Written by: Start Pac
Summary: Ground power units can improve an aircraft’s battery life and starting performance.
Connecting a ground power unit, such as a gas turbine start up unit, to your aircraft will essentially replicate the plane’s onboard 28VDC electrical flight environment. Now, if the aircraft’s battery is connected directly to the GPU output (in-circuit), the battery will top off the battery, just as it would on flight. This is ultimately beneficial for the aircraft’s battery itself.
Measuring Voltage and Assessing the Importance of GPU Gauges
Note that the initial load to the ground power unit itself will be temporarily higher, even with a fully-charged battery until the battery’s demand on the gas electric hybrid GPU is ultimately satisfied. You can easily observe this by taking a look at the GPUs amp meter – it will tick down until the GPU itself is fully charged and stabilized. Now, if you’re thinking that operating the GPU while the battery is in-circuit will harm the battery, it actually won’t. Furthermore, if the ground power unit is used to operate any onboard device in which the inrush current is significantly greater than 60 amps, it can function correctly if the load is not excess of the GPU’s output.
Topping off a legitimate onboard battery with the ground power unit when preparing the engine’s startup sequence actually improves the battery’s overall output as well as starting performance. Whether you’re using a diesel electric hybrid GPU or a gas electric hybrid GPU as your primary external power source, be wary of the gauges and facilitate when needed. Maintenance is a sensitive process and has very little margin for error.