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Old Feb 21, 2013, 02:25 AM
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Dear Peter, thanks for your post

I tested the setup with these batteries because I don't have any other suitable
after 15~20 seconds of testing the batteries were just warm, which is logical.
That's why I will borrow from a friend a Turnigy 2650mAh 6S 40C pack for the first flights, in order to have a little better flying time and the battery in good condition

as for the "good batteries" you say, I don't think that Nano's are good batteries...
I have many of these and they never deliver their said C rating, even the 65-130C ones....
They also puff very quick in high load applications.

Yesterday I searched the HK webstore and ordered two Rhinos, which they never disappointed me in the past
http://www.hobbyking.com/hobbyking/s...poly_Pack.html
I will run them in series and they also will be a good replacement for my tired 2350mAh 20C for my Sebart Angel
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Old Feb 21, 2013, 05:54 AM
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I have never tried the Rhino... I probably should get at least one I guess.
I only have the Turnigy, Nano, Zippy and Compact. Nano's are the best out of those.
What seems to happen is that the lower IR of Nanos means whatever you use them in will run higher power than say those other three makes (for the exact same capacity and C). So then you actually need the higher C for it to cope.
Plus then the "Need 1.5x their claims" for lower/mid power setups, and "2.0x their ability claims" for high power setups. But it is not as simple and linear as that, that is just a rough guide... the higher power you go the X times grows exponentially.
They can do 0.75 or 0.5 what they say.... but will be dropping more and more volts as the load goes up.
Zippy and Compact are the worst.... so you have to test them and use them in setups that are suitable for them. Turnigy are a reasonable step better, and the Nano even better.
But ALL batteries come down to how you used (abused) them.... what heat you ever let them get to. Even just puffed ONCE is bad for them!

So you need to test things on the bench, then also in the plane (as it will drop power needs a bit), so you can KNOW 100% for sure what power use can cause what when flying - so you never cross into that overfly hot result. And also not to use higher powers after mid flight. (Unless you know you have overkill battery that will still be ok later in the flight).
Not if you want the batteries to last!
Once the chemicals have been very hot, they go 'mushy' and will never recover back to normal again. So you need to make sure you never got to that point!
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Old Feb 21, 2013, 05:57 AM
"Aircraftus Fragmentum"
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Quote:
Originally Posted by kakofonixx View Post
Dear Peter, thanks for your post

I tested the setup with these batteries because I don't have any other suitable
after 15~20 seconds of testing the batteries were just warm, which is logical.
That's why I will borrow from a friend a Turnigy 2650mAh 6S 40C pack for the first flights, in order to have a little better flying time and the battery in good condition

as for the "good batteries" you say, I don't think that Nano's are good batteries...
I have many of these and they never deliver their said C rating, even the 65-130C ones....
They also puff very quick in high load applications.

Yesterday I searched the HK webstore and ordered two Rhinos, which they never disappointed me in the past
http://www.hobbyking.com/hobbyking/s...poly_Pack.html
I will run them in series and they also will be a good replacement for my tired 2350mAh 20C for my Sebart Angel
Agreed - Rhinos are great.... just wish that HK would release some higher C ratings for the 4S and 6S big packs.......all Rhinos I have owned have been very robust and very long lived.
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Old Feb 21, 2013, 07:58 AM
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I have tried Turnigy, Nanos, Zippy and Rhinos.
By far Rhinos are the best of these, then Zippy and last the Nanos. I've never used Turnigy in high amp setups, so I don't have a solid experience.
Nanos never delivered their said C rating

I have 2 Nanos 2250mah 4S 65-130C for my beloved HK Stinger running on the Mercury alloy 4700kV fan, the draw is 72A peak

both of them puffed after ~10 flights! that's unacceptable...
do the math: 2250 x 65 = 146,25A current, 292,5A burst
the battery should come down cold, instead hot and puffed!
They sure have lots of power but I'm not sure if they can deliver it for more than 25~30 cycles

sorry for the off-topic posts...
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Old Feb 21, 2013, 09:28 PM
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Hehe, not quite right....

As mentioned, your 2250mAH 65C is ONLY that number result when fully charged. 2.250 x 65 = 146A
By 1500mA it is 1.500 x 65 = 97A
And lower and lower as it depletes.

The resultant heat/puffing depends on what YOU did during the flight.
If you used WOT after 50% depleted then it would be getting hot.
And also as mentioned, you need 1.5x the "capability" in lower/mid power systems, but in a 4S doing 72Amps that is high power so you want 2.0x really.
In a way I should call it "High Amps" not Power... but it is also relative to cell count. 72A at 6S is NOT high power compared to 4S 72A. So it is a bit more of a complex formula
Thus you want 72 x 2 = 144 Amps "capable"... which that 2250 is only capable off for... oh... 10 seconds or so! By then it will be 2000mA left and only 130A capable.
And getting worse and worse as it deplete... so any WOT use is more and more detrimental to it as the flight goes on.

Basically all you can do is FLY it... preferably TESTING it... by building up to find out what makes it too hot. And with a dose of knowledge on the TWO main things that will cause that....
1) A battery that never was up to its job anyway eg.. 2250 30C in that
2) The way you USED the battery as it capacity depleted.
Then you can work out if it was the wrong battery... or a 'poor' battery... or if even hat you asked of a 'correct' battery was too much, and totally normal and to be expected.

I would say that very few people really know much about Lipos, and electric power overall. They just buy something and throw it in and 'use' it... quite often abusing it. Knowingly or not.
"John said he does it"... so they buy the same.
But you can't even truly know exactly HOW John flew his (used the battery)... you can;t even know in your own from one flight to the next, without a lot of attention to exactly what you do over that whole flight - pretty hard to even do on purpose! Thus makes even testing a very difficult job, flying a plane. (much easier on the bench).

As a very rough and non-scientific report, you might say "I flew it with Nanos and they got hot, I flew it with Rhinos and they did not"... but it is subjective and prove to massive error margins... unknowns.
Even if you abused one battery ONCE you could have fatally flawed it, so from then on it is going to be lack lustre and could easily mislead your view.
So again, a dose of knowledge and also KNOWING what you did (which is hard to do unless you specifically went out with intention to take notes and record it), is required to form a true picture.
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Old Feb 22, 2013, 12:13 AM
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good point peter , i had not considered this .
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Old Feb 22, 2013, 01:04 AM
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Not that I know who knows what, but it seems a lot pf people don't know 'enough'.
Even if knowing it, you still need to make quite an effort and focus on things IF you wanted to know exactly what happened that flight. Most often you don't, or even don't fully remember or think about it - much. I guess I do tend to think about it most of the time... but I also fly on much larger batteries per plane than most people do, and come down at just 60% used on most. More so on EDF's, but some are too limited in space to do that, so those I will do detailed checks on how they do act and plan batteries appropriate to have it as easy as possible for them. (and not WOTting later on in flights).
And a few planes I just abuse the crap out of the batteries - usually only small sized, thus cheap. eg 3S, 4S small aircraft.

Those things mentioned earlier would likely be why there are so many cases of one person saying some battery (or even other things) is 'great' and another saying it is 'no good'. One abused them, even if unknowingly, and the other not.
There are definite battery differences, but if you want to truly know what is what it has to be done scientifically with proper tests and records... not just what you thought you did/saw, with no true references.
You might even have just had a non-typical one. Lots of possible reasons why it was worse, or better, in the results you saw versus most others.

I will have to check out the Rhino's. I have never even looked at them at all, their prices etc. I would guess/hope they could not be as lower end as Zippy's.
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Old Feb 22, 2013, 06:35 AM
TakeOff=optional,Landing= Must
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My build has slowly progressed and I'm just about finished.

Retracts are done.

Power plant (L2855-2300 motor/cs12 EDF) is dynamically balanced and installed.
Tonight I ran it up for a quick test using a new ZIPPY Compact 4000mAh 5S 25C Lipo, WOT ~60Amps 1050Watts. At 3/4 throttle, was ~30-40Amps 700-800Watts. After ~3 minutes mixed throttle bench flying, battery was just warm but the connectors were a bit hot possibly due to having too many connections with the watt meter, adapters ect.

Custom paint job (I've never liked the standard color scheme)

Just need to finalize battery COG placement & radio programming.

My old one (currently flying) weighs approx 950 grams (no battery) and has no landing gear. It does however have a thick coat of paint, lots of glue from repairs and a heavy RC Lander EDF.
This new one is approx 1100 grams (no battery) but will carry a slightly heavier 5S battery instead of 4S.
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Old Feb 22, 2013, 07:26 AM
Retreating Blade Stall
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Looks good FG1972
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Old Feb 22, 2013, 08:22 PM
Quest for Speed!!!
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Meteor in stock at grayson Yay!! ordered one now
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Old Feb 23, 2013, 03:02 AM
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Hmmm, I must have messed up my last post (it never made it).

Nice scheme FG ! Another one to ponder over for my 'one day will do it' second Meteor!! (in the box a year now???),
Are those HobbyKing generic decals? It looks like one of the few sets I grabbed from them, so that would work out well seeing I do not have any jet that looks anything like that quite 'generic/stereo-typical' US fighter. Err, well of the 50's, 60's.. some 90's? Aerobatic team a bit.

That is probably the best suited scheme for me too really!
Handy to see.....
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Old Feb 23, 2013, 05:19 AM
Quest for Speed!!!
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so any quick pointers?


stock electronics on 5 s 3000 mah with 100 amp esc with bec?


Mike
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Old Feb 23, 2013, 07:53 AM
TakeOff=optional,Landing= Must
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Thanks Arcturus and Peter.
They are indeed HobbyKing decals, the logo on the tail is something I just printed out on white paper.
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Old Feb 23, 2013, 08:45 AM
Retreating Blade Stall
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Originally Posted by Mike_eee View Post
so any quick pointers?


stock electronics on 5 s 3000 mah with 100 amp esc with bec?


Mike
Start off stock with 4S, be careful with 5S, have a well balanced fan first.

I burned up two stock motors on 5S. Stock ESC was fine. Others have had success with all stock and 5S.

I moved up to Tacon 2860-2550kv in runner and 80A dynam esc on 5S. I also removed landing gear and steering servo. That new motor is quite a bit heavier so had to shift battery far forward. For sure improved performance, qualitatively.

Also make sure your elevator has full range of movement and see if you can remove some linkage slop.
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Old Feb 23, 2013, 09:04 AM
Quest for Speed!!!
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Fremont,CA
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Quote:
Originally Posted by Arcturus97 View Post
Start off stock with 4S, be careful with 5S, have a well balanced fan first.

I burned up two stock motors on 5S. Stock ESC was fine. Others have had success with all stock and 5S.

I moved up to Tacon 2860-2550kv in runner and 80A dynam esc on 5S. I also removed landing gear and steering servo. That new motor is quite a bit heavier so had to shift battery far forward. For sure improved performance, qualitatively.

Also make sure your elevator has full range of movement and see if you can remove some linkage slop.

thanks for the advise..i have the motor fan setup from the habu foam version..will that work in this for 5 cell?

Mike
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