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Old Jan 01, 2004, 04:23 PM
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Germany
Joined Dec 2001
302 Posts
LiPo Low Voltage Warning for 2-10 cells

These little gadgets will warn you with a superbright LED when your LiPo-pack goes below 3V per cell.

They are user settable for 2 - 10 cells, allowable voltage range is 5-42 Volts!

They use a 1% precision 3.0V voltage reference and 1% precision metal film resistors, so there is no adjustment required.

Weight (without wires) is 1.5 Grams.

If anybody needs one, please send a PM.

Thanks for the bandwidth.
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Old Jan 01, 2004, 04:43 PM
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Pasadena, California, USA
Joined Mar 2002
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If the voltage sags for a very short time does this gadget light the LED long enough to see? Perhaps a steady 5 seconds LED on after a momentary sag and fast blinking with constant low voltage?
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Old Jan 01, 2004, 04:51 PM
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Germany
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I had originally included this feature, but after testing, I found it not very helpful and removed it.

What happens in practice is, that at the end of the flight, voltage drops under load , i.e., when you move the throttle/pitch stick forward. As soon as you reduce throttle/pitch, voltage recovers and the light goes out.

Having the "peak detection" feature somewhat obscured the relationship between pitch and low voltage alarm. So at least to me, it did not look like a desireable feature.
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Old Jan 02, 2004, 12:35 AM
Nimble with Gimbals
San Diego, CA
Joined Apr 2003
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How about a buzzer instead? I would think this would be easier to detect than a visual cue.

I've been following your work with pack balancers and I must say you're a huge asset to this hobby. It's rare to find someone who actually solves the problems we all complain about
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Old Jan 02, 2004, 12:48 AM
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Fairborn, Ohio
Joined Dec 2003
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A remote buzzer hookup would be nice.

Tim
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Old Jan 02, 2004, 01:53 AM
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Germany
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In the next pcb version I will include an optional connection for a buzzer.
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Old May 17, 2004, 11:34 AM
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Jacksonville, FL
Joined Aug 2002
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Are you making these available for sale, and if so, what's the cost? How do we get one?

Looks like a neat gadget that not many vendors have addressed so far. At least not for us guys that already have conventional, pre-LiPo capable ESC's.

Rick
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Old May 17, 2004, 12:22 PM
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United States, CA, San Diego
Joined Dec 1999
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Quote:
Originally Posted by ElectRick
Are you making these available for sale, and if so, what's the cost? How do we get one?

Looks like a neat gadget that not many vendors have addressed so far. At least not for us guys that already have conventional, pre-LiPo capable ESC's.

Rick
Check DMA's web site at "flydma.com". They now have a device called the "Li-Saver" which plugs between the speed controller and Rx. It auto detects the # of cells and sets the cut-off voltage. When the cutoff is reached it reduces the throttle is pulsed between on and off giving the user a warning that it is time to land. It works from 2-12 cell packs and has a opto-isolation option. It is very small--about 1 inch by .25 inches--sort of a wide spot in the wire harness.

Steve
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Old May 17, 2004, 04:27 PM
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Unless the web page for this device is out of date, it's not available until June.

Thanks anyway, though.

Rick
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Old May 17, 2004, 04:29 PM
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Germany
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Quote:
Originally Posted by ElectRick
Are you making these available for sale, and if so, what's the cost? How do we get one?

Looks like a neat gadget that not many vendors have addressed so far. At least not for us guys that already have conventional, pre-LiPo capable ESC's.

Rick
If all goes well, the new version should be available in approx. 4 weeks. It is user programmable for 2-10 (12) cells, 2.5 - 3.5 V/cell cutoff, optional peak hold feature, optional throttle limiter, etc. I have the schematics and PCB layout finished, still some work to do on the software. And then, of course, flight tests in my LiPo-Joker.

Cost will be 15 Euro (approx 18-20 USD).

I'll let the board know when the first batch is in stock.
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Old May 17, 2004, 08:35 PM
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Look on the DIY ELECTRONICS part of this site for the micro scream alarm.
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Old May 20, 2004, 12:26 AM
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San Diego, CA, USA
Joined Nov 2001
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Quote:
Originally Posted by ElectRick
Unless the web page for this device is out of date, it's not available until June.

Thanks anyway, though.

Rick
Rick,

June is only a few days away.

Chuck
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Old May 20, 2004, 01:51 AM
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USA, NY, East Northport
Joined Dec 2003
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The MicroScream alarm posted in the DIY section works quite well. I have one in all my planes, it provides real peace of mind when flying. All my personally built units in my planes are ultra lightweight "dead bug" style builds, using magnet wire to connect to the battery. A couple of installations have the piezo buzzer remote from the electronics, optimizing the location of both electronics and the piezo.

I posted the schematic so people handy with a soldering iron could build it for themselves for the cost of the parts. For those who would prefer to purchase a complete and tested MicroScream low voltage lipo battery alarm; they can be purchased at:

www.like90.com

There are a more formal printed circuit board build. Presently the 2 cell and 3 cell version are being offered. Attached are a couple of photos of the finished alarm.

Jimsky
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Old May 20, 2004, 09:11 AM
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Jacksonville, FL
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Any plans to do a 4 cell version?

The story of my life WRT this hobby...everybody has everything EXCEPT what I need...

Rick
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Old May 20, 2004, 09:50 AM
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USA, NY, East Northport
Joined Dec 2003
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My appoligies to Suzanne, I didn't intend to hijack this thread. Someone mentioned the MicroScream and I just wanted to indicate completed units can be purchased for those that can't wait (or can't/don't want to build circuits) to get low voltage lipo battery protection.

The MicroScream is the essence of simplicity, while Suzanne's device appears to have lots of advanced features. Same goal, different approach.

Contact the guys at like90 for the availability of a 4 cell version, or post on the MicroScream thread in the DIY Forum if you're just inquiring how to build your own. Again Suzanne, sorry for jumping in here.

Jimsky
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