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Low voltage problem in a new plane

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lgold(at)quantum-associat
Guest

Posted: Sun Dec 23, 2007 10:02 pm Post subject: Low voltage problem in a new plane

Robert, 

The low-voltage buss indicator  light stays on in my new plane and I would really appreciate help to understand  what to do about it. 

I just  finished building a Zenith 701 with a new 100-HP Rotax 912 using your Aeroelectric’s Z16 schematic. B&C did  not have the exact Alternator OV detection system shown in the schematic and sold me their BC207-1 over and low  voltage control module that has a warning light which stays on for under and flashes for  over-voltage. The B&C web site says that the low voltage light goes on if  the Buss voltage is under 12.5V. I wired this module exactly as shown in  Z16. 

I flew  the plane for the first time yesterday starting with a fully charged battery and  all seemed well. On the second flight that day I noticed that the Alternator  under voltage (UV) light came on with the engine idling when the electric fuel pump was on. Since  I don’t need the pump (fuel is gravity fed and the engine has a mechanical pump)  I just turned it off and may have advanced  the throttle beyond its high  2000-RPM idle. The UV light went out  as I did this. I was happy  and did my first solo flight in  the plane for a half hour without incident. Today, assuming the  battery was fully charged (I did not check  it), I made some adjustments to the Dynon instrument for about 30 minutes  (drawing about 1 to 2-amps), and started the engine for a few more go-arounds in the pattern. The engine stared immediately so I guess the battery was  charged . However, the low-voltage light came on as soon as  I started-up and would not go off,  even after a 10-minutes warm-up, much of it  above idle RPM, with almost nothing electric turned on. When I taxied  back to the hanger and shut down (with the UV light still on) my battery voltage  read 12.3V (this is a new battery). 

There are probably a lot of things I need to check to isolate the problem  and need advice as to how to go about  doing this.  What is the most likely  cause? What should I check first and second, third… and how do I check them.  Here are some of my (probably dumb) more  specific questions:       Is    this a definite problem or will the this    under voltage light come on as    described above when there are no problems?

   
   There are two fuselinks attached to the Alternator OV/UV    module.  If one of these    blew or got disconnected would it cause this problem? Since this is    easy to check, I plan to look into this first. 

   
   Is it    possible that the problem is in the voltage regulator? How do you check this    out and determine if the    regulator and not the alternator is the    cause? 

   
   I’m not certain how to check the    alternator or AC    voltage. First, is this    a likely source of the problem? Second, if so    how do I check the alternator output? If    the alternator is bad I probably will have to remove the engine and    find a “real” repairman to fix it, so I    hope the problem lies elsewhere.

 

Any help would really be appreciated.<?xml:namespace prefix = o ns =  "urn:schemas-microsoft-com:office:office" /> 

Best  regards and happy holiday, 

Les

   [quote][b]

nuckolls.bob(at)cox.net
Guest

Posted: Mon Dec 24, 2007 10:56 am Post subject: Low voltage problem in a new plane

At 10:00 PM 12/23/2007 -0800, you wrote:



Robert,



The low-voltage buss indicator light stays on in my new

plane and I would really appreciate help to understand what to

do about it.



I just finished building a Zenith 701 with a new 100-HP Rotax

912 using your Aeroelectric’s Z16 schematic. B&C did not have

the exact Alternator OV detection system shown in the schematic

and sold me their BC207-1 over and low voltage control module that

has a warning light which stays on for under and flashes for

over-voltage. The B&C web site says that the low voltage light goes

on if the Buss voltage is under 12.5V. I wired this module exactly

as shown in Z16.



     I presume that you tied the OV/LV warning

     light into the main bus as shown in Z16 but

     wired the module in accordance with instructions

     provided with the device.

I flew the plane for the first time yesterday starting with a

fully charged battery and all seemed well. On the second flight

that day I noticed that the Alternator under voltage (UV) light

came on with the engine idling when the electric fuel pump was on.



     The Rotax alternators don't give you much output at

     idle or taxi speeds. It's possible if not probable that

     the bus voltage was indeed too low to turn out the

     LV warning light.



Since I don’t need the pump (fuel is gravity fed and the engine has a

mechanical pump) I just turned it off and may have advanced the throttle

beyond its high 2000-RPM idle. The UV light went out as I did this.

I was happy and did my first solo flight in the plane for a half hour

without incident.



     Okay. This is pretty much what I would expect.



Today, assuming the battery was fully charged (I did not check it),

I made some adjustments to the Dynon instrument for about 30 minutes

(drawing about 1 to 2-amps), and started the engine for a few more

go-arounds in the pattern. The engine stared immediately so I guess

the battery was charged . However, the low-voltage light came on as

soon as I started-up and would not go off, even after a 10-minutes

warm-up, much of it above idle RPM, with almost nothing electric turned

on. When I taxied back to the hanger and shut down (with the UV

light still on) my battery voltage read 12.3V (this is a new battery).



     Get a voltmeter and put it on the bus while you're

     observing the Under-Voltage warning light. So far, the

     observations you've reported seem pretty common. PM

     alternators on the Rotax engines are, first of all,

     small. The BIG guy on the 912 is an 18A machine and

     then ONLY at cruise RPM. If you ran accessories on your

     battery for a time, then it's going to take some time

     to replace that energy . . . and it's not going to happen

     fast except AFTER engine RPMs are raised to flight ops

     levels.



There are probably a lot of things I need to check to isolate the problem

and need advice as to how to go about doing this.  What is the most likely

cause? What should I check first and second, third… and how do I check them.

Here are some of my (probably dumb) more specific questions:



     For the moment, I don't see that your system is

     performing in an unexpected manner. It's designed

     in limitations for alternator output at low engine

     RPM would account for what you've observed.



Is this a definite problem or will the this under voltage light come

on as described above when there are no problems? There are two

fuselinks attached to the Alternator OV/UV module.  If one of these

blew or got disconnected would it cause this problem? Since this

is easy to check, I plan to look into this first.



Is it possible that the problem is in the voltage regulator? How do

you check this out and determine if the regulator and not the

alternator is the cause?



I’m not certain how to check the alternator or AC voltage. First,

is this a likely source of the problem? Second, if so how do I check

the alternator output? If the alternator is bad I probably will have

to remove the engine and find a “real” repairman to fix it, so I hope

the problem lies elsewhere.



Any help would really be appreciated.



     Let us begin with the reasonable assumption that you

     don't have a problem. Put a smart battery charger

     on the battery and get it topped off. Then go fly

     the airplane. Doesn't your Dynon have a voltage display

     on it?



     I would expect the Low Volts warning to stay lit

     until some time after takeoff. You can tell if the

     alternator is working by watching the voltmeter.

     At ramp idle and with electro-whizzies turned ON,

     bus voltage will be decidedly less than 13.0 volts.



     As soon as you power up for takeoff, the bus voltage

     should rise . . . not high enough perhaps to turn

     out the light, but if the alternator is working at

     all, bus voltage should come up with engine RPM.



     I'm betting the light will go out after a time sufficient

     for the alternator to top off the battery.



     Bob . . .

lgold(at)quantum-associat
Guest

Posted: Mon Dec 24, 2007 12:37 pm Post subject: Low voltage problem in a new plane

Thanks Bob,

You don't know how much this helped. I read your book and came to one of

your weekend sessions but am still a total novice when it comes to

understanding these systems. 

Have a great Christmas,

Les



[quote] --

Joemotis(at)aol.com
Guest

Posted: Mon Dec 24, 2007 1:00 pm Post subject: Low voltage problem in a new plane

In a message dated 12/23/2007 10:05:49 P.M. Pacific Standard Time,  lgold(at)quantum-associates.com writes:

  	  Quote: 	
		  When I    taxied back to the hanger and shut down (with the UV light still on) my    battery voltage read 12.3V (this is a new battery). 	


 

 So,   have  you   checked     voltage    on the    buss    with    the    engine running?     Maybe    the    device    is  accurate and    you really     are    in a     UV  situation.   

  

 Joe    Motis

 Do not   archive.



See AOL's top rated recipes and easy ways to stay in shape for winter.

  [quote][b]

lgold(at)quantum-associat
Guest

Posted: Mon Dec 24, 2007 4:24 pm Post subject: Low voltage problem in a new plane

Joe,

 I will not be able to get  to the plane for a week, but you can be certain i will check the voltage as soon  as i can.  (I think my Dynon shows voltage and current). I guess anything  higher than 12.5V is Ok but am not certain of this.

 Regards,

 Les



 [quote]         From: owner-aeroelectric-list-server(at)matronics.com    [mailto:owner-aeroelectric-list-server(at)matronics.com] On Behalf Of    Joemotis(at)aol.com

Sent: Monday, December 24, 2007 12:58    PM

To: aeroelectric-list(at)matronics.com

Subject: Re:    Low voltage problem in a new plane

   

      In a message dated 12/23/2007 10:05:49 P.M. Pacific Standard Time,    lgold(at)quantum-associates.com writes:

    	  Quote: 	
		  When I taxied back to the      hanger and shut down (with the UV light still on) my battery voltage read      12.3V (this is a new battery). 	


   

   So,   have  you   checked       voltage    on the    buss      with    the    engine running?       Maybe    the    device    is    accurate and    you really       are    in a     UV    situation.   

    

   Joe    Motis

   Do not   archive.



         See AOL's top rated recipes and easy ways to stay in shape for winter.

 	  Quote: 	
		  



href="http://www.matronics.com/contribution">http://www.matronics.com/chref="http://www.matronics.com/Navigator?AeroElectric-List">http://www.matronics.com/Navigator?AeroElectric-List

href="http://forums.matronics.com">http://forums.matronics.com



	
[b]

glastar(at)gmx.net
Guest

Posted: Tue Dec 25, 2007 1:34 am Post subject: Low voltage problem in a new plane

Les,



2 things coming to my mind if you have the Dynon D10A (or the 

D1007DEK180) do NOT connect the keep alive wire (pin 2 on the D10A) if 

you have an internal battery, as it might drain your battery by 

recharging the internal one. Upgrade your Dynon to the 3.x or 4.x software.



Ad I would advise you get into the setup menu of the D10A/100/180 enable 

the info for the voltage on the right or left side. BTW even if you do 

not have enabled this, when you shutdown one with internal battery and 

have software 4.0 loaded the internal battery will show up during the 

grace periode before total shutdown. Good thing to check the internal 

battery voltage.



br Werner



Les Goldner wrote:

[quote] 



 Thanks Bob,

 You don't know how much this helped. I read your book and came to one of

 your weekend sessions but am still a total novice when it comes to

 understanding these systems. 

 Have a great Christmas,

 Les



   

> --

lgold(at)quantum-associat
Guest

Posted: Tue Dec 25, 2007 11:29 am Post subject: Low voltage problem in a new plane

Werner

I have the Dynon 180. Thanks for the advice, which I will follow before the

next engine startup.

Regards,

Les  



[quote] --

lgold(at)quantum-associat
Guest

Posted: Tue Jan 01, 2008 8:42 pm Post subject: Low voltage problem in a new plane

Bob,

I really think there may be a low voltage problem with my aircraft. 

I followed your instructions and put a smart charger on the battery for a

full day before a two-hour flight today. With only minimal current draw from

the Dynon, my ICOM portable VHF, the battery contactor relay, and the

strobes, the low voltage light would not turn off. When the strobes were

turned off, the light did extinguish. I put a voltmeter across the battery

before start-up. It read 12.8V. Is this normal for a new fully charged

battery?. After landing it read 12.3V. Doesn't this indicate that I have a

problem and I could loose battery power on a longer flight or when running

other electrical components?

I checked all my wires and connections. They appear OK. Unfortunately I

don't trust the Dynon 180 voltage so I have to find another meter if I want

in-flight readings. Would you suggest any further testing before

changing-out the voltage regulator?

Thanks again for your help.

Les    



[quote] --

nuckolls.bob(at)cox.net
Guest

Posted: Tue Jan 01, 2008 10:36 pm Post subject: Low voltage problem in a new plane

At 08:41 PM 1/1/2008 -0800, you wrote:



 	  Quote: 	
		  

<lgold(at)quantum-associates.com>



Bob,

I really think there may be a low voltage problem with my aircraft.

I followed your instructions and put a smart charger on the battery for a

full day before a two-hour flight today. With only minimal current draw from

the Dynon, my ICOM portable VHF, the battery contactor relay, and the

strobes, the low voltage light would not turn off. When the strobes were

turned off, the light did extinguish. I put a voltmeter across the battery

before start-up. It read 12.8V. Is this normal for a new fully charged

battery?. After landing it read 12.3V. Doesn't this indicate that I have a

problem and I could loose battery power on a longer flight or when running

other electrical components?

I checked all my wires and connections. They appear OK. Unfortunately I

don't trust the Dynon 180 voltage so I have to find another meter if I want

in-flight readings. Would you suggest any further testing before

changing-out the voltage regulator?

Thanks again for your help.

Les


	


  Absolutely. If you don't already own a good

  multimeter, this is an excellent opportunity to

  acquire one . . . I just realized that all

  of our discussions to date did not include independent

  voltage data from another instrument.



  Suggest you check out one of these products:



http://tinyurl.com/2xkmnq



http://tinyurl.com/yume4t



  Both are an excellent value and offer a next

  order of voltage measurement accuracy for

  resolving any differences between Dynon

  readings and the behavior of the LV warning

  light.



  Your bus voltage in cruising flight with

  light loads should be on the order of 14.2

  to 14.5 volts.



  Bob . . .

nuckolls.bob(at)cox.net
Guest

Posted: Sat Jan 05, 2008 4:11 pm Post subject: Low voltage problem in a new plane

At 08:41 PM 1/1/2008 -0800, you wrote:



 	  Quote: 	
		  

<lgold(at)quantum-associates.com>



Bob,

I really think there may be a low voltage problem with my aircraft.

I followed your instructions and put a smart charger on the battery for a

full day before a two-hour flight today. With only minimal current draw from

the Dynon, my ICOM portable VHF, the battery contactor relay, and the

strobes, the low voltage light would not turn off. When the strobes were

turned off, the light did extinguish. I put a voltmeter across the battery

before start-up. It read 12.8V. Is this normal for a new fully charged

battery?.


	


   Yes . . .



 	  Quote: 	
		    After landing it read 12.3V. Doesn't this indicate that I have a

problem and I could loose battery power on a longer flight or when running

other electrical components?

I checked all my wires and connections. They appear OK. Unfortunately I

don't trust the Dynon 180 voltage so I have to find another meter if I want

in-flight readings. Would you suggest any further testing before

changing-out the voltage regulator?


	


   Check the voltage in flight with a known-good instrument.

   Your alternator should boost the battery to 13.8 to 14.6 volts in cruise.



   Bob . . .

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