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cluros(at)gmail.com
Guest

Posted: Mon Aug 31, 2020 12:19 pm Post subject: Brownout Step Up Converter

My friend has a Harmon Rocket with a GRT EFIS. During start the voltage sags just enough to mess up the GRT so that it usually needs a reset after start. Was there ever consensus on a good ebay dc-dc step up converter? I'm thinking of ordering this one:



https://www.ebay.ca/itm/5A-DC-DC-Boost-Step-up-Volt-Converter-Power-Supply-Module-5V-9V-12V-19V-24V-36V/192243452240Â Â 



The EFIS needs 1A so this should have no problem keeping up. Any thoughts?

user9253

Joined: 28 Mar 2008
Posts: 1927
Location: Riley TWP Michigan

Posted: Mon Aug 31, 2020 12:38 pm Post subject: Re: Brownout Step Up Converter

I don't know if there was ever a recommendation as to which DC-DC 

converter to buy, but there are some that cost between $5 and $10 that 

have a copper coil and look impressive.

Beware of exaggerated ampacity claims.

_________________
Joe Gores

nuckolls.bob(at)aeroelect
Guest

Posted: Mon Aug 31, 2020 1:58 pm Post subject: Brownout Step Up Converter

At 03:13 PM 8/31/2020, you wrote:

  	  Quote: 	
		  My friend has a Harmon Rocket with a GRT EFIS. During start the voltage sags just enough to mess up the GRT so that it usually needs a reset after start. Was there ever consensus on a good ebay dc-dc step up converter? I'm thinking of ordering this one:



  https://www.ebay.ca/itm/5A-DC-DC-Boost-Step-up-Volt-Converter-Power-Supply-Module-5V-9V-12V-19V-24V-36V/192243452240 Â Â 



 The EFIS needs 1A so this should have no problem keeping up. Any thoughts? 	


    email a shipping address and I'll send

    you one to try. I've not had time to characterize

    these on the test bench yet. But if we're

    picking one based on advertised performance,

    this one is as good as any.



 

 

   Bob . . .

johnbright

Joined: 14 Dec 2011
Posts: 166
Location: Newport News, VA

Posted: Mon Aug 31, 2020 7:59 pm Post subject: Re: Brownout Step Up Converter

In case this is interesting.



Analog Devices offers a demo board manufactured by Linear Technology.



Googling "Demo Circuit 1641A" will find an Analog Devices page with much detail as well as a Mouser page where it sells for $128.



"Demonstration circuit DC1641 is DC/DC boost converter featuring the LTC3786 constant frequency current mode boost controller. The DC1641A operates over 5V to 24V input and provides over 5A at 6V input voltage and over 9A of output current at 10V input as shown in figure 3. The 350kHz constant frequency operation results in small and efficient circuit. The converter provides high output voltage accuracy (typically Â±3%) over wide load range with no minimum load requirement. The demonstration circuit can be easily modified to generate different output voltages."



Someone on VAF posted about it: https://vansairforce.net/community/showpost.php?p=1458960&postcount=2

_________________
John Bright, RV-6A, at FWF, O-360
Z-101 single batt dual alt SDS EM-5-F.
john_s_bright@yahoo.com, Newport News, Va
N1921R links

nuckolls.bob(at)aeroelect
Guest

Posted: Tue Sep 01, 2020 1:47 pm Post subject: Brownout Step Up Converter

At 10:59 PM 8/31/2020, you wrote:

  	  Quote: 	
		  --> AeroElectric-List message posted by: "johnbright" <john_s_bright(at)yahoo.com>



 In case this is interesting.



 Analog Devices offers a demo board manufactured by Linear Technology.



 Googling "Demo Circuit 1641A" will find an Analog Devices page with much detail as well as a Mouser page where it sells for $128. 	


   This is one of a large family of such devices.

   Some are quite sophisticated. There's always

   a push to achieve the greatest possible

   efficiency.



   For our purposes, we need a relatively 'tiny'

   boost lasting a second or so at relatively

   low power . . . perhaps 50 watts

   in a worst case (lot's of vulnerable accessories

   on the brownout bus).



   If your battery is in good shape, the brownout

   event is over before the engine starts.  See



  https://tinyurl.com/y294j7zl



   The starter characteristic that precipitates

   the brown out is INRUSH current. This can be

   5 to 10 times greater than cranking current.

   However, as you can see in the plot above,

   it lasts but a handful of milliseconds. Once

   the starter motor spins up, about 100 mS, 

   the battery rises back above 9V.



   The performance questions for commercial off-the-

   shelf supplies is not so much about carrying a

   load but how fast the device comes on line and

   how fast it responds to the dynamics of it's

   bus supply voltage.



   From the time the starter button is pressed

   until the starter inrush event begins is on

   the order of 5-10 milliseconds depending on

   contactor designs. 



   So, from the time the starter push button is

   pressed, we want the boost supply to be

   on the job . . . further, it needs to respond

   to the sudden dip in supply voltage during

   inrush time. But the time that the booster needs

   to grunt a load is very short.



   This is why some of the early, super-capacitor

   based brown-out mitigation schemes were successful.

   But the demands on brown-out bus performance

   outgrew those ideas.



   The exemplar boost supplies I have need

   to be peeked at on the bench. I'll be out

   of town tomorrow but I think I can get

   some 'scope pictures of their performance

   before I mail one out.

 

   Bob . . .

johnbright

Joined: 14 Dec 2011
Posts: 166
Location: Newport News, VA

Posted: Sat Sep 05, 2020 5:27 pm Post subject: Re: Brownout Step Up Converter

Dynon Skyview will operate down to 6V for ten seconds with no backup battery. I wonder how it is done and if we can learn something there.

_________________
John Bright, RV-6A, at FWF, O-360
Z-101 single batt dual alt SDS EM-5-F.
john_s_bright@yahoo.com, Newport News, Va
N1921R links

donjohnston

Joined: 13 Dec 2009
Posts: 231

Posted: Mon Sep 07, 2020 4:56 am Post subject: Re: Brownout Step Up Converter

I used the IPS from TCW Tech.  It worked fine. 



But then I pulled it and installed a backup battery for the HXr.  This allows me to power up the EFIS well before turning on the master or starting the engine in addition to providing brownout prevention.  It also provides an additional power source for the EFIS should things go really sideways in the electrical system. 



GRT also sells a backup battery (12v only).

ceengland7(at)gmail.com
Guest

Posted: Tue Sep 15, 2020 6:12 am Post subject: Brownout Step Up Converter

Situation: I have only one device (EFIS) that's susceptible to brownout, and don't need a relay for my endurance bus.

Is there any reason to *not* leave the brownout booster in the circuit continuously?

Ex: boost/buck inverter between main bus & EFIS input.

In case of inverterÂ death, either a diode (simpler), or a simple switch, wired 'around' the inverter. Only unprotectedÂ failure mode I can see is the inverter going overvoltage; that could be handled with an OV module if the risk is high enough.

Thoughts?

Thanks,

Charlie



 	  Quote:

user9253

Joined: 28 Mar 2008
Posts: 1927
Location: Riley TWP Michigan

Posted: Tue Sep 15, 2020 10:37 am Post subject: Re: Brownout Step Up Converter

Charlie, how about connecting a diode in parallel with the DC-DC converter 

like you mentioned, but instead of running the DC-DC converter continuously, 

set its output at just below 12 volts.  Then the EFIS will normally be powered 

via the parallel diode and not by the DC-DC converter.

  Another option is to use a backup battery.

  Dual diodes in one package like 863-MBRF20L45CTG can power the

EFIS from the source with the highest voltage.

_________________
Joe Gores

ceengland7(at)gmail.com
Guest

Posted: Tue Sep 15, 2020 11:28 am Post subject: Brownout Step Up Converter

On 9/15/2020 1:37 PM, user9253 wrote:

 	  Quote: 	
		   



 Charlie, how about connecting a diode in parallel with the DC-DC converter

 like you mentioned, but instead of running the DC-DC converter continuously,

 set its output at just below 12 volts.  Then the EFIS will normally be powered

 via the parallel diode and not by the DC-DC converter.

    Another option is to use a backup battery.

    Dual diodes in one package like 863-MBRF20L45CTG can power the

 EFIS from the source with the highest voltage.



 --------

 Joe Gores

Good thought on the voltage setting; that's basically what we'd have 
	


with the AEC circuit, too.



I've long thought about using the boost/buck converter to both isolate 

and keep fully charged a backup battery, but I do like the simplicity of 

Bob's 'one battery to rule them all' philosophy. Also, having a backup 

battery outside the EFIS (an old GRT HX) would mean that it wouldn't 

turn off with the master, meaning that I'd soon forget to power it off, 

meaning.... 



Charlie



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user9253

Joined: 28 Mar 2008
Posts: 1927
Location: Riley TWP Michigan

Posted: Tue Sep 15, 2020 3:54 pm Post subject: Re: Brownout Step Up Converter

How about using the DC-DC converter (no backup battery), but only energize 

it during engine start?  A dual diode will allow either the DC-DC 

converter or the power bus to supply current to the EFIS.  Wired that way,

there is no concern about the DC-DC converter malfunctioning during flight.

The 863-MBRF20L45CTG diode only costs $0.83

_________________
Joe Gores

ceengland7(at)gmail.com
Guest

Posted: Tue Sep 15, 2020 4:23 pm Post subject: Brownout Step Up Converter

On 9/15/2020 6:54 PM, user9253 wrote:

 	  Quote: 	
		   



 How about using the DC-DC converter (no backup battery), but only energize

 it during engine start?  A dual diode will allow either the DC-DC

 converter or the power bus to supply current to the EFIS.  Wired that way,

 there is no concern about the DC-DC converter malfunctioning during flight.



 --------

 Joe Gores

That's basically what is shown in Z101. I suppose it's worth giving a 
	


random choice a try configured to the start button, and if it doesn't 

work I could move it to the bus.



Thanks,



Charlie



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nuckolls.bob(at)aeroelect
Guest

Posted: Thu Sep 17, 2020 5:37 am Post subject: Brownout Step Up Converter

At 06:54 PM 9/15/2020, you wrote:

  	  Quote: 	
		  --> AeroElectric-List message posted by: "user9253" <fransew(at)gmail.com>



 How about using the DC-DC converter (no backup battery), but only energize 

 it during engine start?  A dual diode will allow either the DC-DC 

 converter or the power bus to supply current to the EFIS.  Wired that way,

 there is no concern about the DC-DC converter malfunctioning during flight.



 --------

 Joe Gores 	


    Yup . . . see Z101



 



 

   Bob . . .

cluros(at)gmail.com
Guest

Posted: Thu Sep 17, 2020 8:06 pm Post subject: Brownout Step Up Converter

A couple weeks ago I ordered one of these off eBay:



https://www.ebay.ca/itm/192243452240



DC-DC Converter

5 Amps

Input 3-35 V

Output 5-40 V

I'm trying to support ~1 A EFIS during start so I thought 5 A would be plenty but a closer look at the description says it's good for 3 A with a maximum of 5 A. Turns out the 3 A is on the input side, not the output side. With a voltage output set point of 10V and a ~1 A lamp connected, the lamp browns out (literally) as soon as the input voltage sags below 9V. A long way from the 7V minimum I was hoping for. I plugged it into a Battery Analyzer at 1.0 and 0.5 A and momentarily dropped the input voltage to 8V. Even when voltage is restored it takes several seconds to recover back to the set voltage with a 1 A load. A 0.5 A load is fine.



[img]cid:ii_kf7pmvn40[/img]



So I think these things work fine but are undersized for the application. Unfortunately as soon as I look for 10A or 15A ones the minimum input voltage rises to 8.5 or even 10V. I'm ready to give up on this little project unless someone has found a cheap step up converter that will output at least 1 AÂ (at) 10 V with the bus voltage available during engine start.

On Thu, Sep 17, 2020 at 7:08 AM Robert L. Nuckolls, III <nuckolls.bob(at)aeroelectric.com (nuckolls.bob(at)aeroelectric.com)> wrote:



 	  Quote: 	
		    At 06:54 PM 9/15/2020, you wrote:

  	  Quote: 	
		  --> AeroElectric-List message posted by: "user9253" <fransew(at)gmail.com (fransew(at)gmail.com)>



 How about using the DC-DC converter (no backup battery), but only energize 

 it during engine start?Â  A dual diode will allow either the DC-DC 

 converter or the power bus to supply current to the EFIS.Â  Wired that way,

 there is no concern about the DC-DC converter malfunctioning during flight.



 --------

 Joe Gores 	


 Â Â  Yup . . . see Z101



 



 

 Â  Bob . . .

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nuckolls.bob(at)aeroelect
Guest

Posted: Sat Sep 19, 2020 6:27 am Post subject: Brownout Step Up Converter

At 11:02 PM 9/17/2020, you wrote:

  	  Quote: 	
		  A couple weeks ago I ordered one of these off eBay:



  https://www.ebay.ca/itm/192243452240



 DC-DC Converter

 5 Amps

 Input 3-35 V

 Output 5-40 V



 I'm trying to support ~1 A EFIS during start so I thought 5 A would be plenty but a closer look at the description says it's good for 3 A with a maximum of 5 A. Turns out the 3 A is on the input side, not the output side. With a voltage output set point of 10V and a ~1 A lamp connected, the lamp browns out (literally) as soon as the input voltage sags below 9V. A long way from the 7V minimum I was hoping for. I plugged it into a Battery Analyzer at 1.0 and 0.5 A and momentarily dropped the input voltage to 8V. Even when voltage is restored it takes several seconds to recover back to the set voltage with a 1 A load. A 0.5 A load is fine. 	


   Good investigative work sir!  You're

   on the right track. The up-converter

   you have is a bit on the light side.



   I'd go for beefy . . . and the up-converter

   needs to be characterized in Watts.  A converter

   that would support a 5A load at 14V would be

   rated at 70 W or more.



   The test articles I have on hand are, as I recall,

   150 W devices. I'm hoping to put power to them

   to see if I can characterize their dynamic qualities

   before I send you one.



   I'm a bit out of pocket right now. Getting ready for

   some roto-rooter work on my back . . . got a leg

   that occasionally says, "I quit". It would not be

   a good thing to be loading a patient and suddenly

   find yourself on the ground asking the patient

   to help you up!



   Doc says it's a quick fix with excellent

   prospects for success but in the interim,

   my forays about the shop are limited. The

   up converters I have are, I believe, this

   one:



  https://tinyurl.com/yxndk24a



   Price is right, size is convenient . . .

   and there is little risk for having

   one that is too big. Thanks for sharing

   your observations.



 

 

   Bob . . .

ceengland7(at)gmail.com
Guest

Posted: Sat Sep 19, 2020 7:12 am Post subject: Brownout Step Up Converter

On 9/19/2020 9:26 AM, Robert L.       Nuckolls, III wrote:

     

      	  Quote: 	
		                At 11:02 PM 9/17/2020, you wrote:

               	  Quote: 	
		  A           couple weeks ago I ordered one           of these off eBay:

           

                        https://www.ebay.ca/itm/192243452240

           

           DC-DC Converter

           5 Amps

           Input 3-35 V

           Output 5-40 V

           

           I'm trying to support ~1 A EFIS during start so I thought 5 A           would be           plenty but a closer look at the description says it's good for           3 A with a           maximum of 5 A. Turns out the 3 A is on the input side, not           the output           side. With a voltage output set point of 10V and a ~1 A lamp           connected,           the lamp browns out (literally) as soon as the input voltage           sags below           9V. A long way from the 7V minimum I was hoping for. I plugged           it into a           Battery Analyzer at 1.0 and 0.5 A and momentarily dropped the           input           voltage to 8V. Even when voltage is restored it takes several           seconds to           recover back to the set voltage with a 1 A load. A 0.5 A load           is           fine. 	
       

         Good investigative work sir!  You're

         on the right track. The up-converter

         you have is a bit on the light side.

       

         I'd go for beefy . . . and the up-converter

         needs to be characterized in Watts.  A converter

         that would support a 5A load at 14V would be

         rated at 70 W or more.

       

         The test articles I have on hand are, as I recall,

         150 W devices. I'm hoping to put power to them

         to see if I can characterize their dynamic qualities

         before I send you one.

       

         I'm a bit out of pocket right now. Getting ready for

         some roto-rooter work on my back . . . got a leg

         that occasionally says, "I quit". It would not be

         a good thing to be loading a patient and suddenly

         find yourself on the ground asking the patient

         to help you up!

       

         Doc says it's a quick fix with excellent

         prospects for success but in the interim,

         my forays about the shop are limited. The

         up converters I have are, I believe, this

         one:

       

                https://tinyurl.com/yxndk24a

       

         Price is right, size is convenient . . .

         and there is little risk for having

         one that is too big. Thanks for sharing

         your observations.

       

       

                

             Bob . . .                     	
     These:

 https://www.ebay.com/itm/DC-DC-Converter-10-12-15-20A-150-250-300-400-1200W-Step-up-Step-down-Buck-Boost/382219150784?hash=item58fe0965c0:g:6OwAAOSwisVZrgue

     Claim to be good down to 8.5V input. Various wattage versions     available.

     

     Charlie

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cluros(at)gmail.com
Guest

Posted: Sat Sep 19, 2020 8:30 am Post subject: Brownout Step Up Converter

Now I'm getting confused. The converter Bob linked to has a minimum of 10 volts input. Charlie's is 8.5 volts. The only time we want these units working is below 10 volts, and they need to work much lower than that. The last start on my aircraft recorded a 7.6 from a fully charged battery and that's just what the EFIS managed to capture at 1 sample per second.



Looking again I have found a couple units that claim to work at very low voltages:

https://www.ebay.ca/itm/DC-DC-10A-Buck-Boost-Converter-Step-Up-Down-regulator-Module-for-LED-Driver-US/254169431168

https://www.ebay.ca/itm/DC-DC-Buck-Boost-Converter-Adjustable-CC-CV-Step-Up-Down-Power-Supply-Module/124260980594

I'm considering ordering one for further testing.

Bob best wishes for a quick recovery but take your time. Get yourself fully in fettle before worrying about anyone else!





On Sat, Sep 19, 2020 at 8:17 AM Charlie England <ceengland7(at)gmail.com (ceengland7(at)gmail.com)> wrote:



 	  Quote: 	
		                     On 9/19/2020 9:26 AM, Robert L.       Nuckolls, III wrote:

     

      	  Quote: 	
		                At 11:02 PM 9/17/2020, you wrote:

               	  Quote: 	
		  A           couple weeks ago I ordered one           of these off eBay:

           

                        https://www.ebay.ca/itm/192243452240

           

           DC-DC Converter

           5 Amps

           Input 3-35 V

           Output 5-40 V

           

           I'm trying to support ~1 A EFIS during start so I thought 5 A           would be           plenty but a closer look at the description says it's good for           3 A with a           maximum of 5 A. Turns out the 3 A is on the input side, not           the output           side. With a voltage output set point of 10V and a ~1 A lamp           connected,           the lamp browns out (literally) as soon as the input voltage           sags below           9V. A long way from the 7V minimum I was hoping for. I plugged           it into a           Battery Analyzer at 1.0 and 0.5 A and momentarily dropped the           input           voltage to 8V. Even when voltage is restored it takes several           seconds to           recover back to the set voltage with a 1 A load. A 0.5 A load           is           fine. 	
       

       Â  Good investigative work sir!Â  You're

       Â  on the right track. The up-converter

       Â  you have is a bit on the light side.

       

       Â  I'd go for beefy . . . and the up-converter

       Â  needs to be characterized in Watts.Â  A converter

       Â  that would support a 5A load at 14V would be

       Â  rated at 70 W or more.

       

       Â  The test articles I have on hand are, as I recall,

       Â  150 W devices. I'm hoping to put power to them

       Â  to see if I can characterize their dynamic qualities

       Â  before I send you one.

       

       Â  I'm a bit out of pocket right now. Getting ready for

       Â  some roto-rooter work on my back . . . got a leg

       Â  that occasionally says, "I quit". It would not be

       Â  a good thing to be loading a patient and suddenly

       Â  find yourself on the ground asking the patient

       Â  to help you up!

       

       Â  Doc says it's a quick fix with excellent

       Â  prospects for success but in the interim,

       Â  my forays about the shop are limited. The

       Â  up converters I have are, I believe, this

       Â  one:

       

                https://tinyurl.com/yxndk24a

       

       Â  Price is right, size is convenient . . .

       Â  and there is little risk for having

       Â  one that is too big. Thanks for sharing

       Â  your observations.

       

       

                

           Â  Bob . . .                     	
     These:

 https://www.ebay.com/itm/DC-DC-Converter-10-12-15-20A-150-250-300-400-1200W-Step-up-Step-down-Buck-Boost/382219150784?hash=item58fe0965c0:g:6OwAAOSwisVZrgue

     Claim to be good down to 8.5V input. Various wattage versions     available.

     

     Charlie

   

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ceengland7(at)gmail.com
Guest

Posted: Sat Sep 26, 2020 8:49 am Post subject: Brownout Step Up Converter

Hi Sebastian,

Thought I'd share some rough testing on a 4A rated booster, that seems to use the same inverter IC as the one you're using. I bought these:

https://smile.amazon.com/gp/product/B07XG323G8/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1



I used an automotive brake light bulb that measures 2A draw at 14V and ~1.8A at 12.5V (about what a tired battery might be).



My results with the booster in the circuit, set for 11V output, which should be adequate to keep an EFIS alive.Â 

(list is: supply V/AÂ  Â  booster V):Â 

14/2.1Â  12.6

12/2.0Â  11.1

10/2.7Â  11.1

9/3.1Â  11.1

8.5/3.6Â  11.0

8.0/3.4Â  10.5

Supply V/A are read off my cheap Asian variable supply display, and rounded to nearest tenth. Booster output V measured with Fluke meter, rounded to nearest tenth.

After several minutes with the supply at 8V, the booster output starts dropping a bit. I suspect that is because the inverter IC has no heat sink and is beginning toÂ thermal-limit to protect itself. In any case, the booster should be loaded for only a few seconds during the start event.

Note: One thing I did was to insert a 'fat' diode in series with the supply that goes directly to the lamp (also shown in the Z figure). The diode output and the booster output both feed the lamp. When supply voltage drops below booster output, the diode prevents the booster trying to feed back into the supply at the booster's set voltage (obviously impossible).

Did you check your battery voltage at the battery terminals, or were you using the EFIS to monitor battery voltage? My experience is that depending on how the a/c is wired, the EFIS may see a lower than actual voltage, due to diodes (or resistances) in the path to the EFIS input. Battery voltage dropping to the 6V area when starting sounds like either high resistance in the battery circuit, or a tired battery.

My GRT EFIS has multiple diode-isolated inputs, so the next step is to wire the booster from my E-bus to a spare power input on the EFIS & try it out.

Charlie

On Sat, Sep 19, 2020 at 11:36 AM Sebastien <cluros(at)gmail.com (cluros(at)gmail.com)> wrote:



 	  Quote: 	
		  Now I'm getting confused. The converter Bob linked to has a minimum of 10 volts input. Charlie's is 8.5 volts. The only time we want these units working is below 10 volts, and they need to work much lower than that. The last start on my aircraft recorded a 7.6 from a fully charged battery and that's just what the EFIS managed to capture at 1 sample per second.



Looking again I have found a couple units that claim to work at very low voltages:

https://www.ebay.ca/itm/DC-DC-10A-Buck-Boost-Converter-Step-Up-Down-regulator-Module-for-LED-Driver-US/254169431168

https://www.ebay.ca/itm/DC-DC-Buck-Boost-Converter-Adjustable-CC-CV-Step-Up-Down-Power-Supply-Module/124260980594

I'm considering ordering one for further testing.

Bob best wishes for a quick recovery but take your time. Get yourself fully in fettle before worrying about anyone else!





On Sat, Sep 19, 2020 at 8:17 AM Charlie England <ceengland7(at)gmail.com (ceengland7(at)gmail.com)> wrote:



 	  Quote: 	
		                     On 9/19/2020 9:26 AM, Robert L.       Nuckolls, III wrote:

     

      	  Quote: 	
		                At 11:02 PM 9/17/2020, you wrote:

               	  Quote: 	
		  A           couple weeks ago I ordered one           of these off eBay:

           

                        https://www.ebay.ca/itm/192243452240

           

           DC-DC Converter

           5 Amps

           Input 3-35 V

           Output 5-40 V

           

           I'm trying to support ~1 A EFIS during start so I thought 5 A           would be           plenty but a closer look at the description says it's good for           3 A with a           maximum of 5 A. Turns out the 3 A is on the input side, not           the output           side. With a voltage output set point of 10V and a ~1 A lamp           connected,           the lamp browns out (literally) as soon as the input voltage           sags below           9V. A long way from the 7V minimum I was hoping for. I plugged           it into a           Battery Analyzer at 1.0 and 0.5 A and momentarily dropped the           input           voltage to 8V. Even when voltage is restored it takes several           seconds to           recover back to the set voltage with a 1 A load. A 0.5 A load           is           fine. 	
       

       Â  Good investigative work sir!Â  You're

       Â  on the right track. The up-converter

       Â  you have is a bit on the light side.

       

       Â  I'd go for beefy . . . and the up-converter

       Â  needs to be characterized in Watts.Â  A converter

       Â  that would support a 5A load at 14V would be

       Â  rated at 70 W or more.

       

       Â  The test articles I have on hand are, as I recall,

       Â  150 W devices. I'm hoping to put power to them

       Â  to see if I can characterize their dynamic qualities

       Â  before I send you one.

       

       Â  I'm a bit out of pocket right now. Getting ready for

       Â  some roto-rooter work on my back . . . got a leg

       Â  that occasionally says, "I quit". It would not be

       Â  a good thing to be loading a patient and suddenly

       Â  find yourself on the ground asking the patient

       Â  to help you up!

       

       Â  Doc says it's a quick fix with excellent

       Â  prospects for success but in the interim,

       Â  my forays about the shop are limited. The

       Â  up converters I have are, I believe, this

       Â  one:

       

                https://tinyurl.com/yxndk24a

       

       Â  Price is right, size is convenient . . .

       Â  and there is little risk for having

       Â  one that is too big. Thanks for sharing

       Â  your observations.

       

       

                

           Â  Bob . . .                     	
     These:

 https://www.ebay.com/itm/DC-DC-Converter-10-12-15-20A-150-250-300-400-1200W-Step-up-Step-down-Buck-Boost/382219150784?hash=item58fe0965c0:g:6OwAAOSwisVZrgue

     Claim to be good down to 8.5V input. Various wattage versions     available.

     

     Charlie

   

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cluros(at)gmail.com
Guest

Posted: Sat Sep 26, 2020 9:35 am Post subject: Brownout Step Up Converter

Very interesting Charlie. I was only using a 1A automotive bulb for load and as you say my converter looks like it's using the same hardware as yours so maybe the addition of the second power path makes enough of a difference? I would not have thought so but it's worth a try, I'll wire it up again and see.Â 



Also when dropping the voltage down to 8V I'm doing it as quickly as possible with the power supply fine adjustment. Were you slowly decreasing the input voltage or doing so suddenly?

Mine was $10 CAD for one and those ones are $30 for 5 so the price is ok.

On Sat, Sep 26, 2020 at 9:55 AM Charlie England <ceengland7(at)gmail.com (ceengland7(at)gmail.com)> wrote:



 	  Quote: 	
		  Hi Sebastian,

Thought I'd share some rough testing on a 4A rated booster, that seems to use the same inverter IC as the one you're using. I bought these:

https://smile.amazon.com/gp/product/B07XG323G8/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1



I used an automotive brake light bulb that measures 2A draw at 14V and ~1.8A at 12.5V (about what a tired battery might be).



My results with the booster in the circuit, set for 11V output, which should be adequate to keep an EFIS alive.Â 

(list is: supply V/AÂ  Â  booster V):Â 

14/2.1Â  12.6

12/2.0Â  11.1

10/2.7Â  11.1

9/3.1Â  11.1

8.5/3.6Â  11.0

8.0/3.4Â  10.5

Supply V/A are read off my cheap Asian variable supply display, and rounded to nearest tenth. Booster output V measured with Fluke meter, rounded to nearest tenth.

After several minutes with the supply at 8V, the booster output starts dropping a bit. I suspect that is because the inverter IC has no heat sink and is beginning toÂ thermal-limit to protect itself. In any case, the booster should be loaded for only a few seconds during the start event.

Note: One thing I did was to insert a 'fat' diode in series with the supply that goes directly to the lamp (also shown in the Z figure). The diode output and the booster output both feed the lamp. When supply voltage drops below booster output, the diode prevents the booster trying to feed back into the supply at the booster's set voltage (obviously impossible).

Did you check your battery voltage at the battery terminals, or were you using the EFIS to monitor battery voltage? My experience is that depending on how the a/c is wired, the EFIS may see a lower than actual voltage, due to diodes (or resistances) in the path to the EFIS input. Battery voltage dropping to the 6V area when starting sounds like either high resistance in the battery circuit, or a tired battery.

My GRT EFIS has multiple diode-isolated inputs, so the next step is to wire the booster from my E-bus to a spare power input on the EFIS & try it out.

Charlie

On Sat, Sep 19, 2020 at 11:36 AM Sebastien <cluros(at)gmail.com (cluros(at)gmail.com)> wrote:



 	  Quote: 	
		  Now I'm getting confused. The converter Bob linked to has a minimum of 10 volts input. Charlie's is 8.5 volts. The only time we want these units working is below 10 volts, and they need to work much lower than that. The last start on my aircraft recorded a 7.6 from a fully charged battery and that's just what the EFIS managed to capture at 1 sample per second.



Looking again I have found a couple units that claim to work at very low voltages:

https://www.ebay.ca/itm/DC-DC-10A-Buck-Boost-Converter-Step-Up-Down-regulator-Module-for-LED-Driver-US/254169431168

https://www.ebay.ca/itm/DC-DC-Buck-Boost-Converter-Adjustable-CC-CV-Step-Up-Down-Power-Supply-Module/124260980594

I'm considering ordering one for further testing.

Bob best wishes for a quick recovery but take your time. Get yourself fully in fettle before worrying about anyone else!





On Sat, Sep 19, 2020 at 8:17 AM Charlie England <ceengland7(at)gmail.com (ceengland7(at)gmail.com)> wrote:



 	  Quote: 	
		                     On 9/19/2020 9:26 AM, Robert L.       Nuckolls, III wrote:

     

      	  Quote: 	
		                At 11:02 PM 9/17/2020, you wrote:

               	  Quote: 	
		  A           couple weeks ago I ordered one           of these off eBay:

           

                        https://www.ebay.ca/itm/192243452240

           

           DC-DC Converter

           5 Amps

           Input 3-35 V

           Output 5-40 V

           

           I'm trying to support ~1 A EFIS during start so I thought 5 A           would be           plenty but a closer look at the description says it's good for           3 A with a           maximum of 5 A. Turns out the 3 A is on the input side, not           the output           side. With a voltage output set point of 10V and a ~1 A lamp           connected,           the lamp browns out (literally) as soon as the input voltage           sags below           9V. A long way from the 7V minimum I was hoping for. I plugged           it into a           Battery Analyzer at 1.0 and 0.5 A and momentarily dropped the           input           voltage to 8V. Even when voltage is restored it takes several           seconds to           recover back to the set voltage with a 1 A load. A 0.5 A load           is           fine. 	
       

       Â  Good investigative work sir!Â  You're

       Â  on the right track. The up-converter

       Â  you have is a bit on the light side.

       

       Â  I'd go for beefy . . . and the up-converter

       Â  needs to be characterized in Watts.Â  A converter

       Â  that would support a 5A load at 14V would be

       Â  rated at 70 W or more.

       

       Â  The test articles I have on hand are, as I recall,

       Â  150 W devices. I'm hoping to put power to them

       Â  to see if I can characterize their dynamic qualities

       Â  before I send you one.

       

       Â  I'm a bit out of pocket right now. Getting ready for

       Â  some roto-rooter work on my back . . . got a leg

       Â  that occasionally says, "I quit". It would not be

       Â  a good thing to be loading a patient and suddenly

       Â  find yourself on the ground asking the patient

       Â  to help you up!

       

       Â  Doc says it's a quick fix with excellent

       Â  prospects for success but in the interim,

       Â  my forays about the shop are limited. The

       Â  up converters I have are, I believe, this

       Â  one:

       

                https://tinyurl.com/yxndk24a

       

       Â  Price is right, size is convenient . . .

       Â  and there is little risk for having

       Â  one that is too big. Thanks for sharing

       Â  your observations.

       

       

                

           Â  Bob . . .                     	
     These:

 https://www.ebay.com/itm/DC-DC-Converter-10-12-15-20A-150-250-300-400-1200W-Step-up-Step-down-Buck-Boost/382219150784?hash=item58fe0965c0:g:6OwAAOSwisVZrgue

     Claim to be good down to 8.5V input. Various wattage versions     available.

     

     Charlie

   

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ceengland7(at)gmail.com
Guest

Posted: Sat Sep 26, 2020 11:36 am Post subject: Brownout Step Up Converter

I re-ran the test, dialing back to as low as 7V as quicklyÂ as possible while using the pot on the powerÂ supply. No difference in characteristics.Â 

I then tried it with the lamp fed only by the booster; same result. At 7V supply, current demand is a few tenths over the 4A rating of the booster, and output voltage dropped to right at 10V. Below 7V the booster seems to shut down (light slowly goes out) and if V is brought back up to ~12V, it recovers within a second or two. Remember, I'm recording data with Mk1 eyeball & pencil. I'll report again when I get it 'breadboarded' in the plane.

What's the exchange rate & border penalty in Canada these days? I paid less than US$8 for the pack of 5, shipped. (Sincere apologies if you're getting Trumped.)

Charlie

On Sat, Sep 26, 2020 at 12:44 PM Sebastien <cluros(at)gmail.com (cluros(at)gmail.com)> wrote:



 	  Quote: 	
		  Very interesting Charlie. I was only using a 1A automotive bulb for load and as you say my converter looks like it's using the same hardware as yours so maybe the addition of the second power path makes enough of a difference? I would not have thought so but it's worth a try, I'll wire it up again and see.Â 



Also when dropping the voltage down to 8V I'm doing it as quickly as possible with the power supply fine adjustment. Were you slowly decreasing the input voltage or doing so suddenly?

Mine was $10 CAD for one and those ones are $30 for 5 so the price is ok.

On Sat, Sep 26, 2020 at 9:55 AM Charlie England <ceengland7(at)gmail.com (ceengland7(at)gmail.com)> wrote:



 	  Quote: 	
		  Hi Sebastian,

Thought I'd share some rough testing on a 4A rated booster, that seems to use the same inverter IC as the one you're using. I bought these:

https://smile.amazon.com/gp/product/B07XG323G8/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1



I used an automotive brake light bulb that measures 2A draw at 14V and ~1.8A at 12.5V (about what a tired battery might be).



My results with the booster in the circuit, set for 11V output, which should be adequate to keep an EFIS alive.Â 

(list is: supply V/AÂ  Â  booster V):Â 

14/2.1Â  12.6

12/2.0Â  11.1

10/2.7Â  11.1

9/3.1Â  11.1

8.5/3.6Â  11.0

8.0/3.4Â  10.5

Supply V/A are read off my cheap Asian variable supply display, and rounded to nearest tenth. Booster output V measured with Fluke meter, rounded to nearest tenth.

After several minutes with the supply at 8V, the booster output starts dropping a bit. I suspect that is because the inverter IC has no heat sink and is beginning toÂ thermal-limit to protect itself. In any case, the booster should be loaded for only a few seconds during the start event.

Note: One thing I did was to insert a 'fat' diode in series with the supply that goes directly to the lamp (also shown in the Z figure). The diode output and the booster output both feed the lamp. When supply voltage drops below booster output, the diode prevents the booster trying to feed back into the supply at the booster's set voltage (obviously impossible).

Did you check your battery voltage at the battery terminals, or were you using the EFIS to monitor battery voltage? My experience is that depending on how the a/c is wired, the EFIS may see a lower than actual voltage, due to diodes (or resistances) in the path to the EFIS input. Battery voltage dropping to the 6V area when starting sounds like either high resistance in the battery circuit, or a tired battery.

My GRT EFIS has multiple diode-isolated inputs, so the next step is to wire the booster from my E-bus to a spare power input on the EFIS & try it out.

Charlie

On Sat, Sep 19, 2020 at 11:36 AM Sebastien <cluros(at)gmail.com (cluros(at)gmail.com)> wrote:



 	  Quote: 	
		  Now I'm getting confused. The converter Bob linked to has a minimum of 10 volts input. Charlie's is 8.5 volts. The only time we want these units working is below 10 volts, and they need to work much lower than that. The last start on my aircraft recorded a 7.6 from a fully charged battery and that's just what the EFIS managed to capture at 1 sample per second.



Looking again I have found a couple units that claim to work at very low voltages:

https://www.ebay.ca/itm/DC-DC-10A-Buck-Boost-Converter-Step-Up-Down-regulator-Module-for-LED-Driver-US/254169431168

https://www.ebay.ca/itm/DC-DC-Buck-Boost-Converter-Adjustable-CC-CV-Step-Up-Down-Power-Supply-Module/124260980594

I'm considering ordering one for further testing.

Bob best wishes for a quick recovery but take your time. Get yourself fully in fettle before worrying about anyone else!





On Sat, Sep 19, 2020 at 8:17 AM Charlie England <ceengland7(at)gmail.com (ceengland7(at)gmail.com)> wrote:



 	  Quote: 	
		                     On 9/19/2020 9:26 AM, Robert L.       Nuckolls, III wrote:

     

      	  Quote: 	
		                At 11:02 PM 9/17/2020, you wrote:

               	  Quote: 	
		  A           couple weeks ago I ordered one           of these off eBay:

           

                        https://www.ebay.ca/itm/192243452240

           

           DC-DC Converter

           5 Amps

           Input 3-35 V

           Output 5-40 V

           

           I'm trying to support ~1 A EFIS during start so I thought 5 A           would be           plenty but a closer look at the description says it's good for           3 A with a           maximum of 5 A. Turns out the 3 A is on the input side, not           the output           side. With a voltage output set point of 10V and a ~1 A lamp           connected,           the lamp browns out (literally) as soon as the input voltage           sags below           9V. A long way from the 7V minimum I was hoping for. I plugged           it into a           Battery Analyzer at 1.0 and 0.5 A and momentarily dropped the           input           voltage to 8V. Even when voltage is restored it takes several           seconds to           recover back to the set voltage with a 1 A load. A 0.5 A load           is           fine. 	
       

       Â  Good investigative work sir!Â  You're

       Â  on the right track. The up-converter

       Â  you have is a bit on the light side.

       

       Â  I'd go for beefy . . . and the up-converter

       Â  needs to be characterized in Watts.Â  A converter

       Â  that would support a 5A load at 14V would be

       Â  rated at 70 W or more.

       

       Â  The test articles I have on hand are, as I recall,

       Â  150 W devices. I'm hoping to put power to them

       Â  to see if I can characterize their dynamic qualities

       Â  before I send you one.

       

       Â  I'm a bit out of pocket right now. Getting ready for

       Â  some roto-rooter work on my back . . . got a leg

       Â  that occasionally says, "I quit". It would not be

       Â  a good thing to be loading a patient and suddenly

       Â  find yourself on the ground asking the patient

       Â  to help you up!

       

       Â  Doc says it's a quick fix with excellent

       Â  prospects for success but in the interim,

       Â  my forays about the shop are limited. The

       Â  up converters I have are, I believe, this

       Â  one:

       

                https://tinyurl.com/yxndk24a

       

       Â  Price is right, size is convenient . . .

       Â  and there is little risk for having

       Â  one that is too big. Thanks for sharing

       Â  your observations.

       

       

                

           Â  Bob . . .                     	
     These:

 https://www.ebay.com/itm/DC-DC-Converter-10-12-15-20A-150-250-300-400-1200W-Step-up-Step-down-Buck-Boost/382219150784?hash=item58fe0965c0:g:6OwAAOSwisVZrgue

     Claim to be good down to 8.5V input. Various wattage versions     available.

     

     Charlie

   

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