report they ran 'em wet just fine), Metal gears (sure, they're brass - and 1 aluminum) and an aluminum case center for heat dissipation and strength.

Let's not forget ya get a perfectly serviceable clamping aluminum servo horn with 2 pre-drilled holes FREE!

Actual specs are:

Brand: DSSERVO
Item: DS3218MG
Stall Torque (5V): 19 kg/cm (263.8oz/in)
Stall Torque (6.8V): 21.5 kg/cm (298.5 oz/in)
Dead band: 3μs
Speed : 0.16 sec/60°(5V) / 0.14 sec/60°(6.8V)
Operating Voltage: 4.8 ~ 6.8 DC Volts

This servo does NOT need to be ordered direct from China, Taiwan, or Hong Kong - there are US warehouses carrying it, do a Google search and you'll be able to get it as fast as 2 days from now - great in an emergency when you just fried your RTR electronics and need a quick fix.

*My personal experience - I've been running one of these hard in a Ascender K10 with a BPC heavy-gauge steel transverse full-size LiPo tray & 3400mAh packs, SSD brass knuckles, SSD brass rear axle lockout weights, aluminum beadlock wheels, and it's powered by a HobbyWing 1080 ESC with a Holmes Hobbies TrailMaster 550 21t motor.

This isn't a lightweight RC - not when compared to a stock RTR Ascender, it definitely has some heft to it. Unfortunately I have no scale, so I can't tell you exactly what it weighs - but this servo has had no issues with my 4.6" Vaterra TSL Swampers or my newer 4.19" RC4WD Goodyear MT/Rs whatsoever in 7 months.

I highly recommend it, and frankly don't understand why any company selling an RTR RC meant for use on the rough stuff doesn't just stick these in their rigs with their own sticker on them. These DS3218 servos are selling for what a RTR stock replacement servo sells for, and the RTR servo is typically rated at about 150oz-in (roughly 9kg), and is noticeably slower in response time, to boot.

Here are some pics:

Great info, thanks Dirk! I've been checking for a new servo for my TF2 with Hobbywing WP1080 without BEC yet since I've been busy. Stock RC4WD Twister servo is slow and weak and only 4.8-6.0v rated, it gets quite warm even with tiny tires and then gets even weaker.

It appears that there's at least two versions of the DS3218, one with white/red/black leadwires and sticker on top of case like yours (Amazon seller claims it has 270* control angle)
https://www.amazon.com/DS3218-update.../dp/B01N0XZOZU


and one with orange/red/brown lead wires without sticker on top of case (seller claims 180* control angle aka rotational degrees)
https://www.amazon.com/gp/product/B0...k_ql_qh_dp_hza


Specs given for both are exactly the same and voltage claims 4.8-6.8 volts, is one better than the other and who's running it on 7.4v?

[Browneye]

Get the 180. Works on either 6 or 7.4 - have run it both ways on the 1080 internal bec. It works well enough on 6 too, I switch back when I'm going to run led's off the same bec - the 7.4 burned out my cheapo china light controller. LOL

I'm getting spoiled now...the new Blazer steering stalls out so easily! Time for a new servo already and it's only run for an hour or so.

[Natedog]

Thanks Chris, purchased and will give a TF2 whirl!

[durok]

Originally Posted by Natedog

Great info, thanks Dirk! I've been checking for a new servo for my TF2 with Hobbywing WP1080 without BEC yet since I've been busy. Stock RC4WD Twister servo is slow and weak and only 4.8-6.0v rated, it gets quite warm even with tiny tires and then gets even weaker.

It appears that there's at least two versions of the DS3218, one with white/red/black leadwires and sticker on top of case like yours (Amazon seller claims it has 270* control angle)
https://www.amazon.com/DS3218-update.../dp/B01N0XZOZU


and one with orange/red/brown lead wires without sticker on top of case (seller claims 180* control angle aka rotational degrees)
https://www.amazon.com/gp/product/B0...k_ql_qh_dp_hza


Specs given for both are exactly the same and voltage claims 4.8-6.8 volts, is one better than the other and who's running it on 7.4v?

I accidentally bought the 270deg version, it works just the same - the only difference is if the signal given by the radio was turning 270deg, it would be capable of doing so...

[Natedog]

Thanks, I was just wondering if one was actually better than the other, I appreciate the help!

[2mtech]

Originally Posted by Natedog

Thanks, I was just wondering if one was actually better than the other, I appreciate the help!

Huh...I just checked the last four I ordered and realized one of them was the 270° variant. So I've used both and never even noticed any difference. Same packaging even.

It does occur to me now that I had to set the EPA awfully low on one...guess that may explain it!

[Hydrocarbon92]

If one servo has a different EPA, that means the servo isn't reading the feedback pot right, or the pot is out of spec.

It doesn't matter if the servo is designed for 90, 180, or 270 degrees - a normal 90 degree signal will turn all three 90 degrees. If you get a special radio that can do 120 or 180, the 90deg servo will either stop a little after 90 or plow on til it burns out on the bump stops. The 180 and 270 would just move to the same 120 or 180 marks.

[Hydrocarbon92]

Originally Posted by JohnRobHolmes

I can confirm that my v1 gears are compatible with many of the JX servos.

...not a surprise that they connect right up. Yep, just a little higher PWM. Not just a knockoff, a complete ripoff of my v1 housing, motor, gearset, and control board.

I'm guessing we'll find out in the coming year who it is just by the stripped gear complaints. I'm guessing that would explain why the JX gears strip like they are, having some odd flex/bending issues your v2 solved?

[JohnRobHolmes]

You can figure out who it is just by looking at the case, it wasn't changed at all. You are correct about why the JX gears strip, and why I came out with a v2 in the first place. Not to say that my v2 is completely immune to that failure mode, but it takes a lot more beating to get there now. It's basically only mega trucks and u4 rigs breaking v2 servos at this point, which really isn't a surprise. There isn't a tougher install. The v3 will be specifically for heavy hitters like that.

[JohnRobHolmes]

Originally Posted by Hydrocarbon92

If one servo has a different EPA, that means the servo isn't reading the feedback pot right, or the pot is out of spec.

It doesn't matter if the servo is designed for 90, 180, or 270 degrees - a normal 90 degree signal will turn all three 90 degrees. If you get a special radio that can do 120 or 180, the 90deg servo will either stop a little after 90 or plow on til it burns out on the bump stops. The 180 and 270 would just move to the same 120 or 180 marks.

Not exactly correct. Servos will do what they are programmed to do. If they are told that 2500ms and 1500ms signal is max throw, then whatever the max throw is will be mapped to that. If travel is 90 degrees, they will travel 90 from min to max signal. If travel is 180, it will travel twice as far with the same radio signal.

If I programmed my servos for 180 degree vs the normal 90, they will turn twice as far with the same radio signal.

[durok]

Originally Posted by JohnRobHolmes

You can figure out who it is just by looking at the case, it wasn't changed at all. You are correct about why the JX gears strip, and why I came out with a v2 in the first place. Not to say that my v2 is completely immune to that failure mode, but it takes a lot more beating to get there now. It's basically only mega trucks and u4 rigs breaking v2 servos at this point, which really isn't a surprise. There isn't a tougher install. The v3 will be specifically for heavy hitters like that.

Oooohhh.... a v3 Holmes Hobbies SHV?

Sweet!

[Hydrocarbon92]

Originally Posted by JohnRobHolmes

Not exactly correct. Servos will do what they are programmed to do.

Of course, but my point is 99.9% of normal servos are programmed to move +/-45 degrees with +/-500ms. The resolution on said 180 & 270 degree servos is the same since it requires an atypical TX/signal to move it farther. I've been able to get around 120 degrees on most servos and much more when modifying the signal with a microcontroller. Same if you modify the pot's resistance.

As far as the servo case/cap causing pin movement, are you just machining less material from around the holder? Adding a bushing? I was thinking a press-fit steel ring could be added to the v1 to reduce chances of it ovaling.

Also, do most of these issues happen at 12-14v or are they relatively problem free if run at 2S/8.4v?

[2mtech]

Originally Posted by Rekreant

let us know how it pans out!

Figured I'd post impressions of the G13 in a more appropriate place and link here:

http://www.rccrawler.com/forum/vendo...s-servo-2.html

[dweano]

Is there cheap servo hotness that runs on 4S? I think my BEC just died...I measured 4S voltage on the OUTPUT side...so my BEC and servo are dead. I figure if I can I will replace with something that doesn't need a BEC. Is there a budget option that runs on 4s?

[Teng]

Originally Posted by dweano

Is there cheap servo hotness that runs on 4S? I think my BEC just died...I measured 4S voltage on the OUTPUT side...so my BEC and servo are dead. I figure if I can I will replace with something that doesn't need a BEC. Is there a budget option that runs on 4s?

This one? https://hobbyking.com/en_us/jx-bls-1...___store=en_us


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[durok]

Originally Posted by dweano

Is there cheap servo hotness that runs on 4S? I think my BEC just died...I measured 4S voltage on the OUTPUT side...so my BEC and servo are dead. I figure if I can I will replace with something that doesn't need a BEC. Is there a budget option that runs on 4s?

The closest you'll get is a couple JX 12v servos with relatively crap gears that can take 3S direct - someone put 4S through one and almost immediately destroyed it...

Bite the bullet, get a SHV500 Holmes Hobbies for 4S use. You'll be without a working rig looking for replacement parts or another servo in no time using the JX.

[Teng]

Originally Posted by durok

The closest you'll get is a couple JX 12v servos with relatively crap gears that can take 3S direct - someone put 4S through one and almost immediately destroyed it...

Bite the bullet, get a SHV500 Holmes Hobbies for 4S use. You'll be without a working rig looking for replacement parts or another servo in no time using the JX.

Almost forget cheap mostly not good in quality. Stretching out your budget and get the Holmes.


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