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  #1  
Old 01-25-2014, 09:28 PM
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scrollF4 scrollF4 is online now
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Default 70 amp shunt

Does anyone know where I can find a 70 amp shunt? I bought the Dynon Skyview EMS sensor/wiring package which comes with a standard 60 amp shunt, but I'm using a 70 amp alternator. Dynon confirmed that I need:
- a 70 amp shunt
- it must produce 1 millivolt per amp.

Dynon doesn't sell them, and these shunts just didn't pop up on Spruce. Anybody got any leads?
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  #2  
Old 01-26-2014, 12:35 AM
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Quote:
Originally Posted by scrollF4 View Post
Does anyone know where I can find a 70 amp shunt? I bought the Dynon Skyview EMS sensor/wiring package which comes with a standard 60 amp shunt, but I'm using a 70 amp alternator. Dynon confirmed that I need:
- a 70 amp shunt
- it must produce 1 millivolt per amp.

Dynon doesn't sell them, and these shunts just didn't pop up on Spruce. Anybody got any leads?
This one will do it....

http://www.cloudelectric.com/product...ka-100-100.htm

At 100 amps it produces 100mv

The 70 amps you mention is really a max current rating, the 1mv per amp is the critical number.

Same one here, but with a better mounting diagram -

http://www.powerwerx.com/fuses-circu...0-amp-max.html

..and a warning to only use it a 2/3 current if the current is continuous, a fairly rare occurrence on our planes.

Interestingly, my Dynon 60 amp shunt came in a box that had a non-Dynon printed label saying it was a 40 amp shunt...
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Last edited by az_gila : 01-26-2014 at 12:47 AM.
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  #3  
Old 01-26-2014, 04:01 AM
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Default Shunt

My dynon supplied shunt was labeled a 60 amp but the part is a 40 amp. I wonder why?
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  #4  
Old 01-26-2014, 05:32 AM
Mich48041 Mich48041 is offline
 
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Default

Even though the alternator is capable of putting out 70 amps, the actual output is determined by the load. A rule of thumb is to load an alternator at not more than 80 percent of its capacity. For a 70 amp alternator, 80 percent is 56 amps. As long as the load is 60 amps or less, the 60 amp shunt will work fine. In fact, it will even put out the correct millivolts above 60 amps, but at the risk of overheating the shunt. The shunt size is determined by the size of the load, not by the size of the alternator. Like az_gila said, 1mv per amp is the critical number.
Joe Gores
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  #5  
Old 01-26-2014, 08:23 AM
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Default Shunts for VPX/Skyview

Wait a second. As I research this further in my VPX paperwork, I see that "shunt/Hall effect sensor" is listed on the list of things I don't need for VPX. I'll have to check with Vertical Power and Dynon tomorrow.

You guys running a Dynon Skyview and a VPX power system: Did you install a shunt, or leave it out?
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52F NW Regional/Aero Valley Airport, Roanoke TX (home of DR's Van Cave)
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Catch her on YouTube's "Because I Fly!" channel

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  #6  
Old 01-26-2014, 05:02 PM
BigD BigD is offline
 
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Default No shunt for me...

I'm putting together a G3X/VPX combo, so not exactly the same, but have decided based on the installation guide to leave out the shunt. Should be able to display/gonculate all necessary electrical info on the engine display from the VPX, so I'm leaving it out.

==dave==
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  #7  
Old 01-26-2014, 07:32 PM
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Default No shunt for me...

I also went with no shunt. But I did install a GRT Hall Effect Sensor. The VPX will allow you to measure the aircraft loads directly (amps going out of the VPX Box only.)
The added sensor if installed (Hall or Shunt) @ position (A) per the Dynon instruction will now also indicate the current flowing out of your battery or into your battery.
Position (B) will basically indicate what your alternator is putting out. The reason I went with the Hall Effect sensor over the Shunt was cleaner and easier install. The people at GRT will sell you one and the directions on the install are located in the Dynon manual.
I installed mine @ position (A) this way I will be able to see if the battery is charging/discharging and also the total amps (current flow) from the VPX.
The simplest way is just go with the total amps out of the VPX box it?s your choice of how much information you want.





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  #8  
Old 01-27-2014, 10:01 AM
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Default My plan is set

OK, Chris at Dynon confirmed that those two 100amp/100mv shunts will work fine. Gil, I'll probably order the Powerwerx item.

Tom, I agree with the Location A suggestion. I like the idea of having two separate readings: One showing the actual power flow in/out of the battery (location A) and one from the VPX screen showing the Alternator's amp load.

Gil and Terry, Chris said the Dynon-supplied shunt is indeed manufactured for 40 amps. However, they have tested a load of them and verified they carry 60 amps safely and reliably, so they supply that shunt (they mention this briefly on page 7-44 of the installation manual).

Thanks for the help, Team.
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Sid "Scroll" Mayeux, Col, USAF (ret)
52F NW Regional/Aero Valley Airport, Roanoke TX (home of DR's Van Cave)
"KELLI GIRL" N260KM RV-7A tipper
Catch her on YouTube's "Because I Fly!" channel

Exemption waived.
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