Skippers Walker Posted May 4, 2021 Share Posted May 4, 2021 I have acquired a couple of small servos for possible use in a 2M powered glider. The servos are marked HV (Model: DS939HV Operating Voltage: 6.0V / 7.2V Operating Current: 200mA / 240mA), which I presume indicates that they may be connected directly to an appropriate LiPo. Will this type of servo function efficiently just plugged into the receiver as per normally and powered through the usual ESC/BEC & LiPo set up? Thanks for reading I look forward to any comments. SW Quote Link to comment Share on other sites More sharing options...
Shaun Walsh Posted May 4, 2021 Share Posted May 4, 2021 11 minutes ago, Skippers Walker said: I have acquired a couple of small servos for possible use in a 2M powered glider. The servos are marked HV (Model: DS939HV Operating Voltage: 6.0V / 7.2V Operating Current: 200mA / 240mA), which I presume indicates that they may be connected directly to an appropriate LiPo. Will this type of servo function efficiently just plugged into the receiver as per normally and powered through the usual ESC/BEC & LiPo set up? Thanks for reading I look forward to any comments. SW What is the ESC?BEC voltage? Some have adjustable voltages. If not adjustable they normally output 5V which would mean that the speed and torque of the servo will be reduced. If it is adjustable than make sure that the receiver can handle the higher voltage and adjust it to 6 or 7V to take advantage of the higher speed and torque. Quote Link to comment Share on other sites More sharing options...
MattyB Posted May 4, 2021 Share Posted May 4, 2021 (edited) 59 minutes ago, Skippers Walker said: I have acquired a couple of small servos for possible use in a 2M powered glider. The servos are marked HV (Model: DS939HV Operating Voltage: 6.0V / 7.2V Operating Current: 200mA / 240mA), which I presume indicates that they may be connected directly to an appropriate LiPo. Will this type of servo function efficiently just plugged into the receiver as per normally and powered through the usual ESC/BEC & LiPo set up? Thanks for reading I look forward to any comments. SW A fully charged 2S lipo is 8.4V, so be careful! Those servos either need a BEC that can be set to output in the target voltage range or a 2S LiFe pack. LiFe nominal voltage is 3.3V/cell and fully charged 3.6V/cell, so a 2S will be 7.2V fresh off charge. However that will dip down below 7V on load quite quickly, then discharge the rest of it’s capacity on a very flat voltage curve. Edited May 4, 2021 by MattyB Quote Link to comment Share on other sites More sharing options...
Frank Skilbeck Posted May 4, 2021 Share Posted May 4, 2021 They should work fine off the ESC BEC, just that the reduced voltage will reduce the maximum torque (and also the amps drawn). So instead of 2.6 kg/cm @ 6v you might get 2.3kg/cm at 5.5v and speed will drop a little as well. Quote Link to comment Share on other sites More sharing options...
Skippers Walker Posted May 4, 2021 Author Share Posted May 4, 2021 Hi Folks Thanks for the useful and informative responses. I have set up the servos and ESC on a bench test in the model and they appear to work just fine. The ESC/BEC voltage is 5.5v and the Servo spec torque is stated as 2.8kg. Given that the model is a lightweight thermal soarer I guess that the actual working load on the elevator/rudder will not be high. A very useful conversation overall thanks again for responding so quickly. Stay well Chris (SW) 1 Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.