VansAirForceForums  
Home > VansAirForceForums

- POSTING RULES
- Donate yearly (please).
- Advertise in here!

- Today's Posts | Insert Pics


Go Back   VAF Forums > Model Specific > RV-12
Register FAQ Members List Calendar Search Today's Posts Mark Forums Read

Reply
 
Thread Tools Search this Thread Display Modes
  #1  
Old 05-14-2014, 03:25 PM
JRo JRo is offline
 
Join Date: Dec 2011
Location: Poestenkill, NY (near Albany)
Posts: 124
Default battery discharging in flight

Airborne & homeward bound today, my battery began to discharge. It showed around -6 amp, and voltage dropped from 12.9v to 11.8v in the course of a 40 minute ride home. The only system control I could locate in the cockpit was the 30 amp fuse for the generator, which I checked and found OK.

As it was a beautiful day and homeward bound, didn't think an unscheduled landing was called for; pressed on without further incident.

Any ideas?

Thanks,

Jim R.
Reply With Quote
  #2  
Old 05-14-2014, 05:21 PM
2johns 2johns is offline
 
Join Date: Apr 2008
Location: Great Falls, Montana
Posts: 80
Default

Jim-

The first thing I would check is to make sure the plug into the voltage regulator on the lower engine side of the firewall is pushed in all the way.
Reply With Quote
  #3  
Old 05-14-2014, 06:50 PM
Mich48041 Mich48041 is offline
 
Join Date: Apr 2008
Location: Riley TWP MI
Posts: 2,535
Default

There are some suggestions at this website:
Testing the Rotax Regulator
In addition to the tests mentioned, I would also measure the DC voltage between terminal "C" and the regulator case (with master switch on and engine off). The voltmeter should read battery voltage on terminal C. A more meaningful voltage measurement can be made while doing this test if an automotive brake lamp is connected between terminal "C" and ground. The lamp will load the circuit to make any high resistance connections more noticeable. If all of the above tests do not indicate a problem, but the system voltage is less than 13.5 with the engine running, then replace the voltage regulator.
Joe Gores
Reply With Quote
  #4  
Old 05-14-2014, 09:39 PM
jersey jersey is offline
 
Join Date: May 2010
Location: Wharton, Texas
Posts: 122
Default Replaced Regulator

Had similar problem but would indicate a charge for 10 to 15 minutes during flight but would then start discharging. Replaced the voltage regulator and haven't had a problem since.

Jersey
Reply With Quote
  #5  
Old 05-16-2014, 10:02 AM
Paris12Man's Avatar
Paris12Man Paris12Man is offline
 
Join Date: Apr 2010
Location: Paris, TX
Posts: 261
Default Settings

Since reading this post, I made it a point to monitor my voltage during a flight this morning. I noticed the voltage to be 13.4/13.5 but it was in the yellow below the green area. I think 13.4/13.5 is good but puzzled why it would be in the yellow range. WHAT should the voltage reading be during cruise with everything turning on??
__________________
Steve Garrett - 903-272-5639, scgarrett@exede.net
N905RV - 436 hrs to date
Home field XS30
Reply With Quote
  #6  
Old 05-16-2014, 11:54 AM
Bavafa Bavafa is offline
 
Join Date: Oct 2007
Location: Sacramento, CA
Posts: 2,131
Default

Quote:
Originally Posted by Paris12Man View Post
Since reading this post, I made it a point to monitor my voltage during a flight this morning. I noticed the voltage to be 13.4/13.5 but it was in the yellow below the green area. I think 13.4/13.5 is good but puzzled why it would be in the yellow range. WHAT should the voltage reading be during cruise with everything turning on??
What is your normal voltage reading and how much are you drawing (i.e. all the electronics turned on) during the flight? It is possible that you are taxing your alternator a bit too much.

I think most regulators in alternators are set to about 14.1-14.5v. If you start drawing more amps than the alternator can easily handle, then the voltage comes down in relation to the draw. I would think mid 13v would be fair to judge it as the upper part of the yellow, since the 14.x would be the green and 12.x volt would be considered red or near red.
__________________
Mehrdad
RV7A - IO360M1B - SOLD
Dues paid
Reply With Quote
  #7  
Old 05-16-2014, 01:34 PM
RFSchaller RFSchaller is offline
 
Join Date: Oct 2010
Location: Phoenix, AZ
Posts: 2,132
Default

I thought Dynon had a low bus voltage alarm. My bus volts are usually about 13.8V, and my ammeter usually shows a trickle charge of1 or 2 amps.
Reply With Quote
  #8  
Old 05-17-2014, 08:44 AM
JRo JRo is offline
 
Join Date: Dec 2011
Location: Poestenkill, NY (near Albany)
Posts: 124
Default

Pulled the cowl and began testing. About an hour in, we went to remove plug from regulator/rectifier, and found it loose. One of the 2 securing clips was apparently never seated properly from the get-go! My bad. Once properly "clipped in" all systems normal.

Although I feel foolish, really relieved it was an uncomplicated fix. Whew! I had set aside a whole day for the problem, ended up with the rest of the day free. When does that ever happen, right?!

Jim R.
Reply With Quote
  #9  
Old 05-17-2014, 06:29 PM
BigJohn BigJohn is offline
 
Join Date: Nov 2008
Location: Gloversville, NY
Posts: 1,471
Default

Jim, glad to hear it was a minor issue. Now get that new fuel pump and you should be good to go for a long time.
__________________
John Peck, CFII, A&P, EAA Tech Counselor, Flight Advisor.
RV-12 N37JP 120176 Flying since 2012.
VAF paid through 10/2017. Best bargain in town.
Reply With Quote
  #10  
Old 05-18-2014, 12:23 PM
RFSchaller RFSchaller is offline
 
Join Date: Oct 2010
Location: Phoenix, AZ
Posts: 2,132
Default

I like reading about the simple fixes. I file them away as stuff to try first if I have a problem. --- like the statue in Animal House said "Knowledge is good"!
Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump


All times are GMT -6. The time now is 08:19 AM.


The VAFForums come to you courtesy Delta Romeo, LLC. By viewing and participating in them you agree to build your plane using standardized methods and practices and to fly it safely and in accordance with the laws governing the country you are located in.