VansAirForceForums  
Home > VansAirForceForums

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

- Today's Posts | Insert Pics


Go Back   VAF Forums > Avionics / Interiors / Fiberglass > Electrical Systems
Register FAQ Members List Calendar Today's Posts

Reply
 
Thread Tools Search this Thread Display Modes
  #1  
Old 09-17-2016, 07:24 AM
New_RV_Fan New_RV_Fan is offline
 
Join Date: Aug 2016
Location: Vernon, British Columbia
Posts: 9
Default Parasitic electrical drain

Hello. I am a new owner of an RV-6A (IO 360, CS Prop). I've flown 15 hours in the last twelve days of ownership and I'm loving it.

It does have a couple of snags that I'm working on rectifying. The previous owner mentioned the battery dying if he didn't fly the airplane regularly. Indeed I replaced the Odyssey 680 battery last week due to it's low capacity.

I am showing a continuous current drain of 3.9 to 4.6 mAmps. I know it is not much, but I would like to see if I can eliminate it. I work out of town and may be away for weeks at a time. It would be easier to solve the problem than remembering to disconnect the battery each time.

Here is a video: https://www.youtube.com/watch?v=UvmR1pibU7U of what is happening with the battery master off, and the multimeter hooked up in series between the battery NEG post and the battery ground.

The regular nature of the current switching leads me to suspect something digitally or computer controlled. Any suggestions on where to look?

The following is what I have for electrical equipment:

60 Amp ND alternator
Dynon D10 and D10A (with the various sensors)
Unison LASAR ignition
EXPBUS DC load center
Garmin 396 GPS
TruTrak DigiFlight II autopilot
Bendix King KY97A VHF COM
PS 3000 Intercom
XCOM 760 VHF COM
Remote Compass magnetometer in rear fuselage

That's the bulk of the equipment. Any help would be appreciated. Thank you.

John Swallow (the younger one)
Vernon, BC, Canada
Reply With Quote
  #2  
Old 09-17-2016, 07:42 AM
Carl Froehlich's Avatar
Carl Froehlich Carl Froehlich is offline
 
Join Date: Dec 2007
Location: Dogwood Airpark (VA42)
Posts: 2,596
Default

What is connected between the master solenoid and the battery? I suspect the builder added an "always hot" lead to the battery.

Carl
Reply With Quote
  #3  
Old 09-17-2016, 08:53 AM
rapid_ascent rapid_ascent is offline
 
Join Date: Mar 2008
Location: Dublin, CA
Posts: 1,261
Default

Like Carl says it should be pretty easy to find. Look on the main contactor and battery for more than one wire other than the large one. Now finding where it goes to might be more of a challenge.
__________________
Ray Tonks
2020 Donation Paid
Titan IOX-370, Dual PMAGs, 9.6:1 Pistons, FM-150
RV-7 Fuselage in progress
* Cabin Interior - In progress
RV-7 SB Wings
* Both Wings fully skinned
* Fuel Tanks Complete - No leaks finally
* Ailerons Complete
* Flaps Complete
RV-7 Empennage - Complete (a little fiberglass work left)
Vans Training Kit # 2 - Complete
RV-7 Preview Plans
Vans Training Kit #1 - Complete
EAA Sheet Metal Class - Complete
Reply With Quote
  #4  
Old 09-17-2016, 08:57 AM
David Paule David Paule is offline
 
Join Date: Dec 2009
Location: Boulder, CO
Posts: 4,435
Default

What a good opportunity to make a wiring diagram for your airplane!

Dave
Reply With Quote
  #5  
Old 09-17-2016, 09:14 AM
pilot2512 pilot2512 is offline
 
Join Date: Aug 2007
Location: Spring, TX
Posts: 449
Default

I would look for a clock or something that has an always hot input to hold memory.
__________________
Jay
RV-9A
Empennage complete.
Wings complete.
Fuselage in progress
Wiring in progress
2020 Donation made!
Reply With Quote
  #6  
Old 09-17-2016, 10:43 AM
New_RV_Fan New_RV_Fan is offline
 
Join Date: Aug 2016
Location: Vernon, British Columbia
Posts: 9
Default

Thank you all for the quick replies. I just came back from a quick flight in the rain to wash off the detergent from washing the airplane in the rain.

I'm now on my way to pick up some PTFE paste for an oil pressure sensor replacement that I will do today and at that time will more closely investigate and map out my electrical system. As it is a slider, I have to spend some more time on my back to do so. Because of the EXPBUS, it will take me a bit of time to isolate where the various cables, wires and leads go. There is a spot for a keep alive circuit on the bus so I will try to see if it is utilized.

Will report back later.

John
__________________
John Swallow
C-FRVP
RV-6A 180 hp, CS
Vernon, BC
Canada
Reply With Quote
  #7  
Old 09-17-2016, 03:51 PM
New_RV_Fan New_RV_Fan is offline
 
Join Date: Aug 2016
Location: Vernon, British Columbia
Posts: 9
Default Making progress

So. There were four leads attached to the "keep alive" circuit on the EXPBUS. When I removed all four leads, the current drain dropped to a steady 3.33 mAmps. No fluctuation. By re-attaching leads one at a time I determined the following:

Two of the leads (one protected by an automotive style Buss fuse) had no affect on the current drain when detached. I re-attached both of them.

Of the remaining two leads:

i) One brought the current drain up to 3.77 mAmps (0.44 mAmp increase from base 3.33 mAmps)
ii) One brought the current drain up to a 3.51 amps fluctuating to 4.12 amps in the same periodic basis as originally observed.

I will leave the suspect two leads detached and get ready to go flying as soon as the clouds clear and see what capability I have lost.

I now have the steady 3.33 mAmp drain to isolate and will look at the way my ammeter shunt is installed to see if it is continuously "live" and therefore causing the drain. I have been looking to change it's position anyway as the gauge in the cockpit fluctuates between positive and negative amps in flight and I think I'd rather measure the alternator output or the electrical load, vice the battery charge/discharge that I believe I am currently seeing. Mostly so I don't see negatives.

Thank you all for some encouragement. Honestly, I was very reluctant to mess around with the EXPBUS leads, but realize now that I will have to become comfortable with the electrical side of this airplane if I'm going to maintain it myself.

John
__________________
John Swallow
C-FRVP
RV-6A 180 hp, CS
Vernon, BC
Canada
Reply With Quote
  #8  
Old 09-17-2016, 05:35 PM
Mich48041 Mich48041 is offline
 
Join Date: Apr 2008
Location: Riley TWP MI
Posts: 3,070
Default

Is the battery contactor solid state? They can leak a small amount. Regardless, the battery contactor must be allowing a few milliamps to flow if it is the only thing connected to the battery positive terminal. Replace the contactor.
If you want to make sure the contactor is leaking current when off, disconnect the big fat battery cable from it. Then repeat the milliammeter test of the negative battery cable.
__________________
Joe Gores
RV-12 Flying
Reply With Quote
  #9  
Old 09-17-2016, 06:24 PM
Mel's Avatar
Mel Mel is offline
 
Join Date: Mar 2005
Location: Dallas area
Posts: 10,768
Default

Check pin 2 on the Dynon D10A. It is a clock keep-alive circuit.
Dynon recommends that it not be connected if a GPS is connected as the GPS will set the clock at start-up.
__________________
Mel Asberry, DAR since the last century.
EAA Flight Advisor/Tech Counselor, Friend of the RV-1
Recipient of Tony Bingelis Award and Wright Brothers Master Pilot Award
USAF Vet, High School E-LSA Project Mentor.
RV-6 Flying since 1993 (sold)
<rvmel(at)icloud.com>
Reply With Quote
  #10  
Old 09-17-2016, 06:34 PM
AltonD's Avatar
AltonD AltonD is offline
 
Join Date: Sep 2005
Location: Dothan, Alabama
Posts: 1,487
Default

A USB charger for a cell/iPad coming straight off the battery will pull it down. Even if nothing is plugged into it. I was leaving one plugged into the power adapter. Took a while to figure it out.
__________________
Alton DeWeese
N526RV RV7A Tip Up, IO360 180 W/Hartzel BA prop.
Flying ~950 hours since Aug 2010
N4IDH

Construction Log
?The secret of getting ahead is getting started. The secret of getting started is breaking your complex overwhelming tasks into small manageable tasks, and then starting on the first one.?

?Mark Twain
Reply With Quote
Reply



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 01:35 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.