Volt spy question
 

I fly .46 sport plane with 4.8 Nimh battery pack.For safety reason ,I installed vollt spy,for a fresh battery first green light will illuminates,but when i execrise flight control surfaces,thoae LED will blink briefly even those yellow or red LED,Is it safe to fly with this,Or I have to change back to Ni-cad?

RE: Volt spy question
 

If that device is the same as the voltwatch2, it hooks up to a vacant or Y connected port on the receiver. It monitors the voltage once the "system" is powered on.

The flickering LED's indicate usage. Flickering to the yellow is norma. Going to the red may... MAY... indicate that you have a binding linkage.

Operate the controls one at a time to exercise one servo at a time and see what one is causing it to go to the red. Then, look closely at that linkage to see what may be causing the bind. Throttle is usually the culprit, so look at that closely for end points so that, when going to full open or full closed, the servo is not trying to force the control beyond it's physical (mechanical) limit.

If no obvious binds exist, then you may... may.. have a weak battery.

I use, pretty much exculsively, 5 cell (6 volt) packs, about 20% higher capacity than your 4 cell packs, typically at least 1200 mah.

Try that out and let us know how it works out.

CGr.

RE: Volt spy question
 

Thanks first,but the blinking happens only when i execresing,when i release sticks ,it backs to green.

RE: Volt spy question
 

Thats because the currant draw increases when you are wiggling those sticks and goes back to idle when you stop wiggling.

As CGR suggested to find out which control may be binding a bit just wiggle them one at a time.

Now to answer your question as to whether or not to "go back to Nicd" you need to tell us what is the battery capacity of your battery, not just the voltage.

These days I only use five cell batterys (6 volt) and for an ordinary forty sized sport plane using a 2.4 system I prefer to use a minimum of about 1600 mah.

John

RE: Volt spy question
 

I still have a Volt Watch on one plane and use a 6 volt, if I start moving my controls I can get the LEDS to bottom out. No binding but I'm using 5 digital servos on the control surfaces so in a snap roll it is sucking a lot of juice. My Volt Watch is one of the first type that came out 15 or 20 years ago, not the new VW II. I still have a couple of them. I used to take them apart and put the lights behind the instruments in the cockpit. That worked out way cool in scale planes.

RE: Volt spy question
 

If your Voltwatch (or clone of it) is dropping into the red when you cycle the sticks with a fully charged battery, you DO have a potential problem, not just a MAYBE. That means that for a few microseconds or more, the voltage at the point the Voltwatch is plugged into fell to a low value. If you are using a 2.4GHz system, this may be putting you in danger of a brown out condition. There can be several reasons for this, some of which are: Switch with high impedance contacts caused by wear, corrosion or contact size: a battery with a high internal impedance due to under capacity, age or ???; to small a gage wire between the battery and receiver or a defect causing a loss in cross sectional area of the wire somewhere along it's length; a binding servo; a servo being stalled at extreme position. If you are dropping into the red zone, I'd sure recommend that you find the cause if you value your plane. Properly used and evaluated, the Voltwatch is an excellent trouble shooting tool.

RE: Volt spy question
 

So Kuobin what is the capacity of your 4.8 pack? its an important question;)

RE: Volt spy question
 

It is 2200mah.

RE: Volt spy question
 

Kuobin that is an entirely reasonalble capacity for a Nimh pack in a .46 sport airplane and you are not using hugh servos (in terms of output thrust).

I would not go back to Nicd myself. All this is assuming you have made sure that there is no unreasonalble binding on any of the controls and you are properly charging your battery to full capacity.

John

RE: Volt spy question
 

This is something that we have discussed over and over again and that's servo end stops or linkage binding. It really makes a BIG difference in how the receiver will perform as well as how well the aircraft responds to inputs, and of course, the longevity of your aircraft. You don't want your receiver taking a nap caused by a bind in the linkage while flying the plane.

If the linkage binds, the action will be sluggish and be a big drain on the battery pack. In addition to this, if using a 2.4 GHz system, as John mentioned earlier, you take the chance of having the voltage dip below the operating threshold of digital receivers. And, that doesn't matter if you are using Spektrum, Futaba, JR, Turingey, whatever.. that threshold exists. Revovery time varies, but that's a chance you just don't want to take.

Any and all binds, including those caused by end point mis-adjustments, espeically with the throttle, really must be resolved before flying the plane for the first time. You just don't need something that can be avoided to interfere with the maiden flight.

A simple flicker of the LED's on these devices when the sticks are moved is perfectly normal. BUT, when you move the sticks, and the LED's go to the red, this is an obvious indication that something is binding or that a servo is straining at it's end points. As I said, end point problems are usually throttle related. Other binds can exist in the linkage. Regardless, they must be corrected before you fly the plane.

If everything is working ok, and there are no binds or end point issues, well, these devices are great for a quick sanity check before and after each flight.

CGr

RE: Volt spy question
 

I agree with every bit of this except for one thing (and we had a thread on this before). In my mind, the jury isn't out yet on the brown-out comment. The Voltwatch/Voltmagic devices are great...I use them on everything. However, they are very sensitive in voltage measurement and they have a very high sample rate. As a result, they see voltage fluctuations that the receiver does not detect which adds to their early warning value in my mind.

But I'm just not sure how long a voltage dip needs to exist before the receiver sees it and browns out. I can't remember but someone here had the ability to measure this and was going to do some testing. To make matters worse, I'm sure various receivers have different parameters for brownout.

I think it is voltage AND duration that cause the brown out. No?

Tom

RE: Volt spy question
 

We don't really know if there was a problem at all, just that the OP stated that the LED's will "blink briefly" in the yellow zone. We are trying to help him understand why this may happen. What we are trying to point out here is that sustained actrivity of the yellow or red LED's will cause problems regardless of what else is going on and must be corrected to insure longevity and safety in flight of his RC model. It's just that simple. And, yes, it is voltage and duration that can and will cause probems.

Everything stated above is accurate, but one must consider that beginner or intermediate sport aircraft equipment, including servo wiring, battery wiring, switches, and so on are probably not something that a beginner will really need be concerned about. There is absoluely nothing in such aircraft that will have any problems caused by this. The most obvious issues I've see are mainly in setting up the throttle and mis-adjusted control surface throws, with the most likely cuprit being the throttle.

CGr.

RE: Volt spy question
 

On board battery status lights are great, but I like to interpret just what the lights are really telling me. The first time I take a so equipped plane out, I also test the receiver pack periodically with a voltage/load test meter and take note as the light changes. http://www.horizonhobby.com/products...ltmeter-HAN171

Every status light type I've used blinks for the briefest of time the red light if I quickly circulate both sticks at the same time. Digital servos are getting more common and more powerful. These servos really draw current and if your plane is loaded with these, you may need to rethink your battery. I's always a good idea to load test through the switch a least once to see if there a lot of loss in the switch, I've found a few obvious bad ones.

Besides chemistry type, there are three main things to know about your battery. Voltage, Capacity and discharge voltage @ load or what I like to call "current dump". For example: a NiMH AA battery typically has more capacity (more in the tank) than a NiMH 2/3 A, but the 2/3A battery has better dump (less voltage drop under the same load.)

RE: Volt spy question
 

This is a beginners forum. The point here is to show the beginner what should be done prior to flight (and after each flight). We don't tend to overload a beginner with information that is, most likely, unapplicable to basic flight.

I totally agree that battery checks are essential, and that it should be done under load. I have always stated that the voltwatch, or whatever device that is used for a "quick look" at the battery condition is a good thing but that it should be done before a flying day begins with a loaded voltmeter.

I would venture to say that there are no beginners out there that are using a true digital servo.

The bottom line here is that the voltwatch, volt spy, whatever, is a good secondary device and many use them. I do, on everything I have, and rely on them to give me that quick look at battery condition. It saved my plane one time.

CGr.

RE: Volt spy question
 

They are are standard now on most entry/basic radio systems.
Where I've seen problems is when a beginner pieces a system together and sales person suggests servos that may be excessive to the needs, yet the battery is basic.
Several times I've come across this and the plane's voltage was unsafe after only two flights.


I agree 100%, but a voltage/load test meter should be the number one item in the flight box. So many planes I've saved, mostly not mine.

RE: Volt spy question
 

When I refer to "digital servos" I refer to those high precision high power servos that are on many, if not most 3D large scale aircraft. The standard servo, although it may be digital, is not the big current draw that those expensive ones. Note that when a batter is shipped with a tansmitter/receiver are 4.8 volt 600 or 700 mah packs, and those work fine for a few flights and they are just fine with the servos shipped with them. And, when set up properly - no binds and no end-stop issues, their current draw now becomes a matter of how active the pilot is on the sticks. And, another good reason to check before the flying begins on a flying day to make sure that the battery is up where it belongs. Then, upon landing, since it is not practical to dismantle everything to check batteries, the voltwatch 2, for example, obviously there others, do just fine because they do check under the existing load.

CGr.

RE: Volt spy question
 

Every plane I've ever built has a charge jack, no need to pull wings or pop the canopy to test battery condition. These are work great, http://www.troybuiltmodels.com/items/MPI5470.html

It's a combo switch, charge jack, and battery status. Never had one fail and I've put many of them through heck.

Hints: Since this is only a three light, don't start a flight with yellow solidly lit. If the plane is a high wing, if possible mount it under the wing, the yellow light will stand out on a fly-by in the shade of the wing, think about landing soon if you see it. Always mount the switch so that it is "power on" to the rear and "power off" towards the front. The wind or a brush with something wont turn it off and the switch will turn off on impact from inertia. (hopefully few of those). Never mount any switch down wind of the exhaust or fuel spray or leach points like the carb or cowl outlets. Don't over tighten the mounting screws and do use removable thread locker sparingly, (on the threads only!) thread locking fluids cause most plastics to crack in time.

RE: Volt spy question
 

Dick, I was able to catch my Volt Spy with a camera. What I did was pulled down my Hots with the old VW. I had a 6v pack in it and other then getting the lights to flicker when I hit the snap roll switch nothing was going on. I changed the pack to a 4.8 then hit the snap switch. The lights would jump from dead low then go down and hold in the OK area. Very quickly so I was surprised I was able to catch it with the camera. This volt spy is very old and it is only a 4.8 volt. I usually run a 4.8 volt 2000mah in this plane but once in a while it will have a 6 volt pack, like now!;) I use a loaded meter most of the time before each flight, not always but most the time. I never trust the VW. I have the GEM 2000 {1000?} in my CG Extra, it tells you a bunch more if you take the time to memories the blinks and bother to look at it before flight. I have saved My Extra by accidentally looking at that light. The GEM {JEM}? costs more and I'm not sure if they are still made? I still have a couple of them.

RE: Volt spy question
 

Gene: I rely on the voltwatch only after I have checked the battery with a loaded voltmeter. If I didn't get that point across before, I will clarify now.

I use the Voltwatch2 on everything I fly. I use it as a safety check in between flights, and not as a reliability check on arrival at the airfield and initial setup. For that I use a loaded voltmeter, as everyone should. As pointed out above, a loaded voltmeter should be part of everyone's field box.

Now in between flights, I check, as I said before, I check the voltwatch before and after each flight by turning on the electronics, (TX - RX) and once it is settled in (2.4 GHz) operate the sticks through all positions to the extreme while watching the voltwatch. Any deviations into the yellow become suspect and I check that out by working the stick in the direction that caused it to flicker into the yellow. If it goes to the red, I stop and see why that happened.

For anyone interested, I will relate what happened to me a few years ago and perhaps this may clear up a few things for those doubters.

I have a Venus II pattern plane, not a 2 X 2 meter plane, but the intermediate level, with an OS 1.20 AX engine. It has 2.4 GHz (Spektrum DX7) but I don't recall what receiver. I also am using a pair of 1200 mah NiMh packs in parallel, each to an individual slot in the receiver and each one has it's own switch. I power up battery #1 and check things out as stated above. I turn off switch #1 and turn on switch #2 and do the same thing. If all looks good, I power up both by switching #1 back on. I am now operating with both batteries in parallel to the system.

I fly that way, and upon landing, I reverse the above and check both batteries before shutting down. I do this all over again for the next flight.

This one day, after my third or fourth flight, I did the usual routine but when I checked Battery #2, the LED's were pretty much in the red all the time, where battery #1 was ok. I took the wing off and took the battery out and checked it with a loaded voltmeter.. and it was dead. I had a spare and put that in, re-charged battery #1 then started all over again with my battery check process.

The battery #2 went dead in flight. Imagine what would have happened if I didn't have a parallel operation. And, imagine what would have happened if I had not checked my battery operation in between flights.

Yeah, I admit that the same thing can be done using the charge jack and a loaded voltmeter without having to use a voltwatch, however, the voltwatch is simply a tool and a good quick-check of your battery condition.. and that's ALL I am saying.

You (any and all posters) can do what you want. The process is what I follow and it works for me. You can take your chances and not check batteries, or you can be safe and check batteries. The method you follow is totally up to you.

CGr.

RE: Volt spy question
 

OK...and this means there is a problem. If it does this on a full charge, the battery is having trouble meeting the voltage demands of the servos. (ie. either binding, extensions too long, bad switch, too many servos for one battery etc. etc.) If it does it after some flying, the battery is getting low. Wouldn't you agree? I know you understand this stuff, but I just didn't want the OP to think that the readings he is getting are aceptable.

And back to the OP...he has a 4.8 volt 2,200 mah battery. Should be fine but the same thing applies to him. If he is getting these readings on a full charge (and he knows the battery is good), then there is a problem.

Where are you on this now Kuobin? Are you all set? Did you resolve the issue?

Tom

RE: Volt spy question
 

Tom: Agree 100%. If one uses an older technology (if there is such a thing) 2.4GHz system that has not been updated to eliminate (well, lessen the effects) of so-called brown out, if it goes to the red, the voltage is falling below the threshold and could cause the receiver to go into the dead zone until it resets itself. If this happnes during a critical time of flight, well the results are predictable.

This is not the first time this subject has come up, although it may be for the "volt-spy" device, it certainly has come up when debating the Voltwatch and during discussions about using loaded voltmeters. I can assure you that it won't be the last time the subject comes up.

To me, and obviously to most of the experenced pilots, it's an important subject and new pilots should get the basic understanding that one should check batteries. The device one uses is up to the individual, but the barest minimum would be a loaded voltmeter. I choose a loaded voltmeter and a back-up method called voltwatch2.

CGr.

RE: Volt spy question
 

Today i connect a multi-meter to the battery,and then monitor the volt meter reading when i execrise sticks ,You know what?the volt reading never go below 4.8V even RED LED might blinks,Now I am wondering if the voly-spy is too senstive?

RE: Volt spy question
 

What the photos show is my plane with a 4.8 pack using 5 servos in a snap roll, throttle is closed but I guess that still counts as 6 servos, three of them are digital Hitec and three of them are analog JR. When I release the snap roll switch the VW lights drop to the bottom LED showing a full charge. I did a stupid and mounted it aft and under the wing so I tend to forget to look at it before every flight. My bad!! These are fun to take apart and put the LEDs behind the instruments in scale planes. I once did it in a nice Hell Cat scale plane. If you have a real cockpit and canopy it's a good place to mount them so you can see it. This is an old Hots fun fly plane with no real cockpit.

RE: Volt spy question
 

Yes, the VW is quite sensitive, almost as good as an ocilloscope. That is why it is such a valuable trouble shooting tool, it gives you an indication of a problem that a voltmeter or loaded voltmeter will never show. You can get a momentary drop in voltage at the receiver bus that will never show up on a voltmeter, whether loaded or not, that can cause a brown out on a 2.4GHz system. Another great thing about the VW is that it is always connected making it so easy to check at the end of each flight before turning off your receiver to make sure the battery voltage is sufficient for one more flight or more. I see to many people that never take the time to check with a loaded VM before each flight due to the trouble of getting it connected and reading it. Nothing more useless than a meter that is never used.

RE: Volt spy question
 

You know what Kuobin there has been lots of good response's here but its time to go fly its really as simple as that-just go fly.


John