3DHS 48" vyper

[jamief1777]

Hi GYRO,

Here is the battery data I wanted to compare with your Glacier batteries:

Here is what the Icharger measures for internal impedance of the new 4S 35C Nano-techs I am using for the 48" Vyper measured at 13C. (55.4F). Measured at storage V (3.85v).
These batteries only have 3-4 cycles on them so far.

cell 1,2,3,4,Total:
Battery 1: 10,9,11,9, 39 mOhm total.
Battery 2: 9,9,12,9, 39 mOhm total
Battery 3: 9,10,13,12, 44 mOhm total
Battery 4: 10,9,12,10, 41 mOhm total.

my 3 new 25C 3S Rhino's (for the SHP) have the following impedances at 13C. (conventional LiPo's).
Battery1: 25,24,27, 76 mOhm total
Battery2: 24,25,24, 73 mOhm total
Battery3: 26,24,27, 77 mOhm total.


My "good" 6S nano-tech reads: 8,6,10,10,11,13 = 58 mOhm at 15C.
The one with the weak cell reads: 12,18,14,14,13,16 = 87 mOhm at 15C. (18mOhm is weak cell).

What do you see for internal impedances on the 4S 35C Glaciers?

 

[gyro]

Hi GYRO,

Here is the battery data I wanted to compare with your Glacier batteries:

Here is what the Icharger measures for internal impedance of the new 4S 35C Nano-techs I am using for the 48" Vyper measured at 13C. (55.4F). Measured at storage V (3.85v).
These batteries only have 3-4 cycles on them so far.

cell 1,2,3,4,Total:
Battery 1: 10,9,11,9, 39 mOhm total.
Battery 2: 9,9,12,9, 39 mOhm total
Battery 3: 9,10,13,12, 44 mOhm total
Battery 4: 10,9,12,10, 41 mOhm total.

my 3 new 25C 3S Rhino's (for the SHP) have the following impedances at 13C. (conventional LiPo's).
Battery1: 25,24,27, 76 mOhm total
Battery2: 24,25,24, 73 mOhm total
Battery3: 26,24,27, 77 mOhm total.


My "good" 6S nano-tech reads: 8,6,10,10,11,13 = 58 mOhm at 15C.
The one with the weak cell reads: 12,18,14,14,13,16 = 87 mOhm at 15C. (18mOhm is weak cell).

What do you see for internal impedances on the 4S 35C Glaciers?

My records are based on the readings after a charge cycle, when my batteries are full up and ready for the field, and my house is about 70F. I don't have any 4s batteries currently, but my 6 cell's total pack resistance is on average 18-24mHom

In my opinion, you get what you pay for with batteries. While you compared getting 4 nanos for the price of 3 glaciers, try comparing how many glaciers you'd get for the same number of Thunderpowers! The glaciers have actually outperformed the thunderpowers in a published test I read on RCG.

 

[SnowDog]

Hi Gyro & SnowDog,

Thanks for the advice on LiPo brands! I may have to try the Glacier batteries when I need new 4S (Vyper) or 3S (SHP) ones. The Nano-tech 4S 35C's are 4 for $88 from the US warehouse. The Glaciers are 3 for $100.
They have to be good if you are paying 50% more for them than nano-tech's. Go measure the m-ohms of one of them after charging and let me know what you get on each cell. Also tell me the temperature you measured them at and I will try to compare them with the new nano-tech 4S 35C set I just started using.


We have a fellow in our club that races I think 3 or 3.3.Ah nanotech 4S cells and he says that if you always bring them back to storage voltage (3.85V) after flying them that they will not puff, assuming that they are adequately cooled during flying. I will see if that is true or not.. I'm a bit skeptical, but I will try to not leave the new nanotech's at 4.2v for a week or two like I used to do.. I need to research 6S cells more.. They are so expensive..

What advice can you give on learning KE flight? I tried a couple days ago but I think I was on low rates and I neeed to be on full rates to get more rudder deflection. I just got my realflight 7 upgrade in the mail and found some good planes on it that KE pretty easily compared to my old realflight 5.5.

Regarding battery brands, I can only share what I've experienced. Compare the cost vs. lifetime of the batteries and report back with what you find...I'd be interested to find out.

Regarding KE I think the first about KE is to make sure your plane is balanced neutral...if it is too tail/nose heavy, that will make the plane tuck to the gear/canopy in KE. I'm surprised to hear that you think you need more rudder to KE...with the huge rudder on the Vyper, I find that I require very little rudder to KE. What happens to your Vyper when you attempt to enter KE flight?

 

[jamief1777]

Gyro
I charged up a 35C 4S nanotech pack at 70F. and see 5,5,7,5 total 22mOhm for the pack. If you are seeing 3 to 4 mOhm per cell on the Glacier packs that is impressive. If they last longer and don't puff, it may be worth an extra 50% of the nanotech price, especially if they don't puff in the hot summer.

 

[jamief1777]

SnowDog,
I' just measured my rudder throw. On low rates, the throws are only 1 3/4" in each direction as measured near the top of the rudder. Full rates are about 3" each way.. (1 cm from touching elevator). Should 1 3/4" be enough on low rates or should I increase to maybe 2.25"? I've only tried KE once a couple days ago two mistakes high. It was too sloppy to see if it pulled towards gear or canopy. I will have to try it again next time I go to the field. I am not used to full rates so I was trying the KE with low rates..

 

[jamief1777]

I took a few more measurements on my 48" Vyper. All-up weight w 2.2aH 4S battery: 52.5oz. w/o battery: 43.7oz. (I had to add nose weight after choosing push-pull rudder servo placement.)

I have moved CG about 1/8" more forward than the 110mm sport/pattern recommendation from the manual.
This was a recommendation of someone who helped me trim it out for more sports/pattern flying..

Its easy to fly pattern this way, but may be affecting KE. I can try to move the battery back to get to 110mm again. If it is pulling to canopy (which I suspect from having a forward CG), can I just leave it that way and just add a rudder to elevator mix to neutralize it, or is it better to learn to fly with a more rearward CG?

I can get someone to help me look at which way it pulls from a vertical downline also. I think that is part of how you tell if the CG is neutral, right?

 

[SnowDog]

SnowDog,
I' just measured my rudder throw. On low rates, the throws are only 1 3/4" in each direction as measured near the top of the rudder. Full rates are about 3" each way.. (1 cm from touching elevator). Should 1 3/4" be enough on low rates or should I increase to maybe 2.25"? I've only tried KE once a couple days ago two mistakes high. It was too sloppy to see if it pulled towards gear or canopy. I will have to try it again next time I go to the field. I am not used to full rates so I was trying the KE with low rates..

I'll have to go and check mine at some point. I would think KE on your low rates should be just fine and very doable.

When you say "sloppy" what do you mean? What happened when you tried to enter KE flight? What happens in RealFlight when you try to do KE? Which version of RealFlight do you have?

 

[Yowzilla]

I have been all over the map with lipos over the years but found a brand that is rock solid. I fly 600 size helis and a battery was being pushed on ReadyHeli so I tried one of the 10S 4400 mah Thor's almost two years ago. Measured with a 308Duo the mOhm's are still below 7 per cell after 50 plus cycles. Ever since then I have only bought Thor. When they are new they are between 2 - 3 mOhm each cell. I now have 4 3S; 2 2s; and two of the big boys 10S. One more thing, most of mine fly in Helis where I run high head speed constantly. But now have an Addiction X that gets to see the 3S ones.

But as expected they are pricy and I only keep mine at 3.86v / cell until I fly and back to 3.86v when done flying. The chemistry of these batteries breaks down above or below the happy spot of 3.86 vols, so minimize the time below and above and they will keep their capacity and resistance longer.

I did crash my Addiction X with a 3S Thor taking a hit from the motor shaft on the end. It exposed a thin aluminum box on the outside of the battery. I believe this is how they stay so square without any sign of puffiness.

 

[jamief1777]

Hey SnowDog,
The KE on Realflight is fairly easy to do using high rates. I still dork it in after a couple minutes of flying back and forth, but it is getting easier. I like the Yak-54 (ED), and PAU 36% Edge 540 in RF7. The next time I go to the field, I will set the CG a littler further back so it will be a bit more toward neutral and it may make it KE better. I will leave the rudder low rate at 1 3/4" with 75% expo's as it is and try it again.

 

[jamief1777]

Yowzilla,
Thanks for your inputs on LiPo brands. The Thor's seem to be out of stock but are about the same prices as the Glacier's. What you said about keeping the batteries at storage voltage except for right before you fly is what the racing guy at our field said. He charges batteries on the way to the field. I charge my set a couple hours before driving to the field and back to storage voltage when all done.