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7638-38HT – Teledyne Gill 24 Volt DC 12-Cell Main Aircraft Battery
Available now on the Airparts.aero Marketplace.
The Teledyne Gill 7638-38HT is a high-performance, flight-critical 24V Valve Regulated Lead Acid (VRLA) battery, specifically engineered as a main power source for high-utilization turbine and piston aircraft. As a "7000 Series" LT (Lead-Tin) model, the 7638-38HT represents a significant advancement over traditional flooded batteries, utilizing specialized sealed-cell technology that allows for aerobic oxygen recombination. This design eliminates the need for periodic electrolyte replenishment (water addition), making it a virtually maintenance-free solution for modern flight departments.
Designed to deliver exceptional cranking power and emergency standby capacity, the 7638-38HT is built to withstand the rigorous environmental demands of business aviation and regional transport. Its 38 Amp-Hour (Ah) capacity is balanced with a high discharge rate capability, ensuring reliable engine starts in extreme temperature envelopes—from the sub-zero conditions of high-altitude ramp soaks to the high-ambient heat of tropical operations. For the maintenance professional, the "HT" designation signifies "High Temperature" resilience, utilizing proprietary plate chemistry to mitigate the risk of thermal runaway and internal grid corrosion, thereby extending the battery’s operational life and increasing fleet dispatch reliability.
Key Features
LT (Lead-Tin) Technology: Incorporates high-purity lead-tin alloy grids that provide superior conductivity and faster recharge rates compared to standard lead-antimony grids.
Absorbed Glass Mat (AGM) Construction: Features a micro-porous glass fiber separator that completely absorbs the electrolyte, preventing leaks even in the event of case damage and allowing for operation in any orientation.
Sealed VRLA Design: Utilizes a pressure-relief valve system that maintains a slight internal pressure to facilitate oxygen recombination, preventing gas loss and eliminating the risk of acid spray or corrosive venting.
High Cranking Amperage (HCA): Optimized for low internal resistance, allowing the battery to deliver the massive current surges required for turbine engine starter-generators.
Enhanced Vibration Resistance: Internal plate groups are highly compressed and anchored to prevent mechanical failure during high-frequency airframe vibrations or landing impacts.
Technical Specifications
Part Number: 7638-38HT
Manufacturer: Teledyne Gill
Component Type: Valve Regulated Lead Acid (VRLA) / Sealed Lead Acid (SLA)
Nominal Voltage: 24 VDC
Number of Cells: 12 Cells (connected in series)
Rated Capacity: 38 Ah (at the 1-hour rate)
Cold Cranking Amperage: 600A (at -18°C / 0°F)
Peak Power (IPP): 1100A
Weight: 83.0 lbs (37.6 kg)
Electrolyte: Sulfuric Acid (immobilized in AGM)
Case Material: High-impact, fire-retardant polypropylene
Governing Specifications: RTCA DO-160, TSO-C173
Certification: FAA-PMA / OEM Standard Equipment
Aircraft Compatibility
Beechcraft King Air 90, 200, 300, and 350 Series
Cessna 208 and 208B Caravan
Pilatus PC-12 Series
Piper PA-42 Cheyenne
Note: This battery is used across a wide variety of turbine-powered airframes. Always consult the aircraft's Illustrated Parts Catalog (IPC) for specific battery rack compatibility and airworthiness requirements.
Applications
Main Aircraft Power: Serves as the primary source of DC power for engine starting and pre-flight avionics bus energization.
Emergency Standby Power: Provides the critical reserve energy required to power essential flight instruments and emergency lighting for a specified duration (typically 30-60 minutes) following a dual-generator failure.
Load Leveling: Absorbs transient voltage spikes within the DC electrical system, protecting sensitive solid-state avionics.
Why Choose 7638-38HT?
The Teledyne Gill 7638-38HT is the result of decades of electrochemical research specifically for the aerospace industry. By utilizing high-purity lead-tin chemistry, this battery avoids the "shelf-life" degradation common in lower-tier lead-acid alternatives. Choosing the OEM-recommended 7638-38HT ensures that the aircraft's charging system—often tuned for specific impedance and thermal profiles—operates within its certified parameters. For operators, this translates to fewer unscheduled removals, safer engine starts, and the peace of mind that comes with Teledyne's industry-leading warranty and technical support.
The 7638-38HT utilizes a specialized precipitation-strengthened lead-tin (Pb-Sn) grid alloy that is essential for its "High Temperature" (HT) performance. In traditional lead-acid batteries, high operating temperatures accelerate positive grid corrosion, leading to increased internal resistance and eventual capacity loss. By using a tin-doped pure lead matrix, the 7638-38HT maintains a more stable Passivation Layer at the grid-active material interface.
Furthermore, the battery operates on the principle of gas recombination. During charging, oxygen generated at the positive plate diffuses through the partially saturated AGM separator to the negative plate. Here, it undergoes a chemical reaction to form lead oxide, which then reacts with the electrolyte to reform water. This cycle is nearly 99% efficient, preventing the Hindenburg-effect (hydrogen gas buildup) and ensuring the electrolyte saturation levels remain constant over the battery’s service life. The thermal mass of the 38Ah assembly is also engineered to provide a high specific heat capacity, allowing the unit to absorb and dissipate the heat generated during the high-current initial-start phase of a turbine engine without exceeding the critical Electrochemical Stability Window.
Note: The 7638-38HT is a flight-critical component. It must be maintained in accordance with the Teledyne Gill Sealed Lead-Acid (VRLA) Capacity Test and Maintenance Manual. Unlike flooded batteries, VRLA batteries should never be opened or topped with water. Periodic capacity checks (C-checks) are mandatory to ensure the battery can meet the emergency duration requirements specified by the FAA or EASA. Installation must be performed by a certified A&P mechanic.
