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Old Jun 07, 2010, 10:32 PM
The new guy
United States, SD, Rapid City
Joined Jan 2010
162 Posts
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How long will my Lipo last on a nitro plane?

building a 60 size clipped wing cub and I was just curious if anyone could tell me how long my 2200 mAh 3S lipo will last if it is just running my AR6200 and 5 standard servos? I already have a few of these from my foamies and I plan to use them in my cub to save a bit of cash. They run about 15 - 20 min on my PZ corsair so I figure since its not powering a motor it will get at least twice the battery life. Anyone have a more specific answer for me? Thanks.
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Old Jun 08, 2010, 04:09 AM
Registered User
Staffs, UK
Joined Nov 2003
10,551 Posts
You'll need to reduce the voltage with a BEC/voltage regulator. Connecting a 3S lipo direct will fry the RX and servos instantly.

Once you've done that I'd guess a 2200mAh battery would run your RX and servos for at least an hour, possibly two.

Steve
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Old Jun 08, 2010, 11:19 AM
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LtDan's Avatar
Northern CA
Joined Mar 2006
194 Posts
Here's my experience with lipo as a RX battery. I have a Sig 4*40 with a Magnum 52 4S on the front. I decided to try a Lipo as RX power. I used a Thunder Power 1325 Prolite 2cell 7.4 volt battery. Wired through a switch to a Hextronik VR/BEC set to 5vdc. I am using a Spektrum 6200 rx and so far been flying it a month now with this setup. The battery and regulator are way lighter than the 6v pack that I had originally bought for this setup. I remove the battery, which is foam wrapped, after a flying day put it on the charger. Last Sunday I flew three tanks of fuel and when I went to charge the battery it took 83 ma to bring it back to full charge. I have the typical 4 servo setup so I believe that Lipo's can work as an RX /servo power source.
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Old Jun 08, 2010, 01:29 PM
The new guy
United States, SD, Rapid City
Joined Jan 2010
162 Posts
Quote:
Originally Posted by slipstick View Post
You'll need to reduce the voltage with a BEC/voltage regulator. Connecting a 3S lipo direct will fry the RX and servos instantly.

Once you've done that I'd guess a 2200mAh battery would run your RX and servos for at least an hour, possibly two.

Steve
I already have that taken care of. I had some spare parts from a previous PZ corsair that is no longer with us, but the ESC/BEC combo is! So I am just going to not use the ESC part but it works perfect for lowering the voltage, I have tested it. I was just curious how long it would last because the ESC has a voltage cutoff for the engine when it gets too low but I will have no idea when the battery is low now since it will power the servos right up until the moment the battery actually dies which will fry my lipo.
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Old Jun 08, 2010, 04:15 PM
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Melbourne, Australia
Joined Mar 2009
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As I understand it, the engine cuttout comes into effect long before the power to the receiver is cut. Fail safe... sort of.

Others may know more.

Hugh
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Old Jun 08, 2010, 07:07 PM
The new guy
United States, SD, Rapid City
Joined Jan 2010
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Originally Posted by MerlinV View Post
As I understand it, the engine cuttout comes into effect long before the power to the receiver is cut. Fail safe... sort of.

Others may know more.

Hugh
Well the ESC cuts out so that you dont overdraw the battery, the power to the receiver will never cut out on the BEC part of combo until the battery is actually dead. It is designed so that on an electric plane the motor will die and you will still have power to the servos to dead stick land it. However, in my case with using on my glow plane I wont know when it gets to that point because it is only hooked up to servos and no motor. Sooooo, the point to this whole thread is to know how long I can use it without overdrawing it because once it is overdrawn the battery is worthless and could in extreme cases puff up or even start a chemical fire.
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Old Jun 08, 2010, 10:08 PM
Bombs away! Err...landing
Ira NZ's Avatar
Upper Hutt, New Zealand
Joined Apr 2006
2,242 Posts
Quote:
Originally Posted by buechelr View Post
building a 60 size clipped wing cub and I was just curious if anyone could tell me how long my 2200 mAh 3S lipo will last if it is just running my AR6200 and 5 standard servos? I already have a few of these from my foamies and I plan to use them in my cub to save a bit of cash. They run about 15 - 20 min on my PZ corsair so I figure since its not powering a motor it will get at least twice the battery life. Anyone have a more specific answer for me? Thanks.
Assuming you use a switchmode bec which will be a lot more efficient I'd estimate 2200mah 3S would be good for somewhere in the region of 15 hours of actual flight time.

That's based on my experience of using about 400 mah out of a 4 cell pack(admittedly with an average trainer) with 1-1.5ish hours of flight time and with a 2200 3S lipo you'll have roughly 12 times the amount of energy in the battery.

So, I think your estimate of 30-40 minutes is probably going to leave you some 10 hours of flight time cushion
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Old Jun 09, 2010, 12:42 AM
The new guy
United States, SD, Rapid City
Joined Jan 2010
162 Posts
Quote:
Originally Posted by Ira NZ View Post
Assuming you use a switchmode bec which will be a lot more efficient I'd estimate 2200mah 3S would be good for somewhere in the region of 15 hours of actual flight time.

That's based on my experience of using about 400 mah out of a 4 cell pack(admittedly with an average trainer) with 1-1.5ish hours of flight time and with a 2200 3S lipo you'll have roughly 12 times the amount of energy in the battery.

So, I think your estimate of 30-40 minutes is probably going to leave you some 10 hours of flight time cushion
haha awesome, that is what I wanted to hear. I dont think I can fly for even 4 hours in a day let alone 15. I guess these will work perfect.
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