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  #1  
Old 08-31-2019, 02:04 PM
NinerBikes NinerBikes is offline
 
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Location: Granada Hills
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Default Finding battery discharged, again.

Friend of mine owns a 2016 RV-12 he built... N836BL, and he's having difficulty with the battery, quite new, being found in a state of discharge.

Today's voltage read 11.7V, battery was bought new at Aircraft Spruce in May, 2019.

Any suggestions on where to look for phantom drain of this battery such that it goes dead? Any relays?

We believe, currently, that the electrical problem may be intermittent.


Are 20-25 minute flights enough 1x a week for the voltage regulator to go into full 14.4V charge rates in that amount of time, or are longer flights necessary? Is a different Ducati brand VR worth looking into?

Last edited by NinerBikes : 09-02-2019 at 06:52 PM.
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Old 08-31-2019, 04:13 PM
DHeal DHeal is offline
 
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Location: Windsor, California
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While monitoring for parasitic drain at the battery (GOOGLE: Parasitic Drain) deactivate individual circuits by pulling individual fuses to identify suspect drain.

You could also disconnect the battery (remove negative terminal cable) after a flight and reattach the cable at the next flight. If the battery is still strong, it is likely a parasitic drain issue and not a weak battery or defective charging system.

In my experience, those short flights should be sufficient for a stock Odyssey PC-680/Ducati RR system to substantially recharge. Longer flights would likely be better for more thorough battery charging. I have found that frequent flying does wonders for the battery and IMHO trickle chargers are to be avoided.
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  #3  
Old 08-31-2019, 04:35 PM
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FasGlas FasGlas is offline
 
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A cheap DVM with a DC current range can show you if you have any drain on the battery while the system is shut off.
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Old 08-31-2019, 05:07 PM
Mich48041 Mich48041 is offline
 
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Location: Riley TWP MI
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Many Ducati voltage regulators put out less than 14 volts. My Ducati put out
13.8 volts. A friend's Ducati puts out 13.7 volts. I now have a John Deere
voltage regulator that puts out 14.1 when the RPM is above 4000.
If your friend's 20 minute flight includes 10 minutes of warm up and taxiing and
another 5 minutes of closed throttle for landing and taxiing, then that does not
leave very much time to recharge the battery.
Usually a battery maintainer is not recommended. But there are exceptions.
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  #5  
Old 08-31-2019, 06:07 PM
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DaleB DaleB is offline
 
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Also check for anything (like a USB power plug) in the 12V power socket. The socket is wired to the battery, not the master, so if you have a USB power supply plugged in it will suck current from the battery even with the master off.

I moved mine to the switched side of the master, took all of 10 minutes while we had the top cowl off.
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Old 08-31-2019, 06:12 PM
SPX SPX is offline
 
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Quote:
Originally Posted by DaleB View Post
Also check for anything (like a USB power plug) in the 12V power socket. The socket is wired to the battery, not the master, so if you have a USB power supply plugged in it will suck current from the battery even with the master off.

I wouldn't necessarily say that the socket *IS* wired to the battery, not the master.. But rather that it *MIGHT* be. Good suggestion though.
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  #7  
Old 08-31-2019, 06:24 PM
thinkn9a thinkn9a is offline
 
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Location: Mississippi
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Default Odyssey Technical Manual, ninth Ed. 2016 (page 16)

Chart shows for deep cycle operations,...charging at 14.7 volts more than doubles the life of the battery, compared to 14.2 volts....

....wonder where 13.7 volts would lie on the graph, ....(and how far the parasitic load is draining the battery)
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Old 08-31-2019, 06:43 PM
thinkn9a thinkn9a is offline
 
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Default Odyssey TM on parasitic load

Regardless of the application, it is important to make sure your battery does not have a parasitic load; if there is a slow drain, connect the battery to a float (trickle) charger that puts out between 13.5V and 13.8V at the battery terminals. Physically disconnecting one of the battery cables is an alternate method to eliminate the drain.
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Old 08-31-2019, 07:00 PM
Vansconvert Vansconvert is offline
 
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Default Stay alive circuits

Some avionics have a stay alive circuit wired directly to the battery, or to seperate fuse block which is then wired directly to the battery. Dynon D-10 for example. Or maybe a clock.
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  #10  
Old 08-31-2019, 07:05 PM
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DaleB DaleB is offline
 
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Quote:
Originally Posted by SPX View Post
I wouldn't necessarily say that the socket *IS* wired to the battery, not the master.. But rather that it *MIGHT* be. Good suggestion though.
Ah -- yeah, I see they changed that a couple years after mine was built.
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