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Old Jan 03, 2007, 11:56 AM
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Montrose Co
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Here is the pac 15c 2100 Mah 31 amp 42 burst. I will try the 11x 5.5 prop. , but the watt meter says only 300 watts with the 12x 6 prop and 30 amps. It used like 400mah on the 30 second test.Seemed like alot. Must be a 15c , not a 10c My bad.
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Last edited by Dragon 2; Jan 03, 2007 at 12:06 PM.
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Old Jan 03, 2007, 12:13 PM
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Airdrie, AB Canada
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400mah in 30 seconds requires 48A of current. Doubful that your motor is pulling that. If the pack is 31A-42A it is a 15C 20C pack.

But it sounds like the pack is more hype then capable. It may get a little stronger after a few charges if you had treated it gently (break-in). The himax on 2100mah packs and a large prop is going to push them. Much less than the EVO's or Extreme's and you will need pretty solid throttle management. Overrated packs just won't cut it.

300w is still decent power on the plane hopefully ~150w/lb. But if you're tagging lvc you are stressing your batts and they won't last long. 30 seconds is a very long burst for 3D type flight. For pattern/sport if you are going to stay at WOT long you need to prop down or use larger or stronger packs.

Mike
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Old Jan 03, 2007, 12:19 PM
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Montrose Co
Joined Aug 2005
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I'm going to try a 11x 5.5 prop now and see if that helps.I hate to think these packs are over rated as I have been using them on other planes with no problems!! Thanks for the info.
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Old Jan 03, 2007, 12:25 PM
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Airdrie, AB Canada
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Just saw your pack. My understanding of commonsense packs is that they try and be reasonably conservative in their ratings. Unfortunately just because it will run at 30A and not blow up doesn't mean it will hold high voltage there.

Pretty obvious if you're only getting 300w exactly what the pack is capable of as it is the primary limit in that system.

Is your lvc a little high by any chance? Alternatively you can choose to just lower it and take the reduced pack life as it comes at you. Not the end of the world if things don't overheat no biggee. But it will definately reduce pack life. Or be a little easier on the throttle.

Always a trade off. But the choices are simple.

Good luck,

Mike
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Old Jan 03, 2007, 12:45 PM
Fly Fly Fly Crash
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Montrose Co
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Well I went out to try the 11 x5.5 and thats what was on there. I then put on the 12 X6 and the watts went to around 400 and the amps to over 32 I watched the volts and they dropped quickly to like 9.7 . I didnt keep the throttle up very long . I didnt want to ruin the battery. Should I fly with the bigger prop and just manage the throttel or go even smaller than the 11X 5.5. remember I'm at 6000 ft above sea level.Please be paitent as I'm still on the learning curve.
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Old Jan 03, 2007, 01:02 PM
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Portugal
Joined Mar 2004
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Dragon,
your 400w figure didn't seem correct to me:

400W/32A=12.5V under charge

The pack must be VERY good to sustain 12,5V. My charger only charge a 3s pack till 12,6V, then the voltage sag a bit after disconnecting the pack.

more data please.
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Old Jan 03, 2007, 01:05 PM
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Montrose Co
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My LVC is what came on it. Its a castle Creations 45 amp.
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Old Jan 03, 2007, 01:23 PM
Fly Fly Fly Crash
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Montrose Co
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This is all new to me , but my MPI watt meter says 12.42 after full charge.I just did a test with the 12x6 prop. It went to 385 watts 32 amps for about 25 seconds at full throttle and cut off. The volts went down to 9.38 when it shut off. It said I used 270 mah. I have been told my meter is not correct as it should read 12.6 at full charge. I have 7 lipos that all read 12.42 at full charge.I'm letting the battery fully cool then will recharge it and try again with a 11 x 5.5 prop.
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Old Jan 03, 2007, 01:31 PM
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Portugal
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Try to reduce the LVC of the phoenix to 9V (3V per cell)

It seems your lipos can't withstand the current pulled by the himax with a 12x6.

If your Himax is the 1130rpm/V, everybody is using the APCe11x5.5 with good results
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Old Jan 03, 2007, 01:34 PM
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Montrose Co
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Thats the prop (11 x5.5 ) that it shut down with in flight yesterday. Does the altitude effect it? I will try lowering the LVC , but would hate to reduce the life of the pac. New test with the 11x 5.5 to follow.
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Old Jan 03, 2007, 03:22 PM
Fly Fly Fly Crash
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Montrose Co
Joined Aug 2005
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Last test. I think the battery is getiing stronger with a few charges under its belt.This test was with the 11 x 5.5 prop and it ran 315 watts at 29.5 amps and dropped to 9.7 vollts and didnt shut off after at least 30 seconds. It used 301 Mah. The problem may have been the new battery hadnt got to full strength. I guess I should use this prop. thanks for all the input. RB
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Last edited by Dragon 2; Jan 03, 2007 at 05:45 PM.
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Old Jan 03, 2007, 03:50 PM
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EDIT: Problem solved...
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Last edited by jalves; Jan 03, 2007 at 06:25 PM.
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Old Jan 03, 2007, 05:44 PM
Fly Fly Fly Crash
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Montrose Co
Joined Aug 2005
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I'm sorry it 9.7 volts not 7.9 Its been a long couple of days.Does that sound better. It didnt kick off and seems to pull like a horse.
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Old Jan 03, 2007, 06:27 PM
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Portugal
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Glad all is solved

Enjoy the plane, it is very good.

I am recovering mine, should be flying again next weekend.
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Old Jan 03, 2007, 06:33 PM
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Quote:
Originally Posted by Dragon 2
Sorry to hear about your loss.The other guy ran away because he thought it was his fault and didnt want to have to pay. On a brighter note I got to maiden my AM today at our clubs chilli fly. It flew perfect with no trimming needed at all. I was totally impressed. It was 28 degrees, but sunny. Happy New year to all
Yeah, that thing flies like a champ. Here's some pic's.
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