Ground power unit guide for the Cessna Citation jet family. 28V DC GPU specs, start current requirements, and equipment recommendations for CJ, M2, XLS, and Sovereign models.
About the Cessna Citation (CJ/M2/XLS/Sovereign)
The Cessna Citation family is the most popular line of business jets ever produced, spanning six decades and dozens of models from the original Citation 500 to the current CJ4 and Longitude. The family's range means ground power requirements vary significantly — a CJ3 with Williams FJ44 turbofans has different needs than a Sovereign with Pratt & Whitney PW306 engines. What they share is a 28V DC electrical architecture and the NATO 3-pin external power connector.
GPU Requirements
Citation GPU requirements scale with the aircraft's size and engine type. The smallest Citations (CJ2, M2, CJ3) with Williams FJ44 engines draw 2,000 to 2,500A at peak. Mid-size Citations (XLS, XLS+) with Pratt & Whitney PW545 engines push to 2,500 to 3,000A. Larger Citations (Sovereign, Latitude) with PW306 engines can approach 3,000A at peak. Sequential engine starts mean the GPU must recover between starts — typically a 30 to 60 second pause. Continuous power for glass cockpit avionics (Collins Pro Line 21 or Garmin G5000), cabin management, and environmental systems runs 300 to 400 amps.
Cold Weather Considerations
Turbofan engines are generally less cold-sensitive than turboprops, but the fan section adds rotational mass that increases starter torque requirements. Below -15°C, Citation operators at northern airports should expect peak draws at the upper end of the specified range. FBOs in places like Teterboro, Aspen, and Sun Valley keep high-capacity GPUs on the ramp for exactly this reason.
Recommended Ground Power Units
Battery Start Unit
Red Box RB100A
2,400A peak lithium GPU. Handles the smaller Citation models (CJ series, M2) with headroom. Cart-mounted for FBO ramp use.
TRU
ITW GSE 2400T
Mains-powered TRU delivering 2,400A peak. Ideal for corporate flight departments and FBOs that service Citations daily. Unlimited starts and no battery degradation.
Combination GPU
Powervamp Coolspool 600
3,200A peak with 500A continuous. Covers the entire Citation family from CJ2 to Sovereign. The combination format provides both start and maintenance power in one unit.
Need help choosing? See our GPU Sizing Guide for a step-by-step approach to matching ground power equipment to your aircraft, or compare options in our Best GPU 2026 roundup.
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Frequently Asked Questions
What GPU do I need for a Citation CJ3?
The Citation CJ3 (with Williams FJ44-3A engines) requires a 28V DC GPU delivering at least 2,000A peak. For cold-weather reliability, 2,400A or higher is recommended. Continuous output of 200A+ supports the Garmin G3000 avionics during maintenance.
Can one GPU start all Citation models?
A GPU rated at 3,000A+ peak will start any current Citation model, from the M2 through the Longitude. The Powervamp Coolspool 600 and ITW GSE 2400T are examples of units with sufficient capacity across the entire family.
What's the difference between a Citation GPU and a King Air GPU?
Both use 28V DC and NATO 3-pin connectors. However, Citations generally require higher peak current (2,000 to 3,000A) compared to King Airs (1,500 to 2,200A). A GPU sized for a Citation will work fine on a King Air, but not necessarily vice versa.