Lets talk servos and servo power

[reden]

Digital Servo—DS-8325HV
Specification:
Model: Digital Servo—DS-8325HV
Operating Voltage: 6 ~8.5 V
Speed @ 6.0v: 0.145 sec/60°at 6V
Speed @ 8.5V: 0.118 sec/60°at 8.5V
Torque @ 6.0V: 25kg-cm
Torque @ 8.5V: 31kg-cm
Dimensions: 40x20x45mm
Weight: 79g

Savox SA-1283SG Super Torque Steel Gear Digital Servo.
Dimensions(mm): 40.8x20.2x37.4
Weight(g): 80.0
Speed(@4.8V sec/60): .16
Torque(@4.8V oz-in): 347.2
Speed(@6.0V sec/60): .13
Torque(@6.0V oz-in): 416.6
Gear: Unique Steel
Bearing: 2BB
Case: Full Aluminum
25 Tooth Spline

 

[17dean]

I am a serious Savox fan. I have a Sg 1268 sg . Mandatory for all my vehicles no matter on road or crawling it has to be equiped with Savox!"thumbsup"

 

[JeffK11]

Question for you- Does your Savox run hot?? Just got mine- Savox Coreless Digital Servo #SC-1256- was out doing some crawling lately and felt it- definitely very warm to the touch. Anyone else have this issue?? I've got an aluminum guard on mounted on top- thinking of removing it to allow more cooling...?? Any input??

<a href="http://s1188.photobucket.com/albums/z405/jeffkeil11/Losi%20Night%20Crawler/?action=view&current=Screenshot2011-12-19at72553AM.png" target="_blank"><img src="http://i1188.photobucket.com/albums/z405/jeffkeil11/Losi%20Night%20Crawler/Screenshot2011-12-19at72553AM.png" border="0" alt="Photobucket"></a>

 

[vtek]

hitecs are the ONLY servos for me, got 7954, a 7940, two 7955's and a 7980!!! all awsome!

 

[reden]

As I'm also a Futaba fan I will be getting this servo.
The HD DS8325HV broke the ouput shaft just below the splines.:evil:
Cannot find sapre gears locally.

im a fan these badboys

Futaba BLS157HV Digital Brushless High Voltage Servo ($189USD)

Speed @ 7.4V: 0.12sec/60°
Torque @ 7.4V: 514oz in
Input Power: 6.0V - 7.4V

 

[Charlie-III]

As I'm also a Futaba fan I will be getting this servo.
The HD DS8325HV broke the ouput shaft just below the splines.:evil:
Cannot find spare gears locally.

I also have a BLS157HV (came with a roller, usually I run HiTec). Good servo thus far although I DID break off the ears on one side.:roll:

I'm not quite willing to swap over to Futaba though, I have a "few dollars" in decent HiTec aluminum servo arms between my son & I.:lmao::lmao:

 

[reden]

I also have a BLS157HV (came with a roller, usually I run HiTec). Good servo thus far although I DID break off the ears on one side.:roll:

I'm not quite willing to swap over to Futaba though, I have a "few dollars" in decent HiTec aluminum servo arms between my son & I.:lmao::lmao:

Lucky me, everything i've got is 25T splines.8)

 

[Olle P]

Data pitfalls!

Have you noticed the potential traps when reading servo data?

Voltage
The voltage indicated is rarely the voltage actually used, but the nominal voltage of the (fully charged) battery used for testing.
4.8V data tells what you get with a ~5.5V actual feed (4 cell NiMH). 6.0V data stem from a ~7.0V feed (5 cell NiMH). 7.2V and 7.4V data are taken at ~8.4V feed.

Torque
Two types/levels of torque are in use: Standing torque and stall torque.
Standing torque is the upper limit at which the servo can hold the axle somewhat stationary while external force is applied.
Stall torque is the limit at which the servo motor (barely) can rotate the axle. This is lower than the standing torque, for some servos by a substantial margin.

What does this mean?
- Don't compares apples to pears!
- When comparing data from different manufacturers, try to find out if they present the stall torque or the standing torque. Assume standing torque unless otherwise noted.
- To see the performance applicable to you, use the voltage line most representative for your feed. A 6V BEC will give performance slightly above the 4.8V data, while a 7.0V BEC should be spot on the 6.0V data.

 

[Scocrawler]

Hi all. I am sure the answers to my questions are somewhere on this site but I am getting brain cramps reading forum after forum. Please help. I am running an ax-10 scorpion with the stock tx, an ax-1. The stock rx, an ar-1. and the stock esc, an ae-1. (all very sad) I have a hitec 645mg now and it is not enough strength. I know I need to add a bec if I go with any servo that is a considerable upgrade. Ok now the questions. Will adding a bec that is set to deliver 7.4v to the 645mg be enough to help any? If I go to a 7950 or similar servo do I need a radio with end point adjustments or just pay real close attention to the amount of throw I use when I set up my servo horn? Any thoughts or ideas are greatly appreciated. Thanks

 

[Charlie-III]

Hi all. I am sure the answers to my questions are somewhere on this site but I am getting brain cramps reading forum after forum. Please help. I am running an ax-10 scorpion with the stock tx, an ax-1. The stock rx, an ar-1. and the stock esc, an ae-1. (all very sad) I have a hitec 645mg now and it is not enough strength. I know I need to add a bec if I go with any servo that is a considerable upgrade. Ok now the questions. Will adding a bec that is set to deliver 7.4v to the 645mg be enough to help any? If I go to a 7950 or similar servo do I need a radio with end point adjustments or just pay real close attention to the amount of throw I use when I set up my servo horn? Any thoughts or ideas are greatly appreciated. Thanks

An external BEC may help the 645mg for now, but an upgrade to 200inoz+ is likely in order.
Once you get to ~200inoz+, an external BEC is really required.

Having steering EPA's in the TX is nice, but yes, you can be very careful in linkage set-up to prevent issues. It's the PITA way to do it though.8)

 

[Scocrawler]

An external BEC may help the 645mg for now, but an upgrade to 200inoz+ is likely in order.
Once you get to ~200inoz+, an external BEC is really required.

Having steering EPA's in the TX is nice, but yes, you can be very careful in linkage set-up to prevent issues. It's the PITA way to do it though.8)

Thanks. I guess since an external bec is in order either way I will add it and see how the 645mg does. (not gonna get hopes up) Will likely go with the Solar servo since this thing is not a comp rig.

 

[RoadKing]

What is the best servo steering for the Wheely King?I want more torque because upgrade for Clod wheels and tires."thumbsup"

 

[kincer]

What is the best servo steering for the Wheely King?I want more torque because upgrade for Clod wheels and tires."thumbsup"

Best thing to do on that is put the servo on the axle,that will help tons. This will eliminate all that linkage.

Sent from the RAZR's edge

 

[RoadKing]

I put my servo on the axle.The stock servo is to small for the big tire.

 

[kincer]

Ok, sorry if you're on a budget the solar servos are great 772 I believe is the model.

Sent from the RAZR's edge

 

[83GT]

How would the Solar D722 compare to Hitec 645MG? I've stripped some gears in my 645 and I can get the D772 for the same price as a rebuild for the 645. Seems too cheap for the specs!

 

[kincer]

You can buy almost 2 for 1 hitec 645 and they have way more torque.

Sent from the RAZR's edge

 

[83GT]

Yeah, I already have the 645MG, but stripped it running it in a 1/8th truggy. Was debating on the D722 as a replacement VS buying the replacement gear set for the 645. At the price, I guess I should just go ahead and order the D722 and if it bombs out, I can always buy the gear set for the 645 at a later date.

 

[kincer]

I had a D772, I abused it for a while and it worked great.

Sent from the RAZR's edge

 

[83GT]

Got one on the way.