Load tester

[woodturner]

Hi All,

:?: I'm guessiing a load tester would be a good piece of gear. If true any recommendations.. Thanks!!

[Blair]

I've played with the futaba one and liked it alot and own the duralite load checker.

Another option is the BC-6 or Voltwatch as they show the load that was seen during the flight. I've had BC-6's for years and they work well. The Voltwatch will do li-po's/Li-Ions too.



B.

[HelicopterJohn]

I like the one that "Clintstone" uses. It is a combination digital load tester and glow driver all in one unit. It is manufactured by Duralite.

The only down side is the price. I think it costs about $130.00.

:)

[DavidH]

Another option is the BC-6 or Voltwatch as they show the load that was seen during the flight. I've had BC-6's for years and they work well. The Voltwatch will do li-po's/Li-Ions too.


If the above devices are measuring voltage thru a receiver port. How can they be used with Li-Ion and Li-Po's? The Lithium batteries are regulated thru a regulator that is feeding a constant voltage to the receiver. So how would these voltmeters that plug into the receiver know the voltage and condition of the Lithium batteries?
Stop fly voltage on most Lithium batteries is 6.9 volts for a 2 cell setup. Most regulators supplying voltage to the receiver are in the 5.1 to 6 volt range.
Just curious to how these onboard voltmeters will work with the Lithium setup ?

David

[Blair]

Run it before the regulator?
It says it measures the 6+ volt range. You configure it to the range you want.
B.

[DavidH]

Don't think that is possible. Also I don't believe these onboard volt meters puts any load on the batteries. They are just a volt meter.
I know the voltage is adjustable on them, but that still don't make them supply a load on the battery. And if is plugged into the receiver port, it is only going to monitor the incoming regulated voltage what ever the regulator is supplying.

David

[Blair]

You're right...it doesn't load the battery....the heli loads it during the flight and it registers that voltage. I suspect you should still load test the batt before the next flight to be sure, but it would be nice to know how low the pack is getting sucked in the real world environment.

Apples and oranges really.

B.

[DavidH]

the heli loads it during the flight and it registers that voltage.

Ok maybe I don't understand, but if the onboard voltmeter is plugged into a reciever slot. How does it show anything other than the regulated voltage that is being supplied to the receiver? It would not show battery voltage, it would just show the 5.1 to 5.6 voltage that the regulator is supplying to the receiver. That voltage would remain constant depending on what voltage the regulator was set to supply. I don't see how an onboard voltmeter can show condition of the battery when it is plugged into a receiver port that is using a regulated power supply.

David

[HelicopterJohn]

Hi David,

Thanks for the input.

I am running a 7.4 Lipo pack. It typically charges to around 8.2 8.3 volts and I run it down to about 7.0 volts (with 1 amp load test) then charge it.

I monitor my voltage with a checker that puts 1.0 amp load on the battery prior to each flight making sure it is within flying specifications.

This test is done on the battery side of the regulator and (I think?) gives me a good idea of the condition and available charge of the batteries.

The regulator will provide the receiver with a constant 5.1/5.6 volts until the lipo discharges and then the receiver will be short on voltage and unsafe flying will result. Monitoring the voltage on the receiver is useless (I think?) as it only tells you that your batteries (Lipo) have not reached the cutoff point that will no longer give your receiver proper voltage to operate.

The receiver thinks everything is fine as long as it is receiving the required voltage. The big deal (I think?) is knowing the status of charge of the battery prior to the regulator and monitoring the same.

Is my logic correct or am I missing something? I am by no means a battery expert and would like input from others.

:)

[DavidH]

John,
Your correct in what your saying.
All I was saying above is the Voltwatch and other onboard voltmeters that are plugged into a receiver channel port can't be used on a regulated voltage system.

A 2 cell Li-Ion system is dead at 5.5 volts. So if the regulator was 5.1 to 5.6 volts and using an onboard volt meter to monitor the voltage. Well the Li-Ion batteries would be dead and the model crashed before the onboard voltmeter would show a problem. Reason I bring this up, I have ran into a couple of pilots that crashed there models due to the Li-Ion batteries dying. They said there Voltwatch never showed in the red that there was a problem. I then explained to them why it wouldn't show in the red or a low voltage. That is basically all I am trying to explain, unless these voltmeters are hooked directly to the battery and putting a load on it when checking. They are basically useless. And they couldn't keep a 1 amp load all the time on the battery, because it would run it down quicker than the servos would flying the model.

David

[HelicopterJohn]

Hi David,

I agree with you. Like I said:

Monitoring the voltage on the receiver is useless (I think?) as it only tells you that your batteries (Lipo) have not reached the cutoff point that will no longer give your receiver proper voltage to operate.

The only thing that they will tell you is you just crashed.

:(

[Blair]

YOU PUT THE MONITOR BEFORE THE REGULATOR!

:arggg:

Blair

[HelicopterJohn]

Sounds like a good idea

:arggg:

[WayneBrown]

buy a duralite load tester or futaba load tester and quit trying to find a shortcut!
I personally don't care if you crash your chopper, but don't do it near me or any of my freinds because you *think* you are smarter than everyone else.
There are reasons the method David stated work.. It's called LOGIC.
/rant

[Blair]

No shortcut...just suggesting an alternative method....you'll see I suggested the duralite and futaba checkers too.

Just trying to keep an open mind....

B.

[WillJames]

Do they make monitirs that can be set to 6.9V for the red alert?

[Blair]

http://www.voltmagic.com/index.htm

[WillJames]

Interesting...

I try to keep it simple and just check the DL packs under a 1 amp load between flights. I find that adding extra electronics to the heli is not always a good idea for me.

[HelicopterJohn]

woodturner,

There are several things you can do to help you fly safely.

One is to get one of the load testers such as mentioned here that apply an appropriate load to your batteries that would simulate flight conditions checking to insure the batteries while accepting that load are still within the appropriate charge level for safe flying. I check my battery condition prior to every flight.

Another item is on board flight battery monitors. These come in different styles and features depending on the manufacturer.

"Blair" has given us a link to a unit that is available and can monitor the higher voltages associated with LIPO packs. It has a meter that flashes to show you your battery state.

I was, and still am, a fan of the GEM 2000 when I was running 4.8 volt nicad packs with no regulator. I had the remote LED setup on mine which was really nice as you could do a flyby and easily see the condition of the battery by the way the LED was blinking. Some other manufacturers had units that performed some of the same functions but the monitor was not easily seen while the helicopter was in flight. I haven't checked lately and they may now have a unit that can monitor the voltage on the battery side of the regulator i.e 7.2 volts etc.

Some pilots had issues with some on board monitors saying (in their opinion) that the units caused radio interference. This concern has caused caution by some pilots and is the reason they tend not to use them.

Guess you just have to make up your own mine as to which system(s) you care to use to provide the greatest level to flight safety.

:D

[DavidH]

http://www.voltmagic.com/VM_installation.pdf

In reading the instructions for the voltmagic.
VoltMagic can also be plugged into a socket that does not have a
channel signal (such as one for a DSC) or connected directly to a battery (such as a LiPoly).

The above is the only time a Lithium battery is mentioned other than in the charts to set the voltage. It gives pretty detailed instructions how to use it with other systems. But only mentions it can be plugged directly into a Lithium battery.
I think if the manufactuered seriously intended for it to be used with Lithium batteries, they would have given detail instructions also how to use it with Lithium batteries.
I only see something like this as a bling item on a heli. Nothing still beats using a loaded voltmeter to test the batteries. Even Voltmagic states that in the instructions.
Using battery load, discharge, or capacity
test instruments, in addition to VoltMagic, is good practice.
Spend the $40 towards a good voltmeter with a load that will give an accurate reading of the battery.

David

[WillJames]

I agree David. If the voltmagic was like the GEM and had a warning light that you could see while flying your heli in a normal flying scenario and also documented and proven success reading correctly on a LiIon/LiPo maybe you could say it was needed kit, but for me, a volt watch or similar is definitely just another point of failure for me. I try to keep it simple and not include extra E stuff and so far it is working great for me, drastically less crashing than I used to do..

[Blair]

Where I saw the value was in the fact the "Voltmagic" (sorry I called it a Voltwatch before) records the highest load seen IN FLIGHT. I'm thinking an indication of the REAL load seen by the pack is more valuable than some arbitrary 1 amp load applied before the next flight.

Not only would the voltmagic indicate how much juice the heli was using in flight, but, how deep you drain the pack periodically during the flight. We all know discharging the pack below 6.9v is bad and that below 5.5v is terminal. I think it's important to know if your heli is seeing that during a flight. A preflight 1 amp load will not show that until the pack is almost totally drained. My concern is that overtime those large dips will add up and lead to premature pack failure.

Just some musings on a rainy day.

And no I am not associated with Voltmagic in any way, but I have used similar technology (BC-6) on nicads for years with excellent results.

Oh...need to be seen in flight isn't an issue for me. I can wait 10 minutes to look at it :lol:

"Blair"

[WillJames]

If you listen to your setup in a quiet room, youcan get all the info you need about how much binding you have. Not a big deal really unless you are using push pull linkge then you need to be more careful.

[Blair]

It's not the binding I'm worried about but actual flight loads when all the controls are working in high g maneuvers etc. I'm sure the pack is seeing more than a 1 amp load.

"Blair"

[Phaedrus]

It's not the binding I'm worried about but actual flight loads when all the controls are working in high g maneuvers etc. I'm sure the pack is seeing more than a 1 amp load.

"Blair"

Flight loads are not what many think they are. Fromeco wired up a Raptor 50. Take a look at this page. It shows a graph:

http://www.fromeco.org/Shop/aArizona%20reg.htm

Bottom line is they measured an average load of less than 2 amps and a couple of peaks (short lived) of nearly 4 amps.

On my R50 (all digitals 9255/9252/9456) I am getting an average current load of 1.8 amps.

More actual measurements are on this site as well:

http://graphics.tudelft.nl/~wouter/helipage/docs/servos.html

And few more data points:

http://www.airwolfrc.com/

One more comment. Emcotec wired up a 40% aerobatic plane that had 14 LARGE digital servos in it. They measure an average in flight load of 3.2 amps during hard 3D. They also got two 20 millisecond peaks of 20 amps. But those are so short that the system really does not react to them.