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Old Mar 08, 2013, 12:51 PM
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United States, FL, Apopka
Joined Feb 2013
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Near death experience for my EF Edge EXP 60 - thoughts for separate BEC power supply?

Hello, first time poster, long time lurker... most everything I've ever needed already had a thread with the answer I was looking for, thank you all for that.

Today I had a battery ejection straight through the canopy of my Extreme Flight Edge 60" while parachuting inverted about 300' up. Needless to say without the batt, the plane went completely dead and I braced for the worst.

Somehow it just held an inverted elevator the whole way down and fell into some high grass without a scratch (beyond where the batt punched through the canopy of course). I've counted my blessings on that for sure, no one at the field could believe there was literally zero damage from impact.

I use industrial strength velcro and a seat-belt, so it really shouldn't have come loose, must have just pulled too hard.

I now think I'd like to use a separate batt on my CC BEC for safety in this type of event, any thoughts on how many mah I would need minimum for 20 minutes of flight time with 4 HS-255mg and a reciever, would 350-400mah be enough for a few flights?

Looking to keep it light, but with what could have happened today I feel a few extra grams is worth it.
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Old Mar 08, 2013, 12:55 PM
Addicted to 3DHS and EF
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ohio
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Best solution is to just secure the battery down better. Make sure you put velcrow on the battery tray and then use two heavy duty straps to hold the battery. You will never throw one again.
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Old Mar 08, 2013, 01:03 PM
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Ah, guess I was over thinking it.

Thank you. I'll scale up the number of velcro straps.
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Old Mar 08, 2013, 01:08 PM
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ohio
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Originally Posted by midislacker View Post
Ah, guess I was over thinking it.

Thank you. I'll scale up the number of velcro straps.
I have a 51 slick I learned this lesson with, though thankfully I did not eject the battery. I was flying doing full throttle KE spin and when I flattened out my plane was not flying right at all. I managed to land it to find my battery was loose in the plane and about to unplug itself. Ever since then I have thrown out the straps that come with these ARF's and buy some thicker ones at the store and use two. Problem has since been solved.
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Old Mar 08, 2013, 02:54 PM
KJ4WFG
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United States, SC, York
Joined Dec 2007
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I'm a fan of using a separate 2S for the voltage regulator. The VR gets down rated when it's got a 6S feeding it, so I just run a separate 2S feeding the VR running the Rx and servos. I get 4 flights on a 460 mAh 2S on a 48" EXP with ATX 94809 servos all around. I'd jump up to 1000 mAh or so 2S on a 60" with larger servos. If you're going to go to the trouble to run a separate VR (which is a great idea), then you're not adding much weight with a small 2S plus it gives you one more degree of adjustment on fine tuning the CG. Just my $0.02 ....... Bob R.
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Old Mar 08, 2013, 06:41 PM
Addicted to 3DHS and EF
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ohio
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Originally Posted by modbuilder View Post
I'm a fan of using a separate 2S for the voltage regulator. The VR gets down rated when it's got a 6S feeding it, so I just run a separate 2S feeding the VR running the Rx and servos. I get 4 flights on a 460 mAh 2S on a 48" EXP with ATX 94809 servos all around. I'd jump up to 1000 mAh or so 2S on a 60" with larger servos. If you're going to go to the trouble to run a separate VR (which is a great idea), then you're not adding much weight with a small 2S plus it gives you one more degree of adjustment on fine tuning the CG. Just my $0.02 ....... Bob R.
A separate battery in a 48'' plane is too much extra weight and not needed. In a 60'' range a separate battery would not be that bad, but it still is not really needed until the 30cc size.
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Old Mar 08, 2013, 06:51 PM
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United States, MN, Minneapolis
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I use these battery straps in my EF planes. I have velcro on the battery tray, and another piece on my battery, plus two to three straps on the battery. The MXS can pull 15-16 gs coming out of a blender, and on a 4000 mah battery, you need to hold that battery back.
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Old Mar 08, 2013, 06:52 PM
KJ4WFG
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United States, SC, York
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Quote:
Originally Posted by 3Daddict View Post
A separate battery in a 48'' plane is too much extra weight and not needed.
I fly the 460 mAh 2S in a EF 48" MXS, a Vanquish MkII, and an Edge. Have flown them with and without before I converted them all over to separate VR with 2S, and I can't tell the difference.
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Old Mar 08, 2013, 06:54 PM
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Originally Posted by modbuilder View Post
The VR gets down rated when it's got a 6S feeding it, so I just run a separate 2S feeding the VR running the Rx and servos. I get 4 flights on a 460 mAh 2S on a 48" EXP with ATX 94809 servos all around.
Which voltage regulator are you talking about? The Airboss 80's internal BEC does not get downrated when running on 6S from what I know, and as far as I can tell they are not using a linear voltage regulator, so the old rules of thumb for linear voltage regulators don't necessarily apply to switching regulators.
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Old Mar 08, 2013, 07:00 PM
KJ4WFG
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United States, SC, York
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Originally Posted by modbuilder View Post
I fly the 460 mAh 2S in a EF 48" MXS, a Vanquish MkII, and an Edge. Have flown them with and without before I converted them all over to separate VR with 2S, and I can't tell the difference.
Am traveling, so don't have all my data handy, but I think we're talking about adding one ounce to a 4.5 lb plane, or about 1.3% weight increase for the separate battery in a 48" EXP
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Old Mar 08, 2013, 07:18 PM
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United States, FL, Apopka
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Originally Posted by LoneWolfRC View Post
I use these battery straps in my EF planes.
Thank you Wolf, I just ordered a set of these which will arive the same day as the new canopy. With any luck, this will be the last of such issues.

Best,
MS
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Old Mar 08, 2013, 07:20 PM
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Originally Posted by midislacker View Post
Thank you Wolf, I just ordered a set of these which will arive the same day as the new canopy. With any luck, this will be the last of such issues.

Best,
MS
No problem. Better double check the length you need...they come in 12" and 18"...
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Old Mar 08, 2013, 07:29 PM
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Originally Posted by modbuilder View Post
I get 4 flights on a 460 mAh 2S on a 48" EXP with ATX 94809 servos all around.
Thank you Bob, this is good to know, and directly answers my question. I have two 370mah 2s lying around, so If I could get two flights each out of those I would cover the 4 6s batts I have with an added 26 grams.

I'm going to see how the new heavy duty straps I ordered feel and if I have any doubts I can keep this as an option.

Thanks all for the quick replies, it's greatly appreciated.

Best,
MS
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Old Mar 11, 2013, 06:32 PM
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Australia, WA, Kalamunda
Joined Jan 2008
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I run a sperate BEC(CC 10amp) on ALL my planes as they don't weigh very much,from memory they are like 20grams and for me i know I can have just about any power failure and get the ship safely on the ground without thinking I may need a garbage bag.

Only my 2cents
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Old Mar 11, 2013, 07:16 PM
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Originally Posted by 1st timer View Post
I run a sperate BEC(CC 10amp) on ALL my planes as they don't weigh very much.
I agree with this completely and use a CC bec as well, but currently it uses the primary battery for power... When the battery ejected, all power was lost, bec too.

Hoping the new straps I've ordered will prevent such issues in the future.
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