E-C/L ... 3 cell LiPo battery cut off  
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All Forums >> Radios, Batteries, Clubhouse and more >> Control Lines >> E-C/L ... 3 cell LiPo battery cut off
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E-C/L ... 3 cell LiPo battery cut off - 2/8/2008 12:51:13 AM   
skaliwag



Posts: 1117
Joined: 1/9/2003
From: santa cruz, CA, USA
Status: offline 		Has any one tried the Novak Smart -Stop cut off Gizmo #5472 for e-control line?


http://www.teamnovak.com/products/lipo_cutoff_module/index.html

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Real Airplanes have Round Engines and Two Wings.
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RE: E-C/L ... 3 cell LiPo battery cut off - 2/8/2008 2:08:52 AM   
da Rock



Posts: 6654
Joined: 10/11/2005
From: western, NC, USA
Status: online 		From the description, it doesn't sound suited to control line.

It is described as a warning device, not a shut-off. What you need for a CL model is a shut-off.

Do you have further information that explains how to turn it into a switch?

(in reply to skaliwag)
       Post #: 2

RE: E-C/L ... 3 cell LiPo battery cut off - 2/8/2008 2:40:20 AM   
skaliwag



Posts: 1117
Joined: 1/9/2003
From: santa cruz, CA, USA
Status: offline 		The switch is the big Boogga Boo. This thing plugs into Channel 3. Need a way of tricking it into thiinking a switch is a Rx.

< Message edited by skaliwag -- 2/8/2008 2:42:47 AM >

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Real Airplanes have Round Engines and Two Wings.

(in reply to da Rock)
       Post #: 3

RE: E-C/L ... 3 cell LiPo battery cut off - 2/8/2008 3:40:59 AM   
mikeainia


 

Posts: 17
Joined: 12/24/2007
From: Madrid, IA, USA
Status: offline
quote:

ORIGINAL: da Rock

From the description, it doesn't sound suited to control line.

It is described as a warning device, not a shut-off. What you need for a CL model is a shut-off.

.....



You've lost me here -- Every ESC that I'm aware of will act as a
low-battery cut-off. What is it about this device that looks like
it might be useful?

Mike A

(in reply to da Rock)
       Post #: 4

RE: E-C/L ... 3 cell LiPo battery cut off - 2/8/2008 4:15:38 AM   
skaliwag



Posts: 1117
Joined: 1/9/2003
From: santa cruz, CA, USA
Status: offline 		Yes Mike you are right...
I am looking for a way to fly E-C/L.. and not use a timer.
A timer can go on until after you have reached the point of no return for a battery.. I want the motor to cut when a set (low) voltage has been reached.

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Real Airplanes have Round Engines and Two Wings.

(in reply to mikeainia)
       Post #: 5

RE: E-C/L ... 3 cell LiPo battery cut off - 2/8/2008 4:34:15 AM   
mikeainia


 

Posts: 17
Joined: 12/24/2007
From: Madrid, IA, USA
Status: offline 		Well, there are two issues - first, you must use an ESC, at least for a modern
Brushless motor. Since you have to use an ESC, you have to have some
device to tell the ESC whether or not to run the motor. These are commonly
called timers - but probably should be called sequencers - as they do more
than just run the motor for a certain amount of time.

Like I said, every ESC has a battery monitor which will stop the motor if
the voltage goes below a certain level - usually about 3.0 v. / cell, or 9.0 v
for a 3s Lipo. Most can be set for NiMH/NiCd cell too and then they stop
the motor at about .8 v. / cell. In any case, this is the Cut-Off voltage.

If you don't have a timer or some other circuit to drive the ESC, it will just
sit there and never run - it needs to have the throttle pulse from a Receiver
or something that mimics that throttle pulse. You can use a servo
exerciser - a small device that allows an RC servo to be moved without
turning on the transmitter. You could carry this in the plane, set the knob
for the desired RPM, then fly until the ESC hits CutOff voltage - but I can
tell you that this will not be very satisfactory, and will actually be kind of
hard on batteries. You are left with the option of using the "Timer" - and
since they only cost between $15 and $30, they aren't any more expensive
than the servo driver. They are programmable in several ways:
1st - You can precisely set the run time from very short to very long
2nd - You can make it wait before the motor starts and choose how long
than wait is - this gives you time to walk to the handle and get ready
3rd - You can set the motor RPM from slow to Full speed, and most that
I am aware of will slowly increase the speed, to minimize the effects of
a battery that is running down.
4th - They all have some method of warning you that the time is about
up and they are about to shut down, so you don't get halfway through
a loop and lose power.
And lastly, they have a clean and total shut down, so you don't have to
fly around on nearly dead batteries that will barely keep the plane
moving.

I'm not sure what it is that you are trying to avoid by not using a timer -
I've got several different ones and they are all slightly different, but all
are a great asset to C/L flight. With the programmability of the timer,
you can dial the flight in to exactly what you want, and still have the
auto-cutoff of the ESC as a safety back up, in case the timer somehow
runs too long.

Mike A

< Message edited by mikeainia -- 2/8/2008 4:37:33 AM >

(in reply to skaliwag)
       Post #: 6

RE: E-C/L ... 3 cell LiPo battery cut off - 2/8/2008 5:15:00 AM   
skaliwag



Posts: 1117
Joined: 1/9/2003
From: santa cruz, CA, USA
Status: offline 		I fly 1/2A and it's a little annoying that you have to have $50 worth of electronics to turn the motor off when the juice runs out.

_____________________________

Real Airplanes have Round Engines and Two Wings.

(in reply to mikeainia)
       Post #: 7

RE: E-C/L ... 3 cell LiPo battery cut off - 2/8/2008 8:18:23 PM   
mikeainia


 

Posts: 17
Joined: 12/24/2007
From: Madrid, IA, USA
Status: offline 		Are you talking about brushed motors ? If so, then yes, you only need some kind
of switch.

Any brushless motor though, needs the same $50 worth of electronics to
turn the motor ON.

(Actually, you can get a "1/2A size" ESC for under $20, a motor for under $20
and a "timer" for $15).

(in reply to skaliwag)
       Post #: 8

RE: E-C/L ... 3 cell LiPo battery cut off - 2/17/2008 5:49:34 PM   
mikeainia


 

Posts: 17
Joined: 12/24/2007
From: Madrid, IA, USA
Status: offline 		I don't know if you guys are still interested in this thread or not, but I thought I'd show some pix of what it triggered - I decided that I'd just build something so anyone would be able to have a starting point -

This one will be flying on 2-cell packs. All up weight should be right at 8 oz. It was originally going to be a modified Sig 1/2A Skyray, but I decided to just build a new one - the built up wing is one I've built before for glow powered Skyrays. The full fuselage was just kind of a whim.

The motor and ESC cost $16 (as a combo)
The battery packs cost $7 @
The Timer circuit cost $15

The two motors shown both need fairly large props, but there are others available that would turn smaller props at higher speeds. The packs I'll be using are 900 mah, 2 cell lipo's and I expect 5 - 6 minute runs. The timer lets me break that into 2 or 3 short runs if I wish, for training beginners etc.

If anyone wants more information, I'll gladly send or post a list of sources for this stuff.

Mike A.

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(in reply to mikeainia)
       Post #: 9

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