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Old Aug 22, 2007, 11:35 AM
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flying evader's Avatar
United States, TX, Frisco
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do you use an independent battery for AR7000?

Hi,

traditionally i have used BEC's to power my receivers. I'm considering switching one of my hotliners to power the receiver/servos with a seperate 4cell battery pack.

I've heard horror stories with spektrum receivers re-booting or unbinding if the voltage drops below a certain point.

Is this a problem??
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Old Aug 22, 2007, 01:46 PM
Electric Airplane Junkie
bhchan's Avatar
United States, CA, San Mateo
Joined Jun 2000
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I would use a rx battery regardless.

Where do you fly?

Brian, an EAJ
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Old Aug 22, 2007, 02:48 PM
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baylands!
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Old Aug 22, 2007, 07:49 PM
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Joined Jan 2007
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I would not bother if the BEC is up to the task.

I have an AR7000 running off an ESC/BEC and never had an issue - even if I run the battery down to the point where the ESC cut-off kicks in.

Funny thing is, now that I'm setting up a glow outfit with a battery pack, I'm more concerned about voltage levels than I was with a BEC set up.

I'm really tempted to get one of these - http://www.voltmagic.com/

It'll record the lowest voltage seen on a flight (i.e. under actual loads), in addition to the current voltage. At least you will know whether the voltage ever gets down to dangerously low levels - you don't have to guestimate based on dummy loads or manufacturer specs or the like. Would be cheap insurance for anything worth a few dollars.

cheers

- Kevin
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Old Aug 22, 2007, 09:12 PM
Dr John
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Lake Placid, Florida
Joined Dec 2001
2,712 Posts
The big question is if the BEC can keep up with the load placed on it by the Rx and all the servos. If you only need two HS55's almost any BEC will be ok. If you are using four or more hi torque digitals I would use a good stand alone BEC or a separate Rx battery. I am using a five cell 1800mah pack in my Hyperion Yak 54 with four digitals and have a 6v voltwatch on the system. Part of every preflight is to move the right stick rapidly in circles and if the voltwatch drops one light I recharge before flying.

John
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Old Aug 23, 2007, 08:51 PM
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bhchan's Avatar
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Quote:
Originally Posted by flying evader
baylands!
Is this Davin?

Brian, an EAJ
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Old Aug 25, 2007, 02:41 AM
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Christchurch, New Zealand
Joined Jun 2006
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If your BEC is good for the loading, you are SAFER with a BEC than with a 4-cell nickel pack. Basically, whatever you do, you have to ensure that the voltage at the receiver stays over threshold. How you do that is up to you, but a switching BEC in a model that already has a big flight battery is by far the lightest solution. So, an adequately rated BEC is fine... an under-spec nickel pack would be worse.
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Old Aug 26, 2007, 05:54 PM
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Quote:
Originally Posted by bhchan
Is this Davin?

Brian, an EAJ

Rafael. I dont believe we have met. I fly an ION.
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Old Aug 26, 2007, 08:13 PM
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The Northeast Kingdom, Vermont
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Quote:
Originally Posted by Andrew McGregor
If your BEC is good for the loading, you are SAFER with a BEC than with a 4-cell nickel pack. Basically, whatever you do, you have to ensure that the voltage at the receiver stays over threshold. How you do that is up to you, but a switching BEC in a model that already has a big flight battery is by far the lightest solution. So, an adequately rated BEC is fine... an under-spec nickel pack would be worse.
I couldn't agree more.
And you'd be hard pressed to buy a good Nixx pack for the price of this one I don't fly hotliners, but I'm sure you don't want to carry the extra weight.
http://www.castlecreations.com/
Pete
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Old Aug 26, 2007, 08:47 PM
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Laurel, MD
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I don't know if there is enough information to tell him to use a BEC or not. I would want to know the following:

1. How many servos are you using?
2. How many cells in your flight pack?
3. How much current are you running through the setup?
4. Which controller/motor/prop combination are you running?
5. What type of cells are you using for flight pack?

When using a hotliner there are times to use BEC and times to NOT use BEC. Answer these questions and then we can give you a better educated answer.

I consider flight packs and BEC equal when it comes to flying/reliability. You just have to properly design your setup.

Jay
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