What the newest cheap servo hotness?

[TooOldForThis]

Originally Posted by TheLetterJ

So a WP1060/AE2/AE5 can't handle much bigger than my bargain servo with its 2a bec, but the WP860/WP1080's 3a bec can easily handle it with 1.4a to spare. It can't quite run 2 of them though. But can it handle one 2290sg? Knowing the stall current could really help the budget minded choose wisely, afterall, if they're looking to buy a cheap servo, they probably don't want to pony up for an external bec if they don't absolutely need it. Nobody wants to find out the hard way by burning their equipment up either.

I found these BECs on ebay for only a few bucks apiece. I'm wondering if these could be a cheap way to supplement the ESC's BEC output in a situation like the above. For example, lets say you're running lights and a front steering servo on the ESC's BEC, which has it maxed out. Then you add a rear steering servo that is powered separately by the cheapo external BEC. Would this work?

[StomperCrawler]

Originally Posted by TooOldForThis

I found these BECs on ebay for only a few bucks apiece. I'm wondering if these could be a cheap way to supplement the ESC's BEC output in a situation like the above. For example, lets say you're running lights and a front steering servo on the ESC's BEC, which has it maxed out. Then you add a rear steering servo that is powered separately by the cheapo external BEC. Would this work?

Yep, I have several of those. I run my servos on them at 6 volts, and if they fry, just $2 down the drain rather than a $15, $40, or more ESC.

[ColdFox]

Bumping the thread, but I came across this searching for the graal of cheap servo

https://www.ebay.com/itm/182971854719


specs are quite good considering the price

Operating Speed(4.8V): 0.16sec/60degrees

Operating Speed(6.6V): 0.14sec/60degrees

Operating Speed(7.4V): 0.12sec/60degrees

Operating Speed(8.4V): 0.11sec/60degrees

Stall Torque(4.8V): 17kg.cm(236.13oz/in)

Stall Torque(6.6V): 20.5kg.cm(291.69oz/in)

Stall Torque(7.4V): 23kg.cm(319.47oz/in)

Stall Torque(8.4V): 26kg.cm(319.47oz/in)


Anyone ever had a cheap Kingmax servo ? Can't find much about these on the internet :(

[Ditchrat]

Originally Posted by ColdFox

Bumping the thread, but I came across this searching for the graal of cheap servo

https://www.ebay.com/itm/182971854719


specs are quite good considering the price

Operating Speed(4.8V): 0.16sec/60degrees

Operating Speed(6.6V): 0.14sec/60degrees

Operating Speed(7.4V): 0.12sec/60degrees

Operating Speed(8.4V): 0.11sec/60degrees

Stall Torque(4.8V): 17kg.cm(236.13oz/in)

Stall Torque(6.6V): 20.5kg.cm(291.69oz/in)

Stall Torque(7.4V): 23kg.cm(319.47oz/in)

Stall Torque(8.4V): 26kg.cm(319.47oz/in)


Anyone ever had a cheap Kingmax servo ? Can't find much about these on the internet :(

Problem with cheap shyte like that isn't how well it works, but if it works. The QC/QA often suffers, sometimes its good sometimes they are not.

$15.00 is worth a shot, can always make a winch out of it.

[Hydrocarbon92]

Those Kingmax actually look decent, especially for $15. Definitely worth looking into if you want a waterproof case. From what I've seen the specs follow similar to the other 20kg cheapies, all of which out-perform any Savox/Traxxas/HiTec servo for the same price.

Originally Posted by TooOldForThis

I found these BECs on ebay for only a few bucks apiece.

Those clones are not bad, but not fantastic. I tried one and it's okay for a single servo, but cheap enough to use multiple on a 4/6ws app. I have heard of some having that metal cap that covers the circuit rubbing thru the board coating & shorting on the output or input wires.

Right now I'm trying a Henge 8A/12A UBEC from over the sea. It has 5/6/7.4v settings, but I modded it to 5.4/6.6/8.2v - not a prob for the chip it uses. It will be powering two 20KG JX servos, but I can't test it much til spring.

[Hydrocarbon92]

Originally Posted by StomperCrawler

So like one of these 1.8a $1 jobbers?

What kind of capacitor should I use and where to solder it? Would a heatsink help with over-amperage and where to place it? Thanks in advance!

Sorry I didn't see your post. Yes, that's the same unit I use. I had one powering/pulsing an array of 15 RGB LED's (45 LED's total) and it was about 110F after an hour. No heatsink needed since they're 85-95% efficient.

Originally Posted by StomperCrawler

I also bought a 180 and it behaves normally whereas I expected it to rotate 180 degrees, which it does not. :(

If you get a 120, 180, or 270 it will still act normal UNLESS your radio can send a signal way beyond the normal range. A normal radio sends 2000us for 45deg right & 1000us for 45deg left, 1500us center. You'd have to send 2500us and 500us for a 180deg swing.

[StomperCrawler]

Originally Posted by Hydrocarbon92

If you get a (JX servo) 120, 180, or 270 it will still act normal UNLESS your radio can send a signal way beyond the normal range. A normal radio sends 2000us for 45deg right & 1000us for 45deg left, 1500us center. You'd have to send 2500us and 500us for a 180deg swing.

Is that possible with my modded GT3B?

[cartronicshn]

new years bump for the cheapies...

[JatoTheRipper]

Originally Posted by ColdFox

Bumping the thread, but I came across this searching for the graal of cheap servo

https://www.ebay.com/itm/182971854719


specs are quite good considering the price

Operating Speed(4.8V): 0.16sec/60degrees

Operating Speed(6.6V): 0.14sec/60degrees

Operating Speed(7.4V): 0.12sec/60degrees

Operating Speed(8.4V): 0.11sec/60degrees

Stall Torque(4.8V): 17kg.cm(236.13oz/in)

Stall Torque(6.6V): 20.5kg.cm(291.69oz/in)

Stall Torque(7.4V): 23kg.cm(319.47oz/in)

Stall Torque(8.4V): 26kg.cm(319.47oz/in)


Anyone ever had a cheap Kingmax servo ? Can't find much about these on the internet :(

That looks a lot like the PowerHD servos. I like PowerHD servos. They are around $20 to $25 for the ones I use and I've never had a problem.

[Hydrocarbon92]

I ordered one of the Kingmax servos yesterday, I have to give it a shot. I'm thinking using it as the rear servo in my 4ws Waith along with a 32KG coreless JX up front, 8.2v for both.

Also an update on the JX 6221, I cannot suggest >7.4v for it anymore. They worked fine all day long at 7.4v crawling, but at 8.4v in my SCT & snow it burned up. The good thing is they're still faster & stronger at 6v than any servo 2x their price.

Later I'll be trying some crazy stuff with mosfets from Mouser. That JX only fried because the mosfet overheated and the new mosfets will have 1/8 the resistance, or Rds(on). My goal is 8.4v on these cheapies, more for fun since it's not time-efficient. I also noticed the MG958 uses an Atmega processor similar to an Arduino, so it's possible to replace the guts and do external processor/power servos. Cheap programmable 3S servos...

[Jim85IROC]

Originally Posted by Hydrocarbon92

I ordered one of the Kingmax servos yesterday, I have to give it a shot. I'm thinking using it as the rear servo in my 4ws Waith along with a 32KG coreless JX up front, 8.2v for both.

Also an update on the JX 6221, I cannot suggest >7.4v for it anymore. They worked fine all day long at 7.4v crawling, but at 8.4v in my SCT & snow it burned up. The good thing is they're still faster & stronger at 6v than any servo 2x their price.

Later I'll be trying some crazy stuff with mosfets from Mouser. That JX only fried because the mosfet overheated and the new mosfets will have 1/8 the resistance, or Rds(on). My goal is 8.4v on these cheapies, more for fun since it's not time-efficient. I also noticed the MG958 uses an Atmega processor similar to an Arduino, so it's possible to replace the guts and do external processor/power servos. Cheap programmable 3S servos...

Now you've caught my attention.

[Hydrocarbon92]

I ordered a few pairs of the mosfets, first I'll try them on a MG996R and maybe try a 3S demo. The last demo on 3S died literally the last servo twist before I hit record. If that works I'll try it on a JX board, just 2S but "loaded" in a vehicle. This is the kinda weird stuff I like wasting my time on lol.

The 2 mosfets used [in these cheap servos] are 2-channel dual-P & dual-N channel mosfets, each channel connected to a different motor lead. The motor leads are both grounded thru the N-channel while braking, then one N channel and the opposing P channel flip on to feed a motor wire voltage.config. You could externalize them with 4 bigger mosfets and run some very high voltages - like an ESC. You could also cheat like some ESC modders by literally stacking chips on each other, cutting heat per mosfet in half.

The only fear I have is these "bigger" mosfets will draw too much from the driver chip. Some mosfets can pull 10A+, albeit for a few nanoseconds. If anyone wants to donate some servos with ruined cases/gears, particularly these $10-20 cheapies, please let me know. They generally have these 2 mosfets on them: http://forums.parallax.com/uploads/a...043/107413.jpg

[thewildblue77]

Loving my JX 6221s. Got a pair running in my GOM @ 7.4V, happy as anything. This is from my HW 1080.

[Bbknucks]

Any recommendations on a cheap mini servo for a 1/12 scale truck?

[ColdFox]

Originally Posted by Hydrocarbon92

I ordered one of the Kingmax servos yesterday, I have to give it a shot. I'm thinking using it as the rear servo in my 4ws Waith along with a 32KG coreless JX up front, 8.2v for both.

Nice, I'll be interested in your opinion on these.

I haven't ordered anything so far, an eb48 got in the way

[Hydrocarbon92]

Originally Posted by thewildblue77

Loving my JX 6221s. Got a pair running in my GOM @ 7.4V, happy as anything. This is from my HW 1080.

That's good to know. Mine must have been a dud, or the combo of 8.4v plus constant countersteering in the snow built up too much heat. My other 6221's put up with 7v for a few battery packs in 80F weather.

I've got a ton of 6221's but I'm also trying their coreless servos. Can't wait for spring to really test them out.

[Hydrocarbon92]

Has anyone tried a giant scale servo before? I was considering making a dual servo mount then I saw these from JX. They're about 50% larger in each dimension but... 62KG for $36!

https://goo.gl/QH2kdD

This is the other I'm looking at, 35kg for $28:

https://goo.gl/T5hRbq

[Bbknucks]

D@mn those will move something!

[Teng]

JX is junk. Mine ran only last few minute and glitch and glitch only. Luckily got my refund back from HobbyKing. I will never buy this brand again.


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[durok]

Sorry you had a bad experience!

I'm happy to report that on my shakedown run of my Ascender, this less than $19 servo worked just fine:

https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1



Item: DS3218 20KG Large Torque Digital Servo Stall Torque (5V): 19 kg/cm (263.8oz/in) Stall Torque (6.8V): 21.5 kg/cm (298.5 oz/in) Speed : 0.16 sec/60°(5V) / 0.14 sec/60°(6.8V) Operating Voltage: 4.8 ~ 6.8 DC Volts Dead brand: 3μs Weight: 60 g (2.12 oz) Motor Type: DC Motor Gear Type: Copper & Aluminum Working frequence: 1520μs / 333hz Size: 40 x 20 x 40.5 mm ( 1.58 x 0.79 x 1.60 in) Features: - High performance digital standard servo - High-precision metal gears with hard anodizing - CNC aluminium middle Shell - Dual ball bearings Package Included: 1 x DS3218 20KG Large Torque Digital Servo 1 x 25T Adjustable metal servo arm

Anyone wanting a cheap upgrade of their RTR servo should feel safe in going this route - get a free aluminum servo arm along with it!