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Old Sep 24, 2012, 04:21 PM
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I run a CC bec on my great planes patriot with a 3s 2200mah battery and an exceed rc on my Right Flyer 40T and my world models combat seriers P-47. I have tested with my watt meter on my trainer and with all 4 servos going at one once I pull less than an amp, mind you this is on the ground with no air going over the control serfaces. The trainer uses a 2s 1300mah pack and my P-47 uses a 3s 2200mah pack due to all the LEDs on it.
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Old Sep 29, 2012, 04:49 PM
Zor
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Quote:
Originally Posted by Nin3rsAllDay View Post
I run a CC bec on my great planes patriot with a 3s 2200mah battery and an exceed rc on my Right Flyer 40T and my world models combat seriers P-47. I have tested with my watt meter on my trainer and with all 4 servos going at one once I pull less than an amp, mind you this is on the ground with no air going over the control serfaces. The trainer uses a 2s 1300mah pack and my P-47 uses a 3s 2200mah pack due to all the LEDs on it.
It looks to me that you are measuring the idle current after the servos have reached their positon.

Zor
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Old Sep 30, 2012, 04:12 PM
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That was while the servos were moving I put all four under load at once continuously moving my sticks to their extremes and watched what the highest reading was. I am using analog and not digital servos so that may play into it as well.
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Old Sep 30, 2012, 10:44 PM
Zor
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Originally Posted by Nin3rsAllDay View Post
That was while the servos were moving I put all four under load at once continuously moving my sticks to their extremes and watched what the highest reading was. I am using analog and not digital servos so that may play into it as well.
Nin3rsAllDay,

Thanks for the additonal explanations.
It makes more sense.

Zor
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Old Oct 05, 2012, 09:00 AM
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United States, FL, Fort Myers
Joined Nov 2011
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I like using a life battery in my planes and helicopters. Getting rid of a bec is just 1 less thing that can go wrong. You have to keep track of how much you are putting back in as the life battery voltage drops off fast when discharged. I'm using around 300-400 per flight and use a 1800 mah battery. Carry a couple of batteries and fly all day.
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Old Oct 05, 2012, 07:32 PM
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Sydney, Australia
Joined Jan 2008
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All my planes are still running nicads/nimh and i m thinking of changing over to lipo/LiFe's too.

Can you still set up the lipo's like nicads? ie have then buried under the fuel tank etc, would it be risky charging it buried in the plane? or do u guys take the pack out each time to charge?

Do you still run the lipos through the normal switches, and can you charge through the charging jack on the switch?

cheers
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Old Oct 05, 2012, 08:01 PM
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You should have access to the pack so you can remove it occasionally to balance it, or set it up so you can plug the balance jack into the charger while still in the plane. You can charge it using the switch jack, depends on the charger if it will charge without the balance connected. Since you wont be drawing a large load on the pack, I wouldnt worry about heat, they barely get warm if charged correctly. I wouldn't use a Lipo though for an RX, but a LiFe due to the lower voltage they produce, and generally are made for RX use.
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Old Oct 09, 2012, 10:49 AM
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United States, FL, Fort Myers
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Originally Posted by jymz View Post
+1 get rid of the bec and have 1 less thing to go wrong. Pay close attention to the life batteries, the voltage drops fast when discharged. You have to find out how much your putting back in for each flight to know how many flights are safe on a charge. I've been using life batteries in my helis for a while, no problems.
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Old Oct 13, 2012, 06:17 AM
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I too have purchased a lifepo battery. It is a 1450 mah 2s nanotech. The charger set on life settings ended with all voltage at 720 or 360 each cell. What is a safe level to say ok it is time to switch batteries or recharge. I am flying an Avistar 40 with new Futaba 3004 servos five in all. I assume that this voltage will not hurt the servos but I am concerned that the servos are rated for 6 volts input. Any of you have any thoughts? I appreciate it. I also have a load tester from hobbico.
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Old Oct 13, 2012, 06:26 AM
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Originally Posted by tonytiger20 View Post
I too have purchased a lifepo battery. It is a 1450 mah 2s nanotech. The charger set on life settings ended with all voltage at 720 or 360 each cell. What is a safe level to say ok it is time to switch batteries or recharge. I am flying an Avistar 40 with new Futaba 3004 servos five in all. I assume that this voltage will not hurt the servos but I am concerned that the servos are rated for 6 volts input. Any of you have any thoughts? I appreciate it. I also have a load tester from hobbico.
Do not trust voltage on the LiFePo4 cells for when to recharge. You need to measure how much you take from them (during recharge).

Couple of reasons:
  • They hold voltage remarkably well
  • They drop VERY rapidly when near depletion

Here is what I do. I fly 4 or so flights and recharge. Then you can see about how much you put back in. Then I know how many flights I can get before getting to about 70% discharge - leaving a very safe reserve.

I usually recharge them just before flying every outing too. Just like the old NiCad's we used to use - safer.

Also don't worry but the voltage will drop to around 6.6v and stay there for almost the entire pack. If you ever see 6.4 or 6.3 it is very likely almost completely done.

Mike
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Old Oct 13, 2012, 03:02 PM
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United States, OR, Canby
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Quote:
Originally Posted by tonytiger20 View Post
I too have purchased a lifepo battery. It is a 1450 mah 2s nanotech. The charger set on life settings ended with all voltage at 720 or 360 each cell. What is a safe level to say ok it is time to switch batteries or recharge. I am flying an Avistar 40 with new Futaba 3004 servos five in all. I assume that this voltage will not hurt the servos but I am concerned that the servos are rated for 6 volts input. Any of you have any thoughts? I appreciate it. I also have a load tester from hobbico.
A fully charged LiFepo4 will put less voltage to your servos than a fully charged 5 cell NIMH which many of us use, including myself. I am putting LiFe in all my new planes.
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Old Oct 13, 2012, 06:56 PM
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thanks pda4u and 600bob that is exactly what I was needing to hear. Will put it to use
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Old Oct 15, 2012, 06:07 PM
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United States, CT, Old Lyme
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I have a bunch of 1300mah 3s Lipos from my electric planes that I want to run in my .40 size SPADS. I use mainly older S3003 analog servos in my planes. What BEC would you recommend? If I am using a 3s pack with 3-4 servos I should be able to fly at least 4-5 flights per pack correct? Thanks
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Old Oct 16, 2012, 10:29 AM
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Either of these would work. It's best to make a couple of flights then recharge to know how many flights you could get but off hand I would think 4-5 flights would be likely. I use 2100mah LiFe and can get six 15min. flights and not use 50% of the pack.

http://www.heliflightcenter.com/5A_5...FUyCQgod8BAAeQ

http://www.hobbypartz.com/ubube.html...Fc5_QgodzkMAqQ
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Old Oct 16, 2012, 07:43 PM
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United States, CT, Old Lyme
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I think i'm going to go with the castle one. Its only a couple dollars more and seems to have a solid rep. Thanks!
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