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Lew Gallagher

Joined: 04 Jan 2008
Posts: 402
Location: Greenville , SC

Posted: Mon Jul 13, 2015 11:09 am Post subject: Dual battery isolation

Hey Tim O., et al



A little off topic, but related.



I am restoring a bass boat for my step-son.  It will have a main battery for starting, and an auxiliary battery for trolling motor, lights, fish finder etc.



I remember your design for your main and backup batteries having two diodes wired in so that they can be charged from the same source, but not bleed back into the other system.  I've checked and they DO sell "battery isolators" and "automatic charging relay with start isolation" specifically for my marine needs, but they're a little pricey.  They are affordable, but you know I love a challenge and the opportunity to learn something new.



Can I make my own? If so, what are sources and part numbers for the diodes and a diagram?



Thanks, - Lew

_________________
non-pilot
crazy about building
NOW OFICIALLY BUILDER #40549
Fly off completed !

Tim Olson

Joined: 25 Jan 2007
Posts: 2879

Posted: Mon Jul 13, 2015 11:47 am Post subject: Dual battery isolation

I just re-worked this a little for my RV-14 and changed things

ever so slightly, but the Schottky I used for the system this

time is the  DSS2x121-0045B by IXYS.  It handles a lot of

current.



The design basically uses one schottky just to feed from the main

to the aux bus (that feeds the e-bus), just to charge the battery.

(only when the aux master switch is on)  The 2nd schottky was used

primarily because: I turned on the e-bus during engine cranking

to prevent brownout, but then turned it off after it was running.

Without a diode feed, during the switch throw, the power would

be out on the e-bus.  I did some shuffling a little on the new

system to change how it all operates just a tiny bit.  But

one of my initial goals was to NOT have the diode drop (even

the small drop of a schottky) between the main bus that is doing

the charging and the aux batteries, in normal operation. I wanted

that aux battery to get a full voltage charge.



Anyway, above is the part number of the diode I used.

For the diagram, I don't know that what I did will at all

be relevant to what you're trying to do, but it should be

pretty simple to do what you want.  You probably could even

just connect the 2 batteries with just the schottky and

be ok.  Or, if you want full line voltage, you could

just have a 3 way ON-OFF-ON switch so that one path uses

the diode, one uses a plain wire, and center is off.

It should be pretty easy.

Tim





On 7/13/2015 2:10 PM, Lew Gallagher wrote:

 	  Quote: 	
		   



 Hey Tim O., et al



 A little off topic, but related.



 I am restoring a bass boat for my step-son.  It will have a main battery for starting, and an auxiliary battery for trolling motor, lights, fish finder etc.



 I remember your design for your main and backup batteries having two diodes wired in so that they can be charged from the same source, but not bleed back into the other system.  I've checked and they DO sell "battery isolators" and "automatic charging relay with start isolation" specifically for my marine needs, but they're a little pricey.  They are affordable, but you know I love a challenge and the opportunity to learn something new.



 Can I make my own? If so, what are sources and part numbers for the diodes and a diagram?



 Thanks, - Lew



 --------

 non-pilot

 crazy about building

 NOW OFICIALLY BUILDER #40549

 Fly off completed !





 Read this topic online here:



 http://forums.matronics.com/viewtopic.php?p=444698#444698

Lew Gallagher

Joined: 04 Jan 2008
Posts: 402
Location: Greenville , SC

Posted: Mon Jul 13, 2015 6:18 pm Post subject: Dual battery isolation

Thanks for the lightning response, Tim.  I'm on it.  I assume I can just put 

the charge wire from the motor to both diodes, then from each diode to each 

battery?



Later, - Lew

_________________
non-pilot
crazy about building
NOW OFICIALLY BUILDER #40549
Fly off completed !

Tim Olson

Joined: 25 Jan 2007
Posts: 2879

Posted: Tue Jul 14, 2015 3:18 am Post subject: Dual battery isolation

I would just keep the one battery the way it is, charging off the motor, 

and then put

the diode between the positive terminals of the batteries so that the 

second battery

charges off the first battery.  It won't flow power back from that 

second to the

first, but if they're the same type of battery it should keep them both 

charged.

Now, if they aren't the same battery chemistry, I'd rethink it all and 

probably

buy that special charger.  (i.e. if one is a normal starting battery and 

one is

deep cycle or something like that)  I'm not sure what adjustments you'd 

have to

make for the various battery chemistries.  It's much easier if you are 

dealing with

the same battery types.

Tim



On 7/13/2015 9:13 PM, lewgall(at)charter.net wrote:

 	  Quote: 	
		   

 Thanks for the lightning response, Tim.  I'm on it.  I assume I can 

 just put the charge wire from the motor to both diodes, then from each 

 diode to each battery?



 Later, - Lew

Lew Gallagher

Joined: 04 Jan 2008
Posts: 402
Location: Greenville , SC

Posted: Tue Jul 14, 2015 5:05 am Post subject: Dual battery isolation

Hmmm, the part number DSS2x121-0045B looks like it is two diodes side by 

side?  That's why I was thinking total isolation.  I wouldn't want the main 

battery to be drained by running the trolling motor for hours while the 

engine is off.



For RV application, you might be interested in researching this automatic 

charging relay with start isolation by Blue Sea Systems

https://www.bluesea.com/products/7610/SI-ACR_Automatic_Charging_Relay_-_12_24V_DC_120A



I'll see if attaching the pdf instructions to this works.



Later, - Lew



--

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Description:

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Blue_Sea_7610_SI-ACR.pdf

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693.56 KB

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_________________
non-pilot
crazy about building
NOW OFICIALLY BUILDER #40549
Fly off completed !

Tim Olson

Joined: 25 Jan 2007
Posts: 2879

Posted: Tue Jul 14, 2015 5:56 am Post subject: Dual battery isolation

Good point.

For a boat, if it were me, I'd either add a switch then

in series so I could get rid of that connection

when trolling, or, you could stick in a relay that

is either tweaked so that it only closes the relay

when you get a charging voltage over a certain

setpoint, like 13.2V or something...or, it only

closes when the engine is running (detected by

some other means).  Really, personally, I would probably

in real life not even bother to hack this stuff together.

Parts add up to $$ eventually, and I'd rather buy a

product like that $109.97 automatic charging relay,

that is well made.  So I wouldn't even screw with the

stuff you're looking for.



In the plane, it was easy for me to do what I wanted though.

Tim



On 7/14/2015 8:02 AM, lewgall(at)charter.net wrote:

[quote] Hmmm, the part number DSS2x121-0045B looks like it is two diodes side by

 side?  That's why I was thinking total isolation.  I wouldn't want the

 main battery to be drained by running the trolling motor for hours while

 the engine is off.



 For RV application, you might be interested in researching this

 automatic charging relay with start isolation by Blue Sea Systems

 https://www.bluesea.com/products/7610/SI-ACR_Automatic_Charging_Relay_-_12_24V_DC_120A

 I'll see if attaching the pdf instructions to this works.



 Later, - Lew



 --

flying-nut(at)cfl.rr.com
Guest

Posted: Tue Jul 14, 2015 6:19 am Post subject: Dual battery isolation

Sorry guys ..... I just don't understand.

I've deleted a couple of my 'replies' to this thread before I hit 'send' 

already because I can't offer anything really constructive ..... other 

than this is what happens when you violate the 'KISS' principle.

Why do you need two batteries?  Oh, the 'essential buss'.  Well, I have 

switches and fuses for removing all items that do not have their own 

on/off switch.  I can take the time to do that after I get a 'low 

voltage' warning from multiple sources.

Want more cranking power?  Use a higher CCA battery.  Still want to 

isolate that battery and load?  A switch and a high current relay work 

really well but suffers from the human not being automatic .........

So, now we add more and more failure points, weight, and $$$ ........  

it all adds up, an ounce here and a penny there .... soon you have 

pounds and an 'aviation dollar'.

Linn .... KISS supporter (and IMHO)

On 7/14/2015 9:53 AM, Tim Olson wrote:

[quote] 

 Good point.

 For a boat, if it were me, I'd either add a switch then

 in series so I could get rid of that connection

 when trolling, or, you could stick in a relay that

 is either tweaked so that it only closes the relay

 when you get a charging voltage over a certain

 setpoint, like 13.2V or something...or, it only

 closes when the engine is running (detected by

 some other means).  Really, personally, I would probably

 in real life not even bother to hack this stuff together.

 Parts add up to $$ eventually, and I'd rather buy a

 product like that $109.97 automatic charging relay,

 that is well made.  So I wouldn't even screw with the

 stuff you're looking for.

 In the plane, it was easy for me to do what I wanted though.

 Tim

 On 7/14/2015 8:02 AM, lewgall(at)charter.net wrote:

> Hmmm, the part number DSS2x121-0045B looks like it is two diodes side by

> side?  That's why I was thinking total isolation.  I wouldn't want the

> main battery to be drained by running the trolling motor for hours while

> the engine is off.

>

> For RV application, you might be interested in researching this

> automatic charging relay with start isolation by Blue Sea Systems

> https://www.bluesea.com/products/7610/SI-ACR_Automatic_Charging_Relay_-_12_24V_DC_120A 

>

> I'll see if attaching the pdf instructions to this works.

>

> Later, - Lew

>

> --

flysrv10(at)gmail.com
Guest

Posted: Tue Jul 14, 2015 6:44 am Post subject: Dual battery isolation

+1

do not archive.

Rob Kermanj

[quote] On Jul 14, 2015, at 10:15 AM, Linn Walters <flying-nut(at)cfl.rr.com> wrote:

 Sorry guys ..... I just don't understand.

 I've deleted a couple of my 'replies' to this thread before I hit 'send' already because I can't offer anything really constructive ..... other than this is what happens when you violate the 'KISS' principle.

 Why do you need two batteries?  Oh, the 'essential buss'.  Well, I have switches and fuses for removing all items that do not have their own on/off switch.  I can take the time to do that after I get a 'low voltage' warning from multiple sources.

 Want more cranking power?  Use a higher CCA battery.  Still want to isolate that battery and load?  A switch and a high current relay work really well but suffers from the human not being automatic .........

 So, now we add more and more failure points, weight, and $$$ ........  it all adds up, an ounce here and a penny there .... soon you have pounds and an 'aviation dollar'.

 Linn .... KISS supporter (and IMHO)

 On 7/14/2015 9:53 AM, Tim Olson wrote:

> 

> 

> Good point.

> For a boat, if it were me, I'd either add a switch then

> in series so I could get rid of that connection

> when trolling, or, you could stick in a relay that

> is either tweaked so that it only closes the relay

> when you get a charging voltage over a certain

> setpoint, like 13.2V or something...or, it only

> closes when the engine is running (detected by

> some other means).  Really, personally, I would probably

> in real life not even bother to hack this stuff together.

> Parts add up to $$ eventually, and I'd rather buy a

> product like that $109.97 automatic charging relay,

> that is well made.  So I wouldn't even screw with the

> stuff you're looking for.

> 

> In the plane, it was easy for me to do what I wanted though.

> Tim

> 

> 

> 

> On 7/14/2015 8:02 AM, lewgall(at)charter.net wrote:

>> Hmmm, the part number DSS2x121-0045B looks like it is two diodes side by

>> side?  That's why I was thinking total isolation.  I wouldn't want the

>> main battery to be drained by running the trolling motor for hours while

>> the engine is off.

>> 

>> For RV application, you might be interested in researching this

>> automatic charging relay with start isolation by Blue Sea Systems

>> https://www.bluesea.com/products/7610/SI-ACR_Automatic_Charging_Relay_-_12_24V_DC_120A 

>> 

>> 

>> I'll see if attaching the pdf instructions to this works.

>> 

>> Later, - Lew

>> 

>> 

>> 

>> --

deej(at)deej.net
Guest

Posted: Tue Jul 14, 2015 6:53 am Post subject: Dual battery isolation

On 07/14/2015 10:15 AM, Linn Walters wrote:

 	  Quote: 	
		   

 Why do you need two batteries?


	


Brownout.



With a glass panel, cranking the engine causes the panel to reboot,

which is a real PITA.



You can either have independent internal batteries for every electronic

device, or follow the KISS principal and have a single second battery on

an essential buss to keep everything up and running.



-Dj



-- 

Dj Merrill - N1JOV - EAA Chapter 87

Sportsman 2+2 Builder #7118 N421DJ - http://deej.net/sportsman/

Glastar Flyer N866RH - http://deej.net/glastar/

carl.froehlich(at)verizon
Guest

Posted: Tue Jul 14, 2015 8:09 am Post subject: Dual battery isolation

The reason is you can - at low cost and no weight penalty.  With some

thought the result is you can eliminate a plethora of single component

failure scenarios that leave you with a dark panel.  Two PC-625 batteries

provide all the cranking power I need, and each having a 17amp/hr rating

provides plenty of margin.



There are many power distribution schemes out there besides the "essential

buss" that seems to be popular.  Happy to share how I did this on a series

of RVs if interested.



Carl



--

Kellym

Joined: 10 Jan 2006
Posts: 1705
Location: Sun Lakes AZ

Posted: Tue Jul 14, 2015 8:50 am Post subject: Dual battery isolation

IMHO, brownout is one of the lowest priority justifications.

If you expect to fly lots of IFR in areas where widespread IFR is 

common, that might be a reason.

With a glass panel, you only need one panel on for engine start, to 

monitor oil pressure, etc.

Most glass panels today are designed to tolerate down to 8 or 9 volts, 

so brownout is unlikely.

With a glass panel you either want mechanical gyro backup or at least a 

backup battery for the glass panel, by itself.  Navigating and 

communicating can be done with portable backups. Keeping upright is 

better done with keeping the EFIS alive than depending on a portable 

tablet, etc.

Or a couple companies offer mini-EFIS that will run for 3-4 hours on 

batteries, in case you lose all your electrics. I am very comfortable 

with my choices of single electrical system, single battery, with backup 

battery  on each of the two EFIS, with a Dynon D1 mini-EFIS for backup 

and tie-breaking.

On 7/14/2015 7:50 AM, Dj Merrill wrote:

 	  Quote: 	
		   



 On 07/14/2015 10:15 AM, Linn Walters wrote:

> Why do you need two batteries?

 Brownout.



 With a glass panel, cranking the engine causes the panel to reboot,

 which is a real PITA.



 You can either have independent internal batteries for every electronic

 device, or follow the KISS principal and have a single second battery on

 an essential buss to keep everything up and running.



 -Dj

_________________
Kelly McMullen
A&P/IA, EAA Tech Counselor # 5286
KCHD

flysrv10(at)gmail.com
Guest

Posted: Tue Jul 14, 2015 9:16 am Post subject: Dual battery isolation

I do not even turn on my panel before engine start.  I really don’t worry about monitoring oil pressure immediately.  If my engine has performed yesterday, it is likely to perform the same again today.

Do not archive.

 	  Quote: 	
		   On Jul 14, 2015, at 12:45 PM, Kelly McMullen <kellym(at)aviating.com> wrote:

 IMHO, brownout is one of the lowest priority justifications.

 If you expect to fly lots of IFR in areas where widespread IFR is common, that might be a reason.

 With a glass panel, you only need one panel on for engine start, to monitor oil pressure, etc.

 Most glass panels today are designed to tolerate down to 8 or 9 volts, so brownout is unlikely.

 With a glass panel you either want mechanical gyro backup or at least a backup battery for the glass panel, by itself.  Navigating and communicating can be done with portable backups. Keeping upright is better done with keeping the EFIS alive than depending on a portable tablet, etc.

 Or a couple companies offer mini-EFIS that will run for 3-4 hours on batteries, in case you lose all your electrics. I am very comfortable with my choices of single electrical system, single battery, with backup battery  on each of the two EFIS, with a Dynon D1 mini-EFIS for backup and tie-breaking.

 On 7/14/2015 7:50 AM, Dj Merrill wrote:

> 

> 

> On 07/14/2015 10:15 AM, Linn Walters wrote:

>> Why do you need two batteries?

> Brownout.

> 

> With a glass panel, cranking the engine causes the panel to reboot,

> which is a real PITA.

> 

> You can either have independent internal batteries for every electronic

> device, or follow the KISS principal and have a single second battery on

> an essential buss to keep everything up and running.

> 

> -Dj

>

deej(at)deej.net
Guest

Posted: Tue Jul 14, 2015 9:28 am Post subject: Dual battery isolation

On 07/14/2015 12:45 PM, Kelly McMullen wrote:

 	  Quote: 	
		   IMHO, brownout is one of the lowest priority justifications.


	


The beauty of experimental aviation is that we each get to choose our

own priorities.  For me, brownout protection is a high priority.

 	  Quote: 	
		   Most glass panels today are designed to tolerate down to 8 or 9 volts,

 so brownout is unlikely.


	


I can confirm that my panel reboots if the secondary battery is not on,

and several others on here have written similar reports, so I'd actually

say it seems like brownout is very likely without having a secondary

power source for the display.  In your description you say that you have

secondary batteries for each of your two EFIS units, which provide the

same functionality, with a slightly higher maintenance cost but also

slightly higher redundancy.



That's two different ways to solve the same issues, and I'm sure others

have other possible solutions as well.  The important end result is one

that each person feels comfortable with, and none of the solutions are

any more "right" or "wrong" than another.



For me, it is more than just an inconvenience.  My flow is to have

everything powered up, freqs set, checks done, flight plan entered, etc

and then start the engine.



Once the engine is started, your attention needs to be outside of the

aircraft, not focused inside on the pretty displays.  This is basic

safety 101.



-Dj



-- 

Dj Merrill - N1JOV - EAA Chapter 87

Sportsman 2+2 Builder #7118 N421DJ - http://deej.net/sportsman/

Glastar Flyer N866RH - http://deej.net/glastar/

flying-nut(at)cfl.rr.com
Guest

Posted: Tue Jul 14, 2015 9:40 am Post subject: Dual battery isolation

My only response to 'brownout' while cranking is ..... you might have an 

electrical problem.

Most likely causes  would be using the airframe and #4 jumpers across 

the engine mount isolators.



Vans uses flat braid and crimp connectors .... but a lot of builders 

just bolt them down without cleaning the paint from under the lugs.

I ran a #2 ground wire from the battery to the engine case using 

firewall bulkhead connectors (from a race car site).  Yes, a little more 

weight ...... but should not have any electrical issues.



You're right about the internal batteries though, I have two MGL Odyssey 

panels, and each has it's own backup battery ..... same battery used in 

most emergency exit lights.  Yes, I have to flip a switch to charge 

them, and the switches are mounted right next to the panel's power 

switch.  You do not need another huge battery for today's glass panels 

.....

Linn



On 7/14/2015 10:50 AM, Dj Merrill wrote:

 	  Quote: 	
		   



 On 07/14/2015 10:15 AM, Linn Walters wrote:

> Why do you need two batteries?

 Brownout.



 With a glass panel, cranking the engine causes the panel to reboot,

 which is a real PITA.



 You can either have independent internal batteries for every electronic

 device, or follow the KISS principal and have a single second battery on

 an essential buss to keep everything up and running.



 -Dj

deej(at)deej.net
Guest

Posted: Tue Jul 14, 2015 10:00 am Post subject: Dual battery isolation

On 07/14/2015 01:36 PM, Linn Walters wrote:

 	  Quote: 	
		   

 My only response to 'brownout' while cranking is ..... you might have an

 electrical problem.


	


Yes, the problem is that the starter load reduces the voltage to the

other electrical devices, causing them to reboot.



This is a well known and much discussed issue.  Nothing out of the

ordinary at all.



My setup has two separate grounding cables from the engine to a common

grounding block that passes through the firewall to a "forest of tabs"

on the other side.  This is the singular grounding location for the

entire airframe, and nothing uses the airframe itself for grounding.

 	  Quote: 	
		   You do not need another huge battery for today's glass panels


	


Exactly.  My secondary battery is a small 7ah battery much the same as

used in the emergency exit lights or small UPS.  It not only feeds the

two EFIS units, but also the GNS480 and the electronic ignition, so

everything critical has a backup power source.



Rather than having two secondary batteries to maintain like you have, I

just have a single one and it charges automatically via a diode.



Kinda sounds like my system is a bit simpler than yours...  *wink*



-Dj



-- 

Dj Merrill - N1JOV - EAA Chapter 87

Sportsman 2+2 Builder #7118 N421DJ - http://deej.net/sportsman/

Glastar Flyer N866RH - http://deej.net/glastar/

Tim Olson

Joined: 25 Jan 2007
Posts: 2879

Posted: Tue Jul 14, 2015 10:11 am Post subject: Dual battery isolation

I feel the same as Dj.

I'm going to disconnect from the conversation because these

days I tire of the same old discussions, but, I'll give one

more senario that I like having everything stay up for.

When flying IFR, I've had a bunch of occasions where I

sat in the plane and fired up my primary screen, and

my WSI system, to get a good look at dark storm cells

adjacent to my area.  I wanted to check to see what

they were doing and if I could depart and get routed

out of the airport environment without worry.

It takes a few minutes for any weather system to start

putting together the data to get a good display.

So, I have my WSI set up with a small switch to either

use the e-bus or main bus.  But on days like that, I like

to have my panel humming, my flight plan entered and

everything all updated as to WX, before I launch. Sometimes

you have to phone call Clearance delivery and they have you

sit tight a bit.  It's nice to be able to shut down the

engine and just sit it out, and then fire it back up without

having to re-enter and re-boot everything.  Kelly is

just wrong about the EFIS's not rebooting. They can.

There are too many brands and models to make a blanket

statement like that. Mine does. And even if it didn't,

I'd rather have it keep full line voltage. So my

system does what I want it to do.  There are also many

different types of starters, that may draw more or less

current.  Mine seems to take quite a bit.

For many people I would suggest you check out

TCW Tech's various things like Intelligent power stabilizers

and such. They have great products that can make

all this much easier for you.

It takes a lot off your thinking-plate when worrying

about such things.  At any rate as for the way the

electrical system works, I felt I wanted it,

needed it, and could do it, so I did. To each his own.

With that, I'll exit the discussion because with

9+ years of flying behind the system, I'm very happy

with it and it's not going to do me much good to

argue with anyone on it.  To me it's just wasted time

that I can never get back.

Tim

On 7/14/2015 12:25 PM, Dj Merrill wrote:

 	  Quote: 	

 On 07/14/2015 12:45 PM, Kelly McMullen wrote:

> IMHO, brownout is one of the lowest priority justifications.

 The beauty of experimental aviation is that we each get to choose our

 own priorities.  For me, brownout protection is a high priority.

> Most glass panels today are designed to tolerate down to 8 or 9 volts,

> so brownout is unlikely.

 I can confirm that my panel reboots if the secondary battery is not on,

 and several others on here have written similar reports, so I'd actually

 say it seems like brownout is very likely without having a secondary

 power source for the display.  In your description you say that you have

 secondary batteries for each of your two EFIS units, which provide the

 same functionality, with a slightly higher maintenance cost but also

 slightly higher redundancy.

 That's two different ways to solve the same issues, and I'm sure others

 have other possible solutions as well.  The important end result is one

 that each person feels comfortable with, and none of the solutions are

 any more "right" or "wrong" than another.

 For me, it is more than just an inconvenience.  My flow is to have

 everything powered up, freqs set, checks done, flight plan entered, etc

 and then start the engine.

 Once the engine is started, your attention needs to be outside of the

 aircraft, not focused inside on the pretty displays.  This is basic

 safety 101.

 -Dj

flying-nut(at)cfl.rr.com
Guest

Posted: Tue Jul 14, 2015 10:29 am Post subject: Dual battery isolation

Tim, thanks for weighing in before you bailed out .... you raise some 

very valid points.

I'm not trying to change anyone's mind .... just offering a different 

point of view, a result of my experience troubleshooting other peoples 

electrical problems.  Typically the problems are grounds related.  If 

you're suffering brown-out problems go to Sky-Tecs troubleshooting page 

.... http://www.skytecair.com/Troubleshooting.htm.  It may not help 

everyone, but it's worth a try.

Linn

On 7/14/2015 2:08 PM, Tim Olson wrote:

 	  Quote: 	

 I feel the same as Dj.

 I'm going to disconnect from the conversation because these

 days I tire of the same old discussions, but, I'll give one

 more senario that I like having everything stay up for.

 When flying IFR, I've had a bunch of occasions where I

 sat in the plane and fired up my primary screen, and

 my WSI system, to get a good look at dark storm cells

 adjacent to my area.  I wanted to check to see what

 they were doing and if I could depart and get routed

 out of the airport environment without worry.

 It takes a few minutes for any weather system to start

 putting together the data to get a good display.

 So, I have my WSI set up with a small switch to either

 use the e-bus or main bus.  But on days like that, I like

 to have my panel humming, my flight plan entered and

 everything all updated as to WX, before I launch. Sometimes

 you have to phone call Clearance delivery and they have you

 sit tight a bit.  It's nice to be able to shut down the

 engine and just sit it out, and then fire it back up without

 having to re-enter and re-boot everything.  Kelly is

 just wrong about the EFIS's not rebooting. They can.

 There are too many brands and models to make a blanket

 statement like that. Mine does. And even if it didn't,

 I'd rather have it keep full line voltage. So my

 system does what I want it to do.  There are also many

 different types of starters, that may draw more or less

 current.  Mine seems to take quite a bit.

 For many people I would suggest you check out

 TCW Tech's various things like Intelligent power stabilizers

 and such. They have great products that can make

 all this much easier for you.

 It takes a lot off your thinking-plate when worrying

 about such things.  At any rate as for the way the

 electrical system works, I felt I wanted it,

 needed it, and could do it, so I did. To each his own.

 With that, I'll exit the discussion because with

 9+ years of flying behind the system, I'm very happy

 with it and it's not going to do me much good to

 argue with anyone on it.  To me it's just wasted time

 that I can never get back.

 Tim

 On 7/14/2015 12:25 PM, Dj Merrill wrote:

> 

>

> On 07/14/2015 12:45 PM, Kelly McMullen wrote:

>> IMHO, brownout is one of the lowest priority justifications.

>

> The beauty of experimental aviation is that we each get to choose our

> own priorities.  For me, brownout protection is a high priority.

>> Most glass panels today are designed to tolerate down to 8 or 9 volts,

>> so brownout is unlikely.

>

> I can confirm that my panel reboots if the secondary battery is not on,

> and several others on here have written similar reports, so I'd actually

> say it seems like brownout is very likely without having a secondary

> power source for the display.  In your description you say that you have

> secondary batteries for each of your two EFIS units, which provide the

> same functionality, with a slightly higher maintenance cost but also

> slightly higher redundancy.

>

> That's two different ways to solve the same issues, and I'm sure others

> have other possible solutions as well.  The important end result is one

> that each person feels comfortable with, and none of the solutions are

> any more "right" or "wrong" than another.

>

> For me, it is more than just an inconvenience.  My flow is to have

> everything powered up, freqs set, checks done, flight plan entered, etc

> and then start the engine.

>

> Once the engine is started, your attention needs to be outside of the

> aircraft, not focused inside on the pretty displays.  This is basic

> safety 101.

>

> -Dj

>

 -----

 No virus found in this message.

 Checked by AVG - www.avg.com

 07/14/15

Tim Olson

Joined: 25 Jan 2007
Posts: 2879

Posted: Tue Jul 14, 2015 10:56 am Post subject: Dual battery isolation

No problem Linn,

I do believe in the KISS principle.  It usually makes everything

more reliable.  In my case, I actually consider it a pretty

simplistic system....it's just a little complex to think

through on the wiring, but the actual connections involved

aren't complicated at all.  A couple diodes and a couple

relays and you're set.



Regarding the starter, yeah, you can reduce the brown-out issues,

but I don't think it's practical to think you can always keep

your avionics above, say, 10V, and I know there are components

that can't handle less than 9 or 10V, so rather than worry about

it, IMHO it's better to just deal with it.  Even a great

working starter and perfect ground is likely to see a sag that

goes under 10V.



Beyond that, the more battery you put in the plane, the longer

your endurance is if you lose an alternator.  And, the longer

you can run ground tests on items.  I have people I know who

can't hardly configure their systems to do software updates

because they'll drain their battery too quick.  I want to have

a good amount of time for everything.  So there are multiple

goals, and no matter what you do there is a compromise.

The key is fully thinking through YOUR situation with YOUR

equipment, and YOUR goals, and then coming up with what

you need. Then you can optimize your system for your plane

and your methods of flying.



I do, however, agree that KISS counts.  I constantly have to

try to convince other builders and even people at work

when designing network and system redundancy, that often

times the more components you throw in the harder it is to

guarantee reliability.  But there is also a minimum parts

count that works as well.



Tim

On 7/14/2015 1:26 PM, Linn Walters wrote:

 	  Quote: 	
		   



 Tim, thanks for weighing in before you bailed out .... you raise some

 very valid points.



 I'm not trying to change anyone's mind .... just offering a different

 point of view, a result of my experience troubleshooting other peoples

 electrical problems.  Typically the problems are grounds related.  If

 you're suffering brown-out problems go to Sky-Tecs troubleshooting page

 ..... http://www.skytecair.com/Troubleshooting.htm.  It may not help

 everyone, but it's worth a try.

 Linn

 On 7/14/2015 2:08 PM, Tim Olson wrote:

> 

>

> I feel the same as Dj.

>

> I'm going to disconnect from the conversation because these

> days I tire of the same old discussions, but, I'll give one

> more senario that I like having everything stay up for.

>

> When flying IFR, I've had a bunch of occasions where I

> sat in the plane and fired up my primary screen, and

> my WSI system, to get a good look at dark storm cells

> adjacent to my area.  I wanted to check to see what

> they were doing and if I could depart and get routed

> out of the airport environment without worry.

> It takes a few minutes for any weather system to start

> putting together the data to get a good display.

> So, I have my WSI set up with a small switch to either

> use the e-bus or main bus.  But on days like that, I like

> to have my panel humming, my flight plan entered and

> everything all updated as to WX, before I launch. Sometimes

> you have to phone call Clearance delivery and they have you

> sit tight a bit.  It's nice to be able to shut down the

> engine and just sit it out, and then fire it back up without

> having to re-enter and re-boot everything.  Kelly is

> just wrong about the EFIS's not rebooting. They can.

> There are too many brands and models to make a blanket

> statement like that. Mine does. And even if it didn't,

> I'd rather have it keep full line voltage. So my

> system does what I want it to do.  There are also many

> different types of starters, that may draw more or less

> current.  Mine seems to take quite a bit.

>

> For many people I would suggest you check out

> TCW Tech's various things like Intelligent power stabilizers

> and such. They have great products that can make

> all this much easier for you.

> It takes a lot off your thinking-plate when worrying

> about such things.  At any rate as for the way the

> electrical system works, I felt I wanted it,

> needed it, and could do it, so I did. To each his own.

>

> With that, I'll exit the discussion because with

> 9+ years of flying behind the system, I'm very happy

> with it and it's not going to do me much good to

> argue with anyone on it.  To me it's just wasted time

> that I can never get back.

>

> Tim

>

> On 7/14/2015 12:25 PM, Dj Merrill wrote:

>> 

>>

>> On 07/14/2015 12:45 PM, Kelly McMullen wrote:

>>> IMHO, brownout is one of the lowest priority justifications.

>>

>> The beauty of experimental aviation is that we each get to choose our

>> own priorities.  For me, brownout protection is a high priority.

>>

>>

>>> Most glass panels today are designed to tolerate down to 8 or 9 volts,

>>> so brownout is unlikely.

>>

>> I can confirm that my panel reboots if the secondary battery is not on,

>> and several others on here have written similar reports, so I'd actually

>> say it seems like brownout is very likely without having a secondary

>> power source for the display.  In your description you say that you have

>> secondary batteries for each of your two EFIS units, which provide the

>> same functionality, with a slightly higher maintenance cost but also

>> slightly higher redundancy.

>>

>> That's two different ways to solve the same issues, and I'm sure others

>> have other possible solutions as well.  The important end result is one

>> that each person feels comfortable with, and none of the solutions are

>> any more "right" or "wrong" than another.

>>

>> For me, it is more than just an inconvenience.  My flow is to have

>> everything powered up, freqs set, checks done, flight plan entered, etc

>> and then start the engine.

>>

>> Once the engine is started, your attention needs to be outside of the

>> aircraft, not focused inside on the pretty displays.  This is basic

>> safety 101.

>>

>> -Dj

>>

>

Kelly McMullen

Joined: 16 Apr 2008
Posts: 1188
Location: Sun Lakes AZ

Posted: Tue Jul 14, 2015 12:18 pm Post subject: Dual battery isolation

Tim, and others,



I agree that having one screen up and everything running before engine start is useful. Dynon Skyview specifically says it will tolerate cranking with the screen on. I wrongly ass-umed that the other brands would have adopted similar power supplies by now.Â  Yes, having backup battery eliminates the cranking problem if the EFIS won't tolerate low voltage. Most certified avionics these days are designed to comply with latest DO-160 standard. I believe it calls for tolerating 8-32 volts. Of course that just means it won't do damage, but may reboot. It has been rather infrequent for me to operate from an uncontrolled field and go through the gyrations for IFR clearance/release. 

A few systems let you just transfer your flight plan from your Ipad to the PFD/MFD system to eliminate the extra data entry. Heck, in Aridzona it is a really rare day for IFR weather that you would want to penetrate with a single engine piston aircraft.



As always, there is no one right choice for everyone, and experimental lets s all make our own choices.

On Tue, Jul 14, 2015 at 11:52 AM, Tim Olson <Tim(at)myrv10.com (Tim(at)myrv10.com)> wrote:

[quote]--> RV10-List message posted by: Tim Olson <Tim(at)myrv10.com (Tim(at)myrv10.com)>

 

 No problem Linn,

 I do believe in the KISS principle.Â  It usually makes everything

 more reliable.Â  In my case, I actually consider it a pretty

 simplistic system....it's just a little complex to think

 through on the wiring, but the actual connections involved

 aren't complicated at all.Â  A couple diodes and a couple

 relays and you're set.

 

 Regarding the starter, yeah, you can reduce the brown-out issues,

 but I don't think it's practical to think you can always keep

 your avionics above, say, 10V, and I know there are components

 that can't handle less than 9 or 10V, so rather than worry about

 it, IMHO it's better to just deal with it.Â  Even a great

 working starter and perfect ground is likely to see a sag that

 goes under 10V.

 

 Beyond that, the more battery you put in the plane, the longer

 your endurance is if you lose an alternator.Â  And, the longer

 you can run ground tests on items.Â  I have people I know who

 can't hardly configure their systems to do software updates

 because they'll drain their battery too quick.Â  I want to have

 a good amount of time for everything.Â  So there are multiple

 goals, and no matter what you do there is a compromise.

 The key is fully thinking through YOUR situation with YOUR

 equipment, and YOUR goals, and then coming up with what

 you need. Then you can optimize your system for your plane

 and your methods of flying.

 

 I do, however, agree that KISS counts.Â  I constantly have to

 try to convince other builders and even people at work

 when designing network and system redundancy, that often

 times the more components you throw in the harder it is to

 guarantee reliability.Â  But there is also a minimum parts

 count that works as well.

 

 Tim

 

 

 On 7/14/2015 1:26 PM, Linn Walters wrote:

  	  Quote: 	
		   --> RV10-List message posted by: Linn Walters <flying-nut(at)cfl.rr.com (flying-nut(at)cfl.rr.com)>

 

 Tim, thanks for weighing in before you bailed out .... you raise some

 very valid points.

 

 I'm not trying to change anyone's mind .... just offering a different

 point of view, a result of my experience troubleshooting other peoples

 electrical problems.Â  Typically the problems are grounds related.Â  If

 you're suffering brown-out problems go to Sky-Tecs troubleshooting page

 .... http://www.skytecair.com/Troubleshooting.htm.Â  It may not help

 everyone, but it's worth a try.

 Linn

 

 

 On 7/14/2015 2:08 PM, Tim Olson wrote:

  	  Quote: 	
		   --> RV10-List message posted by: Tim Olson <Tim(at)myrv10.com (Tim(at)myrv10.com)>

 

 I feel the same as Dj.

 

 I'm going to disconnect from the conversation because these

 days I tire of the same old discussions, but, I'll give one

 more senario that I like having everything stay up for.

 

 When flying IFR, I've had a bunch of occasions where I

 sat in the plane and fired up my primary screen, and

 my WSI system, to get a good look at dark storm cells

 adjacent to my area.Â  I wanted to check to see what

 they were doing and if I could depart and get routed

 out of the airport environment without worry.

 It takes a few minutes for any weather system to start

 putting together the data to get a good display.

 So, I have my WSI set up with a small switch to either

 use the e-bus or main bus.Â  But on days like that, I like

 to have my panel humming, my flight plan entered and

 everything all updated as to WX, before I launch. Sometimes

 you have to phone call Clearance delivery and they have you

 sit tight a bit.Â  It's nice to be able to shut down the

 engine and just sit it out, and then fire it back up without

 having to re-enter and re-boot everything.Â  Kelly is

 just wrong about the EFIS's not rebooting. They can.

 There are too many brands and models to make a blanket

 statement like that. Mine does. And even if it didn't,

 I'd rather have it keep full line voltage. So my

 system does what I want it to do.Â  There are also many

 different types of starters, that may draw more or less

 current.Â  Mine seems to take quite a bit.

 

 For many people I would suggest you check out

 TCW Tech's various things like Intelligent power stabilizers

 and such. They have great products that can make

 all this much easier for you.

 It takes a lot off your thinking-plate when worrying

 about such things.Â  At any rate as for the way the

 electrical system works, I felt I wanted it,

 needed it, and could do it, so I did. To each his own.

 

 With that, I'll exit the discussion because with

 9+ years of flying behind the system, I'm very happy

 with it and it's not going to do me much good to

 argue with anyone on it.Â  To me it's just wasted time

 that I can never get back.

 

 Tim

 

 

 

 On 7/14/2015 12:25 PM, Dj Merrill wrote:

  	  Quote: 	
		   --> RV10-List message posted by: Dj Merrill <deej(at)deej.net (deej(at)deej.net)>

 

 On 07/14/2015 12:45 PM, Kelly McMullen wrote:

  	  Quote: 	
		   IMHO, brownout is one of the lowest priority justifications.

 	
 

 The beauty of experimental aviation is that we each get to choose our

 own priorities.Â  For me, brownout protection is a high priority.

 

 

  	  Quote: 	
		   Most glass panels today are designed to tolerate down to 8 or 9 volts,

 so brownout is unlikely.

 	
 

 I can confirm that my panel reboots if the secondary battery is not on,

 and several others on here have written similar reports, so I'd actually

 say it seems like brownout is very likely without having a secondary

 power source for the display.Â  In your description you say that you have

 secondary batteries for each of your two EFIS units, which provide the

 same functionality, with a slightly higher maintenance cost but also

 slightly higher redundancy.

 

 That's two different ways to solve the same issues, and I'm sure others

 have other possible solutions as well.Â  The important end result is one

 that each person feels comfortable with, and none of the solutions are

 any more "right" or "wrong" than another.

 

 For me, it is more than just an inconvenience.Â  My flow is to have

 everything powered up, freqs set, checks done, flight plan entered, etc

 and then start the engine.

 

 Once the engine is started, your attention needs to be outside of the

 aircraft, not focused inside on the pretty displays.Â  This is basic

 safety 101.

 

 -Dj

 

 	
 

 

 

 	
	
 

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 -List" rel="noreferrer" target="_blank">http://www.matronics.com/Navigator?RV10-List

 ===========

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 b Site -

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

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_________________
Kelly McMullen
A&P/IA, EAA Tech Counselor
KCHD

Kellym

Joined: 10 Jan 2006
Posts: 1705
Location: Sun Lakes AZ

Posted: Tue Jul 14, 2015 12:46 pm Post subject: Dual battery isolation

Another thought...there are major differences between varying starters, 

as to current draw. The Skytec PM models have among the highest draw. 

Other designs draw a lot less. Peak may be anywhere from 150 amps to 300 

amps.



On 7/14/2015 10:36 AM, Linn Walters wrote:

 	  Quote: 	
		   



 My only response to 'brownout' while cranking is ..... you might have 

 an electrical problem.

 Most likely causes  would be using the airframe and #4 jumpers across 

 the engine mount isolators.

_________________
Kelly McMullen
A&P/IA, EAA Tech Counselor # 5286
KCHD

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