What the newest cheap servo hotness?

[durok]

My DS3218 has been working just fine on my Ascender for the last few months... I paid less than $19 with an included aluminum servo horn.

 

[Hydrocarbon92]

Thank you for your input. With and arduino you can do what ever you want but this is not the case.
And yes, it is a servo issue; a standard servo usually rotates 90º, a 180º servo rotates around 180º, and a 270º servo rotates 270º, with standard TX travel set at 100%, actually they usually turn a little bit more than those angles.

I think the real prob is you aren't understanding the specs listed. That servo lists clearly: "Max frequency: 500-2500us; Max Rotation Angle: 180°/270° Optional". That means IF you can feed it 500-2500us signals, it will give you 180°. If 1000-2000us gave you 180°, then 500-2500us would give you 360° - that's just impossible with a typical servo design. You'd need an optical or magnetic sensor like the servo in my last link below. Keep in mind Aliexpress is like a fleamarket in the sense they only care that they get their money & you get your item. Their price does NOT budget marketing, instructions, nor tech support.

Another prob is resolution. You either get a good price and 1/2 or 1/3 the resolution ("notchy" since movement for each step is doubled or tripled), or you pay thru the nose for a control board with a true 12-16 bit ADC that has 2-4x resolution.

Here's an example where it's marketed clearly, a standard servo with a possible 180 range. "Arm travel range: 180° ( 90°/one side pulse traveling 600usec)". That means with a normal signal it's a 90° servo, but with a 600-2400us signal it's a 180° servo. 98% of servos listed as 180° will be like this.

https://hobbyking.com/en_us/turnigy...c-7LxkK59DnCqR4hiPRoCeaUQAvD_BwE&gclsrc=aw.ds

Here's an example of a non-standard 180° servo. It takes a standard pulse and doubles the travel. More importantly, note the price. This is very uncommon because the robotics ppl that need 180 can increase their signal range.

https://hobbyking.com/en_us/dms1801...zuS4KN_cDuq4SDxIayxoCc8wQAvD_BwE&gclsrc=aw.ds

 

[TheLetterJ]

I recently bought a $33 Turnigy/Towerpro mg959v2 and have 2 runs on it. Besides that it sounds like a parakeet chirping when it cycles, it seems to work well and has a fancy cnc milled housing. It's rated at 30kg @ 6v (or 32kg @ 6v depending which site you get your info from) which is adequate for my application, but I can't help but wonder... has anyone run one on 7.4v? If it works, what would the calculated torque be? I didn't want to be the guinea pig this time since I'm out of spare servos and this one took a month to arrive.

...aaaaaannnddd, it's dead. I haven't taken it apart yet, but I'm 99% sure it's a stripped gear. It turns left, but won't turn passed center to the right. I'm hoping I'll get lucky and it'll be a big gear that I can just rotate 180° and be back up and running. It's always a bummer when a part doesn't even last as long as the time it took to ship, but we take our chances. If it's not an easy fix, I may just stop screwing around and go PM470, Savox 1283, or 2290.

 

[mikemcE]

Hang up and Drive

 

[JatoTheRipper]

Hang up and Drive

Did you kill anymore of them?

 

[TheLetterJ]

Use your words Mike. I know the Promodeler is a good servo, I bought a 420 a couple years ago for my first Wraith when they were $79, have another faster/lighter duty PM in my Baja Rey too. I recently convinced a friend to buy a PM470 when his $100 Spectrum quit AGAIN. We don't always get what we pay for. With over a dozen cars in my own collection, spending $100 a pop for a servo is not an option for all of them when a (much) cheaper servo may have been sufficient.

I think the point of this thread was to hopefully identify inexpensive options that have proven to actually be a good value, not just cheap. I took a chance on the 959v2 as I hadn't heard of any failures of them either. I know you tried out that Evo-something-or-other that turned out to be a dud too. I've got a traxxas 2075 that's got to be 5+ years old that just won't die. Reliable? In it's application, yes, but there's certainly no "hotness" about its performance. Then there's the big powerhouse's that have a crap track record for reliability (Bluebird's come to mind.)

I think what many are looking for here is reasonable reliability (if it could last a full year I'd be happy) adequate performance (300oz @ .15s would be fine for MOST of my cars) with a low cost (+/- $30) should be attainable. The $11 MG958 has proven close enough for me in those aspects, but a couple of my cars have demanded more. It's when we step outside of those threshold's of performance that things seem to be hit or miss.

Like I said, maybe this particular car is just demanding more than the low budget options can reliably offer. I'm not against spending more either, but only if it's required.

 

[TheLetterJ]

...to update:

It was the biggest gear/bottom of the output shaft that stripped on my mg959v2. It's clearly aluminum. I'll dig through my NFG electronics to see if a gear from something else fits, otherwise I'll pull the stop pin out of this gear and install it 180° off.

 

[Browneye]

I think what many are looking for here is reasonable reliability (if it could last a full year I'd be happy) adequate performance (300oz @ .15s would be fine for MOST of my cars) with a low cost (+/- $30) should be attainable.

^^ This. So which is it?

I like the Savox 0231 but I don't think it's quite 300oz, more like 200 or something. But I never think about it when running, so it must work fairly well.

I have two of the ADS-15's and they're more money and not as good.

 

[TheLetterJ]

Bam! back in action! Had to trim it out quite a bit since the 25t output ends up 1/2 a tooth off when spun 180°. I probably ought to start planning for a big dog for this car and move the 959 to a lighter car with shorter tires.

Browneye: Meeting the performance requirements seems to be the easy part, reliability, not so much. The PowerHD 20kg seems to be the most popular for about $20, I've been content with the 277oz @ .15s that my mg958's give for $11.

 

[Browneye]

What kind of amp pull at stall on 6v?
Looks like there's a LW and a LF - what's the difference?

The 0231 works just fine with the built in bec on the hw1080. It's plenty fast.

 

[TheLetterJ]

I couldn't tell you the difference between the LW and LF, but if you go back one page I put a link to a video (not mine) that compares a few servos for torque and amp draw at stall, the LW-20mg being one of them.

 

[svt923]

Looks like there's a LW and a LF - what's the difference?

One is blue and costs a little more the other is red and costs a little less.

The blue one is "waterproof" but that means there is a couple of o-rings on the case (the red one may have these o-rings too). I was not impressed by the factory waterproofing efforts when I opened mine up. Wouldn't be surprised if both servos are completely identical aside from the color and price.

 

[Browneye]

Browneye: Meeting the performance requirements seems to be the easy part, reliability, not so much. The PowerHD 20kg seems to be the most popular for about $20, I've been content with the 277oz @ .15s that my mg958's give for $11.

Good on ya for fixing it...I would have tossed it. [shrug]

Found that MG958 on Banggood - holy that's a bargain part. "thumbsup"
I think I'll pick up a couple for backup. It doesn't say they're waterproof, or did I miss that? I don't drive through water anyway. ;-)
They reference others too, but I'm not very good at deciphering differences in all the specs. Surely I'd pick the wrong one!

I'll go see if I can find the vid...

I need to find some alternates for my buddy's new TRX4 - he's a noob and just got the rig, already seeing his steering stall out. I told him not to expect the server last very long, so we better have a spare on hand. I guess the bec in that rig isn't squat either - like 1ah or something. :roll:


EDIT: found the vid...skipped to 6min for the wrap up and rating, shocking to see amp pull at stall. Since my HW1080 puts out 3ah I'll stick with the lower rated servos 'till I find they don't have enough pull, then upgrade to an external bec and make a decision at that time.
I liked the first 1080 esc I got so well I bought four more, all three rigs have one and I have an extra since it was on sale for $30. I haven't tried the other servos, but the 0231 I have in the one rig works better than a stock ascender one, and better than the ARRMA one they put in their 6s-powered fast rigs - typhon, kraton, etc. For $32 I though the Savox was a bargain. I'm glad I didn't go for the 01230 - 7amps at stall?? :shock:

The ADS-15 is a HV so you can run it at 7.4, which the HW1080 will do, and it does work a lot better there, but I was afraid I was going to burn out my LED lights and controller at that voltage so I set it back to 6v. The Savox 0231 runs on 6v.

For my comp rig I may well have to break down and do some fancy wiring (BEC) :mrgreen:

EDIT2: The MG958 servo is not waterproof. Found reference in the Q&A section of the product listing. They could not even recommend something compatible that is. I'll stick with my Savox 0231.

 

[TheLetterJ]

The mg958 is not waterproof, but it does have o-rings where the cases meet and at the output shaft. Good enough for me to be comfortable with the amount of moisture I run in (maybe a 1/4" deep puddle here & there, or driving in short wet grass.) I was a little surprised to find the mg959v2 had NOTHING for seals or waterproofing.

I don't want you to think I'm touting the 958 as some bad ass servo. It's just that it's been reasonably reliable for me (I've got 1 that is at least a year and a half old, and 3 or 4 newer ones in service) I've killed 2 of them in ~2 years of frequent use, but I bet I could make one good one out of those 2. Their performance is good enough that you can run them in pretty much any surface application and not be totally disappointed, so they're good to keep around as spares if you've got a bunch of cars. If you buy the 4 pack, they're usually less than $40 shipped, so there won't be any heart break when you kill one hucking your non-servo-savered car off a 30' dune (who, me?), or tumbling to the bottom of the rock pile (no really, I had it parked there the whole time!) Towerpro lists the stall current at 1.6a @ 6v so all but the crappiest esc's internal bec's can run them no sweat.

btw: do you ride a TE630?

 

[Hydrocarbon92]

I think the MG958 is good if you are limited to 6v - it's slightly faster than the 6221 and almost as strong. The 6221 is much faster when upped to 7.4v and considerably stronger. The MG958 lets out magic smoke over 7v.

PowerHD seem to be as strong as the 6221, but much slower. The nice thing is they're waterproof & seem to have finer steps.

I'll stick with my Savox 0231.

I just wouldn't recommend buying another. They are painfully slow and very weak compared to the $15-20 waterproof cheapies. They'll last for the same reason a Toyota transmission will last 500k miles, because there's no power to stress it. At the very least pump some power into it, Savox reps actually tell people they do 7.4v despite being rated for 6v.

Hang up and Drive

You should send that in to the servo tester guy and see how it compares to the $35 959v2. I do NOT consider $89 to be a cheap servo. A cheap servo IMO is $20 or less, $40 if we're talking insane specs. When I got into this hobby at age 12, I could barely afford a Tower Hobbies 3003 knock-off. When I was 16 $70 saved would have bought a LOT crawler event travel gasoline.

Maybe I'm reading your wordless post wrong, and you're indicating we shouldn't be sucked in by a servo with pointless external machining?

 

[mikemcE]

If the picture of the PM gears bothers you, I’m a cheap SOB.
I bought 3 of the $30. Servos, all 3 lasted a total of 2months. I’ve not replaced a PM yet, one is 18months old, the other a year. So simply put I’ve saved a fortune by not spending $150 on a servo or $300 on ten servos in that time span.

Hang up and Drive

 

[durok]

I'm throwing my Promodeler in one Bomber, HH shv500 into the other, but my Ascender is doing fine with a $19 DS some-number I forget servo, and a I have a mid-priced JX 12v brushless due any day from Gearbest as a backup for the HH, as it is a first generation model... Might bend a pin on it...

Anyway, I think I'm covered!

 

[Hydrocarbon92]

If the picture of the PM gears bothers you, I’m a cheap SOB.
I bought 3 of the $30. Servos, all 3 lasted a total of 2months.

This whole thread is about sharing info. It would probably be more constructive to post carnage pics & list their model numbers. At least that's how I'd make my case for a different servo. I looked thru your last 300 posts and only found 1 carnage pic referencing them as "the others".

 

[mikemcE]

This whole thread is about sharing info. It would probably be more constructive to post carnage pics & list their model numbers. At least that's how I'd make my case for a different servo. I looked thru your last 300 posts and only found 1 carnage pic referencing them as "the others".

I could take a picture of my savox, tower, and assorted Taiwanese junk, not sure why proof is needed. The picture I posted as "the other" is an Holmes HV500, V1 which was replaced under warranty and seems to work well now.

My issue with these servos is I want / need 700 oz and pay for 500.

In fairness most of the others were 300oz, and waaaaay to weak.

Again all the other "cheapies" cost me far more $ and time in the overall

 

[mikemcE]

Did you kill anymore of them?

Nope, that must have been a fluke, John couldn't find anything wrong, but replaced it under warranty. "thumbsup"