These Digital/Graphic Instruments are solid state and hold their accuracy over time and a range of environmental conditions. The colorful Graphic Analog display emits green, yellow, or red light enabling the pilot to spot problems immediately without interpreting a needle. The Digital display constantly provides an exact indication of each instrument function. Gauges mount in 2-1/4" instrument holes. These instruments (except fuel level) are STCd & TSOd for certificated aircraft.VA-1A VOLTS/AMPS INTERNAL AND EXTERNAL SHUNTS
The VA-1A is a FAA/PMA approved instrument which features a discharge warning light to act as an early warning device alerting you as soon as discharging begins. This is critical in giving the pilot as much time as possible to reduce electrical load and extend the life of the battery in flight. Also, by monitoring load currents to .1 amps the pilot can check important aircraft functions such as retracts, boost pumps, transmitter power, pilot heat, navigation lights, transponder, strobes, and any other electrical equipment. The VA-1 can replace your existing amp gauge. It is backlit for night operation and operates on 12 or 24 volt systems. Available with internal or external shunt. Wt. 9 Oz.E.I. products include all documentation.
I switched out the old ammeter on my Cherokee 140 which gave an indication of amps only. It is very nice knowing how much charge your battery holds as well. On a recent flight, my alternator failed and the yellow discharge light came on. I was able to land safely before all electrical components failed because of a dead battery. Well worth it.
Worked well right from the start. Easy to see and the warning light gives a good indication of battery discharge. Installation was simple according to the avionics tech.
Does not fit stock cessna 172 unless you drill 4 mounting holes for the 2&1/4 inch circle stock cessna ammeter uses a spring click to hold it in place
EI makes both versions as some aircraft have an external or internal shunts for there volt/ammeter. You will have to check your aircraft as neither we nor EI know exactly what your aircraft shunt set-up is. You will have to check with your A&P or check to see if behind the panel you have a shunt before the wires go to the gauge (external) or if the wires for volt/ammeter go direct to the gauge (internal).
EI offers this unit in a 300 amp shunt, PN 10-01394.
Yes, this is good for up to 100 amp.
Per the manufacturer, the S-50 is actually a 100amp shunt and will work fine with a 70 amp alternator. They calibrate all of their volt/amp instruments at 50mV (and the S-50 is calibrated at 50amp.)
The studs are 0.240 inches wide. The total available thread is 0.287 inches
The dimensions are 2.5" X 2.5" but the mounting holes are 1.849 inches apart.