Aircraft Overview
| Aircraft | Airbus H145 |
| Also Known As | EC145 / BK117 D-2 / D-3 |
| Type | Twin-Engine Helicopter |
| Engine | 2× Safran Arriel 2E (951 shp each) |
| Electrical System | 28V DC |
GPU Requirements
The Airbus H145 is the backbone of HEMS (helicopter emergency medical services) fleets across Europe, North America, and Australasia. Its twin Safran Arriel 2E engines require a GPU that can deliver sequential starts without the bus voltage dropping below 24V — the second engine start occurs when the GPU is already partially depleted from the first. Many EMS bases keep a dedicated GPU at each helipad to minimize turnaround time between missions. The H145 D-3 variant with Helionix avionics has higher continuous electrical demands than the D-2, approaching 180A with full mission equipment active (patient monitors, ventilator power, cabin lighting, communication suite). Duty cycle ratings matter when the unit supports multiple start cycles per shift at a busy HEMS base — some high-volume bases see 8–12 starts per GPU per day.
| Specification | Requirement |
|---|---|
| Starting Voltage | 28V DC |
| Peak Amps Required | 1,800–2,400A |
| Continuous Draw | 120–180A (D-3 with full mission suite) |
| Battery Chemistry | Lithium (higher energy density for sequential starts) |
| Recommended Unit Weight | Under 50 lbs |
| Duty Cycle | Must support 2 sequential starts per charge |
Our Recommendation
Primary pick: Red Box RB75A or Start Pac Portable 2400
Twin-engine starting demands sustained high amps through sequential starts without voltage sag. The RB75A strikes the ideal balance — 45 lbs, 2,400A peak — for the H145 HEMS and law enforcement operators who need rapid-turnaround capability between missions.
Alternative: Powervamp Coolspool 480 or ITW GSE 7400
Cold Weather & Special Operations
For operations below -10°C, a continuous power supply or mains-connected start cart is recommended over battery-only GPUs. Busy HEMS bases in Scandinavia and northern Canada install fixed 28V power outlets at each helipad connected to a central power supply, eliminating portable GPU logistics entirely. For field operations in cold weather, store the GPU above 0°C between uses — lithium cells lose 20–30% capacity below freezing and may not recover until warmed.
Related Guides
For a broader comparison of GPU manufacturers, see our Best Aircraft GPU 2026 review. For battery chemistry decisions, our Lead Acid vs Lithium analysis breaks down total cost of ownership. The GPU Sizing Guide covers voltage, amperage, and duty cycle calculations for any aircraft.
Product Categories
- Battery Start Units — portable starting power
- Continuous Power Supplies — sustained avionics power
- Combination GPU — start + continuous in one unit
- Frequency Converters — 400Hz AC power
- Aircraft Tugs — ground movement equipment
Frequently Asked Questions
Can a single GPU start both engines on an H145?
Yes, but the GPU must hold voltage above 24V through the first engine start and retain enough charge for the second engine immediately after. Units rated above 2,000A peak handle this reliably. Verify the manufacturer’s rated starts-per-charge — you need at least 2 to cover both Arriel 2E engines.
What’s the most popular GPU for H145 EMS operations?
The Red Box RB75A and Start Pac Portable 2400 dominate HEMS fleets globally. Both are field-proven at major HEMS operators including ADAC Luftrettung, DRF Luftrettung, and Air Methods, valued for weight, reliability, and sequential-start capability.
Does the H145 need 28V or 24V?
The H145 electrical system is 28V DC nominal. Your GPU must supply 28V and hold at least 24V under peak starting load. A GPU that drops below 24V during cranking risks a hung start — not just an operational inconvenience but a potential engine maintenance event that requires a borescope inspection.
What changed between the H145 D-2 and D-3 for GPU purposes?
Starting power requirements are similar between variants. The D-3’s Helionix avionics suite draws approximately 15–20% more continuous power than the D-2’s Meghas system, which matters during extended ground operations, system checks, and patient-loading procedures.
Editorial Policy
Red Box Power is editorially independent. We may earn commissions from links on this page, but this never influences our rankings or recommendations. All GPU assessments are based on published specifications and verified operator feedback.