Battery Size for HBK2 w/3900kv Motor?  
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All Forums >> RC Helicopters >> Electric RC Helis >> Esky Helicopters >> Battery Size for HBK2 w/3900kv Motor?
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Battery Size for HBK2 w/3900kv Motor? - 6/27/2008 4:31:34 AM   
warpnine


 

Posts: 150
Joined: 6/11/2008
From: Reston, VA, USA
Status: offline 		I am in the process of upgrading my HBK2 to a 3900kv motor (with a new 25A ESC) and am planing to use a 10T pinion for it. (Stock main gear). I found something in this article ( http://www.the-radio-controlled-airplane.com/esky-honey-bee-king-2-necessary-upgrades.html ) that puzzles and concerns me:

"Supplied with the King 2 is a 1000mah Lipo. This will work fine with the 3900kv motor and 9t pinion. If you go up in pinion size, you will probably exceed its safe ability so don’t use it then."

I current have two of the stock 1000mah Li-Polymer batteries (although one is not made by Esky and looks to be better quality). I am replacing the original battery connectors with more heavy-duty Deans connectors. So why would the size of the battery I am using have anything to do with the number of teeth on the pinion, since I would not think that the one additional gear tooth would increase the load noticably? Any idea what the article's author means by exceeding its "safe ability"?

When I brought the helicopter I was advised not to go bigger than about a 1500mah battery , and wound up getting an identical spare so the balance would not be messed up each time I switched. Was this good advice? What is a reasonable sized battery for the HBK2?

I also don't understand the battery "C" rating. What does that mean?

Thanks for any information!
       Post #: 1

RE: Battery Size for HBK2 w/3900kv Motor? - 6/27/2008 5:19:45 AM   
DumbDawg



Posts: 591
Joined: 3/11/2008
From: Osoyoos, BC, CANADA
Status: offline

I have 22 and 2420Mah batteries... they work great. The 1000's are way to small and get very hot. C is amperage burst

happy fly'n

_____________________________

Something had better fly

(in reply to warpnine)
       Post #: 2

RE: Battery Size for HBK2 w/3900kv Motor? - 6/27/2008 12:06:06 PM   
funflier


 

Posts: 681
Joined: 11/29/2004
From: South City, CA, USA
Status: offline 		I run 2200 mah 20c batteries in mine. Actually improves the balance however due to the weight it handles a little slower but thats ok as I do mostly hovering in the yard. The 3900 motor doesnt draw a lot of amps so a 20C battery is fine, might want to move up on the ESC to a 30 amp and go with a 3rd party as the stock Esky is not all that dependable and does tend to run hot.

_____________________________

King ll, 3900 w/10t pin, cnc head, custom cnc/trex tail, 43t + upgrade, Telebee gyro, Dx6i TX w/6100e RX, HS-65 servos. etc.

(in reply to DumbDawg)
       Post #: 3

RE: Battery Size for HBK2 w/3900kv Motor? - 6/27/2008 8:25:16 PM   
crimsonrain22


 

Posts: 472
Joined: 5/10/2007
From: Martinsville, IN, USA
Status: offline 		I have been flying mine with stock batterys for over a year now with no problems. I have a total of 4 stock esky batterys on the 3900/10t combo with no problems so far.

_____________________________

If the wings are moving faster the the Fuselage its probably a helicopter and therefor unsafe.......

(in reply to funflier)
       Post #: 4

RE: Battery Size for HBK2 w/3900kv Motor? - 6/27/2008 8:51:39 PM   
Druss


 

Posts: 3656
Joined: 8/10/2007
From: Edmonton, AB, CANADA
Status: online 		I think a 1350 or 1500mah 20C pack would be best for the king2. The 2200's are a bit heavy and the 1000mah too short flight times. I've got a couple 1500mah that I use with my 3800kv motor and works well.

(in reply to crimsonrain22)
       Post #: 5

RE: Battery Size for HBK2 w/3900kv Motor? - 6/27/2008 9:20:00 PM   
kenhiraihnl



Posts: 401
Joined: 7/2/2005
From: Pearl City, HI, USA
Status: offline 		batteries get hot and puff when voltage drops and amps have to increase to maintain watts necessary to fly the heli (ohms law)...a high-c battery in the 1320 to 1500 range is light, and has the capacity for 4-5 minute flights - at which time my brain starts glitching, and it's time for me to land anyway...ken

_____________________________

Raptor50V2│Raptor30V2│Logo10-3D(stretch)│Logo10(stretch) │Esky HBK2 2.4 │Gaui 200 2.4 │Walkera 4#3 2.4

(in reply to Druss)
       Post #: 6

RE: Battery Size for HBK2 w/3900kv Motor? - 6/27/2008 10:45:58 PM   
Rosebud6


 

Posts: 327
Joined: 1/6/2008
From: Auburn Hills, MI, USA
Status: offline 		I fly 2 1500 15c and 2 2200 20c with the 3800 + 11t. 1500's are nice because they are light enough to give me the extra punch I will need when I do go inverted and the 2200 are nice for cruz flying. 2200's would prob be a bit heavy for 3d as I notice the extra weight just doing FFF.

(in reply to kenhiraihnl)
       Post #: 7

RE: Battery Size for HBK2 w/3900kv Motor? - 6/27/2008 11:01:12 PM   
USHobbySupply


 

Posts: 1399
Joined: 7/12/2006
From: Takoma Park, MD, USA
Status: offline 		I love the 1800's in my K2. Great power, flight time and balances just right!

Michael

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Michael Bernstein, President, USHobbySupply
Please PM me if i miss your question in a thread.

(in reply to Rosebud6)
       Post #: 8

RE: Battery Size for HBK2 w/3900kv Motor? - 6/28/2008 3:10:35 AM   
KCinNC



Posts: 402
Joined: 8/4/2007
From: LKN, NC, USA
Status: offline 		1500's are perfect for me

(in reply to USHobbySupply)
       Post #: 9

RE: Battery Size for HBK2 w/3900kv Motor? - 6/28/2008 3:46:25 AM   
Zimatosa


 

Posts: 616
Joined: 2/7/2008
From: San Jose, CA, USA
Status: offline 		I have been getting 8-10 minute flights out of my 2nd generation MegaPower(previously Mega Puffer) 1350 15C batteries. Are you sure that4-5 minutes is all you get Ken? i am running 10T at the moment with a Hyperion 3700(P-1913)

Z

_____________________________

Without deviation from the norm, progress is not possible.

(in reply to KCinNC)
       Post #: 10

RE: Battery Size for HBK2 w/3900kv Motor? - 6/28/2008 6:37:09 AM   
kenhiraihnl



Posts: 401
Joined: 7/2/2005
From: Pearl City, HI, USA
Status: offline 		hi z...nah, i probably get more, but i'm a boring flyer...hover out, 90-degree turn to the right, coupla left-hand circuits, coupla loops, coupla rolls, coupla stall turns, coupla slow pirouettes...same thing every damn time, over and over and over...actually, i find that if i don't mix it up, my brain gets stuck and i can't even hover tail-in...have you ever had that happen to you? ken

_____________________________

Raptor50V2│Raptor30V2│Logo10-3D(stretch)│Logo10(stretch) │Esky HBK2 2.4 │Gaui 200 2.4 │Walkera 4#3 2.4

(in reply to Zimatosa)
       Post #: 11

RE: Battery Size for HBK2 w/3900kv Motor? - 6/28/2008 8:59:58 PM   
Zimatosa


 

Posts: 616
Joined: 2/7/2008
From: San Jose, CA, USA
Status: offline 		I think you fly real good judging by your videos. The piloting skills you posses are what every pilot should be striving for, especially if they are going to make the jump to 3D. Although i am not interested in heli's on crack, I do love to do FFF and nice sweeping turns. You should do like i do when I feel like i am losing concentration and blanking out...I FFF nose in right toward my self. It raises the awareness and gets a good heartbeat going. The adrenaline then satisfies the mind and it feels new again! Hovering real close and/or directly overhead makes me happy too. I let my imagination run wild....One of my fav vids on youtube is the "rescue" of the lego figure. Some day I will try something like that....

Toy's R Us is callin'!

Peace,

Z

_____________________________

Without deviation from the norm, progress is not possible.

(in reply to kenhiraihnl)
       Post #: 12

RE: Battery Size for HBK2 w/3900kv Motor? - 6/29/2008 12:04:54 AM   
DumbDawg



Posts: 591
Joined: 3/11/2008
From: Osoyoos, BC, CANADA
Status: offline

Zim I love that vid too.. I've been try'n that with my Lama3 in the house on crappy outside days. Only I don't have any little men to rescue just yet but I try to land on things small,top of lamps, TV etc.... don't get nervous type of things and not in view of the wife...

But one day I shall have to get me a lego man or girl I'm not fussy, and try a rescue.

happy fly'n

_____________________________

Something had better fly

(in reply to Zimatosa)
       Post #: 13

RE: Battery Size for HBK2 w/3900kv Motor? - 6/29/2008 1:53:24 AM   
warpnine


 

Posts: 150
Joined: 6/11/2008
From: Reston, VA, USA
Status: offline 		I can borrow some lego men from my kids, but need to get the heli put back together and working - and learn to fly better - before I can try anything like that at all!

I ordered a 1800mah 20C high discharge battery ( http://www.ushobbysupply.com/product_info.php?cPath=25&products_id=634&osCsid=8a75fc935363757c3063020130d54fb0 ) and an Align Balance Charger - which is almost the "average" of everything you guys have suggested here.

While I was at it, I also ordered a Dx6i transmitter (with matching receiver) too - so now I'll have something else to figure out as part of my endless stream of upgrades! (Brushless motor, ESC, new tail drive pulley, new Logitech 2100T HH gyro and tail servo, and now the new transmitter and receiver - all from U.S. Hobby Supply). It should fly real nice once I can get everything upgraded and repaired - but is going to take me a while... I'm learning each task as I go - and sometimes get stuck longer than seems rational... Only took me two and a half weeks to replace the tail boom (I twisted the belt when I put it back together the first time)! At least there are lots of useful posts and videos to help!

Thanks everyone!

Dave

(in reply to DumbDawg)