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Old Jan 20, 2013, 08:35 PM
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United States, MO, St Charles
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My Gamma 370 Pro - Voltages/Battery/Filter..

My Gamma 370 Pro should be here late this week.
I am still having a hard time wrapping my head around a few things.
Mostly because there are numbers involved. I am one of those guys who can see code and plow right through it, but I get confused when numbers are given to me.

Anyways, I am going to ask my questions, if you could dumb it down for me that would be great.
Also, I will use my Gamma as the example, with the thinking that I can apply what you guys explain to me to future planes.

Battery - Includes two propeller options for use with 2S 7.4V or 3S 11.1V 800-1300mAh LiPo batteries
What determines the voltage? I assume that if I use a higher voltage I will cause problems, but how do they determine 7.4 or 11.1? (by the way, I understand what voltage and capacity means from reading this link)
Let's say I wanted to fly longer, is there a limit (whether it is weight or whatever) that I can't go to a higher capacity batter? Is there a determination on why that capacity was suggested? All of this applies to the Tx as well since i would like to put a lipo in the Tx at some point.
Charger - Can I just buy any charger for my batteries such as THIS? Or is there a determination on this as well?
Voltage Alarm - I would like to setup an alarm (for both my Tx and Rx) to let me know when voltage is low and I need to land. Is there a standard here, or is it based off of the specific battery. Again, how do you determine this?

Filter ADC: Sing, OSMP, FILT
Ok, I think I have part of this. Resolution is for the servo movement. The higher the resolution, the smaller the move of the servo? Higher resolution also results in more latency?
Why would I need the above, or is it a necassity? If it is needed, what do most people use and why? I would think the above three settings would be additional but do one of the three have to be on?

Slowly figuring this stuff out. Voltages and anything electrical are my problem points right now.
Ugh, and I just realized after looking over the features of my plane, I thought it came with a battery and charger, but I do not think it does, I think the RTF version does.

Hopefully I am flying a week or so after my stuff arrives
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Old Jan 20, 2013, 11:28 PM
trying to fly
Joined Dec 2012
29 Posts
1 lipo cell is 3.7v. Wired in series, you add up the voltage. 2S = 7.4v, 3S = 11.1v, etc. I think there are other important stat on a battery you should look in addition to capacity. Those are discharge rate (20C, 25C, etc) and weight. Probably something on the ESC too, but I don't really know what I'm talking about.
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Last edited by darvos; Jan 20, 2013 at 11:49 PM.
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Old Jan 21, 2013, 05:22 AM
An itch?. Scratch build.
eflightray's Avatar
South Wales U.K.
Joined Mar 2003
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"Let's say I wanted to fly longer,"
The easiest way is to take more batteries of the same size with you. Landing and taking-off are important parts of learning. Just about any beginner can keep a plane airborne for quite a while, few can land it where they want and not need repairs.
Going to a bigger capacity has some downsides, more weight, (extra to carry needing more power, + will it change the CG), bigger, (will it fit in the battery compartment).

"Charger - "
The one you link to is very similar to mine and is perfectly Ok. The slight downside is you need a supply for it, such as a car/leisure battery or a mains to DC supply, (check the specs).

"Filter ADC: Sing, OSMP, FILT"
I haven't a clue, my Tx isn't that fancy, (Spektrum Dx7), but still has just about everything I need and things I will probably never use.

Hope you ordered a 'wattmeter' as they are very very useful. They let you know watts, volts, and amps being drawn from the battery. Too much and that 'magic smoke' escapes and you're in to buying a replacement.

Timers etc, I would have thought your Tx has one built in.
Tx Lipo ?, I still use Nimh, trust them and know I have to charge before going flying, I'm happy with them.
Flying for a long time can get boring, you may be surprised just how long 10 minutes of flying feels like. Don't forget the landing practice.
Long flights is something for the future to decide on and may depend on what your next planes are.

Take it slow, don't try to learn too much and miss the fun side.
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Old Jan 21, 2013, 07:37 AM
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United States, MO, St Charles
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Thanks eflight, appreciate the response.

Hopefully someone else can take a look at my questions as well.
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Old Jan 21, 2013, 07:40 AM
buyer of the farm
United States, FL, DeLand
Joined Mar 2009
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Hey, I think "Filter ADC: Sing, OSMP, FILT" means that you have to change the motor oil every 60 hours. Use 0W-30 synthetic.
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Old Jan 21, 2013, 09:46 AM
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Willmar, Minnesota, United States
Joined Sep 2004
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you've got a FrSky transmitter? :
Filter ADC: (ADC is the 'analog to digital' converter... )
i. SING: Single conversion. This is the fastest conversion but base resolution is 1024.
ii. OSMP: Oversampling. This uses extra samples to increase resolution to 2048. Just slightly
slower than SING.
iii. FILT: Filtered. This is in case you have excessive noise from the conversion (servo jitters).
This will filter the input and prevent that noise. It will, however, increase latency by
~30msec.



don't worry, I've had to dumb down a lot of these so I can understand em
the resolution is very similar to the resolution for a tv or a computer monitor... simply put, think of the resolution as the total number of possible positions a servo can be commanded to ... with digital RC systems, the transmitter is not able to command a servo to go to ANY POSSIBLE position, it's only capable of commanding the servo to one of 1024 positions... (assuming it's set for 1024 resolution. if you consider the servo itself can only move 90 degrees of travel, those 1024 positions work out to less than one tenth of a degree each)
if you were using 2048 resolution, the transmitter would then have twice as many possible positions to where it could command a servo to move to. (it would have a much higher resolution)
latency: you can think of latency as the amount of time between moving a stick on the TX and when the servo actually moves to that newly commanded position.
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Old Jan 21, 2013, 04:26 PM
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United States, MO, St Charles
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Quote:
Originally Posted by Jim Buzzeo View Post
you've got a FrSky transmitter? :
Filter ADC: (ADC is the 'analog to digital' converter... )
i. SING: Single conversion. This is the fastest conversion but base resolution is 1024.
ii. OSMP: Oversampling. This uses extra samples to increase resolution to 2048. Just slightly
slower than SING.
iii. FILT: Filtered. This is in case you have excessive noise from the conversion (servo jitters).
This will filter the input and prevent that noise. It will, however, increase latency by
~30msec.
I have (in a few days) a Turnigy 9x.

Do people normally use one of the 3 settings?

Can anyone help with my other questions?
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Old Jan 21, 2013, 06:54 PM
Wake up, feel pulse, be happy!
C₄H₁₀'s Avatar
United States, AK, Fairbanks
Joined Aug 2009
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For the battery voltages, they include two props so that you can use a 2S (7.4V nominal, 8.4V full) or 3S (11.1V nominal, 12.6V full) lipo with the plane. The reason for the different props is that a higher input voltage will make the motor turn faster, so it'll draw more current for a given prop size. Motor current is a fairly hard limit, but you want to get as much power out of the motor as possible without overheating and wrecking it. Running lower voltage means you can use a bigger prop to get the same current draw. There are advantages and disadvantages to the bigger, slower prop and the smaller, faster prop.

The only limit to how big of a battery you can use (capacity-wise) is the weight and size of the thing. At some point, even if it fits inside the plane, the extra weight will start to noticeably affect how the plane flies. More weight means higher wing loading, which results in higher stall speed and maybe more difficult handling. A bigger-capacity battery may also have lower internal resistance, which will effectively result in a slight increase in RPMs and power at the motor.

For the transmitter, it's best to get a dedicated transmitter pack. A regular flight battery will degrade quickly over time if you leave it fully charged, but a transmitter battery has a very low output capability (and requirement), so it's more stable. Transmitters will normally have a built-in voltage display and often an audible alarm as well.

Voltage alarms on models are a little less useful since the battery voltage will sag by an unpredictable and often inconsistent amount in flight due to motor current draw. A better way to do it is just calculate a baseline flight time and then work from there, measuring the pack's resting voltage after each flight until it's in the ~3.70-3.85V/cell range, then just set a timer to let you know when to land.
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Old Jan 21, 2013, 07:33 PM
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Two more questions.

What is storage voltage?

Can anyone recommend a charger, specifically one that will stop charging when the battery is fully charged? The turnigy charger I originally linked to was what I was going to get based on price, but it will not beep or stop charging when battery is fully charged.
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Old Jan 21, 2013, 07:45 PM
Wake up, feel pulse, be happy!
C₄H₁₀'s Avatar
United States, AK, Fairbanks
Joined Aug 2009
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Quote:
What is storage voltage?
"Storage voltage" is the voltage that the pack should be at when you won't be using it for long periods of time (a week or more). Generally you want to store lipos around 3.80-3.85V/cell.

Quote:
Can anyone recommend a charger, specifically one that will stop charging when the battery is fully charged? The turnigy charger I originally linked to was what I was going to get based on price, but it will not beep or stop charging when battery is fully charged.
Where are you seeing this? I don't know of any lipo charger that will continue feeding power to a battery once a full charge is reached; this would be useless and extremely dangerous. A "balance charger", in fact, actually has to stop charging when full in order to balance the voltage of the cells.
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Old Jan 21, 2013, 07:51 PM
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Quote:
Originally Posted by C₄H₁₀ View Post
Where are you seeing this? I don't know of any lipo charger that will continue feeding power to a battery once a full charge is reached; this would be useless and extremely dangerous. A "balance charger", in fact, actually has to stop charging when full in order to balance the voltage of the cells.
I thought I saw it in the comments.
So for the charger here is the LINK

Sorry man, there's no voltage limit setting for nimh in this charger. only current limit. At least for the one I have here. And they're pretty recent, just December 2012. The ones without the calibration option.

Maybe I am confused then, there it said nimh and not lipo, but are the charging mechanisms different? i just assumed since there is no limit for nimh there would be none for lipo.
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Old Jan 22, 2013, 12:17 AM
trying to fly
Joined Dec 2012
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Quote:
Originally Posted by lardo5150 View Post
Can anyone recommend a charger, specifically one that will stop charging when the battery is fully charged? The turnigy charger I originally linked to was what I was going to get based on price, but it will not beep or stop charging when battery is fully charged.
I have that exact one ordered November 2012. I don't know about nimh, but It beeps and stops charging when a lipo is fully charged. It also has the calibration option.
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Old Jan 22, 2013, 09:15 AM
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yup, my (92 year old) Father has one of those chargers, yes it absolutely does stop charging the lipo pack when it's fully charged. I have not tried charging Nicad / NiMh batteries with it, but I would assume it at least goes into 'trickle charge' mode. (Nicad /Nimh batteries are nowhere near as critical for overcharging as Lipo's are.)
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Old Jan 22, 2013, 09:51 AM
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Lardo, I really think you are over thinking this. The Ares Gamma 370 line is built around the first time flier, and so no real analysis of wattage, rpm, or battery specifics is necessary. When I got my original Gamma 370, I just charged the battery and flew it. The smaller prop gave a little more speed, and the larger prop was really slow flying. As for the Gamma 370 Pro, same thing. The manual says, that the smaller prop is for an 11.1 volt battery the large for the 7.2. I basically just use the same batteries in the Pro that I use form my HZ Firebird Stratos and Super Cub. I just make sure that the 11.1v E-Flight battery isn't all the way forward in the battery compartment to keep the CG right. Charge the battery and go fly. It's as simple as that. I have a Dynamite Vision Ultra charger that I hook up to my car battery while I am at the field. It works like a charm.
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Old Jan 23, 2013, 07:44 AM
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United States, MO, St Charles
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Ya, I am. I know it to.
I think it has to do more with I am trying to learn this hobby in 5 minutes
I have always been like that though.

Everything should be here by the weekend. I will have the wife record when I try her out.
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