HS-5085MG: What is a proper power supply?
06-20-2012, 04:40 AM
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HS-5085MG: What is a proper power supply?
I need some assistance to ensure that I have the proper power supply for my servo set-up in one of my aircraft. I've talked to an RCU member (tomf) and while we did some trouble shooting I'd like to get the input of a Hitech professional. Here is a thread of the discussion before I knew this location existed:
http://www.rcuniverse.com/forum/m_11..._1/key_/tm.htm
I'm getting some odd feedback on myHobbicoVoltWatch[/b]and am seeking some insight and assistance.
The Set Up[/b]
http://www.rcuniverse.com/forum/m_11..._1/key_/tm.htm
I'm getting some odd feedback on myHobbicoVoltWatch[/b]and am seeking some insight and assistance.
The Set Up[/b]
- [*]E-flite 25 Texan (converted to glow) w/.25 O.S. 2-stroke[*]5Hitech HS-5085MGDigitalBB Metal Gear Mighty Micro Servos (ailerons, elevator, rudder, throttle)[*]NiMH 4C 4.8V 2000mAh Receiver Pack[*]Hobbico VoltWatch Meter (set to 4.8V)[*]E-flite 90 degree retracts[/list]
The issue[/b]
Freshly charged battery (it's new), inspected and not damaged servos (I'm the only owner), proper installation of electronics (done this numerous times), but when I start moving control surfaces (e.g., ailerons, elevator, etc.) the VoltWatch lights up like a christmas tree all the way down to the red. Stop moving surfaces, and then we're solid green. I've seen this before but no so severe and I'm wondering A) Do I need a larger battery to power the servos, or B) Is the VoltWatch damaged? I'm having a hard time thinking that 5 micro servos pull that much juice.
Any assistance would be of great help.
06-20-2012, 09:00 AM
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RE: HS-5085MG: What is a proper power supply?
The symptoms say your battery voltage is dropping below the lower limit of your monitor. 4.8 volts is the nominal pack voltage and you are setting it as the warning? Iwould make sure there are not binding surfaces or linkages. Then Iwould change to a 6 volt battery. You don't mention what radio RX and TX you are using. I have had similar problems to what you report and have changed all my glow models to 6 volt. Iuse Ni-cad batteries for my RX packs. I am not a battery expert but have read that Ni-mh batteries have good capacity but limited current surge. The Hitec Aurora 9 and Optima Rx systems have been great in that with the battery voltage downlinked to the TX from plane Ihave been alerted to these transient battery things.
I have a Kyosho P-17 ARF with an OS-70 4 stroke and five standard servos which Iflew for serveral years on Hitec 72mhz with a 4.8 volt Ni-cad 1200mah. In 2010 after changing to Hitec2.4GHZ with the battery TM, Isaw that when ever Iwould do a hard manuver (fast roll or snap roll) I would get the battery alarm at the TX which Ihad set for 4.6 volts. Ifound with my glow models that rowing the sticks on the ground would drop the battery voltage to 4.5 volts time after time. Running them with a 6 volt ni-cad at 1200mah has eliminated these problems.
Have fun
I have a Kyosho P-17 ARF with an OS-70 4 stroke and five standard servos which Iflew for serveral years on Hitec 72mhz with a 4.8 volt Ni-cad 1200mah. In 2010 after changing to Hitec2.4GHZ with the battery TM, Isaw that when ever Iwould do a hard manuver (fast roll or snap roll) I would get the battery alarm at the TX which Ihad set for 4.6 volts. Ifound with my glow models that rowing the sticks on the ground would drop the battery voltage to 4.5 volts time after time. Running them with a 6 volt ni-cad at 1200mah has eliminated these problems.
Have fun
06-20-2012, 09:52 AM
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RE: HS-5085MG: What is a proper power supply?
I just read the other thread... there is a lot of good info there as well as Jims reply above which hits the nail on the head. The bottom line is the voltage will sag with any battery but it depends on the load and internal resistance of the pack as to how much. Anything over about .8v from the resting voltage means that you don't have the proper battery for the job. High capacity AA size NiMh packs are the worst when asked to deliver power; they are great for TX's but not for digital servos.
These would be a better choice: http://store.batteriesamerica.com/sa...wireleads.aspx
Mike.
These would be a better choice: http://store.batteriesamerica.com/sa...wireleads.aspx
Mike.
06-20-2012, 11:58 AM
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RE: HS-5085MG: What is a proper power supply?
Also, you said that the battery pack is new. In my experience, nimh packs require several charge/discharge cycles (3-4) before they are able to perform to their capacity.
07-02-2012, 04:10 PM
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RE: HS-5085MG: What is a proper power supply?
Mike,
I have a voltage issue that is related. I use the A9 so I can see the high and low voltage. I was dropping to 3.8 volts from a 6.2 volt regulated power supply. I have done some testing so here it the skinny...
Setup is optima 9, Fromeco 2600 lion, reg, badger. Servos Spectrum A6030 x3 (I know, you going to say should have used hitec) for the tail, Small digital hitec on the thottle, Bluebird digitals on the ailerons.
I tried dual packs to the receiver but it still dropped to like 4.5 volts.
I disconnected all servos except one A6030 and still get a drop to 5.0 from 6.2
Now I have taken a plain Optima 7, 6 volt nimh, and any random servo including a hitec digital and get a huge drop from 6.5 down to 5.0 or lower.
After typing this all out I think the common factor is a bunch of batteries that I have not kept good track of, but they all charge well.
This is on a 50cc ultimate but my bench testing making me wonder what to try next.
I have a voltage issue that is related. I use the A9 so I can see the high and low voltage. I was dropping to 3.8 volts from a 6.2 volt regulated power supply. I have done some testing so here it the skinny...
Setup is optima 9, Fromeco 2600 lion, reg, badger. Servos Spectrum A6030 x3 (I know, you going to say should have used hitec) for the tail, Small digital hitec on the thottle, Bluebird digitals on the ailerons.
I tried dual packs to the receiver but it still dropped to like 4.5 volts.
I disconnected all servos except one A6030 and still get a drop to 5.0 from 6.2
Now I have taken a plain Optima 7, 6 volt nimh, and any random servo including a hitec digital and get a huge drop from 6.5 down to 5.0 or lower.
After typing this all out I think the common factor is a bunch of batteries that I have not kept good track of, but they all charge well.
This is on a 50cc ultimate but my bench testing making me wonder what to try next.
07-03-2012, 08:37 AM
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RE: HS-5085MG: What is a proper power supply?
As discussed... high capacity AA size NiMh cells have difficulty providing adequate amperage for high powered servos although that high of a drop with a single servo is excessive! Sometimes the problems can be with just one servo in the bunch so you might want to see how each of them affects the battery voltage when tested.
Mike.
Mike.
07-03-2012, 06:17 PM
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RE: HS-5085MG: What is a proper power supply?
I kind of understood that. I was using a 2600 LIon fromeco and reg so I thought that would get me close to handling one servo!! I just doubled them up straight to the receiver and got some satifactory results. I ordered two A123 packs and plan to switch to that. I will properly recycle the LIons at the next swap meet.
