Vehicle auxiliary power units
Silent auxiliary power for armoured platforms
What it is
Vehicle auxiliary power units (APUs) supply electrical, hydraulic or pneumatic power to an armoured platform's sights, radios, launchers and cooling without running the main engine. They are what makes silent watch possible: the vehicle stays awake while its acoustic and thermal signature stays down.
How it is employed
APUs are specified per platform, not per catalogue: output type, voltage set and mounting are configured to the vehicle, from main battle tanks and infantry combat vehicles to mounted gun systems, missile handlers and radar installations. Because the unit powers the mission systems during static tasks, its qualification envelope has to match the platform's own, from desert heat to high-altitude cold.
Why it matters now
A vehicle fleet whose auxiliary power comes from a major-power supplier inherits that supplier's export gates on exactly the subsystem that keeps sensors and communications alive. Sourcing the APU from an independent manufacturer keeps a fleet upgrade or retrofit programme inside the buyer's own control, on end-use terms rather than a bloc's release schedule.
Procurement & integration
APU programmes usually begin with a platform survey: what loads must run engine-off, what output types the vehicle's architecture expects and what qualification standards the fleet is governed by. Unstrat structures configuration, qualification evidence and in-region sustainment as one accountable engagement rather than a unit purchase.
Capability
- Output classes from 2 kW to 32.5 kW: hybrid hydraulic-electrical packs, multi-voltage electrical units (28 VDC to 330 VDC, 230/415 VAC), integrated starter-generators and welding-rectifier variants with battery charging
- Fielded across main battle tanks, infantry combat vehicles, mounted gun systems, missile handling systems and radar installations, including an 11 kW dual-voltage unit rated at 16,000 ft for MBT application
- Designed for extreme environments: −40 °C to +70 °C design envelope, IP-65/IP-67 sealing, dust-qualified, low noise and low thermal signature
- Qualified against MIL-STD-461 C/E/F/G EMI control, MIL-STD-1275 vehicle power, MIL-STD-704F and JSS 55555
- High volume-to-power ratio, fuel-efficient engines, low noise and low thermal signature
The Unstrat difference
01Independent, non-aligned origin, with no political exposure to any major-power ecosystem.
02One accountable team from first briefing through delivery and in-region sustainment.
03Configured to the platform: electrical, hydraulic or pneumatic output, integrated starters, welding rectifiers, not a fixed catalogue unit.
Sourcing routes compared
| Consideration | Major-power prime | Independent principal via Unstrat |
|---|---|---|
| Configuration | A fixed catalogue unit the platform must adapt to | Electrical, hydraulic or pneumatic output configured to the vehicle |
| Political conditions | Disclosure rules, re-export restrictions and upgrade approvals held by a foreign government | Independent, non-aligned origin, accountable to the buyer's flag |
| Accountability | Multiple contractors and a foreign prime's release schedule | One accountable team from first briefing through delivery and in-region sustainment |
| Sustainment | Support tied to the supplier's home market and political relationship | Sustainment, spares and training delivered in-region for the life of the system |
Comparison is qualitative. Detailed specifications are shared under briefing once the export-control position for your market is confirmed.
Related capabilities
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Vehicle auxiliary power units: questions
What are Vehicle auxiliary power units?
Vehicle auxiliary power units are Unstrat's Land (Land Domain) capability: A main battle tank that has to run its engine to keep the radios and sights alive is loud, hot and burning fuel it will want later. These auxiliary power units solve that: compact, ruggedised packs from 2 kW to 32.5 kW that deliver electrical, hydraulic or pneumatic power to tanks, infantry combat vehicles, mounted gun systems, missile handlers and radar installations, qualified to MIL-STD-461 and JSS 55555, with variants rated for operation at altitudes up to 5,500 metres. In service with national armed forces, and configurable to the platform, not the other way around.
How do Vehicle auxiliary power units work?
Vehicle auxiliary power units deliver their effect through output classes from 2 kW to 32.5 kW: hybrid hydraulic-electrical packs, multi-voltage electrical units (28 VDC to 330 VDC, 230/415 VAC), integrated starter-generators and welding-rectifier variants with battery charging, Fielded across main battle tanks, infantry combat vehicles, mounted gun systems, missile handling systems and radar installations, including an 11 kW dual-voltage unit rated at 16,000 ft for MBT application and Designed for extreme environments: −40 °C to +70 °C design envelope, IP-65/IP-67 sealing, dust-qualified, low noise and low thermal signature, capabilities matched to the requirement and confirmed under briefing rather than published.
Who makes Vehicle auxiliary power units?
Vehicle auxiliary power units are built by The Defence Power Group, whose focus is defence power systems & strategic cold chain. Unstrat represents The Defence Power Group to government and enterprise buyers worldwide as an independent, non-aligned prime vendor.
Why choose Vehicle auxiliary power units over a major-power alternative?
Vehicle auxiliary power units are sourced from an independent, non-aligned manufacturer, so they carry no major-power disclosure rules, upgrade-locks or political ramifications. Concretely: configured to the platform: electrical, hydraulic or pneumatic output, integrated starters, welding rectifiers, not a fixed catalogue unit. The capability is accountable to you, not to a foreign vendor's government and its release schedule.
How are Vehicle auxiliary power units procured, and where can it be exported?
Keep sights, radios and launchers powered without running the main engine: auxiliary power engineered for armoured platforms, from an independent source with three decades of manufacturing behind it. Every engagement begins with a briefing, and export eligibility is confirmed per market under briefing rather than published. Where controlled capabilities are involved, the classification and end-user-certificate chain is confirmed first. Vehicle auxiliary power units are then sustained in-region by one accountable team from briefing through long-term operation.
Questions buyers ask
What does auxiliary power do for an armoured vehicle fleet?
It keeps the platform's sights, radios, launchers and cooling running without the main engine, which is what makes silent watch possible. At fleet level it is a doctrine decision as much as an equipment one: a force that can hold static observation with engines off changes its acoustic and thermal signature across every deployed vehicle.
Why is APU sourcing a sovereignty question?
The auxiliary power unit sits under exactly the subsystems a force most needs to operate independently: sensors, communications and weapon power. A fleet whose APUs come from a major-power supplier inherits that supplier's export gates on retrofits, spares and upgrades. Sourcing from an independent manufacturer keeps the fleet programme on end-use terms rather than a bloc's release schedule.
What is silent watch in armoured operations?
Silent watch is holding an observation or firing position with the main engine off while the vehicle's sensors, radios and weapon systems stay powered. It depends on an auxiliary power source sized to the mission loads. The units we represent span output classes from 2 kW to 32.5 kW, fielded across main battle tanks, infantry combat vehicles and mounted gun systems.
See: Vehicle auxiliary power capabilityThe product behind the capability
Planning an APU retrofit programme across a mixed armoured fleet
A retrofit programme starts from a platform survey rather than a catalogue page: which loads must run engine-off on each vehicle type, what output the architecture expects and what qualification standards govern the fleet. Because the units are configured to the platform, electrical, hydraulic or pneumatic, one programme can cover tanks, combat vehicles and gun systems without forcing a single fixed unit onto all of them.
Auxiliary power as part of a wider vehicle electronics modernisation
Modernisation programmes add sensors, jammers and digital radios faster than vehicle alternators grow, and the power gap usually surfaces mid-programme. Treating auxiliary power as a programme line of its own, sized against the modernised load list rather than the original one, keeps the electronics upgrade from being throttled by the platform's generation capacity.
See: Vehicle auxiliary power capabilityObsolescence management capability
Qualification standards to specify in an APU tender
The fleet's governing standards should lead the tender. The units we represent are qualified against MIL-STD-461 EMI control across the C, E, F and G revisions, MIL-STD-1275 vehicle power, MIL-STD-704F and JSS 55555, with a design envelope of minus 40 to plus 70 degrees Celsius, IP-65 and IP-67 sealing and variants rated to 5,500 metres. A tender written around those anchors gets comparable bids.
See: Compliance detail on the product pageEMI standards against the published field
Independent APU supplier evaluation against VINCORION and Kinetics
The comparison page sets our units against the incumbents line by line, with every competitor figure cited to its source. The structural difference is not a single specification: it is configuration to the platform rather than a fixed unit, and supply from an independent source without a major-power approval gate behind the sale.
High-altitude armoured deployments and auxiliary power planning
Altitude derates every combustion power source, so a fleet that deploys to mountain garrisons needs the rating stated, not assumed. The range we represent includes variants rated for operation to 5,500 metres, including an 11 kW dual-voltage unit rated at 16,000 feet for main battle tank application. That figure belongs in the requirement, not the negotiation.
What APU data should a vehicle programme office request that is not published?
Per-unit weight and dimensions for each output class, cooling method per configuration, the fuel compatibility list, nominal current and generator type, and a noise figure in dB(A) at a stated distance. We do not publish those figures on this site; they are provided in direct discussions against the specific configuration, and the comparison page records where competitors publish theirs.
How should a land forces programme decide between fitting APUs and simply buying more batteries for silent watch?
Batteries buy hours; an APU buys the night. Battery-only silent watch is bounded by stored energy and recharge discipline, and recharging means running the main engine, which surrenders the signature advantage. An APU regenerates the vehicle's power continuously at a fraction of the main engine's fuel burn and signature. The honest analysis compares mission duration requirements against both, and for sustained observation tasks the APU case usually closes first.
What does an APU acquisition look like from first briefing to fielded units across a national fleet?
It runs platform survey, configuration, qualification evidence, then recurring supply and sustainment, structured as one accountable engagement rather than a unit purchase. The configuration stage is the substance: output type, voltage set and mounting are engineered to each vehicle class. Sustainment is delivered in-region for the life of the fleet, so the programme does not depend on a distant vendor's service network.
Can a fleet standardise on one auxiliary power family when its vehicles need electrical, hydraulic and pneumatic output?
Yes, and that is the argument for a configurable family over a fixed catalogue unit. The range we represent spans hybrid hydraulic-electrical packs, multi-voltage electrical units from 28 VDC to 330 VDC and 230/415 VAC, integrated starter-generators and welding-rectifier variants with battery charging. One supply relationship covers the fleet's output diversity instead of three vendors covering it by accident.
How does a buyer verify that an auxiliary power unit will not interfere with the vehicle's own radios and sensors?
Through the EMI qualification record, not assurances. The units we represent are qualified against MIL-STD-461 EMI control, which is the standard a vehicle integration authority can test against. The comparison page sets our EMI position against what the incumbent suppliers publish, so an evaluation can be run on cited evidence rather than brochure language.
What is the sustainment model for auxiliary power units once a fleet programme moves past delivery?
Sustainment, spares and training are delivered in-region for the life of the system, under the same accountable team that ran the delivery. For a subsystem fitted across a fleet, that matters more than the unit price: an APU line that goes unsupported converts every fitted vehicle into a degraded one at once.
Where does auxiliary power sit in a sovereign land systems programme that also covers ground robots and counter-drone equipment?
It is the quiet enabler under both. Unmanned ground vehicles and counter-UAS systems add sensors and effectors that draw power at the platform and at the position, and both are typically procured from the same land systems budget line. Treating power as part of the programme architecture, rather than an accessory per purchase, is what keeps the additions usable in the field.
See: Counter-UAS capabilityVehicle auxiliary power capability