[Susan]

Susan on September 27, 2025 at 10:42 am #25627

Thanks, Steve. I will do.

[STEVE]

STEVE on September 26, 2025 at 9:51 am #25626

Hi Susan,
It’s my understanding that shunts are used to sample current flow into and out of the battery or out of the alternator. The original idea behind a shunt was to avoid having to connect large electrical cables (wires) to the ammeter or loadmeter indicator. Installation of the shunt–that’s only sampling current flow–creates a much cleaner “behind panel” installation since the shunt “signal” wires can be as small as 22 gauge. 

I believe, but am not sure that you can install all the other connections to the GI 275 when using it as an EIS and that it will provide all the engine data (CHT, EGT, FF, etc) except the current flow if you don’t install the shunt and “signal” wiring. I believe Piper installed a loadmeter in your Cherokee–I believe you’ll need to include a loadmeter if you’re removing the original Piper loadmeter.

I recently installed a shunt on the firewall of my Comanche in accordance with the installation instructions that were included with the Electronics International CGR-30P and 30C EIS. 

If the installation manual calls for the use of a shunt, I suggest you install the shunt if you want current flow data.

Let me know what you decide.

Steve

[Susan]

Susan on September 25, 2025 at 2:27 pm #25625

I have a 1968 Piper Cherokee 140/160 with a newly-overhauled engine; I’ve owned the plane since 2015 but have not flown it with the new engine. I am putting in a GI275 used as an EIS. Is it necessary to use a shunt, whether battery or alternator, for the EIS to give me engine information? The plane never had a shunt before; why does it seem to be considered needed now? I understand the rest of my EIS install, but the shunt puzzles me. Can someone help me understand?Thanks,Susan