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Old Aug 08, 2008, 04:35 AM
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GeorgeC's Avatar
Perth, Tasmania, Australia
Joined May 2000
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Hacker B40-5L 4.4:1 LiPo question

I have a Hacker B40-5L (carbon) 4.4:1 in my 2m Organic. I am currently using a 14x9.5 with GP2200's. I am looking to move to LiPo and have been told that 2S is the maximum. I have tested this on a Hyperion 2S 3300 but I am only able to draw around 40A. Volts drop quickly to about 6.4 and only 270W.

I read reports of people with the same battery but using 15X8 drawing 100A! Does anyone have any experience with this set up?

George
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Old Aug 08, 2008, 04:42 AM
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Woodstock 1's Avatar
Ireland, County Kerry, Kerry
Joined Dec 2005
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Hi George

How many GP cells are/were you using?
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Old Aug 08, 2008, 06:29 AM
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GeorgeC's Avatar
Perth, Tasmania, Australia
Joined May 2000
354 Posts
Quote:
Originally Posted by cvanscho
Hi George

How many GP cells are/were you using?
Hi Chris,
Sorry, I should have said 7 cells (this complied with the 7 cell LMR competition). I am now restricted to 6600mAh for LiPo which is 2S 3300 or 3S 2200 etc.
I was advised by Hacker USA that 2S was the limit for the B40-5L.

George
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Old Aug 08, 2008, 06:34 AM
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CV580drvr's Avatar
Sink City, USA
Joined Oct 2007
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George...just to clarify something here.

2S 3300 is still 3300ma. 3S 2200ma is still 2200ma. A series connected battery does not increase the "capacity"....only the voltage.

Paralleling cells is another story. Voltage remains the same, and capacity increases.

That said...

You might get more feedback to your question by posting it in the "High Performance" section above. I'm sure somebody there can help you make your Hacker glow cherry red!
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Old Aug 08, 2008, 06:35 AM
RIP Ric
Andy W's Avatar
Marietta, GA
Joined Jun 1999
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No, you can run 2s 6600mAh. The mAh is the cell capacity, doesn't matter how many you have in series (although, in the case of 7-cell LMR, you're limited to 2s LiPo)..

I use 2s Neu 4900's - which is a little lighter than 7-cell 2200 - and just a tad over 100A for the 45s task. They must be warmed up before the flight, however, for peak performance.
..a
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Old Aug 08, 2008, 07:17 AM
working to the closest cm
jirvin_4505's Avatar
brisbane australia
Joined Nov 2002
2,127 Posts
Quote:
Originally Posted by GeorgeC
I have a Hacker B40-5L (carbon) 4.4:1 in my 2m Organic. I am currently using a 14x9.5 with GP2200's. I am looking to move to LiPo and have been told that 2S is the maximum. I have tested this on a Hyperion 2S 3300 but I am only able to draw around 40A. Volts drop quickly to about 6.4 and only 270W.

I read reports of people with the same battery but using 15X8 drawing 100A! Does anyone have any experience with this set up?

George
George I am doing some figuring for the Aussi LEG rules (6600 ie 2x3300mah ...3x2200mah etc)

I have the carbon 5l hacker on the bigger g/box 6.?/1

got if off rcgroups from ClayH

Testing with 17x13 rfm prop .. you will have to work backwards from this for your props
Tested the rfm 17x13 on the rfm prop hub (38mm yoke?) with the master 105 controller

firstly 2s with my 2500 neu 30/60 pack 97/102 amps 4400/4700 rpm

3s 5000mah 30/60 neu pack =====> prop flew off - doh!!!!
retest...
175/180 amps 5200/5700 rpm give or take a few, little difficult doing
all this on my own and keeping the bursts down to 3 seconds. 17x13 looks like
too much prop for leg 3s 2200 cells?

temps after 3s 5000 tests 4 bursts of 3 seconds in quick succession..
Motor 43 degree C and controller 41 degree c.

Although the 3s tests are way outside the controller and motor
recomendations and will be outside a 3s 2200 batteries ability
it did show what was possible

>warm battery.. I am finding out about this now that winter has hit QLD. I am using neu 2s 3300 cells driving a hyperion z3025/6 at 70-80amps and find that i have to warm up the batteries so that the LVC doesn't prematurly cut in on my hyperion opto 80 controller.

cheers Jeff
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Old Aug 08, 2008, 09:29 AM
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Ed Franz's Avatar
USA, KY, Burlington
Joined Sep 2001
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Quote:
Originally Posted by Andy W
No, you can run 2s 6600mAh. The mAh is the cell capacity, doesn't matter how many you have in series (although, in the case of 7-cell LMR, you're limited to 2s LiPo)..

I use 2s Neu 4900's - which is a little lighter than 7-cell 2200 - and just a tad over 100A for the 45s task. They must be warmed up before the flight, however, for peak performance.
..a

Andy, you sure about that? I read the rules differently, this is from the rules LEG rule book:

LiPo cells up to 6600 cell-mAH max

Li Ion cells up to 10000 cell-mAH max

The maximum Cell-mAH of a flight pack is found be multiplying the number of individual cells in the pack by their rated capacity. This must be below the limits shown above.

Some examples of valid packs are:

2S 3300, 2S 3200 mAH Lipo
3S 2200, 3S 2170 mAH Lipo
4S 1600, 4S 1500 mAH Lipo
5S 1200 mAH LiPo
4S 2300 mAH Li Ion (A123 cells)
7 * GP 3700, GP 2200, IB 4200 (or any other) NiMh
6 * any NiMH cells

Or, are we talking a different event?

Ed
www.commonsenserc.com
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Old Aug 08, 2008, 11:09 AM
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Andy W's Avatar
Marietta, GA
Joined Jun 1999
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OK, they have their own rules, sorry. 7-cell sailplane (Class A over here) AMA event has been modified to "8.4V nominal" which is 2s lipo, of ANY capacity.
..a
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Old Aug 08, 2008, 10:40 PM
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GeorgeC's Avatar
Perth, Tasmania, Australia
Joined May 2000
354 Posts
Hi all,
Thanks for the replies. Just to clarify, the 6600mAh is a "nominal" figure used to limit LiPo use in our local LEG competition. In the same way 7 cell was used previously. i.e. it is the product of multiplying the #cells by the capacity and is limited to a maximum of 6600 (2x3300, 3x2200 etc). I am still a little perplexed as to why I only get 40A?

George
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Old Aug 08, 2008, 10:50 PM
working to the closest cm
jirvin_4505's Avatar
brisbane australia
Joined Nov 2002
2,127 Posts
>I am still a little perplexed as to why I only get 40A?

Temp of the 2s pack prior to testing? - Was it cold - are we talking Tasmania here, only 100NM from the South Pole and it is winter?

What amps and volts did you get with 14x9.5 with GP2200'
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Old Aug 09, 2008, 12:03 AM
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GeorgeC's Avatar
Perth, Tasmania, Australia
Joined May 2000
354 Posts
Quote:
Originally Posted by jirvin_4505
>I am still a little perplexed as to why I only get 40A?

Temp of the 2s pack prior to testing? - Was it cold - are we talking Tasmania here, only 100NM from the South Pole and it is winter?

What amps and volts did you get with 14x9.5 with GP2200'
Jeff,
Yes it is cold here in Tassie .We struggle to find thermals in our AEFA LEG events (unless they are the ones we are wearing ). I don't really have anything to test the LiPo temp (maybe if I tape my sensor to the pack?)

I'll set up the GP2200's again and do a test (I usually charge at 4.5A to get some heat in them first). I'll report back tomorrow.

George
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Old Aug 09, 2008, 02:29 AM
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CV580drvr's Avatar
Sink City, USA
Joined Oct 2007
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Jirvin...

Innocent bystander here in the Arc welder forum but...

Unless you're loading your system the same....you can't deliver the same amperage. You're running 40A....they're running 100+. It's not battery temp.

Crank up the prop size until stuff starts burning...then you'll be there.
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Old Aug 10, 2008, 03:24 AM
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GeorgeC's Avatar
Perth, Tasmania, Australia
Joined May 2000
354 Posts
Quote:
Originally Posted by CV580drvr
Jirvin...

Innocent bystander here in the Arc welder forum but...

Unless you're loading your system the same....you can't deliver the same amperage. You're running 40A....they're running 100+. It's not battery temp.

Crank up the prop size until stuff starts burning...then you'll be there.
I agree that cranking up the prop size will increase the amps but we should be comparing apples with apples. I am comparing my 14x9.5 getting 40A on a 2S3300 LiPo with their 100A on a 15x8.

My readings using 7xGP2200 charged at 4.4A

Prop 15 x 9.5
Charge finish temp 27degrees C
Volts 6.7
Amps 77
Watts 516
RPM 5730

Prop 14 x 9.5
Charge finish temp 27degrees C
Volts 6.84
Amps 69
Watts 469
RPM 6060

My test with Hyperion LVX3300 2S

Prop 15 x 9.5
Charge temp 15degrees C
Volts 6.5
Amps 55
Watts 360
RPM 5025

Prop 14 x 9.5
Charge temp ?
Volts 6.33
Amps 39
Watts 252
RPM 4500

Strangely Electricalc estimates 120A for the 2S and 14 x 9.5 setup and 103A for 7xGP2200.

I'm still at a loss.

George
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Old Aug 10, 2008, 05:36 AM
turn, turn, turn.
Athol, Massachusetts
Joined Oct 2005
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Maybe the motor is mislabeled.
Are your batteries 40-50 C?

I am perplexed as well. You should be drawing more current.
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Old Aug 10, 2008, 05:55 AM
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GeorgeC's Avatar
Perth, Tasmania, Australia
Joined May 2000
354 Posts
Quote:
Originally Posted by kkens4
Maybe the motor is mislabeled.
Are your batteries 40-50 C?

I am perplexed as well. You should be drawing more current.
I can't see the motor as being mislabeled - I bought them new.
Battery is 25-40C (40C short burst)

George
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