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Old Nov 15, 2011, 03:48 PM
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United States, LA, Moss Bluff
Joined Nov 2008
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I'll have a red one tomorrow, hmmm, $800, never flown? hehe

I'll probably put my 72 Extra up for sale depending on the Edge. Haven't really decided yet. Last one to fly it was Aaron(thekm). The weather hasn't been the best and I only like flying it with a good runway.
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Old Nov 15, 2011, 03:59 PM
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Arlington, TX
Joined Jul 2009
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Originally Posted by G.P. View Post
I thought that running an Rx pack and a bec was a bad idea because the bec would try to charge the pack if it went bad...possibly letting the smoke out of the bec. Is there something available to isolate the Rx pack if it goes bad?
Been flying electrics for about 3 yrs and never heard of such a thing as a BEC trying to chage a battery. Why would a BEC try to "charge" a battery?
A BEC is basically a step-down transformer used to bring voltage down to 5 or 6 volts from whatever battery you connect it to. (some are limited as to a max voltage). Some are programmable via jumper for 5 or 6 volts. It's not a device used to charge anything.

I'm currently using two 2 cell LIPO receiver packs, each with it's own BEC, to run the receiver and ignition on my gas engined bird. Never a problem. The LIPOs seem to last forever. I can fly all day and not worry about low batteries. I charge them at home so they're ready for the next trip to the field and, after a full day's flying, they generally read about 7.6 volts (full charge is 8.4 volts).

Good switching BECs can be had for very little money. ....OR you can buy a Smart Fly module for about $60 that will do the same thing with two LIPO batteries.
http://smart-fly.com/Products/Regulator/3.htm


RJ
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Old Nov 15, 2011, 05:58 PM
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United States, NC, Hertford
Joined Oct 2007
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Quote:
Originally Posted by rowdyjoe View Post
Been flying electrics for about 3 yrs and never heard of such a thing as a BEC trying to chage a battery. Why would a BEC try to "charge" a battery?
A BEC is basically a step-down transformer used to bring voltage down to 5 or 6 volts from whatever battery you connect it to. (some are limited as to a max voltage). Some are programmable via jumper for 5 or 6 volts. It's not a device used to charge anything.

I'm currently using two 2 cell LIPO receiver packs, each with it's own BEC, to run the receiver and ignition on my gas engined bird. Never a problem. The LIPOs seem to last forever. I can fly all day and not worry about low batteries. I charge them at home so they're ready for the next trip to the field and, after a full day's flying, they generally read about 7.6 volts (full charge is 8.4 volts).

Good switching BECs can be had for very little money. ....OR you can buy a Smart Fly module for about $60 that will do the same thing with two LIPO batteries.
http://smart-fly.com/Products/Regulator/3.htm


RJ
Right you use a RX pack(2s lipo or that other battery type ) is to power the BEC.
Its not to be hooked up in parellel with the RX pack as it would then try to charge the battery and that could cause the BEC to burn out unless you hook up a diod to it to prevent power from going that direction. Thats about the only way to do that but man that just OVERKILL
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Old Nov 15, 2011, 06:52 PM
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San Jose, CA
Joined Jan 2008
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If you plug a battery and a BEC into a receiver, since they will both be plugged into a parallel power buss, (as are the servos) the BEC "will" try to charge the battery or burn up the BEC unless as Matt said, you put a diode on both the BEC and the battery to keep the current from flowing to the battery or BEC.

SteveT
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Old Nov 15, 2011, 08:39 PM
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United States, MD, Dundalk
Joined Feb 2009
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Got a couple Xoar 20x10's today to replace the Apc I have been running. Nothing wrong with the Apc but I wanted to try the Xoar as I like the performance on the 48 edge vs the Apc. The Apc 20x10 thin E prop weights 85.3 grams and The Xoar 20x10 E prop was 61.8. I knew the Xoar was lighter but didn't realize it was 28%. Hopefully I'll get a slight amount of punch increase out of it. I also installed a white EF spinner which was about 5 grams lighter that the blue Dubro I had on here. It's not much total weight loss but every little bit helps.
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Old Nov 15, 2011, 10:52 PM
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Arlington, TX
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Quote:
Originally Posted by SteveTtoooo View Post
If you plug a battery and a BEC into a receiver, since they will both be plugged into a parallel power buss, (as are the servos) the BEC "will" try to charge the battery or burn up the BEC unless as Matt said, you put a diode on both the BEC and the battery to keep the current from flowing to the battery or BEC.

SteveT
You guys sure know how to make a mountain out of a mole hill.
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Old Nov 16, 2011, 01:22 AM
iumop ap!sdn w,I
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Joined May 2005
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Originally Posted by rowdyjoe View Post
You guys sure know how to make a mountain out of a mole hill.
...says the guy with the ridiculously long post and bold lettering to inform me what a bec is...

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Old Nov 16, 2011, 05:08 AM
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Bridgeton, NJ
Joined Mar 2009
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Originally Posted by rowdyjoe View Post
You guys sure know how to make a mountain out of a mole hill.
Only a "mole hill" if you want to burn your stuff up. You simply can't run both a BEC and battery without additional protection long term. Simple as that.

Information sharing like this is important so please don't down play it when people try to educate others, especially if you don't understand it thoroughly.

Really not tying to criticize you or anything but you should read up on it,
Carlo
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Old Nov 16, 2011, 05:09 AM
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Bridgeton, NJ
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Originally Posted by G.P. View Post
...says the guy with the ridiculously long post and bold lettering to inform me what a bec is...

"ridiculously long post" Nah, that was a "shorty".
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Old Nov 16, 2011, 06:34 AM
Sippin the Koolaid!
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United States, NC, Hertford
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Originally Posted by cayars View Post
"ridiculously long post" Nah, that was a "shorty".
Didnt you get the badge for longest post
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Old Nov 16, 2011, 07:50 AM
iumop ap!sdn w,I
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Originally Posted by cayars View Post
"ridiculously long post" Nah, that was a "shorty".
Yeah, it's all relative!

Would "overly complicated" be better?

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Old Nov 16, 2011, 08:17 AM
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Florida
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I have an 8S setup and run an 1800 mAH 6.6V LIFe Rx pack on my Slick. It's great because my servos see 6 Volts of power and I have had a situation where the main packs departed and I was able to glide the plane down safely. Also the extra pack is nice because it's one more way to get the CG dialed in where you want it.
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Old Nov 16, 2011, 08:19 AM
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Florida
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Also for an 8.5 min flight I take out about 90 mAH from the Rx flight, considering I only have 8 4S batteries I never run into an issue w/ love Voltage on the Rx pack. Plus since it's a LiFe battery I can store it full charged and charge it in the plane w/ worrying about taking it out of the plane.
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Old Nov 16, 2011, 08:22 AM
Barefoot Birkinsomething
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United States, CA, Hayward
Joined Aug 2004
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Quote:
Originally Posted by tominator06 View Post
Got a couple Xoar 20x10's today to replace the Apc I have been running. Nothing wrong with the Apc but I wanted to try the Xoar as I like the performance on the 48 edge vs the Apc. The Apc 20x10 thin E prop weights 85.3 grams and The Xoar 20x10 E prop was 61.8. I knew the Xoar was lighter but didn't realize it was 28%. Hopefully I'll get a slight amount of punch increase out of it. I also installed a white EF spinner which was about 5 grams lighter that the blue Dubro I had on here. It's not much total weight loss but every little bit helps.
i dont know if you will get a punch increase, infact i think you will get a tad less punch going from an apc 20x10 to a xoar 20x10. the xoar will be smoother, and may have just a touch more top end, but the apc's do tend to bite a little better
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Old Nov 16, 2011, 08:28 AM
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Bridgeton, NJ
Joined Mar 2009
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Quote:
Originally Posted by losifanatic View Post
Didnt you get the badge for longest post
Yea, that's why I said his was a "shorty"
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