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nuckollsr

Joined: 24 Mar 2009
Posts: 95
Location: Medicine Lodge, KS

Posted: Fri Aug 16, 2013 7:30 pm Post subject: Re: Failed brownout battery experiment

[/quote] Did you mean 14 *volts*? How can you tell that it would support that for a half a second brownout?[/quote]

The dc-dc converter in consideration is a step-up device with an input range of 3-32 volts, an output range of 5-35 volts. The only constraints on picking an operating point is to have the output set to always be greater than the input . . . which can in this case be as much as 15 volts. So some comfortable head-room above 15 is in order. The higher the selection, the lower the current demanded by the Dynon's switchmode power supply. 17 would probably work too. Here's some input/output combinations the supplier says this critter will handle.



Test comparison sample reference:

   Input 3V Output 12V 0.4A 4.8W

   Input 5V Output 12V 0.8A 9.6W

   Input 7.4V Output 12V 1.5A 18W

   Input 12V Output 15V 2A 30W

   Input 12V Output 16V 2A 32W

   Input 12V Output 18V 1.6A 28.8W

   Input 12V Output 19V 1.5A 28.5W

   Input 12V Output 24V 1 A 24W



Our 'target low input' is on the order of 7 v so we're asking the little feller to put out 14 watts max with 7v in and some output with headroom above 15volts . . . 19 seemed like a handy number.

Actually if wired so the converter gets input power only with the starter button pushed, we can eliminate the possibility of operation with the alternator running. So adjusting for say 15 volts output would suffice for the fully charged, unloaded battery case . . . with all bases covered for battery voltage profile during cranking . . . especially during starter inrush.



Good question.

user9253

Joined: 28 Mar 2008
Posts: 1938
Location: Riley TWP Michigan

Posted: Sat Aug 17, 2013 4:09 am Post subject: Re: Failed brownout battery experiment

 	  Quote: 	
		  AA cells are not well suited to 1+ amp discharge situations but as you've discovered, D-cells took the hit nicely. A d-cell array is certainly cost attractive but gives you another battery to maintain. 	


Actually my successful experiment used 4 AA batteries.  Two D batteries did not keep the D-180 from rebooting, nor did 3 AA.  I did not try 3 or 4 D batteries, mainly because I did not have battery holder.

A capacitor or DC-DC booster will offer a more elegant solution.  Or perhaps a combination of DC booster supplying a higher voltage to a capacitor.  Mouser sells a 25volts 150000uF part number 647-LNR1E154MSE at a reasonable cost.  Joe

_________________
Joe Gores

rickofudall

Joined: 19 Sep 2009
Posts: 1392
Location: Udall, KS, USA

Posted: Sat Aug 17, 2013 7:05 am Post subject: Failed brownout battery experiment

Thanks Bob, I learned a little more.I have a day of machining parts, about which I know a fair amount, followed by removing the fuel filter, which is in the fuel tank and about which I know next to nothing, from my wife's car. Should things go badly with the car I can at least reflect on the knowledge that I have learned a little about the mysteries of electron herding so I can probably learn about in tank fuel filters and possibly about replacing an in tank fuel pump, too. I feel better already. 



Rick

do not archive





On Fri, Aug 16, 2013 at 10:30 PM, nuckollsr <bob.nuckolls(at)aeroelectric.com (bob.nuckolls(at)aeroelectric.com)> wrote:

  	  Quote: 	
		  --> AeroElectric-List message posted by: "nuckollsr" <bob.nuckolls(at)aeroelectric.com (bob.nuckolls(at)aeroelectric.com)>

  

 

	
 Did you mean 14 *volts*? How can you tell that it would support that for a half a second brownout?[/quote]

 

 

 The dc-dc converter in consideration is a step-up device with an input range of 3-32 volts, an output range of 5-35 volts. The only constraints on picking an operating point is to have the output set to always be greater than the input . . . which can in this case be as much as 15 volts. So some comfortable head-room above 15 is in order. The higher the selection, the lower the current demanded by the Dynon's switchmode power supply. 17 would probably work too. Here's some input/output combinations the supplier says this critter will handle.

  

 Test comparison sample reference:

    Input 3V Output 12V 0.4A 4.8W

    Input 5V Output 12V 0.8A 9.6W

    Input 7.4V Output 12V 1.5A 18W

    Input 12V Output 15V 2A 30W

    Input 12V Output 16V 2A 32W

    Input 12V Output 18V 1.6A 28.8W

    Input 12V Output 19V 1.5A 28.5W

    Input 12V Output 24V 1 A 24W

 

 Our 'target low input' is on the order of 7 v so we're asking the little feller to put out 14 watts max with 7v in and some output with headroom above 15volts . . . 19 seemed like a handy number.

 

 

 Actually if wired so the converter gets input power only with the starter button pushed, we can eliminate the possibility of operation with the alternator running. So adjusting for say 15 volts output would suffice for the fully charged, unloaded battery case . . . with all bases covered for battery voltage profile during cranking . . . especially during starter inrush.

  

 Good question.

 

 

 

 

 Read this topic online here:

 

 

http://forums.matronics.com/viewtopic.php?p=406904#406904

 

 

 

 

 

 

 

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 http://forums.matronics.com

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 le, List Admin.

 ="_blank">http://www.matronics.com/contribution

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[/quote]



-- 

Zulu Delta

Mk IIIC

Thanks, Homer GBYM

It isn't necessary to have relatives in Kansas City in order to be unhappy.

   - Groucho Marx

 

  [quote][b]

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The smallest miracle right in front of you is enough to make you happy....

nuckollsr

Joined: 24 Mar 2009
Posts: 95
Location: Medicine Lodge, KS

Posted: Sat Aug 17, 2013 9:21 am Post subject: Re: Failed brownout battery experiment

 	  Quote: 	
		  Actually my successful experiment used 4 AA batteries.  Two D batteries did not keep the D-180 from rebooting, nor did 3 AA.  I did not try 3 or 4 D batteries, mainly because I did not have battery holder.

A capacitor or DC-DC booster will offer a more elegant solution.  Or perhaps a combination of DC booster supplying a higher voltage to a capacitor.  Mouser sells a 25volts 150000uF part number 647-LNR1E154MSE at a reasonable cost.  Joe 	




  Yeah, a smaller capacitor charged to a higher voltage would probably do it too. The AA experiment obviously worked but even though their 'sag' under load did not torpedo the experiment, it's going to affect service life.  Consider a 4xD as a soldered up pak with flying leads. I'm pretty sure this would give you a good service life . . . probably a couple of years as long as your airplane is not stored in a closed hangar under an Arizona sun.



The dc to dc converter we looked at first set for a 12v output and driven from the downstream side of your starter button seems pretty elegant.

user9253

Joined: 28 Mar 2008
Posts: 1938
Location: Riley TWP Michigan

Posted: Sat Aug 17, 2013 5:42 pm Post subject: Re: Failed brownout battery experiment

Bob,

Thanks for the advice.

I will use 4 AA batteries temporarily and order a DC-DC booster for a long term solution.  Do you think that the DC-DC converter will come alive and boost the voltage before the starter contactor energizes the starter motor?

Electronics should be faster than a mechanical device.

Thanks, Joe

_________________
Joe Gores

peter(at)sportingaero.com
Guest

Posted: Sat Aug 17, 2013 11:35 pm Post subject: Failed brownout battery experiment

Talking of dc-dc converters, this is probably more than many might want 

to spend, but TCW produces some well thought out components.



http://www.tcwtech.com/IPS-12v.htm



Peter



On 17/08/2013 18:21, nuckollsr wrote:

 	  Quote: 	
		   

> Actually my successful experiment used 4 AA batteries.  Two D batteries did not keep the D-180 from rebooting, nor did 3 AA.  I did not try 3 or 4 D batteries, mainly because I did not have battery holder.

> A capacitor or DC-DC booster will offer a more elegant solution.  Or perhaps a combination of DC booster supplying a higher voltage to a capacitor.  Mouser sells a 25volts 150000uF part number 647-LNR1E154MSE at a reasonable cost.  Joe



    Yeah, a smaller capacitor charged to a higher voltage would probably do it too. The AA experiment obviously worked but even though their 'sag' under load did not torpedo the experiment, it's going to affect service life.  Consider a 4xD as a soldered up pak with flying leads. I'm pretty sure this would give you a good service life . . . probably a couple of years as long as your airplane is not stored in a closed hangar under an Arizona sun.



 The dc to dc converter we looked at first set for a 12v output and driven from the downstream side of your starter button seems pretty elegant.





 Read this topic online here:



 http://forums.matronics.com/viewtopic.php?p=406922#406922

uuccio(at)gmail.com
Guest

Posted: Sat Aug 17, 2013 11:54 pm Post subject: Failed brownout battery experiment

On Aug 17, 2013, at 5:30, "nuckollsr" <bob.nuckolls(at)aeroelectric.com> wrote:



 	  Quote: 	
		   

 

 	
 Did you mean 14 *volts*? How can you tell that it would support that for a half a second brownout?[/quote]

 

 [...]

 

 Our 'target low input' is on the order of 7 v so we're asking the little feller to put out 14 watts max with 7v in and some output with headroom above 15volts . . . 19 seemed like a handy number.

 

 [...]

 

Thanks for the explanation Bob!
[/quote]



Do not archive

nuckolls.bob(at)aeroelect
Guest

Posted: Mon Aug 19, 2013 6:49 pm Post subject: Failed brownout battery experiment

At 08:42 PM 8/17/2013, you wrote:

 	  Quote: 	
		  



Bob,

Thanks for the advice.

I will use 4 AA batteries temporarily and order a DC-DC booster for 

a long term solution.  Do you think that the DC-DC converter will 

come alive and boost the voltage before the starter contactor 

energizes the starter motor?

Electronics should be faster than a mechanical device.


	


   Yes, the push button simultaneously applies

   power to the starter contactor and input to

   the dc-dc converter. The contactor has a pull-in

   delay on hte order of 5-10 milliseconds . . .

   plenty of time for the dc-dc converter to

   wake up.



   Bob . . .

user9253

Joined: 28 Mar 2008
Posts: 1938
Location: Riley TWP Michigan

Posted: Tue Aug 20, 2013 2:34 pm Post subject: Re: Failed brownout battery experiment

 	  Quote: 	
		  The contactor has a pull-in 

delay on hte order of 5-10 milliseconds . . . 

plenty of time for the dc-dc converter to 

wake up. 

	


Thanks Bob

_________________
Joe Gores

Eric M. Jones

Joined: 10 Jan 2006
Posts: 565
Location: Massachusetts

Posted: Thu Aug 22, 2013 4:36 pm Post subject: Re: Failed brownout battery experiment

--Edited to add Bob's correction to the schematic:



Most supercap designs seem targeted to electric vehicles or locomotives. Here is one to keep the Dynon from rebooting during starting. Bob N knows a hundred times more than I do about the Dynon, but this design should work, or at the very least provide a starting place for one that will by adding more caps. This design is for 12V, but a higher voltage design is easy, too. 



The advantage of this design is that it is about the size of a pack of chewing gum and cost about $30. It is easy to build on a perf-board. Add your own features as you like.



How it works: Ordinarily the power is fed through the DS1 to the Dynon Power Input. The DS2 supplies power to charge the supercaps through current limiter R1.  Since they are in series, the stack is actually only 250,000 uF X 20V max. R2-5 are voltage equilizers and draw 30 mA. R1 dissipates 25W initially when charging the supercaps.



When the bus slumps below the charge voltage of the supercaps, current flows

through DS3 to supply the required power, then gets recharged as above.



BDZ is a bidirectional Zener to keep the Schottkys healthy, but it is optional. You might want a 3A solid state fuse in the input.



Good luck. Note that this design is experimental and has not been tested.

supercap revA.pdf

Description:

Rev A corrected Supercap to lower ESR

Download

Filename:

supercap revA.pdf

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76.95 KB

Downloaded:

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_________________
Eric M. Jones
www.PerihelionDesign.com
113 Brentwood Drive
Southbridge, MA 01550
(508) 764-2072
emjones(at)charter.net

Last edited by Eric M. Jones on Fri Aug 23, 2013 6:01 am; edited 1 time in total

user9253

Joined: 28 Mar 2008
Posts: 1938
Location: Riley TWP Michigan

Posted: Thu Aug 22, 2013 6:39 pm Post subject: Re: Failed brownout battery experiment

Thanks Eric.  I have already ordered the DC to DC booster from eBay (China).  If that does not work out, I will build your circuit.

  Since the Dynon normally is powered through a separate terminal, I believe that DS-1 can be eliminated and DS-3 can be shorted.  Since this circuit will only be needed for less than a second during engine start, does R1 need to have such a high wattage rating?

Joe

_________________
Joe Gores

Eric M. Jones

Joined: 10 Jan 2006
Posts: 565
Location: Massachusetts

Posted: Fri Aug 23, 2013 1:07 pm Post subject: Re: Failed brownout battery experiment

 	  Quote: 	
		  Since the Dynon normally is powered through a separate terminal, I believe that DS-1 can be eliminated and DS-3 can be shorted. Since this circuit will only be needed for less than a second during engine start, does R1 need to have such a high wattage rating? 

Joe 	




Joe, I think DS1 and 3 are needed. Bob?

Does R1 need to be 35W? This is a TO-220 resistor, so it's pretty small. When the circuit is first charged (or after sitting) the capacitor current is a dead short. So no, 35W is excessive, but it has to be high wattage. 1.4A x 1.4A x 10=20W. You might get by with a lot smaller part.



Make sure you note that Bob N. pointed out that the Supercaps needed to be pulse rated, so I've changed them.

_________________
Eric M. Jones
www.PerihelionDesign.com
113 Brentwood Drive
Southbridge, MA 01550
(508) 764-2072
emjones(at)charter.net

user9253

Joined: 28 Mar 2008
Posts: 1938
Location: Riley TWP Michigan

Posted: Fri Aug 23, 2013 2:03 pm Post subject: Re: Failed brownout battery experiment

Thanks Eric

This circuit might have to be powered on when ever the D-180 is on (instead of through the start swtch) in order to give the capacitors time to charge.  According to an online time constant calculator, it could take up to 2.5 seconds.

http://easycalculation.com/engineering/electrical/capacitor-energy-rc-time-constant.php

_________________
Joe Gores

nuckollsr

Joined: 24 Mar 2009
Posts: 95
Location: Medicine Lodge, KS

Posted: Mon Aug 26, 2013 7:04 am Post subject: Re: Failed brownout battery experiment

This has been an interesting thread from the IT perspective . . . not all posts to the thread showed up in my mailbox but did appear in the matronics browser app for list access. I didn't get Eric's corrected drawing link . . . 



In this particular discussion for supplying power t the Dynon's external backup input pin, we're told that this pin is loaded ONLY IF adequate power is not available from the normal power input pin -OR- an internal battery. In this case, DS1 could be eliminated (open) and DS3 replaced with a short.



If this circuit were used to buffer the one and only power input pin to

a brownout sensitive appliance, then a path for steady state power at normal operating currents is needed . . . you couldn't power the device continuously through the DS2/R1 pathway.



Many power resistors have 'pulsed' current ratings that can be quite large compared to the steady state dissipation for the device . . . but it's highly dependent upon THERMAL connection between the resistive element, thermal mass and ambient.  I've studied some wire-wound resistors that were pretty disappointing for surge rating . . . others that were happily capable of considerable short-term abuse. You have to study the data sheets for the specific products. Generally speaking, resistors with flat surfaces that bolt to a chassis (thermal mass) will have pretty good pulse ratings . . . wire leaded devices that hang out in the breeze not so good.



The data sheet for these devices



http://tinyurl.com/msjo2va



. . . says you can hit them with 2x rated power for 5 seconds so this resistor would probably be fine as a 20W. At the same time, since we're not intending that this circuit charge rapidly in response to a starter-push button, the charging resistance could probably be raised by a factor of 2 without affecting circuit performance while reducing dissipated power by 75% in increasing capacitor charging time. Since the design goal being considered is to support a piece of equipment that has already been ON long enough to boot up and offer data, then the increase in time to charge the brown-out support is not significant.

user9253

Joined: 28 Mar 2008
Posts: 1938
Location: Riley TWP Michigan

Posted: Mon Aug 26, 2013 4:31 pm Post subject: Re: Failed brownout battery experiment

It turns out that it really is a "Failed brownout battery experiment".  After flying for several hours and starting the engine several times, there no longer  is any brownout protection because (I assume) the 4 AA batteries have run down.  I checked the batteries (no load) with a voltmeter: 1.4 volts each.  I removed the AA batteries from the airplane so they will not cause any problems.  I will await delivery of the DC-DC voltage booster that I ordered from eBay.

_________________
Joe Gores

Eric M. Jones

Joined: 10 Jan 2006
Posts: 565
Location: Massachusetts

Posted: Mon Aug 26, 2013 4:37 pm Post subject: Re: Failed brownout battery experiment

I just placed a Digikey order for the parts and will build a prototype. Stay tuned.

_________________
Eric M. Jones
www.PerihelionDesign.com
113 Brentwood Drive
Southbridge, MA 01550
(508) 764-2072
emjones(at)charter.net

user9253

Joined: 28 Mar 2008
Posts: 1938
Location: Riley TWP Michigan

Posted: Tue Sep 24, 2013 5:14 pm Post subject: Re: Failed brownout battery experiment

Failed again.

The DC to DC voltage booster arrived from China.  I connected it to the battery bus through an inline fuse and an on-off switch.  The output of the voltage booster is connected to Dynon D-180 pin 15, the external backup power input.  When the primary power to the D-180 pin 1 was shut off, the D-180 stayed on for a few seconds, then rebooted, shut off and rebooted, shut off and rebooted, over and over.  The output of the DC to DC booster is set at 13 VDC.  I then measured the voltage with the digital meter set to the AC range.  It measured 28 volts AC.  The D-180 must not like that.  I tried connecting a 22,000 microfarad capacitor to the output of the DC to DC booster, but that did not help.  So I removed the voltage booster and gave up on that idea.

Joe

_________________
Joe Gores

Eric M. Jones

Joined: 10 Jan 2006
Posts: 565
Location: Massachusetts

Posted: Wed Sep 25, 2013 4:40 am Post subject: Re: Failed brownout battery experiment

Joe,



If you want, I'll send you my prototype DeSlumpifier for testing, since it is just sitting on my desk gathering cat hair.



Contact me at Perihelion at charter dot net.



Eric

_________________
Eric M. Jones
www.PerihelionDesign.com
113 Brentwood Drive
Southbridge, MA 01550
(508) 764-2072
emjones(at)charter.net

nuckolls.bob(at)aeroelect
Guest

Posted: Wed Sep 25, 2013 6:59 am Post subject: Failed brownout battery experiment

At 07:40 AM 9/25/2013, you wrote:

 	  Quote: 	
		  



Joe,



If you want, I'll send you my prototype DeSlumpifier for testing, 

since it is just sitting on my desk gathering cat hair.



Contact me at Perihelion at charter dot net.


	


   Joe, it would be an excellent experiment to put

   Eric's hardware to the test in real hardware.

   In the mean time, send me the booster you

   bought and let me do some tests on it as well.

   There should be NO significant AC component on

   its output.



   Bob . . .

nuckolls.bob(at)aeroelect
Guest

Posted: Wed Sep 25, 2013 7:40 am Post subject: Failed brownout battery experiment

At 08:14 PM 9/24/2013, you wrote:

 	  Quote: 	
		  



Failed again.

The DC to DC voltage booster arrived from China.  I connected it to 

the battery bus through an inline fuse and an on-off switch.  The 

output of the voltage booster is connected to Dynon D-180 pin 15, 

the external backup power input.  When the primary power to the 

D-180 pin 1 was shut off, the D-180 stayed on for a few seconds, 

then rebooted, shut off and rebooted, shut off and rebooted, over 

and over.  The output of the DC to DC booster is set at 13 VDC.  I 

then measured the voltage with the digital meter set to the AC 

range.  It measured 28 volts AC.  The D-180 must not like that.  I 

tried connecting a 22,000 microfarad capacitor to the output of the 

DC to DC booster, but that did not help.  So I removed the voltage 

booster and gave up on that idea.

Joe



--------

Joe Gores


	


   Which booster did you order?





   Bob . . .

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