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Complex Electrical for Lancair

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scuperhead

Joined: 30 Oct 2018
Posts: 7
Location: Burbank

Posted: Mon Nov 05, 2018 12:17 pm Post subject: Complex Electrical for Lancair

Hi Guys,



Need some help here.  I have a Lancair 360 build that has a 28 volt air conditioner that pulls 50 amps max.  Everything else is 14 volt.  I have a B and C 60 amp alternator that can run either 14 or 28 volt.  I also have a 40 amp B and C that can run 14 or 28.  There are two 14 volt EarthX batteries in series that make up the system.  Here are the options i am considering.



1. Run the 60 amp at 28 volt and the 40 amp to one of the 14 volt batteries that all the 14 volt items are on. I dont expect the 14 volt buss demand to exceed 20 amps.  



2. Run both at 28 volt and use a step down converter for all the 14 volt systems.  



Any comments or other suggestions would be appreciated.  



Thank you,

Craig

_________________
Blue Skies,
Craig

henry(at)pericynthion.org
Guest

Posted: Mon Nov 05, 2018 1:10 pm Post subject: Complex Electrical for Lancair

Hi Craig,

On Mon, Nov 5, 2018 at 12:28 PM scuperhead <craig(at)skybolt.net (craig(at)skybolt.net)> wrote:



 	  Quote: 	
		  Need some help here.Â  I have a Lancair 360 build that has a 28 volt air conditioner that pulls 50 amps max.Â  Everything else is 14 volt.Â  I have a B and C 60 amp alternator that can run either 14 or 28 volt.Â  I also have a 40 amp B and C that can run 14 or 28.Â  There are two 14 volt EarthX batteries in series that make up the system.Â  	




I sometimes wish my Lancair 360 had air conditioning, but damn - that sounds like a bit of a mess electrically.

Â 

 	  Quote: 	
		  Here are the options i am considering.

 

 1. Run the 60 amp at 28 volt and the 40 amp to one of the 14 volt batteries that all the 14 volt items are on. I dont expect the 14 volt buss demand to exceed 20 amps.Â  

	




The trouble with this is that if you don't connect the 28V one to batteries at all, then it won't regulate properly. If you do connect it to the two batteries in series, but also have one of those batteries driving loads and being charged with a separate alternator, the two batteries will become unbalanced. This is a particularly bad problem with EarthX lithium batteries.

Â 

 	  Quote: 	
		   2. Run both at 28 volt and use a step down converter for all the 14 volt systems.Â  

	




This could be a better bet. Assuming you do want to keep the air con, I would consider converting to a primarily 28V system - see which of the currently-14V loads could be inexpensively changed to run on 28V, and add a step-down converter for the remainder. Some starters can be rewired for 28V operation (or just swap the starter, it's only a few hundred bucks). Most modern avionics will run on either voltage. Light bulbs are easily changed.

Good luck,

Henry

scuperhead

Joined: 30 Oct 2018
Posts: 7
Location: Burbank

Posted: Mon Nov 05, 2018 2:09 pm Post subject: Complex Electrical for Lancair

This is the first one I have done that is all electric.  Cooled great on the bench testing.  I have a compressor driven on my lancair.  Has to be the best thing I have ever done to it.   

  

Craig 

   

From: "owner-aeroelectric-list-server(at)matronics.com" <owner-aeroelectric-list-server(at)matronics.com> on behalf of Henry Hallam <henry(at)pericynthion.org>

 Reply-To: "aeroelectric-list(at)matronics.com" <aeroelectric-list(at)matronics.com>

 Date: Monday, November 5, 2018 at 1:22 PM

 To: "aeroelectric-list(at)matronics.com" <aeroelectric-list(at)matronics.com>

 Subject: Re: Complex Electrical for Lancair 

  

  

  

Hi Craig,   

    

On Mon, Nov 5, 2018 at 12:28 PM scuperhead <craig(at)skybolt.net (craig(at)skybolt.net)> wrote: 

   	  Quote: 	
		   

Need some help here.  I have a Lancair 360 build that has a 28 volt air conditioner that pulls 50 amps max.  Everything else is 14 volt.  I have a B and C 60 amp alternator that can run either 14 or 28 volt.  I also have a 40 amp B and  C that can run 14 or 28.  There are two 14 volt EarthX batteries in series that make up the system.   	
  

  

  

I sometimes wish my Lancair 360 had air conditioning, but damn - that sounds like a bit of a mess electrically. 

  

  

  	  Quote: 	
		   

Here are the options i am considering.

 

 1. Run the 60 amp at 28 volt and the 40 amp to one of the 14 volt batteries that all the 14 volt items are on. I dont expect the 14 volt buss demand to exceed 20 amps.   	
  

  

  

The trouble with this is that if you don't connect the 28V one to batteries at all, then it won't regulate properly. If you do connect it to the two batteries in series, but also have one of those batteries driving loads and being charged  with a separate alternator, the two batteries will become unbalanced. This is a particularly bad problem with EarthX lithium batteries. 

  

  

  	  Quote: 	
		   

2. Run both at 28 volt and use a step down converter for all the 14 volt systems.   	
  

  

  

This could be a better bet. Assuming you do want to keep the air con, I would consider converting to a primarily 28V system - see which of the currently-14V loads could be inexpensively changed to run on 28V, and add a step-down converter  for the remainder. Some starters can be rewired for 28V operation (or just swap the starter, it's only a few hundred bucks). Most modern avionics will run on either voltage. Light bulbs are easily changed. 

  

  

  

Good luck, 

  

Henry

_________________
Blue Skies,
Craig

scuperhead

Joined: 30 Oct 2018
Posts: 7
Location: Burbank

Posted: Mon Nov 05, 2018 3:09 pm Post subject: Complex Electrical for Lancair

The 28 volt alternator will be connected to two EarthX batteries in series.  The other alternator would be regulated to 14 volt and connected to one of those batteries.   

  

Craig 

   

From: "owner-aeroelectric-list-server(at)matronics.com" <owner-aeroelectric-list-server(at)matronics.com> on behalf of Henry Hallam <henry(at)pericynthion.org>

 Reply-To: "aeroelectric-list(at)matronics.com" <aeroelectric-list(at)matronics.com>

 Date: Monday, November 5, 2018 at 1:22 PM

 To: "aeroelectric-list(at)matronics.com" <aeroelectric-list(at)matronics.com>

 Subject: Re: Complex Electrical for Lancair 

  

  

  

Hi Craig,   

    

On Mon, Nov 5, 2018 at 12:28 PM scuperhead <craig(at)skybolt.net (craig(at)skybolt.net)> wrote: 

   	  Quote: 	
		   

Need some help here.  I have a Lancair 360 build that has a 28 volt air conditioner that pulls 50 amps max.  Everything else is 14 volt.  I have a B and C 60 amp alternator that can run either 14 or 28 volt.  I also have a 40 amp B and  C that can run 14 or 28.  There are two 14 volt EarthX batteries in series that make up the system.   	
  

  

  

I sometimes wish my Lancair 360 had air conditioning, but damn - that sounds like a bit of a mess electrically. 

  

  

  	  Quote: 	
		   

Here are the options i am considering.

 

 1. Run the 60 amp at 28 volt and the 40 amp to one of the 14 volt batteries that all the 14 volt items are on. I dont expect the 14 volt buss demand to exceed 20 amps.   	
  

  

  

The trouble with this is that if you don't connect the 28V one to batteries at all, then it won't regulate properly. If you do connect it to the two batteries in series, but also have one of those batteries driving loads and being charged  with a separate alternator, the two batteries will become unbalanced. This is a particularly bad problem with EarthX lithium batteries. 

  

  

  	  Quote: 	
		   

2. Run both at 28 volt and use a step down converter for all the 14 volt systems.   	
  

  

  

This could be a better bet. Assuming you do want to keep the air con, I would consider converting to a primarily 28V system - see which of the currently-14V loads could be inexpensively changed to run on 28V, and add a step-down converter  for the remainder. Some starters can be rewired for 28V operation (or just swap the starter, it's only a few hundred bucks). Most modern avionics will run on either voltage. Light bulbs are easily changed. 

  

  

  

Good luck, 

  

Henry

_________________
Blue Skies,
Craig

scuperhead

Joined: 30 Oct 2018
Posts: 7
Location: Burbank

Posted: Mon Nov 05, 2018 3:16 pm Post subject: Re: Complex Electrical for Lancair

Hi Henry,



Flaps, electric boost pump, and landing gear have to run at 14 volt as well as my Electo Air Ignition.  The radios, lights can be 28.  The Vertical Power pro can run on either and will step down for trim but not flaps.  



So far I am favoring option 1.  This creates an automatic backup should either alternator fail.  AC is the only item I would run at 28 volts and that doesn't need to be on in a failure situation.  The starter has the option for 14 or 28 with a jumper select.  



I think the key is setting the regulators at the exact correct voltage to keep both batteries in balance. 



Craig

_________________
Blue Skies,
Craig

nuckolls.bob(at)aeroelect
Guest

Posted: Mon Nov 05, 2018 5:24 pm Post subject: Complex Electrical for Lancair

At 05:16 PM 11/5/2018, you wrote:

  	  Quote: 	
		  --> AeroElectric-List message posted by: "scuperhead" <craig(at)skybolt.net>



 Hi Henry,



 Flaps, electric boost pump, and landing gear have to run at 14 volt as well as my Electo Air Ignition.  The radios, lights can be 28.  The Vertical Power pro can run on either and will step down for trim but not flaps.  



 So far I am favoring option 1.  This creates an automatic backup should either alternator fail.  AC is the only item I would run at 28 volts and that doesn't need to be on in a failure situation.  The starter has the option for 14 or 28 with a jumper select.  



 I think the key is setting the regulators at the exact correct voltage to keep both batteries in balance. 	


    I've been pondering this configuration and I'm not sure

    there is a concern for 'keeping things balanced'.



    With independent, voltage regulated, engine driven

    power sources, the two batteries have no interaction.

    The 12v battery is a security blanket for the

    14v system irrespective of the upper battery.

   

    The only 'battery duties' to be performed by the

    12v + 12v stack is to isolated the 28v alternator

    from compressor motor inrush currents . . . an

    event that is tens of milliseconds long and very

    low energy event. Once the a/c motor is running

    and the 28v bus stable, the battery is free to

    recharge for the inrush event . . . after that

    it just sits there fat, dumb and happy.



    The fault condition to be managed is failure or

    shutdown of the 28v alternator whereupon I think

    I would plan for a auto-shutdown of the a/c motor

    if the 28v bus voltage falls below 25 or so for

    more than say 5 seconds.



    If all else in the aircraft can run happily

    at 14v, then the lower battery is always in

    place to do it's expected house-keeping tasks.

    The existence of the upper battery-alternator

    should be transparent to the lower battery-

    alternator except during the 28v alternator

    event which I think is easily managed.



    In this case, the batteries need not be the

    same size but it wouldn't hurt if they were.

    You could swap them between slots say every

    oil change.



    



 



 



 

   Bob . . .

scuperhead

Joined: 30 Oct 2018
Posts: 7
Location: Burbank

Posted: Mon Nov 05, 2018 6:35 pm Post subject: Re: Complex Electrical for Lancair

Hi Bob,



I like your thinking on this and I agree with everything you said. I really think that this is the way to go and I like your idea of a cut off at say 25 volts.  I would run the starter on 28. The Ac has a soft start so there is never a spike on start and the max it could ramp to is 50 amps on a hot day. Not so hot days are 35 to 40 amps.

_________________
Blue Skies,
Craig

argoldman(at)aol.com
Guest

Posted: Mon Nov 05, 2018 6:57 pm Post subject: Complex Electrical for Lancair

Just a thoughtâ€”-Most modern avionics are pretty happy with either 12(14) or 24(2 V no need to reduce there. For others that require 12v, if necessary, a reducer of much smaller size. Lead acid batter

Agree totally with the charging /using/differentialy can be a problem

KISS. Use gen 2 wth a voltage set slightly lower but still in charging range to become active as an aux easier to monitor state and charging

Rich



Sent from my iPhone



On Nov 5, 2018, at 3:10 PM, Henry Hallam <henry(at)pericynthion.org (henry(at)pericynthion.org)> wrote:

 	  Quote: 	
		  Hi Craig,

On Mon, Nov 5, 2018 at 12:28 PM scuperhead <craig(at)skybolt.net (craig(at)skybolt.net)> wrote:



 	  Quote: 	
		  Need some help here.  I have a Lancair 360 build that has a 28 volt air conditioner that pulls 50 amps max.  Everything else is 14 volt.  I have a B and C 60 amp alternator that can run either 14 or 28 volt.  I also have a 40 amp B and C that can run 14 or 28.  There are two 14 volt EarthX batteries in series that make up the system.  	




I sometimes wish my Lancair 360 had air conditioning, but damn - that sounds like a bit of a mess electrically.

 

 	  Quote: 	
		  Here are the options i am considering.

 

 1. Run the 60 amp at 28 volt and the 40 amp to one of the 14 volt batteries that all the 14 volt items are on. I dont expect the 14 volt buss demand to exceed 20 amps.  

	




The trouble with this is that if you don't connect the 28V one to batteries at all, then it won't regulate properly. If you do connect it to the two batteries in series, but also have one of those batteries driving loads and being charged with a separate alternator, the two batteries will become unbalanced. This is a particularly bad problem with EarthX lithium batteries.

 

 	  Quote: 	
		   2. Run both at 28 volt and use a step down converter for all the 14 volt systems.  

	




This could be a better bet. Assuming you do want to keep the air con, I would consider converting to a primarily 28V system - see which of the currently-14V loads could be inexpensively changed to run on 28V, and add a step-down converter for the remainder. Some starters can be rewired for 28V operation (or just swap the starter, it's only a few hundred bucks). Most modern avionics will run on either voltage. Light bulbs are easily changed.

Good luck,

Henry

nuckolls.bob(at)aeroelect
Guest

Posted: Mon Nov 05, 2018 8:23 pm Post subject: Complex Electrical for Lancair

At 08:36 PM 11/5/2018, you wrote:

  	  Quote: 	
		  --> AeroElectric-List message posted by: "scuperhead" <craig(at)skybolt.net>



 Hi Bob,



 I like your thinking on this and I agree with everything you said. I really think that this is the way to go and I like your idea of a cut off at say 25 volts.  I would run the starter on 28. The Ac has a soft start so there is never a spike on start and the max it could ramp to is 50 amps on a hot day. Not so hot days are 35 to 40 amps. 	




   Then both batteries should be the same

   size and starter-capable . . . PC680 or

   beefier.



 

 

   Bob . . .

scuperhead

Joined: 30 Oct 2018
Posts: 7
Location: Burbank

Posted: Mon Nov 05, 2018 8:52 pm Post subject: Re: Complex Electrical for Lancair

Hi Bob,



Both batteries are EarthX replacements for PC680.  I have used EarthX batteries before and they are way better than the PC680.

_________________
Blue Skies,
Craig

user9253

Joined: 28 Mar 2008
Posts: 1921
Location: Riley TWP Michigan

Posted: Tue Nov 06, 2018 5:57 am Post subject: Re: Complex Electrical for Lancair

One thing not mentioned yet is over-voltage protection.  It is mandatory for EarthX batteries per the manufacturer.  EarthX batteries will automatically disconnect incoming current when the voltage is above a certain point.  But that automatic system has its limits which can be exceeded by a runaway alternator.

_________________
Joe Gores

nuckolls.bob(at)aeroelect
Guest

Posted: Tue Nov 06, 2018 11:05 am Post subject: Complex Electrical for Lancair

At 10:52 PM 11/5/2018, you wrote:

  	  Quote: 	
		  --> AeroElectric-List message posted by: "scuperhead" <craig(at)skybolt.net>



 Hi Bob,



 Both batteries are EarthX replacements for PC680.  I have used EarthX batteries before and they are way better than the PC680. 	


  Agreed . . . please keep us aprised of your

  experience in the proposed configuration.

  LiPO4 does pose a challenge over SVLA

  due to the spread between nominal charge/

  discharge voltages. Your 28v lo-volt shutdown

  sensor may need to be more precise . . . or

  perhaps you'll want to put a CURRENT sensor

  on the top battery that effects a/c shutdown

  if the battery is being DISCHARGED for some

  significant magnitude/time.



  Flight tests are called for . . . and this

  List is your source for crafting the optimum

  architecture and hardware . . .



 

 

   Bob . . .

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