Align DS610 servos = high current

[BruceW]

Posted this over on RCG but figured it might be interesting to others:

I picked up some of the new Align DS610 servos for a 70" 3DHS Slick (plane) and figured fast and powerful would be good. Well, the speed and power comes at a price. I was able to brownout my RX on the bench with simple stick stirring while running 4 of the servos with no load!

At first I thought there was something wrong with the servos but there was not a single one causing the current overload, it was just the 4 of them running together. These are rated at 166 oz-in and 0.08 sec / 60deg @ 6V and appear to be very fast. This is a good competitive servo to the JR8717 if you want to run at 6V instead of 7.4V.

So here is what I found when testing the servos:
Note: I had the Spektrum data logger plugged in so I could watch the voltage
Note2: I tried this with and without loads on one of the servos and did not see a difference in voltage drop.
Note3: CC = Castle Creations, WR = Western Robotics

1. With CC BEC @ 6V - brownout of RX with just a few quick movements - voltage dropped below 5V easily.
2. With CC BEC @ 6V + Spektrum Capacitor - harder to brownout but lots of stick movement could eventually drop the voltage - CC BEC was warm.
3. With WR 5A BEC @ 6V - brownout with aggressive stick movement in all corners - BEC was still ambient temp and voltage would drop below 5V.
4. With WR 5A BEC @ 6V + Spektrum Capacitor - took a lot of stick stirring to make it brownout and I think this would be fine for most flights.

FYI - To get brownout you need to be in the low 4V range. Since I have the latest firmware (v1.6) on my AR7000, the RX came back quickly and I couldn't really notice any lose of control.

When I did the same test with the 3x BLS451 at 6V (150 oz-in) which I run in the Logo 500, the voltage only made a small drop with massive stick stirring (lowest was 5.8v). Looks like that speed up of 0.02 sec for 60deg comes at a price.

Conclusion:
These really need to be run with the WR Super-mini. For the plane I don't need anything this fast but I do need the torque rating of 150+ oz-in. Its also very helpful to use the Spektrum Capacitor and I saw a big difference when using it. I'm starting to think the fast speed might make the plane too crisp in movement but will probably need to dial up the expo. If I were only running 3 of these on collective in the helicopter then it might not be as bad but you definitely want a high current BEC.

I think I'll put these in the helicopter (3x) and use the Futaba BLS451 on ailerons and elevator and the DS610 on rudder. Either way, it looks like I'll get the WR Super-mini rated at 10A to run these servos.

Just thought I let you guys know about these servos if anybody was looking into them.

Bruce

[zguy]

GREAT report Bruce! Thanks

You confirmed many things for me:
-BLS's low current draw vs. the Align servo
-WR BEC vs CCBEC
-Spectrum LV brownouts
-Spectrum capacitor validity

I did just recently convert to V-Bar ( Great BTW ) and added the capacitor to help compensate for the added servo current draw. Glad to know it actually makes a difference

[MrMel]

Yup, I flew Align DS620 on the cyclic and they pulled quite alot more then JR8717 in the same machine.

BLS451 is VERY low-current-draw in comparison, but not much slower really.

Remember though, higher voltage = higher ampdraw in servos, so backing down from 6v might do the trick...

[BruceW]

I thought about going down to 5V but then I'm that much closer to the RX voltage limit to get a brownout. I guess there is some tradeoff but I'll give it a try tonight and see what happens and report back.

Overall, I would not buy these again and I might end up selling them. They only cost $240 for 4 which seemed like a good deal at the time from GrandRC.

Rob, I originally bought my BLS451s because of your report and I've been very happy with them. They definitely require very little current in comparison.

[NTM]

That's interesting, I'm running those 610's in my v-bar 500.
The esc cut out on me at the bottom of a long tailslide where I rather violently pancaked the machine to a dead stop out of the terminal velocity dive. It then fell the remaining eight feet to the ground with the blades barely spinning.
The jive was flashing a code for a reciever disconnect, I thought I had merely overamped the jive and the blades being tangled up in the wreckage had stalled the servos out enough to cause the jive's bec to overheat and shutdown.
Perhaps what actually happened was that the huge load I threw at the servos at the bottom of that maneuver caused them to draw more than the jive's internal bec could handle ?
I sure hope not.

Regards,
Nathan

[BruceW]

That doesn't give me too much confidence to put these in my L500 if the Jive can't handle the current from them. I was under the impression that the Jive could take spikes of 15A and if you did brownout the RX due to voltage drop then I will not use these. Dropping out of a tail slide with massive pitch is something I like to do and would hate to watch my heli drop to the ground.

[bobmagoo]

I am building up myL600 vbar and was planning on using the DS610 servos. But after reading these posts, I'm quite hesitant. Maybe if I install a spektrum capacitor will make it better? Or how about the DS620's? Will there be similar concerns?

[NTM]

It still could have been the esc overamping in my case.
I'm going to load all three servos up tommorow, with the eagletree on, for five minutes and see what happens.

[MrMel]

Jive can take it, Jive can take the DS620 which are even faster.
Well, it did on mine

Be careful testing though (load up the servos for a long time) I dont think the BEC in the jive will shutdown, it will burn up, it works until it fails.
But stirr the stick and watch voltage to determine if it holds.

[BruceW]

As MrMel said, backing off of 6V did work a little better. I put the WR at 5V and did the stick stir. Without the Spektrum Cap I was able to induce a brownout but it took a lot more effort and with it on I only got it to shutdown once. Of course this is all without a load so not sure what to expect on a real flight yet.

I'm a bit worried about running these on my Logo so I think I'll get a WR Super--mini and run them at 5.2V in the plane. Since the BLS451 work so well in my current setup I don't want to mess up a good thing. Also, if I get a shutdown on the ESC in a plane its easier to deal with than the ESC on a helicopter. Looks like I'll get about 144 oz-in at 5.2V so that should be close enough to the spec of 150 oz-in.

[BruceW]

Fredrick, are you still running those DS620s or did you swap them out?

[MrMel]

I run BLS451 on all my helis now except one that has JR8717....

[NTM]

Originally Posted by MrMel

Be careful testing though (load up the servos for a long time) I dont think the BEC in the jive will shutdown, it will burn up, it works until it fails.

I don't know, as I walked up to the wreckage the cyclic servos were binding, the tail was twitching every couple of seconds, and when I untangled what was left of the blades to stop the cyclic servos binding, the twitching stopped and the v-bar gave a double bump on the collective ?

Everything seems to work fine now, only the blades, canopy and skids were damaged in the crash.
I'm changing to a jive 100 lv from the 80 lv that's in there now.

[Jamesppp]

I wish all servo manufactures would list the current drain specs.

It is hard to find any info on most most of them.

They need to list: Idle current
No load operating
Stall current
And list the drain on different voltages.
Hyperion servos which are cheap but decent for some applictions list these parameters.

On my Outrage 550 using cyclic servos with a listed 2.0a stall current drain, the highest Eagletree spike I could get using the servo current sensor was a little over 3.1amps total. This included an JR8900 tail servoThe no load operating current of the cyclic servos is listed at 350ma each on 6v.

[MrMel]

its not only the servo itself, its how the unit is driven, for sample vbar 3.6 would spike 12amp where v4 on same servo only spike to 5amp.

some servos has filter built in, some dont, so there is other factors then just stallcurrent.

[Michaelsen]

On my 500 3D V-bar i use DS620 on cyclic and DS610 on tail. I recon they are power hungry, so i use a "FlightTech 8A Linear Volt Regulator" bec. It has both dual input wires, and dual output, so you can run one on RX and one on V-bar. (Or 2 on RX)
For me it works ok, and the voltage don't drop to much.

[NTM]

I worked the snot out of the 610's on my logo 500 v-bar for ten minutes straight today and couldn't replicate any kind of shutdown.
I presume my crash was the result of my jive 80 lv doing a hardware overcurrent on me at the bottom of a very fast tail slide.
So at this point I'd say the 610's are fine with the jive's internal bec.

[jvthert]

Did you use a capacitor on your receiver or did it happen without one? I'm in doubt right now. I thought the 610 would be the perfect swash servo (price/quality wise).

Would any of you guys run 610's on a vbar 600 with a Jive HV? Or should I use a better (if there are any at 12s?) ubec?

[bobmagoo]

I thought I was decided on the DS610s for my conversion to L700. I was going to use the WR 5A HBEC HC with it. Anxiously waiting for more flight feedback from NTM before I do. Although his first report makes me feel a little better on these servos. Thanks NTM!

[NTM]

No cap when I tested it, but I've added one just to be safe.