Amp Shunt

[g zero]

What’s the difference in a Garmin / Dynon or Amazon Amp Shunt If they all have the same electrical values . Huge price spread .

 

[GalinHdz]

What’s the difference in a Garmin / Dynon or Amazon Amp Shunt If they all have the same electrical values . Huge price spread .

The mv per amp value. If they are 1mv per amp (common in aviation) then the difference is the physical size and the price spread.

 

[Walt]

Quality is the usual difference. If the shunt fails, you lose the alternator.

 

[airguy]

Quality is the usual difference. If the shunt fails, you lose the alternator.

I've lost two shunts from Dynon where the base cracked out, the electrical components continued to work just fine but were now loose. I was lucky to catch them before they arced against the firewall.

 

[bjdecker]

I've lost two shunts from Dynon where the base cracked out, the electrical components continued to work just fine but were now loose. I was lucky to catch them before they arced against the firewall.

Off-Topic somewhat -- I'm trying to wrap my pea-brain around this -- what kind of environment/mounting were these shunts when they failed?

 

[Carl Froehlich]

Quality is the usual difference. If the shunt fails, you lose the alternator.

Walt makes a good point. The only thing I can add is some of the shunt installs I’ve seen the shunt connections and such would be the more likely failure mode.

Considering voltage is the primary indication of electrical system health, I never install a shunt as it just adds unnecessary complexity. I do measure current of various panel and electrical configurations when doing system testing, but I use a regulated (and instrumented) power supply. This data goes into the airplane book and is used to develop POH emergency procedures The point - I never had a need to know current flow in real time (just like I don’t need to know it in my car).

So:
- 14.1 to 14.2 VDC tells me all is normal
- 13.5 to 13.8 VDC tells me the primary alternator has failed and I’m on the standby Monkworx generator (that and the little yellow light from the primary alternator B&C regulator is on, as well as the “AUX ALT” indicator on the SkyView EMS is on).
- Less than 13.4 VDC and the EMS ”Low Voltage” indication tells me I’m on battery power and have 2-3 hours of IFR flight capability.

Carl

 

[kms001]

The other thing to consider is use a hall effect sensor, instead of a shunt, then there is no failure of the primary feed only the measurement would fail. A voltmeter would verify that the system was still good.