Matronics Email Lists :: View topic - EFIS / EIS combo units

Matronics Email Lists
Web Forum Interface to the Matronics Email Lists

Get Email Distribution Too! FAQ Search Memberlist Usergroups Register

Profile Log in to check your private messages Log in

EFIS / EIS combo units
Goto page Previous 1, 2

Matronics Email Lists Forum Index -> Zenith-List

View previous topic :: View next topic

Author Message

p.mulwitz(at)worldnet.att
Guest

Posted: Mon May 08, 2006 9:12 am Post subject: EFIS / EIS combo units

Frank,



One comment on your battery backup system.  I wouldn't use a Schottky 

diode.  They leak like sieves.  That means a lot of your battery 

power will be used to try to charge the dead electrical system you 

are trying to avoid.  If you are not happy with the voltage drop over 

a standard silicon diode you can build something with no drop at all 

using a power transistor of some sort.



Paul

XL wings

do not archive



At 09:18 AM 5/8/2006, you wrote:

 	  Quote: 	
		  The other point is with an electrically dependant airplane there are

easy ways to provide a redundant system for the whole airplane. If you

wanted to backup the A/P you can simply buy a very  small lead acid

battery (like 1.2AH) to run the A/P. This battery is then charged from

the airplane alternator with a diode (preferably a shotkey diode for

$25) in the feedline...That way if there is a major short in the ships

power the backup battery won't backfeed the fault and the A/P will

continue to fly your airplane


	


--

- The Matronics Zenith-List Email Forum -

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

http://www.matronics.com/Navigator?Zenith-List

frank.hinde(at)hp.com
Guest

Posted: Mon May 08, 2006 9:37 am Post subject: EFIS / EIS combo units

Really?....Wow that's the first I have heard of this.



You mean they actually backflow current? No one has evr mentioned this

(as far as I am aware on the aeroelctric list)



In the ZOD I use a standard diode and it works OK...I have a shotkey on

the RV.....I might have to do some tests.

Thanks



Frank 



--

- The Matronics Zenith-List Email Forum -

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

http://www.matronics.com/Navigator?Zenith-List

craig(at)craigandjean.com
Guest

Posted: Mon May 08, 2006 10:16 am Post subject: EFIS / EIS combo units

I wired my Schottky up backwards to 12 volts and measured the current, 110

microamps. I wouldn't call that significant. This is a International

122NQ030.



-- Craig

- The Matronics Zenith-List Email Forum -

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

http://www.matronics.com/Navigator?Zenith-List

p.mulwitz(at)worldnet.att
Guest

Posted: Mon May 08, 2006 11:21 am Post subject: EFIS / EIS combo units

Frank,



I guess I am not shocked you haven't heard this before.  Perhaps the 

fact I designed electronic circuits for a couple of decades makes me 

better informed than the average poster on the net.



You need to look at the data sheets to confirm this.  The forward 

voltage drop on a Schottky diode is around half that of a junction 

diode.  This makes lots of folks think it is a good idea to use them 

for the application of battery backup charging.  The problem is the 

leakage current when the voltage applied is backwards is a lot higher 

than the junction diode.



The proper use of Schottky diodes is in extremely high speed 

switching circuits - not tortoise speed battery backup 

circuits.  They switch faster than regular diodes at the expense of 

high leakage in the reverse direction.  You would be much better off 

to stick to the standard diodes.  You'll probably save money too.



Paul

XL wings

recovering electrical engineer

do not archive





At 10:30 AM 5/8/2006, you wrote:

 	  Quote: 	
		  Really?....Wow that's the first I have heard of this.



You mean they actually backflow current? No one has evr mentioned this

(as far as I am aware on the aeroelctric list)



In the ZOD I use a standard diode and it works OK...I have a shotkey on

the RV.....I might have to do some tests.

- The Matronics Zenith-List Email Forum -

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

http://www.matronics.com/Navigator?Zenith-List

frank.hinde(at)hp.com
Guest

Posted: Mon May 08, 2006 12:03 pm Post subject: EFIS / EIS combo units

Yes considerably!...I'll have to do a current check on my shotkey...I'm

using the single battery, dual alternator system for the RV so I could

afford a little more volt drop...But losing current backwards is not a

good deal.



Thanks



Frank



Do not archive 



--

- The Matronics Zenith-List Email Forum -

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

http://www.matronics.com/Navigator?Zenith-List

Display posts from previous:

	Matronics Email Lists Forum Index -> Zenith-List	All times are GMT - 8 Hours Goto page Previous 1, 2
Page 2 of 2

Jump to:

You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
You cannot attach files in this forum
You can download files in this forum